Determinants of methicillin-resistant Staphylococcus aureus carriage in nursing homes

Active Surveillance and Decolonization Without Isolation Is Effective in Preventing Methicillin-Resistant Staphylococcus aureus Transmission in the Psychiatry Units

Background

 Control of methicillin-resistant Staphylococcus aureus (MRSA) is difficult in select populations. We used molecular typing to study the effect of universal surveillance and decolonization of carriers, without isolation, on MRSA transmission in a specialized unit.

Methods

 Patients admitted to the unit were screened for nasal MRSA at admission and discharge. Those who acquired MRSA during their stay were identified and linked to carriers with shared time in unit. Molecular typing of isolates was performed to identify transmission.

Results

 Of 3285 admissions, 82% were tested for MRSA nasal carriage; the discharge screening compliance was 64.7%. Admission prevalence was 2.3% among patients screened, and 7 (0.42%) acquired nasal MRSA during their stay. All patients who acquired MRSA shared time in the unit with a colonized patient. There were 3.9 MRSA acquisitions per 1000 at-risk days. Isolates from 5 patients that acquired MRSA during their stay as well as their potential donors (11 donor: recipient patient pairs) were available for typing. Pulsed-field gel electrophoresis matched 1 acquisition isolate to a colonized patient isolate. There were no MRSA infections during the study period.

Conclusions

 Despite less than perfect nasal screening compliance and exemption from traditional isolation precautions, acquisition of MRSA was 0.42% in this patient population over a course of 4.75 years, including a single case of acquisition, genetically similar to a known potential donor source. Screening for MRSA colonization and decolonizing of carriers was sufficient in reducing transmission in this vulnerable population.

Antimicrobial resistance and stewardship in long-term care settings

Infections and antimicrobial resistance (AMR) in long-term care facilities (LTCFs) are a public health challenge and a future infectious disease threat. More and more data show the dimension and impact of AMR and of inappropriate use of antimicrobials in this setting. Recently, the spread of carbapenemase-producing Enterobacteriaceae has provided new insights into the dangerous role the long-term care sector may play in the AMR problem in a community. Implementation of effective infection and surveillance control programs in LTCFs is challenging, due to scarce resources (personnel, expertise, diagnostic and supportive services), and no or poor coordination of medical care. However, interventions in LTCFs have been proven to be effective: inappropriate use of antibiotics for asymptomatic bacteriuria may be reduced; hand hygiene compliance may be improved; and the transmission of multidrug-resistant organisms may be halted. This paper reviews the most recent epidemiological information on this issue, providing references to valuable intervention programs.

Transmission of methicillin-resistant Staphylococcus aureus in the long term care facilities in Hong Kong

Background

The relative contribution of long term care facilities (LTCFs) and hospitals in the transmission of methicillin-resistant Staphylococcus aureus (MRSA) is unknown.

Methods

Concurrent MRSA screening and spa type analysis was performed in LTCFs and their network hospitals to estimate the rate of MRSA acquisition among residents during their stay in LTCFs and hospitals, by colonization pressure and MRSA transmission calculations.

Results

In 40 LTCFs, 436 (21.6%) of 2020 residents were identified as ‘MRSA-positive’. The incidence of MRSA transmission per 1000-colonization-days among the residents during their stay in LTCFs and hospitals were 309 and 113 respectively, while the colonization pressure in LTCFs and hospitals were 210 and 185 per 1000-patient-days respectively. MRSA spa type t1081 was the most commonly isolated linage in both LTCF residents (76/121, 62.8%) and hospitalized patients (51/87, 58.6%), while type t4677 was significantly associated with LTCF residents (24/121, 19.8%) compared with hospitalized patients (3/87, 3.4%) (p < 0.001). This suggested continuous transmission of MRSA t4677 among LTCF residents. Also, an inverse linear relationship between MRSA prevalence in LTCFs and the average living area per LTCF resident was observed (Pearson correlation −0.443, p = 0.004), with the odds of patients acquiring MRSA reduced by a factor of 0.90 for each 10 square feet increase in living area.

Conclusions

Our data suggest that MRSA transmission was more serious in LTCFs than in hospitals. Infection control should be focused on LTCFs in order to reduce the burden of MRSA carriers in healthcare settings.

Antibiotic prescription in nursing homes for dependent elderly people: a cross-sectional study in Franche-Comté

OBJECTIVES

We had for objective to determine the rate of patients treated with antibiotics and the determinants of antibiotic stewardship in nursing homes for dependent elderly people (French acronym EHPAD), of a French region (Franche-Comté).

PATIENTS AND METHODS

A representative sample of EHPAD, in Franche-Comté, was included in a cross-sectional study made between April and June 2012. An external auditor and the EHPAD head physician collected data on the facility and on residents receiving antibiotics on the study day. An infectious diseases specialist and an infection control practitioner analyzed each prescription, a posteriori, to assess criteria of antimicrobial stewardship including re-assessment of the prescription between 48 and 72h after initiation of antibiotic treatment.

RESULTS

Sixty-one (2.76%) of the 2210 residents in 18 nursing homes were under antibiotic treatment. This rate ranged from 0% to 7.5% among nursing homes. Sixty-two percent of prescriptions complied with recommendations regarding the choice of the drug, and 41.5% could not be improved by choosing an agent with a weaker ecological impact. Globally, 17.8% of prescriptions met all stewardship criteria including re-assessment of the prescription between 48 and 72h after initiation of antibiotic treatment.

CONCLUSIONS

The study results differed. The rate of antibiotic prescription was low in Franche-Comté EHPAD compared to available European data, but antibiotic therapy could be greatly improved. This stresses the need to better train EHPAD physicians for antibiotic stewardship.

Prevalence, risk factors, and molecular epidemiology of methicillin-resistant Staphylococcus aureus nasal and axillary colonization among psychiatric patients on admission to an academic medical center

BACKGROUND

Infection control data from psychiatric units and clinics are limited.

METHODS

This time series study was designed to determine the prevalence and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) colonization and/or infection among 500 men and women on admission to psychiatric units at The Johns Hopkins Hospital. Discharge surveillance was conducted to measure incidence. Molecular characterization was performed.

RESULTS

Five hundred subjects (52% male) were enrolled. The prevalence of MRSA colonization was 5.2% (26 of 498). Seven of 29 patients (24.1%) admitted with a skin and soft tissue infection (SSTI) was MRSA-positive; 4 of these patients had no other positive site, raising the total admission prevalence to 6.0%. A history of abscess (current or within the past 6 months) on admission (odds ratio [OR], 6.06; 95% confidence interval [CI], 2.40-15.31; P < .001), HIV infection (OR, 4.03; 95% CI, 1.52-10.71; P = .005), previous isolation (OR, 5.03; 95% CI, 1.76-14.35; P = .003), and unknown history of isolation (OR, 4.10; 95% CI, 1.41-11.98; P = .01) were associated with increased odds of MRSA colonization. Seven (2.6%) new MRSA colonizations were identified at discharge. Molecular analysis identified USA300 clonal MRSA isolates.

CONCLUSIONS

The prevalence of MRSA colonization in this study population was greater than reported in the general population. Further studies are needed to identify transmission dynamics in this environment.

Prevalence, risk factors and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) colonization in residents of long-term care facilities in Luxembourg, 2010

A prevalence survey of methicillin-resistant Staphylococcus aureus (MRSA) was performed in 2010 in 19 long-term care facilities in Luxembourg. Of the 954 participating residents, 69 (7·2%) were colonized by MRSA. Previous history of MRSA [odds ratio (OR) 7·20, 95% confidence interval (CI) 3·19-16·27], quinolone therapy in the previous year (OR 2·27, 95% CI 1·17-4·41) and ≥24 h care administered per week (OR 4·29, 95% CI 1·18-15·56) were independent risk factors for MRSA colonization. More than 75% of strains were of clonal complex (CC)5, mainly spa-type t003 or sequence type (ST)225 and ST710, which is a rapidly emerging lineage prevalent in central Europe. Five residents were colonized by livestock-associated genotypes belonging to CC398. Previously dominant CC8 strains have recently been replaced by more resistant CC5 strains in Luxembourg.

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.

[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.

Evaluation of the Xpert MRSA assay for rapid detection of methicillin-resistant Staphylococcus aureus from nares swabs of geriatric hospitalized patients and failure to detect a specific SCCmec type IV variant

Rapid and reliable detection of methicillin-resistant Staphylococcus aureus (MRSA) carriers is crucial for control of MRSA nosocomial transmission. We aimed to evaluate the performance of the GeneXpert real-time PCR system using the Xpert MRSA assay on a collection of 40 representative Belgian MRSA strains and for MRSA screening of geriatric inpatients. Double nasal swabs were used: the first swab for the Xpert MRSA assay and the second for culture onto chromogenic selective medium and enrichment broth. All but 1 of the 40 collection strains were recognized as MRSA by the Xpert MRSA assay. Nares swabs were prospectively collected from 246 inpatients including 25 nasal MRSA carriers. Compared with enriched cultures, the sensitivity, the specificity, and the positive and negative predictive values of the Xpert MRSA assay were 69.2%, 97.7%, 78.3%, and 96.3% respectively. The 7 evaluable false-negative results according to the assay were due to its possible lack of sensitivity (n = 3) and to the occurrence of a Belgian MRSA clone carrying a particular staphylococcal chromosomal cassette mec (SCCmec) type IV variant (n = 4) not targeted by the current Xpert MRSA assay. Because of the evolution of SCCmec in MRSA, new primers should be designed and further studies are warranted to ensure continuous monitoring of this assay.

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.

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.

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.