Staphylococcus aureus Carrier State Among Elderly Residents of a Long–Term Care Facility

Decolonization of Staphylococcus aureus

Staphylococcus aureus infections are associated with increased morbidity, mortality, hospital stay, and health care costs. S aureus colonization has been shown to increase risk for invasive and noninvasive infections. Decolonization of S aureus has been evaluated in multiple patient settings as a possible strategy to decrease the risk of S aureus transmission and infection. In this article, we review the recent literature on S aureus decolonization in surgical patients, patients with recurrent skin and soft tissue infections, critically ill patients, hospitalized non-critically ill patients, dialysis patients, and nursing home residents to inform clinical practice.

Screening for Methicillin-resistant Staphylococcus aureus in a residence home for elderly in Germany

BACKGROUND

Since many hospitals report high MRSA colonization rates among elderly patients, and because it has been shown that S. aureus colonization increases with advancing age, there are concerns about the introduction of MRSA into nursing homes by MRSA positive patients discharged from hospital. So far, admission screening and subsequent longitudinal screening in residence homes or screening at time of hospital discharge is not established on a regular base. On the other hand, MRSA is acquired frequently during hospital stay. Therefore, the MRSA status of residents remains unclear at the time of re-admission to the residence home. This study was conducted to evaluate the rate of nasal MRSA carriage among residents and nursing staffs of 2 nursing homes for the elderly, the potential acquisition of MRSA during a hospital stay and the feasibility to perform direct screening tests in nursing homes for elderly.

METHODS

In a study period of 5 months, possibility of active PCR-based screening for MRSA has been tested within 2 residence homes for the elderly, with the obligation to avoid inconvenience to the daily working time and working schedule. Residents and staff members were included in the study and positive test results were confirmed with MRSA culture.

RESULTS

Feasibility of active on site screening in a residence home for the elderly using a rapid PCR method has been confirmed. 154 of 156 residents participated on baseline testing for all current and new admitted residents. In 9 participating residents with former unknown status, nasal carriage with MRSA was confirmed (5.8%). Among 32 documented and eligible movements between the nursing home and the hospital, MRSA could be confirmed after return to the residence home in 2 cases (6.3%). MRSA could also be detected in 1 of 14 participating nursing staff (7.1%).

CONCLUSION

Prevalence of MRSA was in a range that has been observed for nursing homes in Germany in previous studies. Residents can acquire MRSA during a hospital stay so that further spread after re-admission into the nursing home cannot be excluded. This study shows that easy to perform direct screening tests in outpatient facilities for nursing of the elderly are promising tools as part of potential new strategies for transmission and infection control in such facilities. Additional studies are needed to investigate if screening followed by interventional hygiene measures can reduce MRSA transmission and infection in such facilities.

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.

Characteristics That Promote Transmission ofStaphylococcus aureusin German Nursing Homes

Objective:

To determine factors that influence transmission ofStaphylococcus aureusin nursing homes in the Rhine-Neckar region of southern Germany.

Design:

Ecologie study.

Setting:

Forty-seven nursing homes in the region.

Participants:

Residents of the approached nursing homes who agreed to participate.

Methods:

Personal data and swabs of the nares were collected from participants. Swabs were examined for growth ofS. aureus.AllS. aureusisolates were typed using pulsed-field gel electrophoresis (PFGE). Transmission rates were calculated by dividing the number of transmissions (ie, cases in which two inhabitants shared the same PFGE type) by the number of S.aureuscarriers. Characteristics of the nursing homes were correlated with a home's transmission rate.

Results:

In each nursing home, 12% to 54% of the residents were colonized with S.aureus.The transmission rates for the 47 nursing homes ranged from 0% to 70%. A linear regression model revealed that a stay in the nursing home of longer than 6 months and accommodation in a room with 3 or more beds were positively associated with the transmission rate. Receipt of antibiotics during the 4 weeks preceding the study was negatively associated with transmission.

Conclusions:

Stays beyond 6 months and accommodation in rooms with multiple beds are important for the transmission of S.aureus.One way to reduce transmission would be to design facilities with single and double rooms. However, the social needs of the residents must be evaluated and respected.

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

spa typing alone is not sufficient to demonstrate endemic establishment of meticillin-resistant Staphylococcus aureus in a low-prevalence country

BACKGROUND

The prevalence of meticillin-resistant Staphylococcus aureus (MRSA) in Norway is low but increasing. Over the last decade, numerous nursing homes have experienced MRSA outbreaks. One genetic lineage, spa type t304, has been identified at multiple nursing homes and has caused large outbreaks lasting for several years.

AIM

To evaluate whether spa typing is sufficient for the detection of MRSA spread and endemic establishment in a low-prevalence area, using spa type t304 as the test organism.

METHODS

All spa type t304 isolates detected in 1991-2010 in the most densely populated area of Norway were included. Time and place of bacterial sampling were recorded. The isolates were analysed using multi-locus sequence typing, staphylococcal cassette chromosome mec typing, detection of lukS/F-PV and pulsed-field gel electrophoresis (PFGE).

FINDINGS

In total, 181 spa type t304 isolates were identified in three of 23 municipalities. Most (91%) of the isolates could be linked to 13 nursing homes, eight of which experienced outbreaks. PFGE analysis revealed three PFGE types, consisting of 19 PFGE patterns; 95% of the isolates were PFGE type 2. In total, PFGE types 2 and 3 accounted for 99% of all nursing home isolates, and included isolates from different nursing homes, different outbreaks and different time periods. Additional genetic analyses did not further differentiate between the spa type t304 isolates.

CONCLUSION

MRSA spa type t304 appears to have established itself as an endemic genetic lineage in the study area. spa typing does not provide sufficient resolution when investigating the spread of an endemic-like genetic lineage in a low-prevalence area, and should be supplemented by additional typing techniques.

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.

A short-term, multicomponent infection control program in nursing homes: a cluster randomized controlled trial

OBJECTIVES

To assess the impact of a hygiene-encouragement program on reducing infection rates (primary end point) by 5%.

DESIGN

A cluster randomized study was carried out over a 5-month period.

SETTINGS AND PARTICIPANTS

Fifty nursing homes (NHs) with 4345 beds in France were randomly assigned by stratified-block randomization to either a multicomponent intervention (25 NHs) or an assessment only (25 NHs).

INTERVENTION

The multicomponent intervention was targeted to caregivers and consisted of implementing a bundle of infection prevention consensual measures. Interactive educational meetings using a slideshow were organized at the intervention NHs. The NHs were also provided with color posters emphasizing hand hygiene and a kit that included hygienic products such as alcoholic-based hand sanitizers. Knowledge surveys were performed periodically and served as reminders.

MEASUREMENTS

The primary end point was the total infection rate (urinary, respiratory, and gastrointestinal infections) in those infection cases classified either as definite or probable. Analyses corresponded to the underlying design and were performed according to the intention-to-treat principle. This study was registered (#NCT01069497).

RESULTS

Forty-seven NHs (4515 residents) were included and followed. The incidence rate of the first episode of infection was 2.11 per 1000 resident-days in the interventional group and 2.15 per 1000 resident-days in the control group; however, the difference between the groups did not reach statistical significance in either the unadjusted (Hazard Ratio [HR] = 1.00 [95% confidence interval (CI) 0.89-1.13]; P = .93]) or the adjusted (HR = 0.99 [95% CI 0.87-1.12]; P = .86]) analysis.

CONCLUSION

Disentangling the impact of this type of intervention involving behavioral change in routine practice in caregivers from the prevailing environmental and contextual determinants is often complicated and confusing to interpret the results.

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.

Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in residents of Veterans Affairs long-term care facilities: role of antimicrobial exposure and MRSA acquisition

OBJECTIVE

To identify risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) acquisition in long-term care facility (LTCF) residents.

DESIGN

Multicenter, prospective cohort followed over 6 months.

SETTING

Three Veterans Affairs (VA) LTCFs.

PARTICIPANTS

All current and new residents except those with short stay (<2 weeks).

METHODS

MRSA carriage was assessed by serial nares cultures and classified into 3 groups: persistent (all cultures positive), intermittent (at least 1 but not all cultures positive), and noncarrier (no cultures positive). MRSA acquisition was defined by an initial negative culture followed by more than 2 positive cultures with no subsequent negative cultures. Epidemiologic data were collected to identify risk factors, and MRSA isolates were typed by pulsed-field gel electrophoresis (PFGE).

RESULTS

Among 412 residents at 3 LTCFs, overall MRSA prevalence was 58%, with similar distributions of carriage at all 3 facilities: 20% persistent, 39% intermittent, 41% noncarriers. Of 254 residents with an initial negative swab, 25 (10%) acquired MRSA over the 6 months; rates were similar at all 3 LTCFs, with no clusters evident. Multivariable analysis demonstrated that receipt of systemic antimicrobials during the study was the only significant risk factor for MRSA acquisition (odds ratio, 7.8 [95% confidence interval, 2.1-28.6]; P = .002). MRSA strains from acquisitions were related by PFGE to those from a roommate in 9/25 (36%) cases; 6 of these 9 roommate sources were persistent carriers.

CONCLUSIONS

MRSA colonization prevalence was high at 3 separate VA LTCFs. MRSA acquisition was strongly associated with antimicrobial exposure. Roommate sources were often persistent carriers, but transmission from roommates accounted for only approximately one-third of MRSA acquisitions.

High prevalence of methicillin-resistant Staphylococcus aureus among residents and staff of long-term care facilities, involving joint and parallel evolution

Six long-term care facilities were surveyed for methicillin-resistant Staphylcoccus aureus (MRSA). Among 191 residents, 14% were carriers; 1 strain predominated (ST5-SCCmec II). Among 132 staff members, 11% were positive; 2 strains predominated (ST5-SCCmec II, ST8-SCCmec IV). All strains were Panton-Valentine leukocidin-negative. The epidemiology of MRSA among residents and staff involved joint and parallel evolution.

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.

[Generalized or targeted screening for carriage of MRSA on admission to a geriatric hospital]

OBJECTIVES

To confirm previously risk factors for MRSA carriage in our geriatric patient population and to suggest a simplified risk score with a combination of these risk factors, to test the Novel Score and to check if a targeted MRSA screening on admission is possible to reduce the screening workload and cost.

DESIGN

a prospective in-hospital cohort study.

SUBJECTS

1125 geriatric patients were screened for MRSA carriage within 24 hours after admission to a geriatric hospital.

METHODS

Risk factors, based on recently published risk scores (Preop Score and Ger Score) were determined.

RESULTS

Prevalence of MRSA carriage was 8.44%. In a multivariate analysis age > or = 87 year (OR 1,864; 95% CI 1,145-3,035), presence of a long-term catheter (OR 2,813; 95% CI 1,562-5,065) and prior carriage of MRSA (OR 13,25; 95% CI 8,007-21,926) remained predictors of MRSA carriage. The Novel Score (cut-off > or = 1) had a sensitivity of 73.7%, a specificity of 64%, PPV 15.9%, NPV 96.3% and AUC of 0.688. The Novel Score allows reduction of the screening load by 57.2%, but misses 26% of positive cases. 16% of MRSA carriers develop an infection that needs to be treated with vancomycin.

CONCLUSION

With targeted MRSA screening on admission based on a risk score a substantial reduction of workload and costs is possible compared to generalized screening for MRSA. Because MRSA carriers can be missed with a risk score, the epidemiological context and the risk of transmission and infection with MRSA must be taken in to account when introducing a targeted screening.

Cluster randomised controlled trial of an infection control education and training intervention programme focusing on meticillin-resistant Staphylococcus aureus in nursing homes for older people

The aim of this cluster randomised controlled trial was to test the impact of an infection control education and training programme on meticillin-resistant Staphylococcus aureus (MRSA) prevalence in nursing homes. Nursing homes were randomised to intervention (infection control education and training programme; N=16) or control (usual practice continued; N=16). Staff in intervention homes were educated and trained (0, 3 and 6 months) in the principles and implementation of good infection control practice with infection control audits conducted in all sites (0, 3, 6 and 12 months) to assess compliance with good practice. Audit scores were fed back to nursing home managers in intervention homes, together with a written report indicating where practice could be improved. Nasal swabs were taken from all consenting residents and staff at 0, 3, 6 and 12 months. The primary outcome was MRSA prevalence in residents and staff, and the secondary outcome was a change in infection control audit scores. In all, 793 residents and 338 staff were recruited at baseline. MRSA prevalence did not change during the study in residents or staff. The relative risk of a resident being colonised with MRSA in an intervention home compared with a control home at 12 months was 0.99 (95% confidence interval: 0.69, 1.42) after adjustment for clustering. Mean infection control audit scores were significantly higher in the intervention homes (82%) compared with the control homes (64%) at 12 months (P<0.0001). Consideration should be given to other approaches which may help to reduce MRSA in this setting.

Prevalence of methicillin-resistant Staphylococcus aureus colonization in residents and staff in nursing homes in Northern Ireland

OBJECTIVES

To determine the prevalence of, and factors associated with, methicillin-resistant Staphylococcus aureus (MRSA) colonization in residents and staff in nursing homes in one geographically defined health administration area of Northern Ireland.

DESIGN

Point prevalence study.

SETTING

Nursing homes.

PARTICIPANTS

Residents and staff in nursing homes.

MEASUREMENTS

Nasal swabs were taken from all consenting residents and staff. If relevant, residents also provided urine samples, and swabs were taken from wounds and indwelling devices.

RESULTS

A total of 1,111 residents (66% of all residents) and 553 staff (86% of available staff) in 45 nursing homes participated. The combined prevalence rate of MRSA in the resident population was 23.3% (95% confidence interval (CI)=18.8-27.7%) and 7.5% in staff (95% CI=5.1-9.9%). Residents who lived in nursing homes that were part of a chain were more likely to be colonized with MRSA (odds ratio (OR)=1.91, 95% CI=1.21-3.02) than those living in independently owned facilities. Residents were also more likely to be colonized if they lived in homes in which more than 12.5% of all screened healthcare staff (care assistants and nurses) were colonized with MRSA (OR=2.46, 95% CI=1.41-4.29) or if they lived in homes in which more than 15% of care assistants were colonized with MRSA (OR=2.64, 95% CI=1.58-4.42).

CONCLUSION

The findings suggest that there is substantial colonization of MRSA in nursing home residents and staff in this one administrative health area. Implementation of infection control strategies should be given high priority in nursing homes.

Screening for methicillin-resistant Staphylococcus aureus (MRSA) carriage on admission to a geriatric hospital

Our objective is to identify risk factors for carriage of MRSA on admission to a geriatric hospital where MRSA is endemic. A prospective screening for MRSA carriage was conducted by swabbing anterior nares and anal skin for 6 weeks. One hundred and thirty-eight patients aged over 65 were enrolled after obtaining their informed consent. Swabs of anterior nares and anal skin of patients were submitted for culture for MRSA. The demographic, administrative, and clinical data for each participant were recorded, and their association with MRSA carriage was determined by stepwise regression analysis. MRSA was recovered from 11 patients (11/138 patients, 8.0%), and from anal skin in 8 of them. Without screening of anal skin, 5 out of 11 carriers had been missed. Multivariate analysis revealed that hypoalbuminemia (adjusted risk ratio, RR=6.39, 95% confidence interval, CI=1.08-37.84) and bedridden status (RR=8.26, CI=1.04-65.31) were independent risk factors. Screening of elderly patients for gastrointestinal colonization on admission had implications for early detection of the reservoir of MRSA. Systematic selective screening for MRSA carriage targeting high-risk patients with hypoalbuminemia or bedridden status would be useful for infection control of this resistant organism.

Community-Acquired Methicillin-Resistant Staphylococcus aureus (CA-MRSA) Colonization and Infection in Intravenous and Inhalational Opiate Drug Abusers

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen in hospital-acquired and community-acquired infections. We hypothesized that drug abuse is a risk factor for community-acquired MRSA (CA-MRSA) infection, and we employed a rapid multiplex PCR technique for MRSA identification. The study was conducted on MRSA isolates from 60 opiate addicts (intravenous and inhalational drug users) to detect the rate and location of MRSA colonization and infection among them in comparison to 60 non-addict patients and 15 healthy volunteer controls. The proportion of addicts with MRSA colonization (and/or infection) was significantly higher than non-addict patients with MRSA colonization. MRSA colonization was associated with infection in 58% of MRSA-colonized addicts. The MRSA nasal carriage in the addicts was significantly higher than MRSA carriage elsewhere, whether in the addicts group or in the non-addict patients group. Moreover, the nasopharyngeal carriage rate of MRSA among addicts was significantly higher than among the non-addict patients. Increasing the duration of addiction resulted in a significant increase in CA-MRSA colonization in opiate addicts. Both inhalational and intravenous drug use led to significant MRSA colonization in the addict population. In conclusion, this study demonstrated how drug abusers, a high-risk group for infections with MRSA, could be a source or a reservoir of CA-MRSA infection in the non-addict population.

Importance of bacterial burden among methicillin-resistant Staphylococcus aureus carriers in a long-term care facility

OBJECTIVE

To evaluate the prevalence and transmission of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization, as well as risk factors associated with MRSA carriage, among residents of a long-term care facility (LTCF).

DESIGN

Prospective, longitudinal cohort study.

SETTING

A 100-bed Veterans Administration LTCF.

PARTICIPANTS

All current and newly admitted residents of the LTCF during an 8-week study period.

METHODS

Nasal swab samples were obtained weekly and cultured on MRSA-selective media, and the cultures were graded for growth on a semiquantitative scale from 0 (no growth) to 6 (heavy growth). Epidemiologic data for the periods before and during the study were collected to assess risk factors for MRSA carriage.

RESULTS

Of 83 LTCF residents, 49 (59%) had 1 or more nasal swab cultures that were positive for MRSA; 34 (41%) were consistently culture-negative (designated "noncarriers"). Of the 49 culture-positive residents, 30 (36% of the total of 83 residents) had all cultures positive for MRSA (designated "persistent carriers"), and 19 (23% of the 83 residents) had at least 1 culture, but not all cultures, positive for MRSA (designated "intermittent carriers"). Multivariate analysis showed that participants with at least 1 nasal swab culture positive for MRSA were likely to have had previous hospitalization (odds ratio, 3.9) or wounds (odds ratio, 8.2). Persistent carriers and intermittent carriers did not differ in epidemiologic characteristics but did differ in mean MRSA growth score (3.7 vs 0.7; P<.001).

CONCLUSIONS

Epidemiologic characteristics differed between noncarriers and subjects with at least 1 nasal swab culture positive for MRSA. However, in this LTCF population, only the degree of bacterial colonization (as reflected by mean MRSA growth score) distinguished persistent carriers from intermittent carriers. Understanding the burden of colonization may be important when determining future surveillance and control strategies.

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.

Prevalence and risk factors of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in an Israeli long-term care facility

The purpose of this study was to ascertain the prevalence of extended-spectrum beta-lactamases (ESBLs) among Escherichia coli and Klebsiella pneumoniae strains obtained from urine samples of residents of a long-term care facility and to determine the risk factors for acquisition of ESBL-producing strains. All urine samples collected from January 2003 to October 2003 that were positive for E. coli or K. pneumoniae were tested for the presence of ESBL. Records of patients with ESBL-positive (ESBL-P) samples were analyzed for clinical and demographic data. The records of a matched control group of patients whose urine samples were positive for E. coli or K. pneumoniae but were ESBL-negative (ESBL-N) were also analyzed. The overall rate of ESBLs among the E. coli and K. pneumoniae samples was 25.6%. Of 350 urine samples that grew E. coli, 77 (22%) were positive for ESBL; 34 of 84 (40.5%) samples that grew K. pneumoniae were ESBL-P. Male sex, treatment in the subacute care unit, recent antimicrobial treatment, pressure sores, (percutaneous endoscopic gastrostomy) PEG tube, anemia, hypoalbuminemia, permanent urinary catheter, and any recent invasive procedure were all associated with ESBL-P bacteria in the univariate analysis. The multivariate analysis revealed three independent risk factors for the presence of an ESBL-producing strain: anemia, permanent urinary catheter, and previous antibiotic use. Fluoroquinolones were most strongly associated with the development of ESBL-producing bacteria. The prevalence of ESBL-producing E. coli and K. pneumoniae in the long-term care facility investigated was unexpectedly high and corroborates the notion that long-term care facilities could be important reservoirs of resistant bacteria. Identification of the risk factors for ESBLs is the first step in formulating an effective strategy to curtail the spread of ESBL resistance in long-term care facilities.

Changing epidemiology of methicillin-resistant Staphylococcus aureus in Finland

Data on methicillin-resistant Staphylococcus aureus (MRSA) cases notified to the National Infectious Disease Register (NIDR) and antibiotic resistance profiles of MRSA isolates sent to the national reference laboratory between 1997 and 2002 were analysed. In addition, the diagnostic methods used for MRSA identification in Finnish microbiology laboratories, the number of MRSA screening specimens studied, and the MRSA situation in long-term care facilities in 2001 were reviewed. MRSA cases notified to the NIDR rose from 120 in 1997 to 597 in 2002 (from 2.3 to 11.5 cases per 100,000 population). The increase was greatest in elderly people and outside Helsinki metropolitan area, in the districts where the proportion of non-multiresistant strains was most prominent. The National Committee for Clinical Laboratory Standard's guidelines for the oxacillin disk diffusion test were followed, except for the incubation temperature and time, which may have hindered detection of some MRSA strains. There was a wide geographic variation in the rates of MRSA, but this was not related to screening activity. MRSA isolates from long-term facilities accounted for more than half of the notifications to the NIDR in 2001.

In vivo efficacy and pharmacokinetics of AC98-6446, a novel cyclic glycopeptide, in experimental infection models

AC98-6446 is a novel semisynthetic derivative of a natural product related to the mannopeptimycins produced by Streptomyces hygroscopicus. Naturally occurring esterified mannopeptimycins exhibited excellent in vitro activity but only moderate in vivo efficacy against staphylococcal infection. The in vivo efficacy and pharmacokinetics of AC98-6446 were investigated in murine acute lethal, bacterial thigh and rat endocarditis infections. Pharmacokinetics were performed in mice, rats, monkeys, and dogs. Acute lethal infections were performed with several gram-positive isolates: Staphylococcus aureus (methicillin-susceptible and methicillin-resistant staphylococci), vancomycin-resistant Enterococcus faecalis, and penicillin-susceptible and -resistant Streptococcus pneumoniae. The 50% effective dose for all isolates tested ranged from 0.05 to 0.39 mg/kg of body weight after intravenous (i.v.) administration. Vancomycin was more than fivefold less efficacious against all of these same infections. Results of the thigh infection with S. aureus showed a static dose for AC98-6446 of 0.4 mg/kg by i.v. administration. Reduction of counts in the thigh of >2 log(10) CFU were achieved with doses of 1 mg/kg. i.v. administration of 3 mg/kg twice a day for 3 days resulted in a >3 log(10) reduction in bacterial counts of vancomycin-susceptible and -resistant E. faecalis in a rat endocarditis model. Pharmacokinetics of AC98-6446 showed an increase in exposure (area under the concentration-time curve) from mouse to dog species. The i.v. half-life (t(1/2)) increased threefold between rodents and the higher species dosed. Efficacy of AC98-6446 has been demonstrated in several models of infection with resistant gram-positive pathogens. This glycopeptide exhibited bactericidal activity in these models, resulting in efficacy at low doses with reduction in bacterial load.

Can better prescribing turn the tide of resistance?

In the wake of concerns about the level of antibiotic resistance, governments worldwide are pressing for reduced antibiotic use, hoping thereby to reverse resistance trends. Is success likely? The evidence is mixed, and expectations should be tempered by the growing realization that many resistant bacteria are biologically fit, making them difficult to displace. If resistance is unlikely to be reduced significantly by changing prescription practices, how can clinicians outpace increased resistance, particularly when much of 'big pharma' is abandoning antibiotic development?

The need for new antibiotics

Politicians and public health officials have joined specialist professionals in recognising antibiotic resistance as a threat to modern medicine. Their response has centred on minimising unnecessary antibiotic prescribing, aiming to reduce selection pressure for resistance. Despite a few hopeful trends (e.g., declining penicillin resistance among pneumococci in the UK), established resistance is proving hard to displace; moreover, new resistances continue to emerge and to proliferate at new sites. There consequently remains a strong need for new antibiotics, particularly those directed against multiresistant Gram-negative bacteria in hospitals. Already some nonfermenters of the genera Acinetobacter and Pseudomonas are resistant to all good antibiotics and many Enterobacteriaceae are resistant to all except carbapenems. There is also a growing need for new agents against community-acquired pathogens, including the agents of tuberculosis, gonorrhoea and urinary tract infections. Unless antibacterial development is re-energised, there is a serious risk that a growing proportion of infections, especially in hospitals, will become effectively untreatable.