Utility of surveillance cultures for antimicrobial resistant organisms in infants transferred to the neonatal intensive care unit.

Background: Infections with antibiotic resistant organisms (AROs) are an important source of morbidity and mortality among infants hospitalized in the neonatal intensive care unit (NICU). To identify potential reservoirs of AROs in the NICU, active surveillance strategies have been adopted by many NICUs to detect infants colonized with AROs. However, the yield, risks, benefits and costs of different strategies have not been fully evaluated.

Methods: We conducted a retrospective study in 2 level III NICUs from 2004 to 2010 to investigate the yield of surveillance cultures obtained from infants transferred to the NICU from other hospitals. Cultures were processed for methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci and antibiotic-resistant gram-negative rods. Risk factors, selected outcomes and laboratory costs associated with ARO colonization were assessed.

Results: Among 1751 infants studied, the rate of colonization for methicillin-resistant S. aureus, vancomycin-resistant enterococci and antibiotic-resistant gram-negative rods was 3%, 1.7% and 1%, respectively. Age at transfer was the strongest predictor of ARO colonization; infants transferred at ≥ 7 days of life had 5.8 increased odds of ARO colonization compared with infants <7 days of age. Transferred infants who were colonized had similar rates of mortality, ARO infection and duration of hospitalization compared with those who were not colonized. The laboratory cost of surveillance cultures during the study period was $58,425.

Conclusions: The rate of colonization with AROs at transfer was low particularly in infants <7 days old. Future studies should examine the safety of targeted surveillance strategies focused on older infants.