Methicillin-resistant Staphylococcus aureus nasal colonization in a level III neonatal intensive care unit: Incidence and risk factors.
OBJECTIVE
To describe epidemiologic features and identify risk factors for methicillin-resistant Staphylococcus aureus (MRSA) acquisition in a level III neonatal intensive care unit (NICU).


METHODS
A prospective, cohort study in a university-affiliated NICU with an infection control program including weekly nasal cultures of all neonates.


METHODS
Demographic, clinical, and microbiologic data were prospectively collected between June 2009 and June 2013. Molecular characterization of MRSA isolates was done by multilocus variable number tandem repeat fingerprinting, staphylococcal cassette chromosome mec typing, and on representative isolates by multilocus sequence typing and spa typing.


RESULTS
Of 949 neonates, 217 (22.87%) had a culture growing MRSA, including 117 neonates testing positive at their first sampling. Of these latter infants, 96 (82.05%) were inborn and 59 (50.43%) had been transferred from the nursery. Length of stay and colonization pressure were strong independent predictors of MRSA acquisition. Among MRSA isolates, 7 sequence types were identified, with ST22-IVa, spa type t223, being the predominant strain.


CONCLUSIONS
In an endemic area, early MRSA acquisition and high colonization pressure, likely related to an influx of colonized infants from a well-infant nursery, can support persistence of MRSA in NICUs. Surveillance, molecular tracking of strains, and reinforcement of infection control practices, involving well-infant nurseries in a comprehensive infection control program, could be helpful in containing MRSA transmission.
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy; Azienda Ospedaliera Universitaria Policlinico "P. Giaccone", Palermo, Italy.
Mario
M
Giuffrè
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy.
Emanuele
E
Amodio
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy; Azienda Ospedaliera Universitaria Policlinico "P. Giaccone", Palermo, Italy.
Celestino
C
Bonura
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy.
Daniela M
DM
Geraci
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy; Postgraduate Specialty School in Hygiene and Preventive Medicine, University of Palermo, Palermo, Italy.
Laura
L
Saporito
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy.
Rita
R
Ortolano
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy; Azienda Ospedaliera Universitaria Policlinico "P. Giaccone", Palermo, Italy.
Giovanni
G
Corsello
Department of Sciences for Health Promotion and Mother-Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy; Azienda Ospedaliera Universitaria Policlinico "P. Giaccone", Palermo, Italy. Electronic address: caterina.mammina@unipa.it.
Caterina
C
Mammina
D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D017720:Molecular Epidemiology; D058889:Molecular Typing; D009297:Nasal Mucosa / Q000382:microbiology*; D011446:Prospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology
Active surveillance; Colonization pressure; Infection control