No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Pseudomonas in the sinks in an intensive care unit: Relation to patients
Abstract
Sink drains in a medical-surgical intensive care unit (ICU) were cultured during six consecutive weeks as part of a seven month prospective study of acquisition of Pseudomonas aeruginosa by ICU patients. Isolates were typed serologically and by aminoglycoside and chlorhexidine susceptibility patterns. All 11 sinks contained multiple strains of P aeruginosa; some strains persisted for weeks while others were isolated once. Of the sink isolates 56% had high level resistance to gentamicin and tobramycin whereas none of the strains found in patients. In sink isolates chlorhexidine resistance correlated with aminoglycoside resistance and with the presence of a chlorhexidine dispenser at a sink. The sequence of recovery of phenotypically similar isolates suggested that sinks were the source of at most two acquisitions of P aeruginosa by patients during the six weeks. Our study confirms that sinks may be reservoirs for large numbers of highly resistant P aeruginosa but are rarely the source of organisms colonising patients in our ICU.
... (9)(10)(11)(12) There are also decades of studies that document an association between Gammaproteobacteria from sink drainage systems (including from sink drains, traps, drainpipes, and/or air samples above sink drainage outflow) and hospital-acquired colonization or infection of patients or healthcare workers. (13)(14)(15)(16)(17)(18)(19)(20)(21) The first suggestions to heat sink traps or modify sink construction to reduce splashing were made more than 40 years ago. (22) Despite this, it is only the increasing transmission of carbapenem-resistant organisms in hospitals that has refocused attention on the possible role of sink drainage systems as a reservoir. ...
... We screened 39511 records and identified 52 studies that met the inclusion criteria ( Figure 1). (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) The characteristics of these studies are summarized in Table 1. All studies were conducted in acute care hospitals; 35/48 (73%) (13, 15, 17-23, 33, 36-39, 41, 43, 45, 48, 49, 51, 52, 54-58, 60-62, 64, 65, 69-72) were identified as tertiary care or university/teaching hospitals. ...
... (20,21,23,33,39,55,62,65,(67)(68)(69)(70) The number of patients colonized or infected with Gammaproteobacteria that were also cultured from sink drainage systems was not consistently reported. Patients underwent some screening for carriage; most commonly from rectal (19/52 studies, 37%), (15, 19, 21, 23, 36, 38, 39, 43-45, 50, 52, 55, 56, 62, 68, 70-72) , throat (14/52, 27%), (13,15,17,22,36,37,43,44,50,52,56,68,70,71) , faeces (8/52, 15%), (17,35,37,40,42,46,67,70) , nasal (8/52, 15%), (13,38,39,41,42,44,50,72) wound (7/52, 13%), (14,36,37,43,47,55,60,65) or sputum (7/52, 13%) (17,22,37,44,49,65,71) specimens. In the 16 studies that reported numerator and denominator data for screening, 411/5932 (6.9%) (14, 15, 17, 22, 23, 35, 37, 38, 40, 42-44, 55, 67, 68, 72) patients were colonized with the same Gammaproteobacterial species found in sink drainage systems, with a median of 13.5% (range 0.01-68.8%) ...
Increasing rates of antimicrobial resistant organisms have focused attention on sink drainage systems as reservoirs for hospital-acquired Gammaproteobacteria colonization and infection. We aimed to assess the quality of evidence for transmission from this reservoir. We searched eight databases and identified 52 studies implicating sink drainage systems in acute care hospitals as a reservoir for Gammaproteobacterial colonization/infection. We used a causality tool to summarize quality of evidence. Included studies provided evidence of co-occurrence of contaminated sink drainage systems and colonization/infection, temporal sequencing compatible with sink drainage reservoirs, some steps in potential causal pathways, and relatedness between bacteria from sink drainage systems and patients. Some studies provided convincing evidence of reduced risk of organism acquisition following interventions. No single study provided convincing evidence across all causality domains, and the attributable fraction of infections related to sink drainage systems remains unknown. These results may help to guide conduct and reporting in future studies.
... D espite early reports (1)(2)(3)(4)(5), the premise that hand-wash sink traps can act as reservoirs of bacteria that cause nosocomial infections has been frequently overlooked. There has recently been an alarming increase in sink-related outbreaks worldwide, with many reports establishing an observational link (6)(7)(8)(9)(10)(11)(12)(13). ...
... Many recent reports demonstrate that P-traps become colonized with highly consequential Gammaproteobacteria, which then results in nosocomial transmission (29,31,32). The retained water in a sink P-trap is present to provide a water barrier to prevent off-gassing of sewer smell, but it may inadvertently provide favorable conditions for pathogenic and opportunistic antibiotic-resistant microorganisms to survive and develop resilient biofilms (3,33). However, the mechanism of dispersal of the bacteria in the P-trap to patients or the surrounding health care area had not been fully elucidated. ...
There have been an increasing number of reports implicating Gammaproteobacteria as often carrying genes of drug resistance from colonized sink traps to vulnerable hospitalized patients. However, the mechanism of transmission from the wastewater of the sink P-trap to patients remains poorly understood. Herein we report the use of a designated hand-washing sink lab gallery to model dispersion of green fluorescent protein (GFP)-expressing Escherichia coli from sink wastewater to the surrounding environment. We found no dispersion of GFP-expressing E. coli directly from the P-trap to the sink basin or surrounding countertop with coincident water flow from a faucet. However, when the GFP-expressing E. coli cells were allowed to mature in the P-trap under conditions similar to those in a hospital environment, a GFP-expressing E. coli-containing putative biofilm extended upward over 7 days to reach the strainer. This subsequently resulted in droplet dispersion to the surrounding areas (<30 in.) during faucet operation. We also demonstrated that P-trap colonization could occur by retrograde transmission along a common pipe. We postulate that the organisms mobilize up to the strainer from the P-trap, resulting in droplet dispersion rather than dispersion directly from the P-trap. This work helps to further define the mode of transmission of bacteria from a P-trap reservoir to a vulnerable hospitalized patient.
IMPORTANCE
Many recent reports demonstrate that sink drain pipes become colonized with highly consequential multidrug-resistant bacteria, which then results in hospital-acquired infections. However, the mechanism of dispersal of bacteria from the sink to patients has not been fully elucidated. Through establishment of a unique sink gallery, this work found that a staged mode of transmission involving biofilm growth from the lower pipe to the sink strainer and subsequent splatter to the bowl and surrounding area occurs rather than splatter directly from the water in the lower pipe. We have also demonstrated that bacterial transmission can occur via connections in wastewater plumbing to neighboring sinks. This work helps to more clearly define the mechanism and risk of transmission from a wastewater source to hospitalized patients in a world with increasingly antibiotic-resistant bacteria that can thrive in wastewater environments and cause infections in vulnerable patients.
... Enzymatic detection method had higher positivity: 14% for manual, 29% for foot operated and 16% for faucets Charron et al. (2015) Study (6 weeks) 56% of drains strains, high level of antibiotic resistance. For 2 of 5 infected patients, same strain as the one isolated in the drain Levin et al. (1984) Outbreak Demonstrated that aerosols from the drains were contaminating personnel's hands. Resolution through the use of a heating device on drains (70°C) to eliminate presence of P. aeruginosa Döring et al. (1991) on the magnetic valve by the manufacturer (Berthelot et al., 2006). ...
... Shower and sink drains are also probable sources of P. aeruginosa infections ( Table 2, Breathnach et al., 2012;Hota et al., 2009;Levin, Olson, Nathan, Kabins, & Weinstein, 1984;Maltezou et al., 2012;Schneider et al., 2012). In a newly constructed hospital, an outbreak of P. aeruginosa was linked to a contaminated sink drain (Hota et al., 2009). ...
Pseudomonas aeruginosa is an opportunistic bacterial pathogen that is widely occurring in the environment and is recognized for its capacity to form or join biofilms. The present review consolidates current knowledge on P. aeruginosa ecology and its implication in healthcare facilities premise plumbing. The adaptability of P. aeruginosa and its capacity to integrate the biofilm from the faucet and the drain highlight the role premise plumbing devices can play in promoting growth and persistence. A meta-analysis of P. aeruginosa prevalence in faucets (manual and electronic) and drains reveals the large variation in device positivity reported and suggest the high variability in the sampling approach and context as the main reason for this variation. The effects of the operating conditions that prevail within water distribution systems (disinfection, temperature, and hydraulic regime) on the persistence of P. aeruginosa are summarized. As a result from the review, recommendations for proactive control measures of water contamination by P. aeruginosa are presented. A better understanding of the ecology of P. aeruginosa and key influencing factors in premise plumbing are essential to identify culprit areas and implement effective control measures.
... The hands of attendants have been implicated as the mode of transmission (Maki, 1982). Although the environment may be a major reservoir of microorganisms, this type of flora rarely colonizes patients (Levin et al. 1984) and contributes little to hospital infections (Maki et al. 1982). Practically all these studies are done in hospitals and usually in patients admitted to the intensive care units. ...
... (4) Criteria for determining the relation between sink and patient isolates. It was considered that an elderly patient may have acquired a sink strain if the following criteria were met: the patient's and the sink isolate had the same type and susceptibility pattern; the strain was found in a sink before it was cultured from the patient; and the strain had not been isolated from any other patient just before or during the period of acquisition (Levin et al. 1984). ...
Sinks in a new long-stay hospital (LSH) were cultured weekly during 4 consecutive months to evaluate the microbial profile before and after occupancy of the hospital. From the elderly patients admitted to the patient care rooms oral and rectal specimens were collected to examine the contribution of the patients' flora to the sink contamination. Isolates were typed biochemically, serologically and by susceptibility pattern. Before occupancy Gram-negative bacilli were not isolated. Once the elderly patients, who were highly colonized on admission, occupied their rooms identical strains gradually contaminated the sinks. Escherichia coli, Klebsiella, Pseudomonas and Acinetobacter species were the major correlating strains. The mean concentration of the correlating isolates was higher in throat and intestines compared to the mean concentration of the non- correlating strains. These strains seem to have a greater chance to be shed and then transferred via the hands of personnel to sinks. This resport shows that the major route of environmental contamination is from patient carriers to sinks, and not the reverse way.
... Earlier studies have shown that NFGNBs has been mostly isolated from the pus sample8 .In our study also NFGNBs were isolated from the pus sample. Pseudomonas aeruginosa, Ac.baumanii was the most common isolate, Local infections like cellulitis, diabetic foot, and burns in our study which was similar to other studies9,10 . Ps.aeruginosa as the main etiological agent responsible for 31.1% of urinary tract infections, and 27.5% of local infections in our study, however, it was higher in studies by Resmi Rajan et al 89.9%,72.5% in Cristiane et al study ...
Non –fermenting Gram-negative bacilli are a group of heterogeneous, aerobic, nonsporing bacteria. They are saprophytes in nature and are also found as commensals in man and other animals. This study aims to isolate and identification of NFGNB from various clinical specimens and to find out their clinical significance among the in-patients admitted at Vijayanagar Institute of Medical Sciences, Bellary. 110 isolates from various age groups and sexes were included in the study. A detailed history was elicited and the clinical specimens were collected under aseptic precaution and subjected to preliminary biochemical tests and further speciation was done. In the present study commonest isolates were Pseudomonas aeruginosa, Acinetobacter baumannii, Acinetobacter haemolyticus, Pseudomonas fluorescence, Acinetobacter lwoffi Acinetobacter junii, Acinetobacter radioresistant and from urinary tract infection which accounted for (34.5%), followed by respiratory tract infection (21.2%), local infection (20.9%), Post operative infection (8.18%), infection related to the abdomen (6.36%), Septicemia (5.45%), and post-traumatic infection (2.7%) in decreasing order of frequency. They showed variability in their antibiotic susceptibility results, Most of them were sensitive to Carbapenem groups of drugs.
... Bei diesem Vorgehen gilt es kritisch anzumerken, dass durch das Abspülen unter fließendem Wasser Aerosole entstehen, die die Umgebung und das Personal kontaminieren können. Auch eine Kontamination der TK durch eine ungünstige Waschbecken-und Armatur-Installation ist denkbar [14,15]. Aus Gründen des Arbeitsschutzes sollte die Vorreinigung unter einem Wasserspiegel erfolgen. ...
... Table (2) shows the distribution of the pure culture according to their sites and type of genus. The pure culture were divided into two groups depending on Gram stain, accordingly 24 Gram positive isolates and 44 Gram Negative isolates were identified ( were identified which also had been found by ( 17 ) , while E. coli represent only 6.8% of total Gram -ve bacteria which show inconsistency with a study that had been done in Erbil 2002 (18) where an extremely high percentage ( 46.21%) of contamination with this species was found , this may be due to the differences of the sites of swabs being taken from the environment of the hospital as a whole in Erbil or may be explained by the level of health awareness of both , patients and health staff in different communities (19) .The percentage of contamination with Pseudomonas aeruginosa was 1.4% and according to (20) this species regarded one of sources of infection in ICU, beside Greenwood et al. (21) antibiotics specifically amoxicillin and to a lower extent Piperacillin could be related to many causes ; production of β lactamase enzymes and its effect which lead to the breakdown of the β -lactame cycle in penicillins and cephalosporines changing it into inactive compounds (22) , or may be because of the changes being occurred in the porins of the cellular membrane and ultimately it`s effect on the cell permeability (23) , some Gram -ve bacteria are resistant for β -lactame antibiotic because it has an Efflux pump system which lead to pump the antibiotics from intracellular to extracellular space (24) .The gradual increase in the resistant of enterobacteriaceae against β-lactam antibiotics ( 1 st and 2 nd generation of penicillin and cephalosporines) reduce the efficacy of these antibiotics in eradicating diseases of bacterial etiology completely since these resistance will lead to continuous change in the epidemiology of these disease (25) , while the effect of extended spectrum β -lactamase ( ESBLs ) became more evident against the 3 rd generation of penicillins and cephalosporines (26) The resistant against recently introduced βlactam antibiotic ; Aztreonam is related to many causes ; it`s sensitivity for β -lactamases enzyme produced by Proteus mirabilis , Klebsiella pneumoniae , and E.coli, or may be due to the weak affinity of antibiotic to the penicillin binding proteins in cell wall (27). The high sensitivity of the studied isolates for Imipenem belong to Carbapenems group and one of the recently used antibiotic, could be due to its limited use in Iraq. ...
To identify the cause and the source of bacterial infection among patients of intensive care unit and to identify the ability of bacteria to produce biomass this study had been conducted in Al-Imam Al-Hussein hospital in Thi-qar province for the period from 1 st September to end of December 2011 .A total of 320 swabs and samples were collected from 17 different sites of Intensive Care Unit environment and inoculated on a normal cultural media ,then incubated at 37 ° C for 24 hour. The growth revealed different bacterial colonies which had been tested for their morphological and biochemical characteristics. Sixty eight of pure isolates were obtained including 24 (35.29%) Gram positive bacterial isolates, 44(64.71%) of Gram negative bacterial isolates , the highest rates (19.11%) of bacterial contamination had been found on the walls and the floor. Sensitivity tests for all isolates were done using 25 types of commonly used antibiotics in Iraq , the results revealed that the genus Enterobacter spp. had a high resistance as a Gram negative bacteria , and Staphylococcus spp. had a high resistance as a Gram positive bacteria to most of the tested antibiotics, The tendency of some isolates to develop a biomass as biofilm , an important virulence determinant related to infection , was investigated in vitro using microtiter plates. The highest optical density (O.D.= 0.634 n.m.) was recorded by the isolate from pressure material by Pseudomonas aeruginosa and the least O.D. was recorded by medical instruments-use manual isolate (O.D. was 0.106 n.m.) by Pantoea spp .
... Faucets, associated components, drains and connection plumbing can function as reservoirs for Pa, especially in the presence of microbial biofilms, which can harbor microorganism communities, protecting them from environmental stresses and favoring their growth [10]. Indeed, prospective studies have established that up to 100% of faucets [11][12][13] and drains [14][15][16] in hospitals are contaminated with Pa. However, the identification of the environmental sources associated to opportunistic pathogen infections represents an important and growing challenge. ...
Identifying environmental sources of Pseudomonas aeruginosa (Pa) related to hospital-acquired infections represents a key challenge for public health. Biofilms in water systems offer protection and favorable growth conditions, and are prime reservoirs of microorganisms. A comparative genotyping survey assessing the relationship between Pa strains recovered in hospital sink biofilm and isolated in clinical specimens was conducted. Environmental strains from drain, faucet and sink-surface biofilm were recovered by a culture method after an incubation time ranging from 48 to 240 h. The genotyping of 38 environmental and 32 clinical isolates was performed using a multiple-locus variable-number of tandem repeats analysis (MLVA). More than one-third of Pa isolates were only cultivable following ≥48 h of incubation, and were predominantly from faucet and sink-surface biofilms. In total, 41/70 strains were grouped within eight genotypes (A to H). Genotype B grouped a clinical and an environmental strain isolated in the same ward, 5 months apart, suggesting this genotype could thrive in both contexts. Genotype E grouped environmental isolates that were highly prevalent throughout the hospital and that required a longer incubation time. The results from the multi-hospital follow-up study support the drain as an important reservoir of Pa dissemination to faucets, sink surfaces and patients. Optimizing the recovery of environmental strains will strengthen epidemiological investigations, facilitate pathway identification, and assist in identifying and controlling the reservoirs potentially associated to hospital-acquired infections.
... As part of the traditional hospital hand hygiene strategy and patient care, sinks are present in virtually all hospital wards and patient rooms. While sinks in the proximity of patients are advocated as a best practice of ICU design [9], involvement of these sinks in hospitalassociated infections have been reported as early as the 1970s [10][11][12][13][14]. Recent publications have highlighted the role of sinks as a source of outbreaks and transmission of multidrug-resistant gram-negative bacilli (MDR-GNB) in intensive care units, including paediatric and neonatal ICUs [15][16][17][18][19][20][21][22][23][24][25][26][27][28]. ...
Background
Sinks in patient rooms are associated with hospital-acquired infections. The aim of this study was to evaluate the effect of removal of sinks from the Intensive Care Unit (ICU) patient rooms and the introduction of ‘water-free’ patient care on gram-negative bacilli colonization rates.
Methods
We conducted a 2-year pre/post quasi-experimental study that compared monthly gram-negative bacilli colonization rates pre- and post-intervention using segmented regression analysis of interrupted time series data. Five ICUs of a tertiary care medical center were included. Participants were all patients of 18 years and older admitted to our ICUs for at least 48 h who also received selective digestive tract decontamination during the twelve month pre-intervention or the twelve month post-intervention period. The effect of sink removal and the introduction of ‘water-free’ patient care on colonization rates with gram-negative bacilli was evaluated. The main outcome of this study was the monthly colonization rate with gram-negative bacilli (GNB). Yeast colonization rates were used as a ‘negative control’. In addition, colonization rates were calculated for first positive culture results from cultures taken ≥3, ≥5, ≥7, ≥10 and ≥14 days after ICU-admission, rate ratios (RR) were calculated and differences tested with chi-squared tests.
Results
In the pre-intervention period, 1496 patients (9153 admission days) and in the post-intervention period 1444 patients (9044 admission days) were included. Segmented regression analysis showed that the intervention was followed by a statistically significant immediate reduction in GNB colonization in absence of a pre or post intervention trend in GNB colonization. The overall GNB colonization rate dropped from 26.3 to 21.6 GNB/1000 ICU admission days (colonization rate ratio 0.82; 95%CI 0.67–0.99; P = 0.02). The reduction in GNB colonization rate became more pronounced in patients with a longer ICU-Length of Stay (LOS): from a 1.22-fold reduction (≥2 days), to a 1.6-fold (≥5 days; P = 0.002), 2.5-fold (for ≥10 days; P < 0.001) to a 3.6-fold (≥14 days; P < 0.001) reduction.
Conclusions
Removal of sinks from patient rooms and introduction of a method of ‘water-free’ patient care is associated with a significant reduction of patient colonization with GNB, especially in patients with a longer ICU length of stay.
Electronic supplementary material
The online version of this article (doi:10.1186/s13756-017-0213-0) contains supplementary material, which is available to authorized users.
... T he potential for the home environment to act as a reservoir for bacterial pathogens has long been considered by epidemiologists (1,2). In particular, the domestic sink drain has been identified as a potential risk due to continual hydration and nutrient availability, which promotes microbial growth and the establishment of taxonomically diverse biofilms (3,4). The open nature of the drain allows its continuous inoculation with a plethora of microorganisms originating both from food waste (5) and, potentially, in the case of organisms such as Legionella sp., from the tap water (6). ...
Importance:
Assessment of the risks of biocide use has been based mainly on the exposure of axenic cultures of bacteria to biocides in simple aqueous solution. The current investigation aimed to assess the effects of formulation on the outcome of biocide exposure in multi-species biofilms. Formulation of the cationic biocide BAC significantly increased antimicrobial potency. Bacteria with lower antimicrobial susceptibility that were enriched after low-level biocide exposure were more effectively suppressed by the biocide at in-use concentrations (1% w/v) when formulated than in a simple aqueous solution. These observations underline the importance of simulating normal deployment conditions when considering the risks and benefits of biocide use.
... Many others have shown sinks, taps, and drains to be sources of Pseudomonas outbreaks. [12][13][14][23][24][25] Frequently, replacement of sinks and plumbing has been necessary to eradicate Pseudomonas. 25 Splashing of contaminated water from sinks to equipment and work surfaces in the unit or potentially to the hands of healthcare workers was felt to be the likely mechanism of spread to babies. ...
OBJECTIVE
To use whole genome sequencing to describe the likely origin of an outbreak of Pseudomonas aeruginosa in a neonatal unit.
DESIGN
Outbreak investigation.
SETTING
The neonatal intensive care unit service of a major obstetric tertiary referral center.
PATIENTS
Infants admitted to the neonatal unit who developed P. aeruginosa colonization or infection.
METHODS
We undertook whole genome sequencing of P. aeruginosa strains isolated from colonized infants and from the neonatal unit environment.
RESULTS
Eighteen infants were colonized with P. aeruginosa. Isolates from 12 infants and 7 environmental samples were sequenced. All but one of the clinical isolates clustered in ST253 and no differences were detected between unmapped reads. The environmental isolates revealed a variety of sequence types, indicating a large diverse bioburden within the unit, which was subsequently confirmed via enterobacterial repetitive intergenic consensus–polymerase chain reaction typing of post-outbreak isolates. One environmental isolate, obtained from a sink in the unit, clustered within ST253 and differed from the outbreak strain by 9 single-nucleotide polymorphisms only. This information allowed us to focus infection control activities on this sink.
CONCLUSIONS
Whole genome sequencing can provide detailed information in a clinically relevant time frame to aid management of outbreaks in critical patient management areas. The superior discriminatory power of this method makes it a powerful tool in infection control.
Infect. Control Hosp. Epidemiol. 2015;36(9):1058–1064
... Attempts to decontaminate failed twice; the outbreak stopped when the sinks were replaced by a new design (Hota et al., 2009). Another report found that while sinks and sink traps were a reservoir for Pseudomonas, this source could not be linked to infections, though the findings are limited by the short (7 weeks) follow-up period (Levin, Olson, Nathan, Kabins, & Weinstein, 1984). ...
OBJECTIVE
To assess and synthesize available evidence in the infection control and healthcare design literature on strategies using the built environment to reduce the transmission of pathogens in water that cause healthcare-associated infections (HAIs).
BACKGROUND
Water can serve as a reservoir or source for pathogens, which can lead to the transmission of healthcare-associated infections (HAIs). Water systems harboring pathogens, such as Legionella and Pseudomonas spp., can also foster the growth of persistent biofilms, presenting a great health risk.
TOPICAL HEADINGS
Strategies for interrupting the chain of transmission through the built environment can be proactive or reactive, and include three primary approaches: safe plumbing practices (maintaining optimal water temperature and pressure; eliminating dead ends), decontamination of water sources (inactivating or killing pathogens to prevent contamination), and selecting appropriate design elements (fixtures and materials that minimize the potential for contamination).
CONCLUSIONS
Current evidence clearly identifying the environment's role in the chain of infection is limited by the variance in surveillance strategies and in the methods used to assess impact of these strategies. In order to optimize the built environment to serve as a tool for mitigating infection risk from waterborne pathogens—from selecting appropriate water features to maintaining the water system—multidisciplinary collaboration and planning is essential.
... Water in sink drains and siphons is a known source of gram-negative bacteria in hospitals (1)(2)(3). The most notable is Pseudomonas aeruginosa (P. ...
Water in sink drains is a known source of gram-negative bacteria. We aimed to evaluate the impact of self-disinfecting sink drains on the emission of aerosolised bacteria and on Pseudomonas aeruginosa acquisition among neonates.
Aerosol bacterial growth and patient Pseudomonas aeruginosa acquisition rates were measured at baseline (Phase One), for 13 months after sinks were relocated or redesigned during refurbishment (Phase Two) and for 13 months after introducing self-disinfecting sink drains (Phase Three).
Cultures were positive for bacterial growth in 56%, 24% and 13% of the tested aerosols In Phases One, Two and Three. Comparing Phases Two and Three produced an odds ratio (OR) of 0.47, with a 95% confidence interval (CI) of 0.22-0.99 (p=0.047), for all bacteria and an OR of 0.31 and CI of 0.12-0.79 (p=0.013) for Pseudomonas aeruginosa. Rates of Pseudomonas aeruginosa positive clinical cultures were 0.34, 0.27, and 0.13 per 1,000 patient days during the respective phases, with a significant increase of time to the next positive clinical culture in Phase Three.
Self-disinfecting sink drains were superior to sink replacements in preventing emissions from aerosols pathogens and may reduce hospital-acquired infections. The bio-burden reduction should be confirmed in a larger multi-centre trial. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
... For instance, there are 120 different viruses in human faeces [43]. It is also reported that patient flora can be detected in sinks and building drains [10,12,60]. In a new longstay hospital, it was discovered that identical strains were found in the sinks as well as in the admitted patients [60]. ...
Drainage systems and its role in sanitation related outbreaks are evident but still occluded once it has been installed. This current review evaluates if drainage systems can cause infections and thus be of clinical concern.
A review of the literature was analyzed. Papers, guidelines, and quality management systems have been considered.
Adequate sanitation is fundamental and a prerequisite for safe life and productivity. In contrast, malfunctioning sanitation has been reported to cause outbreaks all over the world. In areas with no sanitation, diarrheal mortality is high and has been shown to decrease by 36% after interventions to improve sanitation. Often, infections are faeces associated and when present in wastewater and sewage sludge poses a high risk of infection upon exposure. Hence, there are working safety guidelines and in industries where infection reduction is essential strict quality assurance systems, i.e. HACCP (hazard analysis critical control points) and GMP (Good Manufacturing Practice) must be complied. Healthcare has recently taken interest in the HACCP system in their efforts to reduce healthcare associated infections as a response to increasing number of ineffective antibiotics and the threat of mortality rate like the pre-antibiotic era. The last few years have called for immediate action to contain the emergence of increasing resistant microorganisms. Resistance is obtained as a result of overuse and misuse of antibiotics in both healthcare and agriculture. Also, by the discharge of antibiotics from manufacturers, healthcare and society. One mechanism of development of novel resistant pathogens has been shown to be by effortless sharing of genetic mobile elements coding for resistance from microbes in the environment to human microbes. These pathogens have been sampled from the drainage systems. These were noticed owing to their possession of an unusual antibiotic resistance profile linking them to the outbreak. Often the cause of sanitation related outbreaks is due to inadequate sanitation and maintenance. However, in general these infections probably go unnoticed.
Drainage systems and its maintenance, if neglected, could pose a threat in both community and healthcare causing infections as well as emergence of multi-resistant bacteria that could cause unpredictable clinical manifestations.
... The importance of environmental contamination with P. aeruginosa and nosocomial disease is still unclear. Contamination of the hospital environment by P. aeruginosa is common, and the bacteria are found in particularly high numbers in drains from sinks and baths (Levin et al. 1984;Doring et al. 1991Doring et al. , 1993. While convincing outbreaks of infection from such sources have been described, P. aeruginosa appears to be more commonly an endogenous rather than an exogenous infection (Gruner et al. 1993). ...
... Similarly, such equipment rested or rinsed in a sink might easily contaminate the trap with patient flora, which may then be transmitted to the tap by splashing or cleaning practices and then become established as resident flora. 8,10,11 Although the literature contains many examples, some listed above, of outbreaks associated with water, only those that have been investigated and reported recently have had the benefit of genomic-based typing. Outbreaks of P. aeruginosa tend to occur in critical settings where patients may be transferred to other providers of care. ...
The problem of Pseudomonas as a nosocomial pathogen is not new, with some authors dating its onset to the start of the antimicrobial era, although other
factors, such as the growth of intensive or augmented care, have a part to play. This paper outlines the historical and environmental
issues that may be associated with a potential increase in the incidence of this difficult-to-treat pathogen.
... Outbreaks because of P aeruginosa contaminating water and other fluids have been well described. [16][17][18][19] To our knowledge, this is the first report of a P aeruginosa outbreak caused by the contamination of feeding bottles. Brown et al reported the contamination of 8 bottles of a human donor milk bank by P aeruginosa. ...
Outbreaks of Pseudomonas aeruginosa have been reported in relationship with contamination of staff fingernails, hands, water baths, hand lotions and others. To our knowledge, contamination of milk and feeding bottles as a source of an outbreak of P aeruginosa infections has not been reported. The incidence of P aeruginosa infection/colonization in our neonatal intensive care unit increased from 1.9 per 1000 patient-days in August 2004 to 8.8 per 1000 patient-days in September 2004.
Samples were collected including hand and body lotions, water from the incubator humidifying system, the health care worker hands, and the feeding bottle preparation room. Strains were epidemiologically characterized by pulsed-field gel electrophoresis of SpeI-digested genomic DNA. P aeruginosa was isolated from a total of 30 neonates during the period September 2004 to December 2004.
All cultures (139) of hand and body lotions, water from the incubator humidifying system, and hands of health care personnel were negative. Nine out of 48 samples collected from the feeding bottle preparation room were positive for P aeruginosa (6 samples of in-house prepared milk and 3 samples of water from dishwashers). Pulsed-field gel electrophoresis with SpeI showed that the strains isolated from neonates and from environmental samples were identical. Discontinuation of in-house preparation of feeding bottles and incorporation of unidose milk bottles stopped the outbreak.
The preparation and solution of milk from multidose powder preparation may be a source of P aeruginosa infections in a neonatal intensive care unit. The use of manufactured, nonmanipulated, unidose feeding bottles should be considered more adequate.
... Others have reported taps and drains as sources of outbreaks of P. aeruginosa colonization and infection. [1][2][3][4]6,7,[19][20][21][22][23][24][25] These reports have been based on the sequential isolation of phenotypically or genotypically related strains from both sinks and clinical specimens, as in the present study. 19-22 P. aeruginosa was generally impossible to eradicate using disinfection techniques alone, and replacement of sinks or sink and/or plumbing components was emphasized as a means to eliminate the organism. ...
Pseudomonas aeruginosa has been increasingly recognized for its ability to cause significant hospital-associated outbreaks, particularly since the emergence of multidrug-resistant strains. Biofilm formation allows the pathogen to persist in environmental reservoirs. Thus, multiple hospital room design elements, including sink placement and design, can impact nosocomial transmission of P. aeruginosa and other pathogens.
From December 2004 through March 2006, 36 patients exposed to the intensive care unit or transplant units of a tertiary care hospital were infected with a multidrug-resistant strain of P. aeruginosa. All phenotypically similar isolates were examined for genetic relatedness by means of pulsed-field gel electrophoresis. Clinical characteristics of the affected patients were collected, and a detailed epidemiological and environmental investigation of potential sources was carried out.
Seventeen of the infected patients died within 3 months; for 12 (71%) of these patients, infection with the outbreak organism contributed to or directly caused death. The source of the outbreak was traced to hand hygiene sink drains, where biofilms containing viable organisms were found. Testing by use of a commercial fluorescent marker demonstrated that when the sink was used for handwashing, drain contents splashed at least 1 meter from the sink. Various attempts were made to disinfect the drains, but it was only when the sinks were renovated to prevent splashing onto surrounding areas that the outbreak was terminated.
This report highlights the importance of biofilms and of sink and patient room design in the propagation of an outbreak and suggests some strategies to reduce the risks associated with hospital sinks.
Aufgrund medizinischer und technischer Fortschritte ließ sich die Prognose der Patienten mit chronischer Atemschwäche in den letzten Jahren stetig optimieren. Die beatmeten Patienten werden nach der Klinikbehandlung entweder in einem spezialisierten Pflegeheim, im eigenen häuslichen Umfeld oder in Wohngemeinschaften pflegerisch und medizinisch betreut 1. Welche Herausforderungen hierbei zu meistern sind, lesen Sie in diesem Beitrag.
The study was done between June 2012 and August 2012 where 180 specimens were obtained from operation rooms in AL-Manathera general hospital which have been divided into 90 specimens from air and 90 specimens from floor ,Isolation and Identification of the microorganisms and their Antibiotics sensitivity pattern were done and following results were obtained Staphylococcus aureus was the most common microorganisms isolated 29 then Pseudomonas aeruginosa 7 and E.Coli three specimen only, The Antibiotics sensitivity pattern showed that Cefatoxime, Cephalothin and Rifampcin were more active against gram positive and gram negative bacteria while the strains were resistant to Oxacillin ,Amoxycillin ,PencillinG, Tetracyclin ,Ampicillin, Lincomycin, Chloramphenicol, Carbenicillin, Cloxacillin, Erthromycin.
Background:
Decades of studies document an association between Gammaproteobacteria in sink drains and hospital-acquired infections, but the evidence for causality is unclear.
Aim:
We aimed to develop a tool to assess the quality of evidence for causality in research studies that implicate sink drains as reservoirs for hospital-acquired Gammaproteobacterial infections.
Methods:
We used a modified Delphi process with recruited experts in hospital epidemiology to develop this tool from a pre-existing causal assessment application.
Findings:
Through four rounds of feedback and revision we developed the Modified CADDIS Tool for Causality Assessment of Sink Drains as a Reservoir for Hospital-Acquired Gammaproteobacterial Infection or Colonization. In tests of tool application to published literature during development, mean percent agreement ranged 46.7 - 87.5, and the Gwet's AC1 statistic (adjusting for chance agreement) ranged .13 - 1.0 (median 68.1). Areas of disagreement were felt to result from lack of a priori knowledge of causal pathways from sink drains to patients and uncertain influence of co-interventions to prevent organism acquisition. Modifications were made until consensus was achieved that further iterations would not improve the tool. When the tool was applied to 44 articles by two independent reviewers in an ongoing systematic review, percent agreement ranged 93-98%, and the Gwet's AC1 statistic 0.91-1.0.
Conclusion:
The modified causality tool was useful for evaluating studies that implicate sink drains as reservoirs for hospital-acquired infections and may help guide the conduct and reporting of future research.
The drain openings of hand washbasins and sinks in hospitals represent a largely overlooked yet ubiquitous reservoir of microbial contamination that is increasingly recognized as a significant cause of patient infection, particularly with carbapenemase-producing Enterobacteriaceae. These bacteria have emerged relatively recently as a major health threat in hospitals globally against which only a very few antimicrobial agents remain active. The three main areas this chapter overviews are: the problem of microbial biofilm contamination of washbasin U-bend traps and drains in hospital hand washbasins and sinks; the associated risks of transmission of infection to patients and healthcare staff; and the approaches that have been investigated to mitigate these risks. First this chapter reviews the underlying causes of trap contamination and current evidence for cross-infection in the hospital setting. The various approaches that have been investigated to minimize infection risks from washbasin traps and drains are then discussed together with their relative advantages and disadvantages. Finally, the chapter examines the development of long-term solutions to the problem using integrated systems for automated decontamination of washbasin drains, U-bend traps, and wastewater pipework in the hospital setting.
Background:
Healthcare-associated infections (HAIs) are a significant cause of increased medical costs, morbidity, mortality, and have been partly associated with sinks, their waste water outlets and associated pipework.
Aim:
To determine whether an engineered sink could limit microbial aerosol contaminants in the air and sink basin.
Methods:
Multiple comparisons were undertaken between an experimental sink, designed to limit aerosolization and p-trap contamination to a control hospital sink, both connected to a common drain system. The experimental sink was equipped with ultraviolet light (UV), an aerosol containment hood, ozonated water generator and a flush system to limit bacterial growth/aerosolization and limit microbial growth in the p-trap. Nutrient material was added daily to simulate typical material discarded into a hospital sink. Surface collection swabs, settle plates and p-trap contamination levels were assessed for bacteria and fungi.
Findings:
The experimental sink had significantly decreased levels of bacterial and fungal p-trap contamination (99.9% for Tryptic Soy (TSA) and Sabouraud agar (SAB) plates) relative to the initial levels. Aerosol-induced contaminant from the p-traps was significantly lower for the experimental vs the control sink for TSA (76%) and SAB (86%) agar settle plates.
Conclusions:
Limiting microbial contamination is critical for the control of nosocomial infections of in-room sinks, which provide a major source of contamination. Our experimental sink studies document that regular ozonated water rinsing of the sink surface, decontamination of p-trap water, and UV decontamination of surfaces limits microbial aerosolization and surface contamination, with potential to decrease patient exposure and reduce hospital acquired infections.
Hospital-wide surveillance of infectious diseases, organized and administered by the institution’s infection control committee, is standard in modern medicine. Through passive and active mechanisms, such institutional surveillance is invaluable for quality assurance and for detecting epidemics in their earliest stages, when they are most amenable to intervention. However, surveillance culturing done at the local level in the intensive care unit (ICU), with the goal of controlling the spread of antibiotic-resistant organisms, is controversial, and the effectiveness of such practice depends upon many circumstances that vary from organism to organism and from unit to unit. There were three principal resistant phenotypes afflicting American and European hospitals in the late 1990s, namely, vancomycin-resistant enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and multiple antibiotic-resistant gram-negative bacilli. The following will review the factors that determine the effectiveness of infection control interventions, including surveillance culturing, in limiting the spread of these three resistant phenotypes.
Background:
Many studies have reported the hospital outbreaks of Pseudomonas aeruginosa due to cross-contamination between patients and water fittings, but the importance of water fittings as sources of sporadic P. aeruginosa colonizations/infections remains ambiguous.
Aim:
To investigate the sources of sporadic P. aeruginosa colonizations/infections in a clinical intensive surveillance, and further analysis the potential of sink trap for P. aeruginosa transmission in intensive care units (ICUs).
Methods:
Patients monitoring and targeted environmental screening for P. aeruginosa was performed prospectively over a 27-week period, in absence of recognized outbreak, in two surgical intensive care units (SICUs). All isolates were genotyped by Pulsed field gel electrophoresis analysis.
Findings:
18.9% (46/244) of water fitting samples harbored P. aeruginosa, and active screening samples from 9.2% (55/595) of hospitalized patients carried with P. aeruginosa. According to genotype results, approximately 50% of P. areuginosa colonizations/infections of patients were of exogenous origin. 64.7% (11/17) of exogenous sourced cases were associated with contaminated sink traps. There was a significant correlation between the incidence of exogenous colonization/infection and the prevalence of P. areuginosa in water fitting in SICU-2 (rs = 0.972; p = 0.014). Furthermore, P. areuginosa from sink trap possessed a higher level of resistance to multi-antibiotics as opposed to cross-transmission from other patients.
Conclusion:
Water fitting especially sink trap act as an important role in sporadic P. aeruginosa transmission in SICU patients. This report highlights the necessity of identification of potential environmental reservoirs, such as sinks, for control of infections of environmentally hardy multi-resistant P. areuginosa.
Chronische oder intermittierende Besiedelung des unteren Respirationstrakts mit Staphylococcus aureus ist als klassisches Zeichen der cystischen Fibrose im Säuglings- und Kindesalter bekannt. In der vorantibiotischen Ära galten bronchopulmonale Infektionen mit Staphylococcus aureus als die häufigste Todesursache. Dieser historischen Beobachtung steht gegenüber, dass die Langzeitprognose bei alleiniger Staphylococcus-aureus-Kolonisation besser ist als bei Übergehen auf eine (Mit-) Besiedelung mit Pseudomonas aeruginosa [3]. Die Erfahrung, dass Staphylococcus aureus bei anderen chronischen Lungenerkrankungen (z.B. Ziliendyskinesie, humorale Immundefekte, chronisch-obstruktive Pneumopathie) keine dominierende Rolle spielt, legt das Vorhandensein einer CF-spezifischen Erreger-Wirt-Beziehung nahe. Diese klinische Beobachtung wird durch die Resultate der experimentellen respiratorischen Infektion der transgenen CF-Maus mit Staphylococcus aureus gestützt [4]
Bacteria resistant to multiple antibiotics are common in hospitals and are often isolated from patients on admission. Spread of these bacteria in the hospital, and occasional epidemics, result from transient contamination of the hands of hospital personnel, environmental contamination, and excessive use of antibiotics. Conventional control measures have relied on improved asepsis and hand-washing, isolation or cohorting of infected and colonized patients, antibiotic control, and elimination of any significant environmental sources (Table 1). Such measures have been recommended primarily in epidemic situations [1]. However, we have advocated that control measures be used in an ongoing fashion for all patients colonized or infected with strains that are known to be problems in hospitals [2]. In this report we present our experience with, and views of, conventional measures for control of resistant bacteria in hospitals.
Microbiological investigations of 106 siphons of washing basins at several wards have been shown that sink drains are emitting water borne microorganisms during regular use of washing basins. Therefore siphons are "active" sources of pathogens and infections. The possibility to prevent nosocomial infections by eliminating sink drains as potential source of pathogens is under a long term investigation. Until now, within a period of 33 months the influence of the self-disinfecting siphon on the number of nosocomial infections at an intensive care unit of Oberlausitz-Kliniken gGmbH at Bischofswerda/Germany has been investigated. A systematic surveillance of nosocomial infections is carried out at this unit since three years. In August 2002 all common sink drains have been exchanged by self-disinfecting siphons BioRec®. Rates of microbial colonisation of patients as well as the rates of incidents of nosocomial infections were sharply decreased by use of self-disinfecting siphons. In November 2003 self-disinfecting siphons were replaced by common standard siphons. This exchange was followed by an increase of number of nosocomial infections. Since a renewed installation of self-disinfecting siphons in March 2004 a decreasing rate of nosocomial infections was observed. These results show that siphons are relevant resources of pathogens and infections. Investigations will be continued.
Antimicrobial resistance in bacteria occurred soon after the first antibiotic was discovered. Hospital infections with resistant microbes have been a threat for several years. Recent outbreaks of food borne infections due to antibiotic resistant bacteria were associated with unusually high morbidity and mortality rates. Multiresistant Salmonella, Listeria, Campylobacter and pathogenic E. coli have been isolated from food animals and food. Genetic characterization of their resistance genes and the location on mobile genetic elements gave rise to the assumption that those elements and genes are transferable with and without selective pressure. The impact of food processing and storage on persistence, transfer or elimination of resistance elements has not been studied yet. However scientific work in this field might elucidate correlations between human infections with antibiotic resistant food pathogens and antimicrobial resistant isolates from food animals.
Sink drains in hospitals are considered to be potential sources of nosocomial infections. In this study, the possibility to prevent them by eliminating those standard drains is examined. Within a period of 15 months (711 patients) the influence of the self-disinfecting siphon trap on the number of nosocomial infections at an intensive care unit of Oberlausitz-Kliniken gGmbH at Bischofswerda has been investigated. A systematic surveillance of bacterial colonisation and nosocomial infections is carried out at this unit since two years. In August 2002 all common sink drains have been exchanged by self-disinfecting drains developed by BIOREC. As a consequence the rates of microbial colonisation of patients as well as the rates of incidents due to nosocomial infections were decreased. Investigations will be continued.
Background: Lavatory sink drains in wards harbor 105 to 10 10 cfu/ml of bacteria, thereof about 103 to 106 cfu/ml proved to be gramnegative rods. To investigate the contamination of siphons we measured the aerogen bacterial load over the sink drains and were able to prove substantial bacterial emission. Method: The bacterial aerosol was measured (n=257) 10 cm above the sinks during tap water running into the sink drain over 1 min and compared with results without running tap water. The study was performed in the following departments: internal, surgical and neonatal intensive care, general and visceral surgery, oncology, and transplantation unit. Results und Conclusions: During the tap water running aerosols containing bacteria from the sink fluid were emitted into the surrounding area. Accordingly sink drains function as open bacterial reservoir. The higher was the microbial burden of the siphon fluid, the more bacteria were emitted into the air. Continuous thermodisinfection in combination with low-frequent vibration of the siphon prevented biofilm formation and eliminated siphons as bacterial reservoir.
The first description of Pseudomonas aeruginosa as a distinct bacterial species was made at the end of the nineteenth century, after Pasteur’s development of sterile culture media. Screening for dyes provided the stimulus for the first scientific study on P. aeruginosa published by pharmacist Carle Gessard in 1882 and entitled “On the blue and green coloration of bandages.”1 This characteristic pigmentation, later attributed to a phenazine derivative, pyocyanine, is reflected in the old names Bacillus pyocyaneus, Pseudomonas polycolor, Bakterium aeruginosa and Pseudomonas pyocyaneus. Although the ability of P. aeruginosa to produce infections was noticed by 1889,2 its pathogenicity was doubted,3 and P. aeruginosa was regarded mainly as a source of potent antimicrobial substances.4 Before 1947 only 91 cases of septicemia attributable to P. aeruginosa were reported in the literature.5 Its importance as a human pathogen, especially in hospitalized patients, did not emerge until the second half of the twentieth century,6 although the organism was certainly present in the inanimate and human environment before then. Because P. aeruginosa is easy to culture and identify it is unlikely that it was missed by clinical microbiologists. Thus, the considerable change in the significance of P. aeruginosa as a nosocomial pathogen probably reflects advances made in the life sciences as well as changes in the susceptibility of patients.
The concepts and practices of modern healthcare have introduced hazards not foreseen by their originators. Some of these have to do with the built environment and those of Legionella and Pseudomonas aeruginosa relate to water distribution within healthcare premises. This chapter outlines the risks to patients and the control of these unintended hazards.
Healthcare-associated infection has become a topic of interest to the general public in the United Kingdom, kindled by media accounts of poor hygiene and the risks of cross-infection. In the spring of 2003, one of the broadsheet newspapers published an article debating the hygiene and infection risks associated with cut flowers brought into clinical areas. There were reports that in many wards this practice is no longer allowed because flowers are considered dirty, trigger allergies and the water is regarded as harbouring bacteria, leading to infection.
Discussion with infection control experts revealed that questions concerning the risks associated with flowers are among those most frequently asked. A literature search was undertaken to establish the evidence base, and a questionnaire study was performed with a purposive sample of 39 nurses to document how they manage flowers in the clinical setting. Empirical research studies were difficult to obtain. Early work had been undertaken to explore the added workload associated with maintaining fresh flowers and ways of reducing it. Later studies revealed that the water in flower vases and cut plants both harbour large numbers of Gram-negative pathogens.
Cross-infection and cases of clinical infection have never been documented, thus flowers have not been considered a risk, except to severely immunocompromised patients. However, scrutiny of the more general literature relating to Gram-negative sepsis indicated that cross-infection has been documented from a wide range of environmental sources and it is possible that it may take place from flowers via the hands of staff if they are not properly decontaminated. Nevertheless, these risks can be reduced by scrupulous attention to hand hygiene and commonsense measures.
Over half the nurses (n = 26, 66.6%) thought that flowers constituted an infection risk and a number of other disadvantages were cited. Most nurses (n = 31, 80%) were not in favour of flowers in the clinical setting and there was some evidence that this attitude was related to the amount of work generated, with infection and other risks used to justify it. Interest in the topic was considerable and the results can be used to stimulate discussion and emphasise the importance of controlling health-related infection.
Degradation of the microbiological quality of water within the water supply system of health-care institutions is linked to the proliferation of microorganisms which can be naturally found in water, and to exogenous contamination.
The water in distribution networks is used for various purposes (cooking, sanitary, medical, or technical) which, besides meeting potable drinking water requirements, require a constant monitoring of possible contamination by opportunist pathogen microorganisms, in risk areas. “Quality” management, based on the principles of risk analysis and monitoring of critical points, must be set up by a multidisciplinary team created and maintained in order to control the microbiological quality of water.
Monitoring water supply contamination consists in identifying contamination factors, analyzing waterborne infectious risks for patients according to water uses, and setting up adapted preventive measures (technical measures, antimicrobiological treatment).
Through observation or regular measurement in critical points of the water distribution system, the monitoring system allows ensuring that preventive measures are carried out and that corrective actions are taken if target standards are not met, thus warranting microbiological control.
A periodic checking of the control plan allows guaranteeing that it meets the standards for the control of waterborne infectious risks. Registering and documenting the implemented actions allows for traceability in the long run.
Antimicrobial resistance is a significant problem in the intensive care unit. Ill patients carry abnormal bacteria, amongst which are the causative organisms of many of the nosocomial infections. Overgrowth of these bacteria predisposes to infection. Further, the excretion of systemically administered antibiotics into the gut selects resistant bacteria from this population. In eliminating overgrowth, oral non-absorbable antibiotics prevent infections and prevent the development of antibacterial resistance. This paper discusses the limited effect of traditional approaches in preventing antibiotic resistance. These rely on restriction of classes of antibiotics used, or by restricting antibiotic use by more specific (often invasive) diagnostic techniques (such as protected brush specimens) for the diagnosis of pneumonia. In contrast we describe the experience of three centres using oral non-absorbable antibiotics finding that antibiotic resistance is not a significant clinical problem. In one 20-bed paediatric intensive care, admitting 1000 children per year, of 390 admissions who stayed more than four days 12 episodes of infection (in eight individuals) were caused by antibiotic resistant bacteria. Oral non-absorbable antibiotics prevent both infections and the emergence of antibiotic resistant bacteria.
Over the last decade, bacterial resistance has increased alarmingly among nosocomial gram-negative bacilli (GNB) in intensive care units (ICUs). In Pseudomonas aeruginosa imipenem-resistance (R) was 18%, quinolone-R 27%, cephalosporin-R 26%, extended spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae >10%, and third-generation cephalosporin-resistant Enterobacter spp 35% (National Nosocomial Infection Surveillance data 2000). In addition, ICU outbreaks caused by multiresistant Acinetobacter baumannii have increasingly been reported worldwide. The role of cephalosporin overuse has been noted in numerous nosocomial outbreaks due to ESBL-producing K. pneumoniaes. Most ICUs face the challenge of managing patients with endemic P. aeruginosa infections, in whom antibiotic therapy seems to play a decisive role selecting bacterial flora. P. aeruginosa pneumonia should always be considered in late ventilator-associated pneumonia (VAP) and in early VAP with previous antibiotic therapy. Nowadays, many strains of A. baumannii are highly resistant to modern β-lactams, aminoglycosides, and fluoroquinolones; of great concern, resistance to carbapenems has already emerged worldwide. Reinforcement of cleaning procedures, handwashing, and isolation methods remain the cornerstone of control programs in A. baumannii outbreaks. Attributed mortality of these infections is a controversial issue but probably low. Because of that, acute clinical judgment in selecting the patients who really need antibiotics is essential. Overall, multiresistant GNB infections in ICUs make their correct therapeutic antimicrobial management a real challenge for physicians. The risk of mortality in patients with life-threatening infections is substantially increased if initial antibiotic therapy is inadequate. However, excessive antibiotic use has been linked with the development of resistance. There is a general consensus that an early broad-spectrum empirical antibiotic therapy with a high probability of covering the likely pathogens should be used for serious VAP or other life-threatening infections. Appropriate general guidelines may be useful to establish a rational antibiotic policy, but their application should take into account the local organism ecology and resistance patterns.
Multidrug-resistant Pseudomonas aeruginosa (MDR-P) expressing VIM-metallo-beta-lactamase is an emerging infection control problem. The source of many such infections is unclear, though there are reports of hospital outbreaks of P. aeruginosa related to environmental contamination, including tap water.
We describe two outbreaks of MDR-P, sensitive only to colistin, in order to highlight the potential for hospital waste-water systems to harbour this organism.
The outbreaks were investigated by a combination of descriptive epidemiology, inspection and microbiological sampling of the environment, and molecular strain typing.
The outbreaks occurred in two English hospitals; each involved a distinct genotype of MDR-P. One outbreak was hospital-wide, involving 85 patients, and the other was limited to four cases in one specialized medical unit. Extensive environmental sampling in each outbreak yielded MDR-P only from the waste-water systems. Inspection of the environment and estates records revealed many factors that may have contributed to contamination of clinical areas, including faulty sink, shower and toilet design, clean items stored near sluices, and frequent blockages and leaks from waste pipes. Blockages were due to paper towels, patient wipes, or improper use of bedpan macerators. Control measures included replacing sinks and toilets with easier-to-clean models less prone to splashback, educating staff to reduce blockages and inappropriate storage, reviewing cleaning protocols, and reducing shower flow rates to reduce flooding. These measures were followed by significant reductions in cases.
The outbreaks highlight the potential of hospital waste systems to act as a reservoir of MDR-P and other nosocomial pathogens.
The microbial biodiversity of bioaerosols in recently occupied hospital rooms was assessed in a pulmonology unit. Environmental
samples and isolates were also screened for antibiotics resistance genes. Biofilms from sink drains were also studied to evaluate
whether sink drains constitute a potential source of bioaerosols in this environment and a reservoir for opportunistic bacteria
and antibiotic resistance genes. Stenotrophomonas maltophilia was by far the most frequently isolated microorganisms from the biofilm, followed by Enterobacter cloacae. Airborne bacterial concentration ranged from 14 to 74CFUm−3 and fungi ranged from 50 to 600CFUm−3. Biofilm bacteria were outnumbered in aerosols by microorganisms affiliated with human skin flora. Nonetheless, they were
recovered from air samples in low concentrations. Erythromycin resistance genes were detected in all air samples collected
from hospital rooms, and tetracycline resistance genes were detected sporadically. Antibiotic resistance genes were found
in a single drain suggesting that genes present in DNA extracts from air samples were not aerosolized from sink drains, but
rather from an unknown source. Results obtained in this study suggest that bacteria from sink drains were not aerosolized
in significant concentration. They still remain a concern because of the risk of aerial transmission associated with their
presence.
KeywordsBiofilm-Bioaerosols-Antibiotic resistance-Biodiversity-Hospital-
Stenotrophomonas maltophilia
IntroductionEnteric pathogens and potable water suppliesOpportunistic pathogens and potable water suppliesIce and ice-making machinesBottled waterDrinks vending machinesReferences
In spite of significant changes in the spectrum of organisms causing nocosomial infections in intensive care units (ICUs), Pseudomonas aeruginosa has held a nearly unchanged position as an important pathogen. Today, the organism is isolated as the second most frequent organism causing ventilator-associated pneumonia, and the third or fourth most frequent pathogen causing septicemia, urinary tract infections, and surgical wound infections. In the past, horizontal transmissions were regarded as the most relevant route of strain acquisition. However, during the last 10 years, a significant proportion of P. aeruginosa isolates were demonstrated to stem from ICU water sites. Studies using molecular typing techniques have shown that up to 50% (in one study 92%) of nosocomial P. aeruginosa acquisitions may result from transmission through tap water. Additional proof of concept of waterborne infection comes from the reports of three recent studies that infection rates may be lowered significantly by eliminating colonized tap water sources or interrupting transmission chains from water sites.
A nosocomial outbreak of Pseudomonas aeruginosa infections which occurred in the Urology Service of a large city hospital was studied. A case-control methodology was used to analyse patients' characteristics and the main risk factors of all cases with a positive culture during the period between March 1987 and March 1988. The usefulness of factor analysis in the definition of a case was examined. There were 74 infections of which 35 (47.3%), had a nosocomial origin. The outbreak took place in December 1987, with a peak incidence of infections of 10.5%, compared with a 2.2% frequency during the preceding months (P less than 0.005). Six of the nine infections occurring in that month, were caused by strains resistant to ticarcillin and gentamicin. The epidemic cases had longer hospital stays than the non-epidemic cases (P less than 0.038) and occurred more frequently in a specific area of the hospital (P less than 0.001). The odds ratio for resistance to gentamicin was 15 (P less than 0.018) and that of resistance to ticarcillin, 127 (P less than 0.0001). Our results suggest that inaccurate case definitions may produce misleading conclusions. Factor analysis appears to be a useful analytical tool when defining a case.
Traditional infection control measures in intensive care units (ICUs) have been directed at limiting person to person spread of infection and improving care of invasive devices. These measures often fail because they have little effect on patients' endogenous flora, which is an important source of infection in ICUs. Improvements in the design and aseptic care of invasive devices have helped to decrease the risk of progression from colonization to infection in individual patients. Interest is growing also in use of selective decontamination to decrease ICU infection rates. Despite these advances, basic hygiene and appropriate, prospectively monitored use of antibiotics remain essential components of ICU care.
An outbreak of septicaemia with Pseudomonas aeruginosa amongst adult men with haematological malignancy involved eight patients on the same ward during a period of 5 weeks. The strains isolated from blood cultures from seven patients were indistinguishable by conventional typing methods. Thymol mouthwash which had been made up and distributed in communal jugs was found to be contaminated with the epidemic strain and was the likely source for this outbreak. A high rate of gastrointestinal colonization with the epidemic strain was found in the patients receiving the contaminated mouthwash. Only those patients with prolonged severe leucopenia developed septicaemia. Communal medications are an unnecessary hazard, particularly in oncology wards.
Gram-negative bacilli that are resistant to commonly used antibiotics are a growing problem in seriously ill, hospitalized patients. Numerous outbreaks involving these organisms have been reported in intensive care nurseries and among critically ill adults. In endemic situations, the major reservoir for these pathogens is the patient; occasionally, transmission from patient to patient occurs through the hands of caregivers. Although the degree of antibiotic use probably plays some role in the emergence of antibiotic-resistant gram-negative bacilli, this relationship has not been uniformly demonstrated, and other factors intrinsic to the organisms themselves and to the critically ill patient may play an important role.
An outbreak of gentamicin, ciprofloxacin-resistant Pseudomonas aeruginosa in an intensive care unit, was investigated. The majority of isolates were from sputum and the organism was not isolated from any other patient in the hospital, except those admitted to the unit. A prospective study was set up, and the organism was found to be associated with contaminated quivers, used to store suction tubing between use on ventilated patients. Once the quivers were disinfected and changed between patients daily, the outbreak stopped. Suction of ventilated patients may be an important source of contamination of the respiratory tract with nosocomial pathogens. It is important that infection control teams regularly review procedures to ensure the correct practices are being followed, so that nosocomial outbreaks of infection may be prevented.
Seventy-three environmental and clinical isolates of Pseudomonas aeruginosa recovered from a single hospital over a 6-month period were compared for epidemiological type characteristics. Environmental isolates were obtained from sinks, taps and water, in rooms where patients were treated. The strains represented only six O-antigenic types and 8.2% of them were not typable. Serotype 011 was most frequent in the environment, whereas serotypes 06, 012 and 02,5 predominated among clinical isolates. More than 60% of all isolates belonged to four pyocin types (1, 10, 33 and 45), and approximately 80% were phage typable. Environmental isolates were more sensitive to antibiotics than clinical isolates. There was little correspondence between the types of strains of P. aeruginosa isolated from patients and those isolated from the environment. However, isolates of identical type were frequently recovered from different patients within the same clinic and were found to be related in time and location. We conclude that the environment was not an important source of P. aeruginosa infection and that transfer of organisms was mainly from patient-to-patient.
Pneumonia caused by Pseudomonas aeruginosa occurs frequently in critically ill patients and is associated with a mortality rate of 70 per cent. An aerosol of polymyxin B was administered (2.5 mg per kilogram per day) to the upper airways of 292 patients in a respiratory-surgical intensive-care unit during a seven-month period, in an attempt to prevent Ps. aeruginosa pneumonia. Although only one of the patients studied acquired pneumonia due to Ps. aeruginosa, 10 others acquired pneumonia caused by a polymysinx-resistant organism. Seven pneumonias were caused by organisms not frequently pathogenic to man (flavobacteria, serratia and Streptococcus faecalis). The mortality rate for acquired pneumonia in this study, 64 per cent, is greater than that in previous studies in which either no polymyxin or cyclic polymyxin therapy was used. Continuous use of polymyxin B aerosol appears to be a dangerous form of therapy.
Potential reservoirs of pseudomonas within a neonatal ICU were evaluated. Colonization of infants by the same pseudomonas pyocin types could be classified as a cluster colonization (occurring over three to ten days), or serial colonization (occurring over longer times). Hands of personnel, sink surfaces, and solutions used to rinse nasopharyngeal catheters were identified as the principle reservoirs. Utilization of a liquid iodophor agent for hand washing and of acetic acid for rinsing suction catheters was associated with a significant reduction in the histologic evidence of sepsis and of pneumonia observed among autopsied infants.
A total of 755 strains of Pseudomonas aeruginosa were recovered in cultures from 242 patients and 13 environmental sources during a 19-month period. These strains were typed
for a determination of prevalence as related to source of those causing infection and!or death by use of seven antisera based
on studies of cross-protection. Types 1, 2, 6, and 7 colonized patients with greater frequency than did the other strains.
There was evidence that different types had certain predilections for particular areas of the body; one or more types could
occur concurrently in the same or different areas. Types that colonized patients were also occasionally recovered from such
areas of the environment as ice machines, sinks, etc. Intraspecies monitoring of P. aeruginosa has further elucidated the behavior of endogenous and exogenous strains of this organism in high-risk patients.
More than 600 strains of nonfermentative Gram-negative bacilli were examined to establish reliable procedures for their detection and identification in a clinical laboratory. Growth on the surface but neither growth nor acid in the butt of Kligler iron agar medium was found to be a completely reliable means for detecting these bacilli. However, some strains of Moraxella fail to grow on this medium, hence cannot thus be detected. Six reagents for the oxidase test were examined. Most gave dependable results and did not require careful timing. Aberrant results were obtained with occasional strains of some species. However, all other features of such strains permitted their correct identification. More than 98% of the strains were identified. Identification was effected with a battery of 12 screening tests followed, with a minority of strains, by completion tests. All strains were assigned to one of six groups on the basis of the screening tests; 60% of the strains were also identified by these tests. Completion tests were usually required for identification of weakly saccharolytic and nonsaccharolytic strains. Alkalinization of buffered amides and organic salts was a major part of the completion tests on nonsaccharolytic strains. Such strains are usually not correctly identified by the tests commonly used in clinical bacteriology.
The efficacy of antibiotic resistance (barrier) precautions for control of aminoglycoside resistance was evaluated from 1978 to 1981. Despite increasing aminoglycoside use and a 13-fold increase in aminoglycoside-resistant isolates on a newly opened oncology unit, the hospital-wide frequency of aminoglycoside resistant Enterobacteriaceae remained low, supporting the continued value of barrier precautions which were initiated in our hospital in 1974. This control enabled us to focus on exceptions to the effectiveness of barrier precautions. These were traced to environmental reservoirs, very chronic and heavily infected patients, asymptomatic carriers of Serratia, and oncology patients receiving oral non-absorbable aminoglycosides. In addition, resistance in Pseudomonas aeruginosa paralleled aminoglycoside use and, as in our prior experience, continued to rise. With increasing adoption of barrier precautions by others such exceptions should be anticipated.
Isolates of gentamicin-resistant gram-negative bacilli from clinical specimens peaked at nine to 10 per month in 1973–1974.
Instituting barrier-type precautions during 1974–1977 was associated with a sustained 87070 reduction in resistant Enterobacteriaceae.
The number of resistant Pseudomonadaceae fell temporarily by 28%, paralleling gentamicin usage. During an endemic 15-month
period in 1976–1977 nonenzymatically mediated resistant Pseudomonas aeruginosa often emerged after aminoglycoside therapy in patients who had prior carriage of sensitive strains of the same serotype (P = 0.002); this resistance was associated with wound or sputum isolates (P = 0.003). Resistant Enterobacteriaceae more often demonstrated the converse, that is, spread of urinary tract isolates with
enzymatically mediated resistance from patients not on aminoglycoside therapy. These findings suggest that control measures
to minimize occurrence of resistant bacilli include barrier-type precautions for patients with resistant Enterobacteriaceae,
evaluation of transfers and readmissions as a source of resistant organisms, and reduction of aminoglycoside use to decrease
the selection of nonenzymatic resistance.
A collection of 802 isolates of Gram-negative bacteria causing urinary tract infections was made from general practice, antenatal clinics, and local hospitals. The organisms were tested for their sensitivity to chlorhexidine, cetrimide, glutaraldehyde, phenyl mercuric nitrate, a phenolic formulation, and a proprietary antiseptic containing a mixture of picloxydine, octyl phenoxy polyethoxyethanol, and benzalkonium chloride. Escherichia coli, the major species isolated, proved to be uniformly sensitive to these agents. Approximately 10% of the total number of isolates, however, exhibited a degree of resistance to the cationic agents. These resistant organisms were members of the genera Proteus, Providencia, and Pseudomonas; they were also generally resistant to five, six, or seven antibiotics. It is proposed therefore that an antiseptic policy which involves the intensive use of cationic antiseptics might lead to the selection of a flora of notoriously drug-resistant species.
The chlorhexidine resistance of 317 strains of Pseudomonas aeruginosa isolated from hospital patients was determined. The distribution pattern of their susceptibility to chlorhexidine clearly revealed two peaks, and the frequency of resistance to chlorhexidine was 84.2%.
Fifty-seven isolates of Gram-negative bacterial species from urinary tract infections in spinal cord injured patients were tested for their sensitivity to chlorhexidine, cetrimide, glutaraldehyde, phenyl mercuric nitrate (PMN), a phenolic disinfectant (Hycolin) and a proprietary antiseptic containing a mixture of picloxydine, octylphenoxypolyethoxyethanol and benzalkonium chloride (Resiguard). None of the isolates were resistant to glutaraldehyde, Hycolin or PMN but a substantial percentage were resistant to chlorhexidine (44 per cent), cetrimide (26 per cent) and Resiguard (42 per cent). The resistant organisms were members of the genera Proteus, Providencia and Pseudomonas and they were also generally resistant to five, six or seven antibiotics. Significant correlations were observed between multiplicity of antibiotic resistance and the minimum inhibitory concentrations of the three cationic antiseptics. It is suggested that an antiseptic policy for the bladder management of spinal cord injured patients that relies on the extensive use of cationic agents might lead to the selection of a flora of notoriously drug-resistant species.
Sink drains from the Veterans Administration Medical Center, University of Oklahoma Health Sciences Center, and the Oklahoma City community were selectively cultured for gentamicin- and amikacin-resistant bacteria. Aminoglycoside-resistant organisms were found in 86% (Veterans Administration Medical Center, 88%; University of Oklahoma Health Sciences Center, 88%; and Oklahoma City community, 77%) of all 233 sink drains sampled. Of 207 sink drains harboring aminoglycoside-resistent organisms, 99% of the organisms were gentamicin resistant and 82% were amikacin resistant. These data suggest that aminoglycoside-resistent organisms are commonly present in the environment.
Department of Medicine, Michael Reese Hospital and Medical Center, Lake Shore Drive at 31st Street
- Requests
- A Robert
- Weinstein
Requests for reprints to: Dr Robert A Weinstein,
Department of Medicine, Michael Reese Hospital and
Medical Center, Lake Shore Drive at 31st Street, Chicago,
Illinois 60616, USA.
References
http://jcp.bmj.com/content/37/4/424#related-urls
Article cited in:
The agar-dilution technique
- Ja Washington
- Ii
Washington JA II. The agar-dilution technique. In: Balows A,
ed. Current techniques for antibiotic susceptbility testing,
Springfield, Illinois: Charles C Thomas, 1974:54-62.