Cohorting based on nasal methicillin-resistant Staphylococcus aureus status: an opportunity to share more than a room

Methicillin-resistenter Staphylococcus aureus (MRSA) – eine zentrale Hygiene-Herausforderung in der Dermatologie

Der Methicillin-resistente Staphylococcus aureus ist ein im täglichen Alltag insbesondere für den Bereich der Dermatologie relevanter multiresistenter gram-positiver bakterieller Erreger. Chronische Wunden und atopische Dermatitis sowie der Typ II-Diabetes mellitus spielen hier als Risikofaktoren eine wichtige Rolle. Dieser Übersichtsartikel fokussiert sich neben Ausführungen zu Bedeutung und klinischem Vorkommen auf eine zusammenfassende Darstellung der Hygieneaspekte bei der Behandlung von MRSA-besiedelten oder -infizierten Patienten. Ziel einer solchen Behandlung mit etablierten Hygienekonzepten ist es, eine mögliche Verbreitung des multiresistenten Erregers von einem Patienten auf andere Personen zu verhindern. Werden diese Hygiene-Maßnahmen umgesetzt und gleichzeitig bei einer Infektion eine evidenzbasierte, nach dem Antibiotic-Stewardship ausgerichtete antibiotische Therapie initiiert, sind dies zwei wesentliche Bausteine, um auch weiterhin, wie in den letzten Jahren schon in Nord- und Mitteleuropa beobachtet, rückläufige MRSA-Prävalenzen zu erzielen.

Collateral benefit of screening patients for methicillin-resistant Staphylococcus aureus at hospital admission: isolation of patients with multidrug-resistant gram-negative bacteria

BACKGROUND

Surveillance at hospital admission for multidrug-resistant (MDR) gram-negative bacteria (GNB) is not often performed, potentially leaving patients carrying these organisms unrecognized and not placed in transmission precautions until they develop infection. Veterans Affairs (VA) facilities screen all admissions for methicillin-resistant Staphylococcus aureus (MRSA) and place positive patients in contact precautions. We assessed how often patients with MDR GNB in clinical cultures obtained within 30 days following admission would have been in contact precautions because of a positive MRSA admission screen.

METHODS

MRSA screening and MDR GNB culture results were extracted from a database of patients admitted to all VA acute care medical facilities from January 2009-December 2012.

RESULTS

Of patients with MDR GNB-positive cultures within 30 days following admission, up to 44.3% (dependent on bacterial species) would have been in contact precautions because of a clinical positive admission MRSA nasal screen. Admissions with a positive MRSA screen had odds for MDR GNB in a culture 2.5 times greater than those with a negative screen (95% confidence interval [CI], 2.4-2.6). Odds ratios were 2.4 (95% CI, 2.3-2.5) for MDR Enterobacteriaceae, 2.7 (95% CI, 2.5-2.9) for MDR Pseudomonas aeruginosa, and 4.3 (95% CI, 3.8-4.8) for MDR Acinetobacter spp.

CONCLUSIONS

Patients may be serendipitously placed in contact precautions for MDR GNB when isolated for a positive admission MRSA screen.

MRSA nasal carriage patterns and the subsequent risk of conversion between patterns, infection, and death

Background

Patterns of methicillin-resistant S. aureus (MRSA) nasal carriage over time and across the continuum of care settings are poorly characterized. Knowledge of prevalence rates and outcomes associated with MRSA nasal carriage patterns could help direct infection prevention strategies. The VA integrated health-care system and active surveillance program provides an opportunity to delineate nasal carriage patterns and associated outcomes of death, infection, and conversion in carriage.

Methods/Findings

We conducted a retrospective cohort study including all patients admitted to 5 acute care VA hospitals between 2008–2010 who had nasal MRSA PCR testing within 48 hours of admission and repeat testing within 30 days. The PCR results were used to define a baseline nasal carriage pattern of never, intermittently, or always colonized at 30 days from admission. Follow-up was up to two years and included acute, long-term, and outpatient care visits. Among 18,038 patients, 91.1%, 4.4%, and 4.6% were never, intermittently, or always colonized at the 30-day baseline. Compared to non-colonized patients, those who were persistently colonized had an increased risk of death (HR 2.58; 95% CI 2.18;3.05) and MRSA infection (HR 10.89; 95% CI 8.6;13.7). Being in the non-colonized group at 30 days had a predictive value of 87% for being non-colonized at 1 year. Conversion to MRSA colonized at 6 months occurred in 11.8% of initially non-colonized patients. Age >70 years, long-term care, antibiotic exposure, and diabetes identified >95% of converters.

Conclusions

The vast majority of patients are not nasally colonized with MRSA at 30 days from acute hospital admission. Conversion from non-carriage is infrequent and can be risk-stratified. A positive carriage pattern is strongly associated with infection and death. Active surveillance programs in the year following carriage pattern designation could be tailored to focus on non-colonized patients who are at high risk for conversion, reducing universal screening burden.