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H Humphreys - One of the best experts on this subject based on the ideXlab platform.
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guidelines for the control and prevention of meticillin resistant staphylococcus aureus mrsa in healthcare facilities
Journal of Hospital Infection, 2006Co-Authors: J E Coia, H Humphreys, G Duckworth, D I Edwards, M Farrington, C Mallaghan, D R TuckerAbstract:Meticillin-resistant Staphylococcus aureus (MRSA) remains endemic in many UK hospitals. Specific guidelines for control and prevention are justified because MRSA causes serious illness and results in significant additional healthcare costs. Guidelines were drafted by a multi-disciplinary group and these have been finalised following extensive consultation. The recommendations have been graded according to the strength of evidence. Surveillance of MRSA should be undertaken in a systematic way and should be fed back routinely to healthcare staff. The inappropriate or unnecessary use of antibiotics should be avoided, and this will also reduce the likelihood of the emergence and spread of strains with reduced susceptibility to glycopeptides, i.e. vancomycin-intermediate S. aureus/glycopeptide-intermediate S. aureus (VISA/GISA) and vancomycin-resistant S. aureus (VRSA). Screening for MRSA carriage in selected Patients and clinical areas should be performed according to locally agreed criteria based upon assessment of the risks and consequences of transmission and infection. Nasal and skin decolonization should be considered in certain categories of Patients. The general principles of infection control should be adopted for Patients with MRSA, including Patient Isolation and the appropriate cleaning and decontamination of clinical areas. Inadequate staffing, especially amongst nurses, contributes to the increased prevalence of MRSA. Laboratories should notify the relevant national authorities if VISA/GISA or VRSA isolates are identified.
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environmental reservoirs of methicillin resistant staphylococcus aureus in Isolation rooms correlation with Patient isolates and implications for hospital hygiene
Journal of Hospital Infection, 2006Co-Authors: T Sexton, P Clarke, Eoghan Oneill, T Dillane, H HumphreysAbstract:Strategies to control and prevent the spread of methicillin-resistant Staphylococcus aureus (MRSA) include early identification of positive Patients through screening, Patient Isolation, hand hygiene, nasal and skin decontamination, and the adequate cleaning and decontamination of clinical areas. However, many national and other guidelines provide few details on environmental decontamination regimens, partly because the role of the environment in the spread of MRSA is not well documented. We prospectively studied the environment of the Isolation rooms of 25 MRSA Patients for up to four weeks, sampling horizontal surfaces and the air using settle plates as well as an air sampler, while continuing regular daily cleaning according to the hospital protocol. We then typed 20 Patient isolates and the corresponding environmental isolates (N=35) to assess the similarity of strains. A high proportion of samples were positive for MRSA; 269/502 (53.6%) surface samples, 70/250 (28%) air samples and 102/251 (40.6%) settle plates. Over half of the surface samples taken from the beds and the mattresses were positive for MRSA. Identical or closely related isolates were recovered from the Patient and their environment in 14 (70%) Patients, suggesting possible environmental contamination of the Isolation rooms, possibly contributing to endemic MRSA. More effective and rigorous use of current approaches to cleaning and decontamination is required as well as consideration of newer technologies to eradicate MRSA and other hospital-acquired pathogens.
Carlos Castillochavez - One of the best experts on this subject based on the ideXlab platform.
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evaluating the efficacy of antimicrobial cycling programmes and Patient Isolation on dual resistance in hospitals
Journal of Biological Dynamics, 2011Co-Authors: Karen Chow, Xiaohong Wang, Roy Curtiss, Carlos CastillochavezAbstract:Antibiotic-resistant bacteria cause a number of infections in hospitals and are considered a threat to public health. A strategy suggested to curb the development of resistant hospital-acquired infections is antimicrobial cycling, in which antibiotic classes are alternated over time. This can be compared with a mixing programme in which, when given two drugs, half of the physicians prescribe one drug over the other. A mathematical model of antimicrobial cycling in a hospital population setting is developed to evaluate the efficacy of a cycling programme with an emphasis on reducing the emergence and significance of dual resistance. The model also considers the effects of physician compliance and isolating Patients harbouring dual-resistant bacteria. Simulation results show that the optimal antimicrobial drug usage programme in hospital populations depends upon the type of resistance being targeted for treatment; a cycling programme is more effective against dual resistance compared with mixing. Patient Isolation and high compliance to a cycling programme is also shown to dramatically decrease dual resistance in hospitalized populations. Ultimately, the exclusive use of antimicrobials in fighting nosocomial infection does not solve the problem but just slows down what appears to be a losing battle against drug resistance. We hope that this paper serves to instigate discussion on the many dimensions of the complex problem of drug resistance in hospital settings.
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sars outbreaks in ontario hong kong and singapore the role of diagnosis and Isolation as a control mechanism
Journal of Theoretical Biology, 2003Co-Authors: Gerardo Chowell, Carlos Castillochavez, Paul W Fenimore, M A CastillogarsowAbstract:In this article we use global and regional data from the SARS epidemic in conjunction with a model of susceptible, exposed, infective, diagnosed, and recovered classes of people ("SEIJR") to extract average properties and rate constants for those populations. The model is fitted to data from the Ontario (Toronto) in Canada, Hong Kong in China and Singapore outbreaks and predictions are made based on various assumptions and observations, including the current effect of isolating individuals diagnosed with SARS. The epidemic dynamics for Hong Kong and Singapore appear to be different from the dynamics in Toronto, Ontario. Toronto shows a very rapid increase in the number of cases between March 31st and April 6th, followed by a significant slowing in the number of new cases. We explain this as the result of an increase in the diagnostic rate and in the effectiveness of Patient Isolation after March 26th. Our best estimates are consistent with SARS eventually being contained in Toronto, although the time of containment is sensitive to the parameters in our model. It is shown that despite the empirically modeled heterogeneity in transmission, SARS' average reproductive number is 1.2, a value quite similar to that computed for some strains of influenza (J. Math. Biol. 27 (1989) 233). Although it would not be surprising to see levels of SARS infection higher than 10% in some regions of the world (if unchecked), lack of data and the observed heterogeneity and sensitivity of parameters prevent us from predicting the long-term impact of SARS. The possibility that 10 or more percent of the world population at risk could eventually be infected with the virus in conjunction with a mortality rate of 3-7% or more, and indications of significant improvement in Toronto support the stringent measures that have been taken to isolate diagnosed cases.
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sars outbreaks in ontario hong kong and singapore the role of diagnosis and Isolation as a control mechanism
Journal of Theoretical Biology, 2003Co-Authors: Carlos Castillochavez, Gerardo Chowell, Paul W Fenimore, M A CastillogarsowAbstract:In this article we use global and regional data from the SARS epidemic in conjunction with a model of susceptible, exposed, infective, diagnosed, and recovered classes of people (“SEIJR”) to extract average properties and rate constants for those populations. The model is fitted to data from the Ontario (Toronto) in Canada, Hong Kong in China and Singapore outbreaks and predictions are made based on various assumptions and observations, including the current effect of isolating individuals diagnosed with SARS. The epidemic dynamics for Hong Kong and Singapore appear to be different from the dynamics in Toronto, Ontario. Toronto shows a very rapid increase in the number of cases between March 31st and April 6th, followed by a significant slowing in the number of new cases. We explain this as the result of an increase in the diagnostic rate and in the effectiveness of Patient Isolation after March 26th. Our best estimates are consistent with SARS eventually being contained in Toronto, although the time of containment is sensitive to the parameters in our model. It is shown that despite the empirically modeled heterogeneity in transmission, SARS’ average reproductive number is 1.2, a value quite similar to that computed for some strains of influenza (J. Math. Biol. 27 (1989) 233). Although it would not be surprising to see levels of SARS infection higher than 10% in some regions of the world (if unchecked), lack of data and the observed heterogeneity and sensitivity of parameters prevent us from predicting the long-term impact of SARS. The possibility that 10 or more percent of the world population at risk could eventually be infected with the virus in conjunction with a mortality rate of 3–7% or more, and indications of significant improvement in Toronto support the stringent measures that have been taken to isolate diagnosed cases.
Ben Cooper - One of the best experts on this subject based on the ideXlab platform.
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estimating the effectiveness of Isolation and decolonization measures in reducing transmission of methicillin resistant staphylococcus aureus in hospital general wards
American Journal of Epidemiology, 2013Co-Authors: Colin J Worby, Julie V Robotham, Dakshika Jeyaratnam, Theodore Kypraios, Philip D Oneill, Daniela De Angelis, Gary French, Ben CooperAbstract:Infection control for hospital pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) often takes the form of a package of interventions, including the use of Patient Isolation and decolonization treatment. Such interventions, though widely used, have generated controversy because of their significant resource implications and the lack of robust evidence with regard to their effectiveness at reducing transmission. The aim of this study was to estimate the effectiveness of Isolation and decolonization measures in reducing MRSA transmission in hospital general wards. Prospectively collected MRSA surveillance data from 10 general wards at Guy's and St. Thomas' hospitals, London, United Kingdom, in 2006-2007 were used, comprising 14,035 Patient episodes. Data were analyzed with a Markov chain Monte Carlo algorithm to model transmission dynamics. The combined effect of Isolation and decolonization was estimated to reduce transmission by 64% (95% confidence interval: 37, 79). Undetected MRSA-positive Patients were estimated to be the source of 75% (95% confidence interval: 67, 86) of total transmission events. Isolation measures combined with decolonization treatment were strongly associated with a reduction in MRSA transmission in hospital general wards. These findings provide support for active methods of MRSA control, but further research is needed to determine the relative importance of Isolation and decolonization in preventing transmission.
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Isolation measures in the hospital management of methicillin resistant staphylococcus aureus mrsa systematic review of the literature
BMJ, 2004Co-Authors: Ben Cooper, G Duckworth, S Stone, C C Kibbler, B Cookson, J A Roberts, G F Medley, Shah EbrahimAbstract:Abstract Objective To evaluate the evidence for the effectiveness of Isolation measures in reducing the incidence of methicillin resistant Staphylococcus aureus (MRSA) colonisation and infection in hospital inPatients. Design Systematic review of published articles. Data sources Medline, Embase, CINAHL, Cochrane Library, System for Information on Grey Literature in Europe (SIGLE), and citation lists (1966-2000). Review methods Articles reporting MRSA related outcomes and describing an Isolation policy were selected. No quality restrictions were imposed on studies using Isolation wards or nurse cohorting. Other studies were included if they were prospective or employed planned comparisons of retrospective data. Results 46 studies were accepted; 18 used Isolation wards, nine used nurse cohorting, and 19 used other Isolation policies. Most were interrupted time series, with few planned formal prospective studies. All but one reported multiple interventions. Consideration of potential confounders, measures to prevent bias, and appropriate statistical analysis were mostly lacking. No conclusions could be drawn in a third of studies. Most others provided evidence consistent with a reduction of MRSA acquisition. Six long interrupted time series provided the strongest evidence. Four of these provided evidence that intensive control measures including Patient Isolation were effective in controlling MRSA. In two others, Isolation wards failed to prevent endemic MRSA. Conclusion Major methodological weaknesses and inadequate reporting in published research mean that many plausible alternative explanations for reductions in MRSA acquisition associated with interventions cannot be excluded. No well designed studies exist that allow the role of Isolation measures alone to be assessed. None the less, there is evidence that concerted efforts that include Isolation can reduce MRSA even in endemic settings. Current Isolation measures recommended in national guidelines should continue to be applied until further research establishes otherwise.
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systematic review of Isolation policies in the hospital management of methicillin resistant staphylococcus aureus a review of the literature with epidemiological and economic modelling
Health Technology Assessment, 2003Co-Authors: Ben Cooper, G Duckworth, C C Kibbler, B Cookson, J A Roberts, G F Medley, S P Stone, R Lai, Shah EbrahimAbstract:OBJECTIVE: To review the evidence for the effectiveness of different Isolation policies and screening practices in reducing the incidence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation and infection in hospital in-Patients. To develop transmission models to study the effectiveness and cost-effectiveness of Isolation policies in controlling MRSA. DATA SOURCES: MEDLINE, EMBASE, CINAHL, The Cochrane Library and SIGLE (1966-2000). Hand-searching key journals. No language restrictions. REVIEW METHODS: Key data were extracted from articles reporting MRSA-related outcomes and describing an Isolation policy in a hospital with epidemic or endemic MRSA. No quality restrictions were imposed on studies using Isolation wards (IW) or nurse cohorting (NC). Other studies were included if they were prospective or employed planned comparisons of retrospective data. Stochastic and deterministic models investigated long-term transmission dynamics, studying the effect of a fixed capacity IW, producing economic evaluations using local cost data. RESULTS: A total of 46 studies were accepted: 18 IWs, 9 NC, 19 other Isolation policies. Most were interrupted time series, with few planned formal prospective studies. All but one reported multiple interventions. Consideration of potential confounders, measures to prevent bias, and appropriate statistical analysis were mostly lacking. No conclusions could be drawn in a third of studies. Most others provided evidence consistent with reduction of MRSA acquisition. Six long interrupted time series provided the strongest evidence. Four of these provided evidence that intensive control measures which included Patient Isolation were effective in controlling MRSA. In two others IW use failed to prevent endemic MRSA. There was no robust economic evaluation. Models showed that improving the detection rate or ensuring adequate Isolation capacity reduced endemic levels, with substantial savings achievable. CONCLUSIONS: Major methodological weaknesses and inadequate reporting in published research mean that many plausible alternative explanations for reductions in MRSA acquisition associated with interventions cannot be excluded. No well-designed studies allow the role of Isolation measures alone to be assessed. Nonetheless, there is evidence that concerted efforts that include Isolation can reduce MRSA even when endemic. Little evidence was found to suggest that current Isolation measures recommended in the UK are ineffective, and these should continue to be applied until further research establishes otherwise. The studies with the strongest evidence, together with the results of the modelling, provide testable hypotheses for future research. Guidelines to facilitate design of future research are produced.
Aldo A Rossini - One of the best experts on this subject based on the ideXlab platform.
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virus induced abrogation of transplantation tolerance induced by donor specific transfusion and anti cd154 antibody
Journal of Virology, 2000Co-Authors: Raymond M Welsh, Thomas G Markees, Bruce A Woda, Keith A Daniels, Michael A Brehm, John P Mordes, Dale L Greiner, Aldo A RossiniAbstract:Treatment with a 2-week course of anti-CD154 antibody and a single transfusion of donor leukocytes (a donor-specific transfusion or DST) permits skin allografts to survive for >100 days in thymectomized mice. As clinical trials of this methodology in humans are contemplated, concern has been expressed that viral infection of graft recipients may disrupt tolerance to the allograft. We report that acute infection with lymphocytic choriomeningitis virus (LCMV) induced allograft rejection in mice treated with DST and anti-CD154 antibody if inoculated shortly after transplantation. Isografts resisted LCMV-induced rejection, and the interferon-inducing agent polyinosinic:polycytidylic acid did not induce allograft rejection, suggesting that the effect of LCMV is not simply a consequence of nonspecific inflammation. Administration of anti-CD8 antibody to engrafted mice delayed LCMV-induced allograft rejection. Pichinde virus also induced acute allograft rejection, but murine cytomegalovirus and vaccinia virus (VV) did not. Injection of LCMV ∼50 days after tolerance induction and transplantation had minimal effect on subsequent allograft survival. Treatment with DST and anti-CD154 antibody did not interfere with clearance of LCMV, but a normally nonlethal high dose of VV during tolerance induction and transplantation killed graft recipients. We conclude that DST and anti-CD154 antibody induce a tolerant state that can be broken shortly after transplantation by certain viral infections. Clinical application of transplantation tolerance protocols may require Patient Isolation to facilitate the procedure and to protect recipients.
Gwendolyn L Gilbert - One of the best experts on this subject based on the ideXlab platform.
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effectiveness of hospital wide methicillin resistant staphylococcus aureus mrsa infection control policies differs by ward specialty
PLOS ONE, 2013Co-Authors: Rosemarie Sadsad, Vitali Sintchenko, Geoff Mcdonnell, Gwendolyn L GilbertAbstract:Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of preventable nosocomial infections and is endemic in hospitals worldwide. The effectiveness of infection control policies varies significantly across hospital settings. The impact of the hospital context towards the rate of nosocomial MRSA infections and the success of infection control is understudied. We conducted a modelling study to evaluate several infection control policies in surgical, intensive care, and medical ward specialties, each with distinct ward conditions and policies, of a tertiary public hospital in Sydney, Australia. We reconfirm hand hygiene as the most successful policy and find it to be necessary for the success of other policies. Active screening for MRSA, Patient Isolation in single-bed rooms, and additional staffing were found to be less effective. Across these ward specialties, MRSA transmission risk varied by 13% and reductions in the prevalence and nosocomial incidence rate of MRSA due to infection control policies varied by up to 45%. Different levels of infection control were required to reduce and control nosocomial MRSA infections for each ward specialty. Infection control policies and policy targets should be specific for the ward and context of the hospital. The model we developed is generic and can be calibrated to represent different ward settings and pathogens transmitted between Patients indirectly through health care workers. This can aid the timely and cost effective design of synergistic and context specific infection control policies.