[Show abstract][Hide abstract] ABSTRACT: The detection of outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) infections and a rapid and accurate identification of sources and routes of transmission should be conducted in hospital settings as early and swiftly as possible. In this study, we investigated the application potential of a new approach based on multiple-locus variable-number tandem-repeat fingerprinting (MLVF) and microfluidics technology for a rapid discrimination of MRSA lineages in outbreak settings. A total of 206 nonrepetitive MRSA isolates recovered from infected patients at the University Medical Center Groningen between 2000 and 2010 were tested. The results obtained by MLVF using microcapillary electrophoresis with newly designed primers were compared to those obtained by spa typing and multiple-locus variable-number tandem-repeat analysis (MLVA). The discriminatory power was 0.980 (107 patterns), 0.969 (85 allelic profiles), and 0.959 (66 types) for MLVF, MLVA, and spa typing, respectively. All methods tested showed a good concordance of results calculated by the adjusted Rand's coefficient method. Comparisons of data obtained by the three approaches allowed us to propose an 88% cutoff value for the similarity between any two MLVF patterns, which can be used in S. aureus epidemiological studies, including analyses of outbreaks and strain transmission events. Of the three tested methods, MLVF is the cheapest, fastest, and easiest to perform. MLVF applied to microfluidic polymer chips is a rapid, cheap, reproducible, and highly discriminating tool to determine the clonality of MRSA isolates and to trace the spread of MRSA strains over periods of many years. Although spa typing should be used due to its portability of data, MLVF has a high added value because it is more discriminatory.
Full-text · Article · May 2012 · Journal of clinical microbiology
[Show abstract][Hide abstract] ABSTRACT: Thermal stability is essential for the survival and well-being of preterm neonates. This is achieved in neonatal incubators
by raising the ambient temperature and humidity to sufficiently high levels. However, potentially pathogenic microorganisms
also can thrive in such warm and humid environments. We therefore investigated whether the level of microbial contamination
(i.e., the bacterial load) inside neonatal incubators can be predicted on the basis of their average temperature and relative
humidity settings, paying special attention to local temperature differences. Swab samples were taken from the warmest and
coldest spots found within Caleo incubators, and these were plated to determine the number of microbial CFU per location.
In incubators with high average temperature (≥34°C) and relative humidity (≥60%) values, the level of microbial contamination
was significantly higher at cold spots than at hot spots. This relates to the fact that the local equilibrium relative humidity
at cold spots is sufficiently high to sustain microbial growth. The abundance of staphylococci, which are the main causative
agents of late-onset sepsis in preterm neonates, was found to be elevated significantly in cold areas. These findings can
be used to improve basic incubator hygiene.
Full-text · Article · Dec 2011 · Applied and Environmental Microbiology
[Show abstract][Hide abstract] ABSTRACT: To the Editor: Methicillin-resistant Staphylococcus aureus (MRSA) is spreading worldwide among humans and animals, including horses. Many reports of MRSA colonization and infection in horses come from Canada and involve MRSA of sequence type (ST) 8, classified by pulsed-field gel electrophoresis (PFGE) as Canadian MRSA-5 or USA500. ST8 is thought to be a human epidemic clone that has adapted to horses (1). Another MRSA type, ST398, has recently begun spreading in Europe and North America and is associated with livestock (2). In the Netherlands, MRSA of ST8 (spa-type t064) and ST398 (spa-type t011), which belong to the livestock-associated CC398, predominate in clinical samples from horses (3). To date, human clinical infections with livestock-associated MRSA are uncommon in persons who have not had contact with pigs or calves (2). In this case study, we describe the suspected transmission of MRSA ST398 between a horse and a girl, which resulted in infection of the girl's right foot.
Full-text · Article · Jun 2011 · Emerging Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: To assess the adequacy of preparedness planning for an influenza pandemic by modeling the pediatric surge capacity of healthcare facility and pediatric intensive care unit (PICU) requirements over time. Governments and Public Health authorities have planned preparedness activities and training for a flu pandemic. PICU facilities will be the limiting factor in healthcare provision for children but detailed analyses for needs and demands in PICU care have not been published.
Based on the Center for Disease Control and Prevention and World Health Organization estimates and published models of the expected evolution of pandemic flu, we modeled the pediatric surge capacity of healthcare facility and PICU requirements over time. Various scenarios with different assumptions were explored. We compared these demands with estimates of maximal PICU capacity factoring in healthcare worker absenteeism as well as reported and more realistic estimates derived from semistructured telephone interviews with key stakeholders in ICUs in the study area.
All hospitals and intensive care facilities in the Northern Region in The Netherlands with near 1.7 million inhabitants, of whom approximately 25% is <18 yrs.
Using well-established modeling techniques, evidence-based medicine, and incorporating estimates from the Centers for Disease Control and Prevention and World Health Organization, we show that PICU capacity may suffice during an influenza pandemic. Even during the peak of the pandemic, most children requiring PICU admission may be served, even those who have nonflu-related conditions, provided that robust indications and decision rules are maintained, both for admission, as well as continuation (or discontinuation) of life support.
We recommend that a model, with assumptions that can be adapted with new information obtained during early stages of the pandemic that is evolving, be an integral part of a preparedness plan for a pandemic influenza with new human transmissible agent like influenza A virus.
Full-text · Article · Mar 2010 · Pediatric Critical Care Medicine
[Show abstract][Hide abstract] ABSTRACT: Recent outbreaks of a novel avian influenza A virus (H5N1) in Asia, Africa and Europe were a chilling reminder that another human pandemic may occur any time. Such a worldwide outbreak will cause intense human suffering, disruption of social systems, major economic losses, and greatly burden health care services. Several pandemics during the last century, like the 'Spanish flu' (1918), the 'Asian flu' (1957), the 'Hong Kong flu' (1968) and SARS (2003) prompted health care authorities for preparedness planning. In The Netherlands the risk of pandemic influenza was stressed by the outbreak of H7N7 which led to culling 30 million chickens (one third of domestic poultry), and with one human casualty, a veterinary surgeon. The influenza pandemic alertness was elevated to Phase 3 by the World Health Organization in 2005. In the Netherlands these events forced health care authorities and health care services to draft and discuss national and regional preparedness plans. In November 2007, the northern part of the Netherlands was confronted with a sudden and -mysterious" disease outbreak in an (exotic) animal's pet store. As there was uncertainty about the nature of this sudden outbreak - infectious, toxic or otherwise - all patients were admitted for quarantine and overnight observation to the University Medical Centre Groningen (UMCG), acting as the regional centre for outbreak management and trauma care. In 2008 a woman died in The Netherlands due to Marburg Haemorrhagic Fever which was acquired during a visit to Uganda. She returned to the Netherlands in good health but after the first symptoms she was admitted to the hospital and deteriorated rapidly with liver failure and severe haemorrhage. These recent incidents emphasise the need for more structured planning and preparation for medical emergencies such as emerging infectious disease outbreaks. Structured planning and preparation for disease outbreaks is not yet common ground for most health services, including hospitals and large tertiary referral centres in affluent countries. It demands commitment from health care services ranging from the level of individual health care workers to government level to provide sufficient strategic decision making and financial resources. It also demands a cultural change in thinking for management and recognizing the ethical impact this has on clinicians and nurses who have to make these decisions. Many clinicians now realize that end-of-life decisions are an integral part of health care which is independent of any specific religious background or culture. With appropriate patient management adequate health care can be provided even during infectious disease outbreaks. Evidence-based medicine and modelling in preparing for disease outbreaks has to be followed by evidence-based management of the health care systems which includes using disease outbreaks models and knowledge about surge capacity on regional, national and international level, to ensure business continuity of the health care system. Business continuity encompasses ethical decisions (use of surge capacity), finances, and preparation (hospital layout). Decision rules have to be adapted to real-time information updates obtained during the course of an outbreak and exchange of information throughout the crisis is pivotal.
[Show abstract][Hide abstract] ABSTRACT: Endoscopes, including duodenoscopes, are medical devices that are frequently associated with outbreaks of nosocomial infections. We investigated an outbreak of multidrug-resistant PSEUDOMONAS AERUGINOSA sepsis affecting three patients after endoscopic retrograde cholangiopancreaticography (ERCP). Epidemiologic investigation supplemented by molecular typing revealed that one ERCP scope was the source of infection with P. AERUGINOSA. No contamination with this microorganism was found after screening of washer-disinfectors, connecting tubes, and environmental surfaces in the endoscopy center. PSEUDOMONAS isolates from blood and endoscope channels before gas sterilization with ethylene oxide (ETO) were characterized by molecular typing as "linked isolates". Though the current surveillance system did not prevent the infections in three patients, our microbiological surveillance protocol with routine culturing of endoscopes was helpful in detecting the source of contamination and probably avoided numerous cross-contaminations in other patients who underwent ERCP procedures with endoscopes.
[Show abstract][Hide abstract] ABSTRACT: Normally, humans are protected against infections by their anaerobic intestinal microorganisms providing colonization resistance. In immunocompromised patients, the endogenous intestinal gram-positive and gram-negative pathogens often cause infectious complications. Therefore, we analyzed the effect of chemotherapy treatment and antimicrobial prophylaxis on intestinal bacterial populations (microbiota) among pediatric patients with acute myeloid leukemia who are prone to intestinal mucositis and infections.
During 36 chemotherapy cycles, fecal samples were collected from pediatric patients with acute myeloid leukemia. Fecal bacterial populations were analyzed by polymerase chain reaction denaturing gradient gel electrophoresis fingerprinting. Fluorescent in situ hybridization analysis with specific bacterial oligonucleotide probes was used to quantify the fecal bacteria.
During chemotherapy treatment, the total number of bacteria in fecal samples was 10(9) per gram of dry weight feces, which was 100-fold lower than than in healthy control samples. Fluorescent in situ hybridization analysis showed that this decrease was the result of an up to 10,000-fold decrease in anaerobic bacteria, partly compensated for by a 100-fold increase in potentially pathogenic enterococci. Additional experiments showed that both prophylactic and therapeutic use of antibiotics could not sufficiently explain the tremendous changes in intestinal microbial composition. In vitro tests showed a direct bacteriostatic effect of chemotherapeutics.
Patients with acute myeloid leukemia treated with chemotherapy and prophylactic antibiotics are unable to maintain colonization resistance because of a decrease in anaerobic bacteria and an increase in potentially pathogenic aerobic enterococci. We hypothesize that this disturbance in the balance between anaerobic and aerobic bacteria will further increase the risk of gram-positive aerobic infections among immunocompromised patients with cancer.
Preview · Article · Aug 2009 · Clinical Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Viridans group streptococci (VGS) are a well-known cause of infections in immunocompromised patients, accounting for severe
morbidity and mortality. Streptococcus mitis group species (Streptococcus mitis, Streptococcus pneumoniae, Streptococcus oralis) are among the VGS most often encountered in clinical practice. Identifying the portal of entry for S. mitis group strains is crucial for interventions preventing bacterial translocation. Unfortunately, tracking the source of S. mitis group strains is dependent on a combination of extremely laborious and time-consuming cultivation and molecular techniques
(enterobacterial repetitive intergenic consensus-PCR [ERIC-PCR]). To simplify this procedure, a PCR analysis with newly designed
primers targeting the household gene glucose kinase (gki) was used in combination with denaturing gradient gel electrophoresis (DGGE). This gki-PCR-DGGE technique proved to be specific for S. mitis group strains. Moreover, these strains could be detected in samples comprised of highly diverse microbiota, without prior
cultivation. To study the feasibility of this new approach, a pilot study was performed. This confirmed that the source of
S. mitis group bacteremia in pediatric patients with acute myeloid leukemia could be tracked back to the throat in five out of six
episodes of bacteremia, despite the fact that throat samples are polymicrobial samples containing multiple S. mitis group strains. In contrast, using the classical combination of cultivation techniques and ERIC-PCR, we could detect these
strains in only two out of six cases, showing the superiority of the newly developed technique. The new gki-PCR-DGGE technique can track the source of S. mitis group strains in polymicrobial samples without prior cultivation. Therefore, it is a valuable tool in future epidemiological
Full-text · Article · Jun 2009 · Journal of clinical microbiology
[Show abstract][Hide abstract] ABSTRACT: The Dutch quality control plan for climatisation of the operating room (OR), which was published in 2005, describes the management and maintenance of the air conditioning system. This management plan proposes a standard for air quality in class 1 ORs. This has been adopted by the Dutch Orthopaedic Society, but not by other surgical societies. The British study which underlies the proposed norm for air quality in class 1 ORs, a study on the infection preventive effect of ultraclean air, dates from 1982 and is inadequately controlled for prophylactic use of antibiotics. Antibiotic prophylaxis in itself already reduces the number of surgical site infections.-More recent studies fail to show an infection preventive effect of ultraclean air in the OR. The Dutch Working Party for Infection Prevention (WIP) ought to take the initiative, together with the medical Scientific Societies and the Society of Infection Prevention and Control in the health care setting (VHIG), to establish enforceable norms for microbiological air quality and to set criteria as to which types of operations are allowed to be performed in which class of OR.
No preview · Article · Jan 2009 · Nederlands tijdschrift voor geneeskunde
[Show abstract][Hide abstract] ABSTRACT: In The Netherlands a major part of preparedness planning for an epidemic or pandemic consists of maintaining essential public services, e.g., by the police, fire departments, army personnel, and healthcare workers. We provide estimates for peak demand for healthcare workers, factoring in healthcare worker absenteeism and using estimates from published epidemiologic models on the expected evolution of pandemic influenza in relation to the impact on peak surge capacity of healthcare facilities and intensive care units (ICUs). Using various published scenarios, we estimate their effect in increasing the availability of healthcare workers for duty during a pandemic. We show that even during the peak of the pandemic, all patients requiring hospital and ICU admission can be served, including those who have non-influenza-related conditions. For this rigorous task differentiation, clear hierarchical management, unambiguous communication, and discipline are essential and we recommend informing and training non-ICU healthcare workers for duties in the ICU.
Full-text · Article · Nov 2008 · Emerging Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Renal aspergillosis is an extremely uncommon complication in HIV-infected patients. In general, prognosis is poor and the need for nephrectomy is emphasized. We report the case of a 37-year-old patient with AIDS since April 2003 (CD4 count 10 cells/mm(3), a high viral load, Candida esophagitis, bilateral pneumonia, HIV encephalopathy). Treatment with zidovudine, lamivudine, nevirapine, and lopinavir/ritonavir was started. Adherence to this medication proved to be a problem, but after 18 weeks of HAART the CD4 count was 110 cells/mm(3) and viral load was undetectable. One year later, he presented with hematuria and flank pain. Computed tomography (CT) scan revealed multiple lesions in both kidneys. Cultures of the abscess aspirates yielded Aspergillus fumigatus. Our review of 18 reported cases shows that prognosis of renal aspergillosis is poor if nephrectomy is not performed. However, in the present case a conservative approach was chosen to avoid life-long dialysis. The patient was treated successfully with a combination of voriconazole, percutaneous drainage, and highly active antiretroviral therapy (HAART). Renal function was completely preserved. Reported cases from the literature of renal aspergillosis in HIV-infected patients are summarized in this paper.
No preview · Article · Feb 2008 · AIDS patient care and STDs
[Show abstract][Hide abstract] ABSTRACT: Using estimates from the Centers for Disease Control and Prevention, the World Health Organization, and published models of the expected evolution of pandemic influenza, we modeled the surge capacity of healthcare facility and intensive care unit (ICU) requirements over time in northern Netherlands (approximately 1.7 million population). We compared the demands of various scenarios with estimates of maximum ICU capacity, factoring in healthcare worker absenteeism as well as reported and realistic estimates derived from semistructured telephone interviews with key management in ICUs in the study area. We show that even during the peak of the pandemic, most patients requiring ICU admission may be served, even those who have non-influenza-related conditions, provided that strong indications and decision-making rules are maintained for admission as well as for continuation (or discontinuation) of life support. Such a model should be integral to a preparedness plan for a pandemic with a new human-transmissible agent.
Full-text · Article · Dec 2007 · Emerging infectious diseases