Molecular epidemiology of methicillin-resistant Staphylococcus aureus in nursing homes: a cross-sectional study

Infection control policies and procedures for meticillin-resistant Staphylococcus aureus in care homes for older people in Northern Ireland: a questionnaire study

ackground: Limited information is available regarding the role of infection control in the prevention of infection in nursing and residential care homes.

Objectives: To determine what infection control policies and procedures are in place in care homes for older people in Northern Ireland.

Methods: Anonymous postal questionnaire survey of all 410 nursing and residential homes in Northern Ireland that provide care to residents over the age of 65.

Results: A total of 318 (78%) questionnaires were returned. Visits from infection control nurses from health boards or community trusts were infrequent, with only 23% of homes receiving such a visit. Nearly all homes (99.7%) had a policy on infection control, with 72.4% and 84.3% of homes having a policy on the admission and care of residents with meticillin-resistant Staphylococcus aureus (MRSA) respectively. Of those respondents that had a policy on admission of persons with MRSA, only a small percentage (9.2%) would not admit residents with MRSA. Only 11% of respondents believed that MRSA was a problem in their particular home, but at least 30% agreed that there was a problem with MRSA in care homes. A desire was expressed for more information and support, with 75% of respondents agreeing that more information should be provided to homes on MRSA.

Conclusions: There is a clear need for additional infection control advice to be available to care homes and for the development of uniform policies and an infection control audit tool. The audit tool could then be used to ensure that the appropriate policies and standards are in place within care homes and that these standards are met on an ongoing basis.

Performance of different culture methods and of a commercial molecular assay for the detection of carbapenemase-producing Enterobacteriaceae in nursing homes and rehabilitation centers

Over the last several years, carbapenemase-producing Enterobacteriaceae (CPE) have been increasingly detected not only among patients in acute care hospitals, but also in long-term care facilities. In this point prevalence survey, residents from three nursing homes and patients in one rehabilitation center were screened for asymptomatic intestinal carriage of CPE by rectal swabs. The first objective was to evaluate the hypothesis of the establishment of a CPE reservoir in a geriatric/chronic care population. Secondly, we evaluated the comparative performances of different culture methods (chromID(®) CARBA, chromID(®) OXA-48, MacConkey with temocillin/meropenem, ertapenem enrichment broth) and a commercial molecular assay (Check-Direct CPE). From the 257 included residents, only one had evidence for CPE carriage. From the rectal swabs of this resident, an OXA-48-producing Klebsiella pneumoniae could be isolated and was confirmed by a molecular assay both on the strain and on the rectal swab. The specificity of the different culture methods and Check-Direct CPE was at least 97 %. Neither enrichment broth nor prolonged incubation up to 48 h increased the yield of CPE. This point prevalence survey shows a low CPE prevalence of 0.39 %. Larger scaled studies are needed in order to confirm the role of chronic care settings as secondary CPE reservoirs and to adjust the infection control and prevention recommendations.

Universal Screening and Decolonization for Control of MRSA in Nursing Homes: A Cluster Randomized Controlled Study

OBJECTIVE

The risk of carrying methicillin-resistant Staphylococcus aureus (MRSA) is higher among nursing home (NH) residents than in the general population. However, control strategies are not clearly defined in this setting. In this study, we compared the impact of standard precautions either alone (control) or combined with screening of residents and decolonization of carriers (intervention) to control MRSA in NHs.

DESIGN

Cluster randomized controlled trial

SETTING

NHs of the state of Vaud, Switzerland

PARTICIPANTS

Of 157 total NHs in Vaud, 104 (67%) participated in the study.

INTERVENTION

Standard precautions were enforced in all participating NHs, and residents underwent MRSA screening at baseline and 12 months thereafter. All carriers identified in intervention NHs, either at study entry or among newly admitted residents, underwent topical decolonization combined with environmental disinfection, except in cases of MRSA infection, MRSA bacteriuria, or deep skin ulcers.

RESULTS

NHs were randomly allocated to a control group (51 NHs, 2,412 residents) or an intervention group (53 NHs, 2,338 residents). Characteristics of NHs and residents were similar in both groups. The mean screening rates were 86% (range, 27%–100%) in control NHs and 87% (20%–100%) in intervention NHs. Prevalence of MRSA carriage averaged 8.9% in both control NHs (range, 0%–43%) and intervention NHs (range, 0%–38%) at baseline, and this rate significantly declined to 6.6% in control NHs and to 5.8% in intervention NHs after 12 months. However, the decline did not differ between groups (P=.66).

CONCLUSION

Universal screening followed by decolonization of carriers did not significantly reduce the prevalence of the MRSA carriage rate at 1 year compared with standard precautions.

Infect Control Hosp Epidemiol 2015;00(0): 1–8

Prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus strains isolated in a multicenter study of nursing home residents in Croatia

BACKGROUND

Residents of nursing homes (NHs) are often hospitalized and could present a potential reservoir for methicillin-resistant Staphylococcus aureus (MRSA). The aim of the study was to determine the prevalence for MRSA carriage in residents and staff in Croatian NHs and to characterize MRSA strains using genotyping techniques.

METHODS

A cross-sectional study was performed among 877 residents and staff of 7 NHs representing 3 major Croatian regions. Nasal swabs from residents and staff and other samples from residents with invasive devices were obtained. Identified isolates were submitted to susceptibility testing and genotyping with SCCmec typing, S aureus protein A (spa) locus typing, and pulsed-field gel electrophoresis (PFGE).

RESULTS

The overall prevalence of MRSA colonization was 7.1% (95 confidence interval, 5.4%-8.8%), ranging from 0% to 28.8%. Four MRSA isolates were found in NH staff. All MRSA isolates were negative for Panton-Valentine leukocidin-encoding genes. SCCmec type II was found in 32 MRSA strains; SCCmec IV, in 27 strains; SCCmec I, in 3 strains. The predominant spa type was t008, found in 49 strains; PFGE analysis revealed 2 major clonal groups.

CONCLUSIONS

MRSA strains were found to be colonizing residents and staff of 7 NHs in Croatia. Our study demonstrates the spread of 2 clones within and among Croatian NHs. The data presented here provide an important baseline for future surveillance of MRSA in NH.

Infection in long term care facility in the kingdom of Bahrain

Infections in long term care facilities (LTCF) are common and are considered a major cause of mortality and morbidity. Endemic infections and outbreaks are observed in LTCF. Of particular concern is the growth of multi-drug resistant organisms. A study was conducted in the Kingdom of Bahrain concerning infections among the residents in a LTCF. The aim was to define the rate, type and outcomes of institutional infections. The different treatment modalities and antimicrobials used were evaluated. Our facility cares for the elderly and a heterogeneous group of patients from different populations (e.g., mentally retarded, bedbound due to various disabilities and other forms of consciousness impairment such as post stroke disability, cerebral palsy and anoxic brain damage). The initial span of six months was changed to seven months to increase the sample size and improve the data analysis. This was a prospective study conducted in Muharaq Geriatric Hospital in the Kingdom of Bahrain. The study was conducted over seven months from January 2013 to July 2013 on 104 patients. During that period, patients with new positive cultures from different sites were included. The clinical features, microbiological features and outcomes of the bacteremic episodes were included. The information was collected by a questionnaire created by the research team. From a total of 104 patients staying in the LTFC, 19 had positive cultures from different sites at different times. The study showed that infections are common, especially urinary tract infections.

Infection control strategies for preventing the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in nursing homes for older people

BACKGROUND

Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin-resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonisation and infection. It is recognised that infection prevention and control strategies are important in preventing and controlling MRSA transmission.

OBJECTIVES

To determine the effects of infection prevention and control strategies for preventing the transmission of MRSA in nursing homes for older people.

SEARCH METHODS

In August 2013, for this third update, we searched the Cochrane Wounds Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), Database of Abstracts of Reviews of Effects (DARE, The Cochrane Library), Ovid MEDLINE, OVID MEDLINE (In-process and Other Non-Indexed Citations), Ovid EMBASE, EBSCO CINAHL, Web of Science and the Health Technology Assessment (HTA) website. Research in progress was sought through Current Clinical Trials, Gateway to Reseach, and HSRProj (Health Services Research Projects in Progress).

SELECTION CRITERIA

All randomised and controlled clinical trials, controlled before and after studies and interrupted time series studies of infection prevention and control interventions in nursing homes for older people were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the results of the searches. Another review author appraised identified papers and undertook data extraction which was checked by a second review author.

MAIN RESULTS

For this third update only one study was identified, therefore it was not possible to undertake a meta-analysis. A cluster randomised controlled trial in 32 nursing homes evaluated the effect of an infection control education and training programme on MRSA prevalence. The primary outcome was MRSA prevalence in residents and staff, and a change in infection control audit scores which measured adherence to infection control standards. At the end of the 12 month study, there was no change in MRSA prevalence between intervention and control sites, while mean infection control audit scores were significantly higher in the intervention homes compared with control homes.

AUTHORS' CONCLUSIONS

There is a lack of research evaluating the effects on MRSA transmission of infection prevention and control strategies in nursing homes. Rigorous studies should be conducted in nursing homes, involving residents and staff to test interventions that have been specifically designed for this unique environment.

Antibiotic use and resistance in long term care facilities

INTRODUCTION

The common occurrence of infectious diseases in nursing homes and residential care facilities may result in substantial antibiotic use, and consequently antibiotic resistance. Focusing on these settings, this article aims to provide a comprehensive overview of the literature available on antibiotic use, antibiotic resistance, and strategies to reduce antibiotic resistance.

METHODS

Relevant literature was identified by conducting a systematic search in the MEDLINE and EMBASE databases. Additional articles were identified by reviewing the reference lists of included articles, by searching Google Scholar, and by searching Web sites of relevant organizations.

RESULTS

A total of 156 articles were included in the review. Antibiotic use in long term care facilities is common; reported annual prevalence rates range from 47% to 79%. Part of the prescribed antibiotics is potentially inappropriate. The occurrence of antibiotic resistance is substantial in the long term care setting. Risk factors for the acquisition of resistant pathogens include prior antibiotic use, the presence of invasive devices, such as urinary catheters and feeding tubes, lower functional status, and a variety of other resident- and facility-related factors. Infection with antibiotic-resistant pathogens is associated with increased morbidity, mortality, and health care costs. Two general strategies to reduce antibiotic resistance in long term care facilities are the implementation of infection control measures and antibiotic stewardship.

CONCLUSION

The findings of this review call for the conduction of research and the development of policies directed at reducing antibiotic resistance and its subsequent burden for long term care facilities and their residents.

Infection control strategies for preventing the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in nursing homes for older people

BACKGROUND

Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin-resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonisation and infection. It is recognised that infection prevention and control strategies are important in preventing and controlling MRSA transmission.

OBJECTIVES

To determine the effects of infection prevention and control strategies for preventing the transmission of MRSA in nursing homes for older people.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2011, Issue 2), the Cochrane Wounds Group Specialised Register (searched May 27th, 2011). We also searched Ovid MEDLINE (from 1950 to April Week 2 2011), OVID MEDLINE (In-process and Other Non-Indexed Citations, April 26th 2011) Ovid EMBASE (1980 to 2011 Week 16), EBSCO CINAHL (1982 to April 21st 2011), DARE (1992 to 2011, week 16), Web of Science (1981 to May 2011), and the Health Technology Assessment (HTA) website (1988 to May 2011). Research in progress was sought through Current Clinical Trials (www.controlled-trials.com), Medical Research Council Research portfolio, and HSRPRoj (current USA projects).

SELECTION CRITERIA

All randomised and controlled clinical trials, controlled before and after studies and interrupted time series studies of infection prevention and control interventions in nursing homes for older people were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the results of the searches. Another review author appraised identified papers and undertook data extraction which was checked by a second review author.

MAIN RESULTS

For this second update only one study was identified, therefore it was not possible to undertake a meta-analysis. A cluster randomised controlled trial in 32 nursing homes evaluated the effect of an infection control education and training programme on MRSA prevalence. The primary outcome was MRSA prevalence in residents and staff, and a change in infection control audit scores which measured adherence to infection control standards. At the end of the 12 month study, there was no change in MRSA prevalence between intervention and control sites, while mean infection control audit scores were significantly higher in the intervention homes compared with control homes.

AUTHORS' CONCLUSIONS

There is a lack of research evaluating the effects on MRSA transmission of infection prevention and control strategies in nursing homes. Rigorous studies should be conducted in nursing homes, to test interventions that have been specifically designed for this unique environment.

Colonization with Staphylococcus aureus in Swedish nursing homes: a cross-sectional study

BACKGROUND

Screening for bacterial colonization among risk populations could provide better estimates of the volume of the bacteria-related disease reservoir and the level of antimicrobial resistance, than do conventional laboratory reports.

METHODS

Two hundred and one participants at 10 Swedish nursing homes were screened for colonization with Staphylococcus aureus between January and October 2009. Of the 201 participants, 61 (30%) were male. The median age was 86 y. All participants were systematically sampled from the nasal mucosa, the pharyngeal mucosa, the groin, and active skin lesions, if any.

RESULTS

Ninety-nine of 199 participants (50%) were colonized with S. aureus. The colonization rate was 34% for the nose, 35% for throat, 10% for groin, and 54% for active skin lesions. An antibiotic-resistant S. aureus isolate was identified in 8.5% of all participants regardless of colonization status. A total of 24 resistant isolates were detected, and 21 of these were resistant to fluoroquinolones. There was no case of colonization with methicillin-resistant S. aureus (MRSA).

CONCLUSIONS

The presence of resistant isolates was generally low, and the greater part of the resistance was fluoroquinolone-related. To achieve reasonable precision, screening programmes of this kind must include samples from both the nose and throat, and, although low, the prevalence of antimicrobial resistance in Swedish nursing homes still calls for reflection on how to use the fluoroquinolones wisely.

MRSA prevalence in European healthcare settings: a review

BACKGROUND

During the past two decades, methicillin-resistant Staphylococcus aureus (MRSA) has become increasingly common as a source of nosocomial infections. Most studies of MRSA surveillance were performed during outbreaks, so that results are not applicable to settings in which MRSA is endemic. This paper gives an overview of MRSA prevalence in hospitals and other healthcare institutions in non-outbreak situations in Western Europe.

METHODS

A keyword search was conducted in the Medline database (2000 through June 2010). Titles and abstracts were screened to identify studies on MRSA prevalence in patients in non-outbreak situations in European healthcare facilities. Each study was assessed using seven quality criteria (outcome definition, time unit, target population, participants, observer bias, screening procedure, swabbing sites) and categorized as 'good', 'fair', or 'poor'.

RESULTS

31 observational studies were included in the review. Four of the studies were of good quality. Surveillance screening of MRSA was performed in long-term care (11 studies) and acute care (20 studies). Prevalence rates varied over a wide range, from less than 1% to greater than 20%. Prevalence in the acute care and long-term care settings was comparable. The prevalence of MRSA was expressed in various ways - the percentage of MRSA among patients (range between 1% and 24%), the percentage of MRSA among S. aureus isolates (range between 5% and 54%), and as the prevalence density (range between 0.4 and 4 MRSA cases per 1,000 patient days). The screening policy differed with respect to time points (on admission or during hospital stay), selection criteria (all admissions or patients at high risk for MRSA) and anatomical sampling sites.

CONCLUSIONS

This review underlines the methodological differences between studies of MRSA surveillance. For comparisons between different healthcare settings, surveillance methods and outcome calculations should be standardized.

Clinical profiles of patients colonized or infected with extended-spectrum beta-lactamase producing Enterobacteriaceae isolates: a 20 month retrospective study at a Belgian University Hospital

Background

Description of the clinical pictures of patients colonized or infected by ESBL-producing Enterobacteriaceae isolates and admitted to hospital are rather scarce in Europe. However, a better delineation of the clinical patterns associated with the carriage of ESBL-producing isolates may allow healthcare providers to identify more rapidly at risk patients. This matter is of particular concern because of the growing proportion of ESBL-producing Enterobacteriaceae species isolates worldwide.

Methods

We undertook a descriptive analysis of 114 consecutive patients in whom ESBL-producing Enterobacteriaceae isolates were collected from clinical specimens over a 20-month period. Clinical data were obtained through retrospective analysis of medical record charts. Microbiological cultures were carried out by standard laboratory methods.

Results

The proportion of ESBL-producing Enterobacteriaceae strains after exclusion of duplicate isolates was 4.5% and the incidence rate was 4.3 cases/1000 patients admitted. Healthcare-associated acquisition was important (n = 104) while community-acquisition was less frequently found (n = 10). Among the former group, two-thirds of the patients were aged over 65 years and 24% of these were living in nursing homes. Sixty-eight (65%) of the patients with healthcare-associated ESBL, were considered clinically infected. In this group, the number and severity of co-morbidities was high, particularly including diabetes mellitus and chronic renal insufficiency. Other known risk factors for ESBL colonization or infection such as prior antibiotic exposure, urinary catheter or previous hospitalisation were also often found. The four main diagnostic categories were: urinary tract infections, lower respiratory tract infections, septicaemia and intra-abdominal infections. For hospitalized patients, the median hospital length of stay was 23 days and the average mortality rate during hospitalization was 13% (Confidence Interval 95%: 7-19). Escherichia coli, by far, accounted as the most common ESBL-producing Enterobacteriaceae species (77/114; [68%]) while CTX-M-1 group was by far the most prevalent ESBL enzyme (n = 56).

Conclusion

In this retrospective study, the clinical profiles of patients carrying healthcare-associated ESBL-producing Enterobacteriacae is characterized by a high prevalence rate of several major co-morbidities and potential known risk factors. Both, the length of hospital stay and overall hospital mortality rates were particularly high. A prospective case-control matched study should be designed and performed in order to control for possible inclusion bias.

Epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) among residents of nursing homes in Belgium

OBJECTIVES

A national survey was conducted to determine the prevalence, risk factors and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) carriage among nursing home (NH) residents in Belgium.

METHODS

A random stratified, cross-sectional prevalence survey was conducted in NH residents who were screened for MRSA carriage by multisite enriched culture. Characteristics of NHs and residents were collected by a questionnaire survey and analysed by two-stage logistic regression modelling. MRSA isolates were genotyped by PFGE, staphylococcal cassette chromosome mec (SCCmec) typing, multilocus sequence typing (MLST) and resistance genes.

RESULTS

Of 2953 residents screened in 60 NHs, 587 (19.9%) were MRSA carriers. Risk factors included hospital contact, antibiotic exposure, impaired mobility and skin lesions at the resident level, and lack of MRSA surveillance, lack of antibiotic therapeutic formulary and the combination of less-developed infection control activities and a high ratio of physicians to residents at the institution level. MRSA isolates showed eight major types, three of which were predominant: B2-ST45-SCCmec IV (49%; where ST stands for sequence type); A21-ST8-SCCmec IV (13%); and A20-ST8-SCCmec IV (10%). Each was recovered in 55, 21 and 25 NHs, respectively. The geographical distribution of NH genotypes paralleled that of acute-care hospitals.

CONCLUSIONS

A high prevalence of MRSA carriage in NH residents was associated with hospital care, co-morbidities and less-developed coordination of institutional care. The predominant MRSA strains from NH residents and hospitalized patients of the same area were identical. Strengthening and coordination of MRSA surveillance and control activities are warranted within and between NHs and hospitals.

Staphylococcus aureus nasal colonization and colonization or infection at other body sites in patients on a burn trauma unit

OBJECTIVE

To determine whether Staphylococcus aureus isolates from the nares of patients on a burn trauma unit were related to isolates colonizing or infecting other body sites.

DESIGN

Active surveillance for S. aureus, a case-control study, and pulsed-field gel electrophoresis of S. aureus isolates.

SETTING

A burn trauma unit of a Midwestern university teaching hospital.

PATIENTS

Patients admitted from February 1, 2002, through March 30, 2007, who had S. aureus isolated either from a nasal culture and from another body site (case patients) or from a nasal culture alone (control subjects).

RESULTS

Nineteen patients met the case patient definition and had paired isolates from the nares and an additional site available for typing. Of the 19 case patients, 8 had infections, 7 of which were caused by methicillin-resistant S. aureus (5 USA100 strain and 2 USA300 strain). A total length of stay of more than 3 weeks (odds ratio [OR], 8.75 [95% confidence interval {CI}, 2.2-34.6]; P = .002), residence in a long-term care facility (OR, 9.4 [95% CI, 2.1-42.5]; P = .004), and diabetes (OR, 3.2 [95% CI, 1.0-10.0]; P = .05) were associated with the isolation of S. aureus from the nares and other sites. Seventeen case patients (89.5%) had closely related isolates obtained from culture of samples from the nares and from other sites.

CONCLUSIONS

Prolonged length of stay, diabetes, or residing in a long-term care facility increased the risk of having S. aureus at sites other than the nares. S. aureus isolates from other body sites usually were closely related to nasal isolates. Most case patients had colonized or infected wounds that could be a source of S. aureus for other patients.

Methicillin-resistant Staphylococcus aureus carriage in a long-term care facility: hypothesis about selection and transmission

BACKGROUND

many studies have identified long-term care facilities (LTCFs) as reservoirs of patients carrying methicillin-resistant Staphylococcus aureus (MRSA). However, few data about the mechanisms of MRSA diffusion in these settings are available.

OBJECTIVES

the purpose of our study was to suggest hypothesis on the possible ways of MRSA transmission to residents in or outside a LTCF.

METHODS

data concerning patients on the day of the survey and within the preceding year were collected. Multivariate analysis was performed by logistic regression to identify characteristics associated with MRSA carriage. MRSA strains were analysed by pulsed-field gel electrophoresis (PFGE) and the relatedness between DNA patterns was studied with Gel Compar software.

RESULTS

the prevalence of MRSA carriage was 37.6%. Treatment with fluoroquinolones or third-generation cephalosporins [odds ratio (OR) = 12.07; 95% confidence interval (CI) = 5.90-24.7], treatment with other antimicrobial agents (OR = 4.40; 95% CI = 2.43-7.97), at least one medical imaging session (OR = 5.08; 95% CI = 2.66-9.69) within the 12 preceding months, and the presence of a subcutaneous catheter on the day of the survey (OR = 3.09; 95% CI = 1.87-5.10) were independently associated with MRSA carriage. Twenty-eight of the 38 strains tested were clustered in two major groups. In each of these groups, strains had at least a 90% relatedness. These strains were isolated in patients hospitalised in different areas of the LTCF.

CONCLUSION

we identified that both molecular and epidemiological arguments support the hypothesis of the possibility of MRSA cross-transmission inside the LTCF. Further studies are needed to confirm and explain the association identified between MRSA carriage and medical imaging.

Infection control strategies for preventing the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in nursing homes for older people

BACKGROUND

Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin-resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonisation and infection. It is recognised that infection control strategies are important in preventing and controlling MRSA transmission.

OBJECTIVES

The objective of this review was to determine the effects of infection control strategies for preventing the transmission of MRSA in nursing homes for older people.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2007, Issue 1), the Cochrane Wounds Group Specialised Register (searched April 2007); the Infectious Diseases Group and EPOC also searched their Specialised Registers for this review (both May 2006). We also searched MEDLINE (from 1966 to March Week 3 2007), EMBASE (1980 to 2007 Week 13), CINAHL (1982 to March Week 3 2007), British Nursing Index (1985 to March 2007), DARE (1992 to March 2007), Web of Science (1981 to March 2007), and the Health Technology Assessment (HTA) database (1988 to March 2007). Research in progress was identified through the National Research Register, Current Clinical Trials (www.controlled-trials.com), Medical Research Council Register, Current Research in Britain (CRIB), and HSRPRoj (current USA projects). SIGLE was also searched in order to identify atypical material which was not accessible through more conventional sources.

SELECTION CRITERIA

All randomised and controlled clinical trials, controlled before and after studies and interrupted time series studies of infection control interventions in nursing homes for older people were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed the results of the searches.

MAIN RESULTS

Since no studies met the selection criteria, neither a meta-analysis nor a narrative description of studies was possible.

AUTHORS' CONCLUSIONS

The lack of studies in this field is surprising. Nursing homes for older people provide an environment likely to promote the acquisition and spread of infection, with observational studies repeatedly reporting that being a resident of a nursing home increases the risk of MRSA colonisation. Much of the evidence for recently-issued United Kingdom guidelines for the control and prevention of MRSA in health care facilities was generated in the acute care setting. It may not be possible to transfer such strategies directly to the nursing home environment, which serves as both a healthcare setting and a resident's home. Rigorous studies should be conducted in nursing homes, to test interventions that have been specifically designed for this unique environment.

Infections in residents of nursing homes

Infectious diseases are a very common occurrence in nursing homes. While the reasons for preventing infections are the same in nursing homes and in acute hospitals, several considerations relevant to prevention of infection differ in nursing homes. Infection control measures should be based upon the particularities of the specific setting of a nursing home and its residents.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolates from regional hospitals in Trinidad and Tobago

OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA), first reported in a British hospital in the early 1960s, has now reached global proportions. Geographic spread of one or several MRSA clones in a city, country, and even among countries and continents has been identified by molecular techniques. We sought to determine whether clonal spread of MRSA has occurred in Trinidad and Tobago from all MRSA isolates collected between 2000 and 2001.

METHODS

Clinical isolates of MRSA from three major hospitals in Trinidad and Tobago were identified by standard laboratory methods and analyzed using multiplex polymerase chain reaction (PCR) and pulsed-field gel electrophoresis (PFGE) after SmaI digestion.

RESULTS

There was a 12.8% prevalence of MRSA in three major regional hospitals in Trinidad and Tobago. All 60 randomly selected MRSA strains from these hospitals produced similar PFGE banding patterns, suggesting a genetic relatedness among strains and that they belonged to a single clonal family. All isolates were negative for the Panton-Valentine leukocidin gene (pvl). These strains shared a PFGE banding pattern approximately (96%) the same as a Canadian strain called CMRSA-6 in the Canadian National Microbiology Laboratory database.

CONCLUSIONS

We conclude that only one major PFGE genotype of MRSA clone is circulating among the three major regional hospitals in Trinidad and Tobago suggesting one of three possible scenarios of microevolution: (1) all were from the dissemination of a single epidemic MRSA clone prevailing in these hospitals in Trinidad and Tobago; or (2) MRSA in Trinidad and Tobago is evolving more slowly than in other countries; or (3) that if other MRSA clones have been present in Trinidad and Tobago, they have not persisted.

Staphylococcus aureus colonization among nursing home residents in a large Finnish nursing home

We studied colonization with methicillin-resistant and -sensitive Staphylococcus aureus (MRSA, MSSA) in the second largest nursing home in Finland, in which the residents volunteered had their nostrils, throats, perineums, skin lesions, and catheter exit sites swabbed, and catheter urines cultured. The specimens were cultured onto non-selective and selective agar, with or without enrichment in salt-containing trypticase soy broth (TSB). S. aureus was identified by routine methods, methicillin resistance was detected by oxacillin and cefoxitin disk diffusion and MIC E-tests, and GenoType MRSA -test was used for mecA gene confirmation. A total of 663 cultures were obtained from 213 residents. Of those, 165 specimens (25%) from 94 residents (44%) were positive for S. aureus, and 3 specimens (0.4%) from 2 (0.9%) residents were positive for MRSA. Of the 165 S. aureus isolates, 31 (19%) from 25 (27%) residents were found only from sites other than nostrils (30 MSSA and 1 MRSA). TSB enrichment detected additional 33 (5%) S. aureus isolates (32 MSSA and 1 MRSA), resulting in 8 (5%) additional residents. None of the MRSA strains would have been found if only nostrils and throat had been screened, and no enrichment broth had been used.

Epidemiology and genetic diversity of methicillin-resistant Staphylococcus aureus strains in residential care homes for elderly persons in Hong Kong

OBJECTIVE

To determine the prevalence and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) strains among residents in residential care homes for the elderly in Hong Kong.

DESIGN

Cross-sectional and descriptive study.

PARTICIPANTS

A total of 949 residents in 13 residential care homes for elderly persons in Hong Kong in January 2005.

METHODS

MRSA colonization was assessed by culture of swab specimens from anterior nares and active skin lesions. Characteristics of residents were obtained by a standard questionnaire. All MRSA isolates were analyzed by polymerase chain reaction for their staphylococcal cassette chromosome (SCC) mec content and were typed by pulsed-field gel electrophoresis (PFGE) and multilocus sequencing.

RESULTS

MRSA colonization was detected in 27 residents (2.8%). No MRSA was found in 2 facilities. The rate of MRSA carriage in the other 11 facilities ranged from 1.9% to 4.2%. In univariate analysis, functional immobility (odds ratio [OR], 1.4), history of hospital admission (OR, 2.3), and the use of nebulized medication (OR, 5.4) were significantly associated with MRSA colonization. The isolates had 11 unique antibiograms, with 14 isolates susceptible to all but 1 or 2 of the non- beta -lactam antimicrobial agents tested. The isolates exhibited SCCmec types I (1 isolate), II (2 isolates), III (1 isolate), IV/IVA (10 isolates), and V (13 isolates). No isolates had the Panton-Valentine leukocidin genes. PFGE analysis clustered all except 1 isolate into 7 PFGE types, designated HKU10 to HKU70. Between 1 and 4 unique PFGE types were found in the individual residential care facilities.

CONCLUSION

This study documented the emergence of SCCmec types IV and V among genetically diverse MRSA strains in residential care homes for elderly persons in Hong Kong.

Molecular epidemiology of an outbreak caused by methicillin-resistant Staphylococcus aureus in a health care ward and associated nursing home

Our point-prevalence survey followed an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in a long-term care facility and identified five MRSA strains, of which two possessed an outbreak genotype not encountered previously and three had another profile. All of them possessed SCCmec type V. Six methicillin-sensitive S. aureus strains were genotypically related to the epidemic strains.

Outbreak of methicillin-resistant Staphylococcus aureus in two nursing homes in Central Norway

Until recently, infections with methicillin-resistant Staphylococcus aureus (MRSA) have mainly been associated with hospital outbreaks in Norway. However, increasingly cases are contracted outside hospitals. This paper reports the first two outbreaks of MRSA in two nursing homes in central Norway, affecting 23 residents and five staff members. Pulsed-field gel electrophoresis analysis showed that all strains from nursing home A were identical and that the strains from nursing home B were genotypically similar with one or two band differences. Multi-locus sequence typing (MLST) showed that the strains from the two nursing homes belong to clonal complex 45, with each strain being a single-locus variant of sequence type 45 (ST 45), a well-known European epidemic strain. No evident source of the two outbreaks was found, and there was no obvious connection between the two outbreaks. The latter is also supported by the minor differences observed by MLST, suggesting a connection at some time in the past. The outbreaks led to a heavier workload and economic strain on both nursing homes. The outbreak in nursing home A was brought to an end, whereas two residents remained colonized in nursing home B despite several eradication attempts. These outbreaks show the potential for MRSA spread in a nursing home. If the prevalence of MRSA in Norway continues to increase, nursing home staff and residents may have to be included in the groups to be screened for MRSA upon hospital admission.

Clustering of multiple endemic strains of methicillin-resistant Staphylococcus aureus in a nursing home: an 8-year study

PFGE was performed on residents' first clinical MRSA isolate (n=94) during 8 years. Sixty-one percent of the isolates were clustered in time (P < .05) and space (P < .05) (i.e., 2 separate statistically significant tests). Isolates from individual units were genetically related, with only the occasional unrelated isolate.

National surveillance of methicillin-resistant Staphylococcus aureus in Belgian hospitals indicates rapid diversification of epidemic clones

Methicillin-resistant Staphylococcus aureus (MRSA) strains (n = 455) collected in 2001 from 100 Belgian hospitals were characterized by molecular typing and by resistance gene distribution to macrolides-lincosamides-streptogramins and to aminoglycoside antibiotics. Rapid diversification of MRSA clones, compared with results of previous surveys, was evidenced by the broad geographic distribution of seven major clones belonging to the pandemic MRSA clonal complexes 5, 8, 22, 30, and 45 by multilocus sequence typing.