Epidemic spread of ST1-MRSA-IVa in a neonatal intensive care unit, Italy

The study NICU practiced an active surveillance program for multidrug-resistant organisms, including weekly cultures for detection of MRSA from nasal swabs among all the admitted neonates. All first isolates from surveillance cultures and all clinical isolates were submitted for susceptibility testing and genotyping. Data from each infant’s medical records were prospectively included in a database, and the clinical features and outcomes of the colonized/infected infants were assessed.A total of 14 infants were colonized or infected by a strain of ST1-MRSA-IVa between April and August 2011. The CA-MRSA strain appeared to have been introduced to the NICU by an infected infant transferred from another hospital. The outbreak was successfully contained by multifaceted infection control interventions.The results of this study confirm that NICU is a healthcare setting with a critical permeability to CA-MRSA. Active surveillance including molecular typing can help to detect and monitor the spread of antimicrobial drug-resistant organisms, and thus trigger timely control interventions.Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged as an important pathogen. CA-MRSA was first identified in infection cases with no previous contact with the healthcare system or other well-recognized risk factors, such as recent antimicrobial drug use [1]. However, it has recently become increasingly identified as a healthcare-associated (HA) pathogen [2]. Neonatal intensive care units (NICUs), nurseries and maternity settings are involved in these CA-MRSA events with alarming frequencies, and as many as 12 out of 18 recent outbreaks in healthcare facilities have occurred in these settings, with seven outbreaks affecting NICUs [3].CA-MRSA outbreaks have usually been traced to the infiltration of a single strain in a healthcare setting [4]. However, their epidemiological patterns are increasingly difficult to understand, as their occurrence and diss