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

• Surveillance for multidrug-resistant gram-negative bacteria is rarely done.
• Patients carrying multidrug-resistant gram-negative bacteria may remain unisolated in hospitals.
• Veterans Affairs screens all hospital admissions for methicillin-resistant Staphylococcus aureus.
• All methicillin-resistant Staphylococcus aureus-positive patients are placed in contact precautions.
• Overall, 30.7% of patients with multidrug-resistant gram-negative bacteria would have been in contact precautions because of a positive methicillin-resistant Staphylococcus aureus screen.

BackgroundSurveillance 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.MethodsMRSA 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.ResultsOf 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.ConclusionsPatients may be serendipitously placed in contact precautions for MDR GNB when isolated for a positive admission MRSA screen.