Seeking vancomycin resistant Staphylococcus aureus among patients with vancomycin-resistant enterococci.

Clinical isolates of Staphylococcus aureus displaying intermediate resistance to vancomycin (VISA) have been identified. The objective of our study was to identify VISA colonization among patients known to be colonized or infected with vancomycin-resistant enterococci (VRE). Eight weekly point prevalence screening surveys for VRE and S. aureus were conducted on 5 hospital units. Of the 243 patients screened, 31 (12.8%) were colonized with VRE. In addition, 18 inpatients were already known to be VRE-positive. Fourteen (28.6%) of the 49 VRE-positive patients were co-colonized with S. aureus. All 30 S. aureus isolates from these 14 patients were methicillin-resistant (MRSA) but remained vancomycin-susceptible (minimal inhibitory concentration [MIC] range, 0.75-2 microg/mL). Population analysis profiling demonstrated no evidence of heteroresistant subpopulations that could grow on agar containing 3 microg/mL vancomycin for any of the MRSA isolates. Although 23 (77%) of 30 staphylococcal isolates had vancomycin MICs of 1.5 or 2 microg/mL, no VISA strains (MICs, 8-16 microg/mL) were recovered.     

Transmission dynamics of epidemic methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci in England and Wales

A simple epidemiological framework for the analysis of the transmission dynamics of hospital outbreaks of epidemic methicillin-resistant Staphylococcus aureus (EMRSA) and vancomycin-resistant enterococci (VRE) in hospitals in England and Wales is presented. Epidemic strains EMRSA-15 and EMRSA-16 are becoming endemic in hospitals in the United Kingdom, and theory predicts that EMRSA-15 and EMRSA-16 will reach respective endemic levels of 158 (95% confidence interval [CI], 143-173) and 116 (95% CI, 109-123) affected hospitals with stochastic fluctuations of up to 30 hospitals in each case. An epidemic of VRE is still at an early stage, and the incidence of hospitals newly affected by VRE is growing exponentially at a rate r=0.51/year (95% CI, 0.48-0.54). The likely impact of introducing surveillance policies if action is taken sufficiently early is estimated. Finally, the role of heterogeneity in hospital size is considered: "Super-spreader hospitals" may increase transmission by 40%-132% above the expected mean.     

Compliance with methicillin-resistant Staphylococcus aureus precautions in a teaching hospital

BACKGROUND: Nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) occurs primarily through the contaminated hands of health care workers who do not follow appropriate precautionary measures. This study investigates various factors associated with compliance with MRSA precautions during routine patient care. METHODS: This observational study took place at a teaching hospital in Montreal, Canada. Nurses (184), physicians (41), occupational therapists and physical therapists (19), orderlies (102), housekeeping personnel (28), other health care workers (65), and visitors (49) were anonymously observed. Compliance with MRSA precautions was measured according to appropriate use of gowns and gloves as well as hand hygiene. RESULTS: In 488 observations, the average compliance was 28%. In multivariate analysis, in comparison with nurses, compliance was lower among physicians (odds ratio [OR], 0.35; 95% confidence interval [CI], 0.14 to 0.86), orderlies (OR, 0.37; CI, 0.2-0.69), visitors (OR, 0.2; CI, 0.08-0.49), housekeeping personnel (OR, 0.06; CI, 0.01-0.47), and other types of health care workers (OR, 0.39; CI, 0.18-0.85), but was higher among occupational and physical therapists (OR, 11.7; CI, 2.55-53.8). CONCLUSIONS: Compliance with MRSA precautions is low. The only significant predictor of MRSA compliance was the professional category of the health care worker.     

Methicillin-resistant Staphylococcus aureus on hospital admission in Turkey

A total of 900 patients were screened for methicillin-resistant Staphylococcus aureus (MRSA) on hospital admission, and 11 MRSA strains (1.2%) were detected. All 11 MRSA strains were positive for the mecA and PVL genes. Eight of the 11 MRSA-positive patients (72%) had a history of hospitalization within the previous 12 months.     

Consideration of age at admission for selective screening to identify methicillin-resistant Staphylococcus aureus carriers to control dissemination in a medical ward

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has become an increasingly important pathogen responsible for hospital-acquired infections. Our study was to evaluate the efficiency of our selective screening program for methicillin-resistant Staphylococcus aureus (MRSA) carriers at admission to nonintensive care units. METHODS: During 6 months, all patients were screened at admission to an internal medicine ward, at which time they were classified as patients at risk of carriage (PRC) and those with no known risk factor. The amplitude of cross transmission was estimated using various indicators during this universal screening period and during the same calendar period of the preceding year (selective screening). RESULTS: The prevalence of MRSA carriage at admission was 5.5%. Among the 22 carriers identified, only 10 were PRC. Age >80 years was significantly associated with MRSA carriage upon admission (OR, 3.5; P < .01). All estimation indicators of MRSA dissemination amplitude were significantly lower during universal screening (relative risks varied from 2.79 to 26.4 according to indicators), demonstrating the need to broaden our criteria defining PRC. CONCLUSION: Adding patients >80 years of age to our PRC definition would increase screening sensitivity (15 carriers identified for 128 patients sampled) and would enable early implementation of barrier precautions for the additional carriers identified.     

Prevalence of methicillin-resistant Staphylococcus aureus in a Spanish hospital

Recent reports of the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Europe are infrequent compared with reports in the 1960s. Annual incidence of the isolation of MRSA was studied in a general hospital in Guipúzcoa (Basque country) over a 9-year period. Overall prevalence was 4.5%-12.93% in the first 3 years (coinciding with an epidemic phase) and later 0.29%, underlining the cyclic and epidemic nature of this infection.     

Spontaneous bacterial peritonitis due to methicillin-resistant Staphylococcus aureus in patients with cirrhosis

A substantial epidemiologic change in the etiology of spontaneous bacterial peritonitis (SBP) has been observed in recent years. Gram-positive, as well as multiresistant bacteria, have emerged as an important cause of SBP mainly among hospitalized patients. In this setting, SBP caused by methicillin-resistant Staphylococcus aureus (MRSA) could become a major clinical problem in the near future. We present two cases of SBP due to MRSA without clinical response to vancomycin, even though in vitro sensitivity was observed in both cases. We review the current literature on the incidence and clinical significance of SBP due to MRSA infection in cirrhotic patients, as well as its prevention and treatment.     

Outbreak of methicillin-resistant Staphylococcus aureus in a Norwegian hospital.

Methicillin-resistant Staphylococcus aureus (MRSA) occurred sporadically in Norwegian hospitals in the 1960s and 1970s, but disappeared in the late 1970s for unknown reasons. Only 1 outbreak has subsequently been reported. We describe herein a second outbreak in a different hospital, this time featuring a more resistant strain. Staff and patients were screened immediately after detection of the first MRSA isolate. Colonized and infected patients were nursed using contact precautions, and the staff were not allowed to work until 3 nose samples were MRSA-negative. We treated colonized persons with topical administration of mupirocin to the nostrils and a chlorhexidine body wash. The outbreak affected 7 patients and 5 healthcare workers. Pulsed-field gel electrophoresis proved all isolates to be of the same type, and the MRSA phage type was M3. There was no sign of transmission of MRSA after contact precautions were implemented. MRSA was eradicated in 4 of the patients and all 5 healthcare workers. One patient died and 1 was still colonized 3 y after onset of the outbreak. Contact precautions proved to be sufficient to prevent transmission of MRSA.     

Risk factors for methicillin-resistance among patients with Staphylococcus aureus bacteremia at the time of hospital admission

BACKGROUND: Community-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) seem to be increasing. Characteristics permitting recognition of patients with such strains would aid infection control efforts and choice of empiric therapy pending culture and susceptibility results. METHODS: Retrospective review of medical records for all adults seen in the Emergency Care Center at Grady Memorial Hospital, Atlanta, Georgia, whose blood cultures taken within 24 hours of entry yielded S. aureus. Risk factors for the presence of methicillin resistance in S. aureus isolates recovered from patients with staphylococcal bacteremia were assessed. RESULTS: S. aureus isolates from 118 (40%) of 297 study patients with bacteremia at the time of admission were methicillin-resistant. Multivariate analysis identified hospitalization in the 6 months preceding admission [odds ratio (OR) = 4.4; 95% CI, 2.0-9.8], receipt of antimicrobial agents in the past 3 months (OR = 5.6; 95% CI, 2.6-11.9], presence of indwelling urinary catheter (OR = 7.3; CI, 2.5-20.9), and nursing home residence (OR = 9.9; 95% CI, 3.9-25.6) to be independently associated with the presence of methicillin resistance. All but 4 of the 118 patients with methicillin-resistant strains had at least 1 of these factors and the proportion of resistant isolates progressively increased as more of these features were present. CONCLUSIONS: The presence of these risk factors should be considered when making decisions about isolation and other infection control procedures as well as empiric antimicrobial therapy with vancomycin for patients with suspected staphylococcal infection at the time of hospital admission. Similar studies could guide practices for dealing with such patients in other centers, because the occurrence of MRSA infections at the time of admission may vary widely by geographic area.     

Legislative mandates for use of active surveillance cultures to screen for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci: Position statement from the Joint SHEA and APIC Task Force

Legislation aimed at controlling antimicrobial-resistant pathogens through the use of active surveillance cultures to screen hospitalized patients has been introduced in at least 2 US states. In response to the proposed legislation, the Society for Healthcare Epidemiology of America (SHEA) and the Association for Professionals in Infection Control and Epidemiology, Inc., (APIC) have developed this joint position statement. Both organizations are dedicated to combating health care-associated infections with a wide array of methods, including the use of active surveillance cultures in appropriate circumstances. This position statement reviews the proposed legislation and the rationale for use of active surveillance cultures, examines the scientific evidence supporting the use of this strategy, and discusses a number of unresolved issues surrounding legislation mandating use of active surveillance cultures. The following 5 consensus points are offered. (1) Although reducing the burden of antimicrobial-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE), is of preeminent importance, the APIC and the SHEA do not support legislation to mandate use of active surveillance cultures to screen for MRSA, VRE, or other antimicrobial-resistant pathogens. (2) The SHEA and the APIC support the continued development, validation, and application of efficacious and cost-effective strategies for the prevention of infections caused by MRSA, VRE, and other antimicrobial-resistant and antimicrobial-susceptible pathogens. (3) The APIC and the SHEA welcome efforts by health care consumers, together with private, local, state, and federal policy makers, to focus attention on and formulate solutions for the growing problem of antimicrobial resistance and health care-associated infections. (4) The SHEA and the APIC support ongoing additional research to determine and optimize the appropriateness, utility, feasibility, and cost-effectiveness of using active surveillance cultures to screen both lower-risk and high-risk populations. (5) The APIC and the SHEA support stronger collaboration between state and local public health authorities and institutional infection prevention and control experts.