[Show abstract][Hide abstract] ABSTRACT: Antibiotic resistance is a worldwide threat to health care as it impairs the effective treatment of bacterial infections. Measures against the spread of resistance are mainly focused on individual health care institutions as these are viewed as the main source of resistance. However, health care institutions are not completely independent in their control of the prevalence of resistance, as movement of patients between hospitals and care institutions can induce movement of resistant micro-organisms. In other words, antibiotic resistance follows the flow of patients. Mapping this flow of patients results in a network that includes all health care institutions, and has a distinctive modular structure. Patients are moved primarily within regions, much less so between regions. We argue that the structure of this health care network should be used to design efficient and effective control strategies. To this end, we advocate (a) regional coordination of control measures, (b) differentiation of investment in infection prevention according to the network position of the institution, and
Nederlands tijdschrift voor geneeskunde 06/2015; 159:A8468.
[Show abstract][Hide abstract] ABSTRACT: Major challenges remain when attempting to quantify and evaluate the impacts of contaminated environments and heterogeneity in the cohorting of health care workers (HCWs) on hospital infections. Data on the detection rate of multidrug-resistant Acinetobacter baumannii (MRAB) in a Chinese intensive care unit (ICU) were obtained to accurately evaluate the level of environmental contamination and also to simplify existing models. Data-driven mathematical models, including mean-field and pair approximation models, were proposed to examine the comprehensive effect of integrated measures including cohorting, increasing nurse-patient ratios and improvement of environmental sanitation on MRAB infection. Our results indicate that for clean environments and with strict cohorting, increasing the nurse-patient ratio results in an initial increase and then a decline in MRAB colonization. In contrast, in contaminated environments, increasing the nurse-patient ratio may lead to either a consistent increase or an initial increase followed by a decline of MRAB colonization, depending on the level of environmental contamination and the cohorting rate. For developing more effective control strategies, the findings suggest that increasing the cohorting rate and nurse-patient ratio are effective interventions for relatively clean environments, while cleaning the environment more frequently and increasing hand washing rate are suitable measures in contaminated environments.
[Show abstract][Hide abstract] ABSTRACT: As MRSA are considered Staphylococcus aureus isolates with oxacillin minimum inhibitory concentration (MIC) of ≥4 mg/L or harboring the mecA gene. However, the presence of mecA does not necessarily lead to oxacillin resistance and mecA gene-carrying isolates may have oxacillin MIC within the susceptible range (≤2 mg/L). During the last few years it has become apparent that oxacillin-susceptible (OS) mecA-positive S. aureus isolates (commonly called OS-MRSA) are rather commonly detected worldwide and may remain undiagnosed using phenotypic susceptibility testing methods. This review will summarize the current reports on OS-MRSA isolations and the underlying mechanisms regulating the expression of oxacillin resistance and also oxacillin susceptibility in mecA-positive S. aureus isolates. As MRSA commonly cause severe infections against which effective therapies are limited, understanding of these mechanisms could enable the identification of new targets for the treatment or reversion of the MRSA phenotype.
Current pharmaceutical design 03/2015; 21(16). DOI:10.2174/1381612821666150310103754 · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Staphylococcus aureus is one of the most important human pathogens and meticillin-resistant S. aureus (MRSA) presents a major cause of healthcare- and community-acquired infections. This study investigated the spatial and temporal changes of S. aureus causing bacteraemia in Europe over a five-year interval and explored the possibility of integrating pathogen-based typing data with epidemiological and clinical information at a European level. Between January 2011 and July 2011, 350 laboratories serving 453 hospitals in 25 countries collected 3,753 isolates (meticillin-sensitive S. aureus (MSSA) and MRSA) from patients with S. aureus bloodstream infections. All isolates were sent to the national staphylococcal reference laboratories and characterised by quality-controlled spa typing. Data were uploaded to an interactive web-based mapping tool. A wide geographical distribution of spa types was found, with some prevalent in all European countries. MSSA was more diverse than MRSA. MRSA differed considerably between countries with major international clones expanding or receding when compared to a 2006 survey. We provide evidence that a network approach of decentralised typing and visualisation of aggregated data using an interactive mapping tool can provide important information on the dynamics of S. aureus populations such as early signalling of emerging strains, cross-border spread and importation by travel.
Eurosurveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 12/2014; 19(49):20987. · 5.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this review was to provide an up-to-date account of the interventions used to prevent the introduction of meticillin-resistant Staphylococcus aureus (MRSA) from the expanding community and livestock reservoirs into hospitals in the USA, Denmark, The Netherlands and Western Australia. A review of existing literature and local guidelines for the management of MRSA in hospitals was performed. In Denmark, The Netherlands and Western Australia, where the prevalence of MRSA is relatively low, targeted admission screening and isolation of predefined high-risk populations have been used for several decades to successfully control MRSA in the hospital. Furthermore, in Denmark and The Netherlands, all identified MRSA carriers undergo routine decolonisation, whereas only carriers of particularly transmissible or virulent MRSA clones are subjected to decolonisation in Western Australia. In the USA, which continues to be a high-prevalence MRSA country, policies vary by state and even by hospital, and whilst guidelines from professional organisations provide a framework for infection control practices, these guidelines lack the authority of a legislative mandate. In conclusion, the changing epidemiology of MRSA, exemplified by the recent emergence of MRSA in the community and in food animals, makes it increasingly difficult to accurately identify specific high-risk groups to screen for MRSA carriage. Understanding the changing epidemiology of MRSA in a local as well as global context is fundamental to prevent the introduction of MRSA into hospitals.
Journal of Global Antimicrobial Resistance 12/2014; 2(4). DOI:10.1016/j.jgar.2014.09.003 · 1.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To describe the prevalence and population structure of Staphylococcus aureus bacteria that colonize pigsat slaughterhouses in northeastern China, nose swabs were collected from pigs in two slaughterhouses inHarbin, Heilongjiang Province, China in 2009. S. aureus isolates were characterized by multilocus sequencetyping (MLST), spa typing, SCCmec typing, antimicrobial susceptibility testing and pvl gene detection. Atotal of 200 S. aureus isolates were collected from 590 pigs (33.9%, 200/590), of which 162 (81%, 162/200)were methicillin-susceptible S. aureus (MSSA) and 38 (19%, 38/200) were methicillin-resistant S. aureus(MRSA). Ninety-nine of the MSSA isolates (99/162, 61.1%) were ST398, which represented the dominantsequence type overall. Eighty-seven isolates were ST9 (87/200, 43.5%), and all MRSA belonged to thatsequence type which consisted of the spa types t899 and t2922. Among the MSSA strains, t034, t899 andt4358 were the most dominant spa types (139/162, 85.8%). All MRSA isolates harbored SCCmec type IVb.The pvl gene was only detected in 3 ST7/t2119 MSSA isolates. All MRSA but more importantly also 82.7%(134/162) of the MSSA isolates were resistant to six or more antibiotics. Moreover, a novel resistancedeterminant-lsa(E) was identified among 22% (44/200) of all isolates. In conclusion, pigs in northeastChina are frequently colonized with ST398 MSSA. MRSA with this sequence type, typically associatedwith pigs in Europe, was not found. High levels of multiple antibiotic resistance among MRSA isolates aswell as MSSA isolates are a public health concern.
[Show abstract][Hide abstract] ABSTRACT: Consecutive non-replicate clinical isolates (n=191) of carbapenem non-susceptible Enterobacteriaceae were collected from 21 hospital laboratories across Italy from November 2013 to April 2014 as part of the European Survey on Carbapenemase-producing Enterobacteriaceae (EuSCAPE) project. Klebsiella pneumonia carbapenemase-producing K. pneumoniae (KPC-KP) represented 178 (93%) isolates with 76 (43%) respectively resistant to colistin, a key drug for treating carbapenamase-producing Enterobacteriaceae. KPC-KP colistin-resistant isolates were detected in all participating laboratories. This underscores a concerning evolution of colistin resistance in a setting of high KPC-KP endemicity.
Eurosurveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 10/2014; 19(42). DOI:10.2807/1560-7917.ES2014.19.42.20939 · 5.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objectives:
The population-level appropriateness of empirical antibiotic therapy can be conventionally measured by ascertainment of treatment coverage. This method involves a complex resource-intensive case-by-case assessment of the prescribed antibiotic treatment and the resistance of the causative microorganism. We aimed to develop an alternative approach based, instead, on the use of routinely available surveillance data.
We calculated a drug effectiveness index by combining three simple aggregated metrics: relative frequency of aetiological agents, level of resistance and relative frequency of antibiotic use. To evaluate the applicability of our approach, we used this metric to estimate the population-level appropriateness of guideline-compliant and non-guideline-compliant empirical treatment regimens in the context of the Dutch national guidelines for complicated urinary tract infections.
The drug effectiveness index agrees within 5% with results obtained with the conventional approach based on a case-by-case ascertainment of treatment coverage. Additionally, we estimated that the appropriateness of 2008 antibiotic prescribing regimens would have declined by up to 4% by year 2011 in the Netherlands due to the emergence and expansion of antibiotic resistance.
The index-based framework can be an alternative approach to the estimation of point values and counterfactual trends in population-level empirical treatment appropriateness. In resource-constrained settings, where empirical prescribing is most prevalent and comprehensive studies to directly measure appropriateness may not be a practical proposition, an index-based approach could provide useful information to aid in the development and monitoring of antibiotic prescription guidelines.
[Show abstract][Hide abstract] ABSTRACT: Background
Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen but little is known about its circulation in hospitals in developing countries. We aimed to describe carriage of S.aureus amongst inpatients in a mid-sized Kenyan government hospital.
We determined the frequency of S.aureus and MRSA carriage amongst inpatients in Thika Hospital, Kenya by means of repeated cross-sectional ward surveys. For all S.aureus isolates, we performed antibiotic susceptibility tests, genomic profiling using a DNA microarray and spa typing and MLST.
In this typical mid-sized Kenyan Government hospital, we performed 950 screens for current carriage of S.aureus amongst inpatients over a four month period. We detected S.aureus carriage (either MSSA or MRSA) in 8.9% (85/950; 95%CI 7.1-10.8) of inpatient screens, but patients with multiple screens were more likely have detection of carriage. MRSA carriage was rare amongst S.aureus strains carried by hospital inpatients – only 7.0% (6/86; 95%CI 1.5-12.5%) of all isolates were MRSA. Most MRSA (5/6) were obtained from burns patients with prolonged admissions, who only represented a small proportion of the inpatient population. All MRSA strains were of the same clone (MLST ST239; spa type t037) with concurrent resistance to multiple antibiotic classes. MSSA isolates were diverse and rarely expressed antibiotic resistance except against benzyl-penicillin and co-trimoxazole.
Although carriage rates for S.aureus and the MRSA prevalence in this Kenyan hospital were both low, burns patient were identified as a high risk group for carriage. The high frequency of genetically indistinguishable isolates suggests that there was local transmission of both MRSA and MSSA.
[Show abstract][Hide abstract] ABSTRACT: The Staphylococcal Cassette Chromosome mec (SCCmec) confers methicillin resistance to Staphylococcus aureus. While SCCmec is generally regarded as a mobile genetic element, the precise mechanisms by which large SCCmec elements are exchanged between staphylococci have remained enigmatic. In the present studies, we observed that the clinical methicillin-resistant S. aureus (MRSA) isolate UMCG-M4 with the sequence type 398 contains four prophages belonging to the serological groups A, B and Fa. Previous studies have shown that certain serological group B bacteriophages of S. aureus are capable of generalized transduction. We therefore assessed the transducing capabilities of the phages from strain UMCG-M4. The results show that some of these phages can indeed transduce plasmid pT181 to the recipient S. aureus strain RN4220. Therefore, we also investigated the possible involvement of these transducing phages in the transmission of the large SCCmec type V (5C2&5) element of S. aureus UMCG-M4. While no transduction of the complete SCCmec element was observed, we were able to demonstrate that purified phage particles did contain large parts of the SCCmec element of the donor strain, including the methicillin resistance gene mecA. This shows that staphylococcal phages can encapsulate the resistance determinant mecA of a large SCCmec type V (5C2&5) element, which may lead to its transfer to other staphylococci.
International journal of medical microbiology: IJMM 06/2014; 304(5-6):764-774. DOI:10.1016/j.ijmm.2014.05.010 · 3.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract The need for global data about the scale of antibiotic resistance (ABR) in a geographical explicit and timely manner has been identified by many stakeholders, including the World Health Organization. This primer should help defining the objectives, scale, scope, and structure of possible future efforts. Stakeholders and their expected information demands were identified to generate an inventory of surveillance objectives. For simplification, an original approach was chosen to bundle sets of objectives that represent common demands and can be addressed by common subject areas, which fall into three areas. Subject area I addresses clinical demands and focuses on patients; subject area II addresses public health demands by focusing on meta-populations; subject area III addresses infection control demands and focuses on pathogens. A division into these areas leads to a separation of surveillance activities suggesting a modular approach which can provide complementary information. Moreover, the modules address the conundrum of ABR at the complementary levels of 1) patient, 2) population, and 3) pathogen, which-rather conventionally-follow the operational and professional fault-lines of the main disciplines involved, namely clinical medicine, public health, and biology. Essential features that define different surveillance systems have been listed and taken into consideration when suggesting templates for future efforts. Putting ABR on the global health map is a daunting task as it requires acceptance, agreements, and engagement but also concessions at many different levels. Given the existing gaps in the global diagnostic service landscape only a step-wise approach which defines achievable aims, objectives, and milestones will succeed to produce a sustainable system of international co-operative surveillance of ABR.
Upsala journal of medical sciences 04/2014; 119(2). DOI:10.3109/03009734.2014.904458 · 1.98 Impact Factor