Epidemic spread of ST1-MRSA-IVa in a neonatal intensive care unit, Italy.
BACKGROUND
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged as an important pathogen in neonatal intensive care units (NICUs). The purposes of this study were to characterize methicillin-resistant isolates from an outbreak in a NICU, to examine the genetic traits and clonality of CA-MRSA, and to review the characteristics and outcomes of the neonatal cases and investigate the routes of entry and transmission of the MRSA outbreak strain in the NICU under study.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Department of Mother and Child, University of Palermo, Palermo, Italy.
Mario
M
Giuffrè
Domenico
D
Cipolla
Celestino
C
Bonura
Daniela Maria
DM
Geraci
Aurora
A
Aleo
Stefania
S
Di Noto
Federica
F
Nociforo
Giovanni
G
Corsello
Caterina
C
Mammina
D015373:Bacterial Typing Techniques; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission; D004196:Disease Outbreaks / Q000517:prevention & control / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D017053:Infection Control; D007363:Intensive Care Units, Neonatal; D007558:Italy; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission