Detection of meticillin-resistant staphylococcus aureus (MRSA) colonization in newborn infants using real-time polymerase chain reaction (PCR).
OBJECTIVE
Meticillin-resistant staphylococcus aureus (MRSA) colonization on neonatal units is a common and important clinical problem. Effectiveness of polymerase chain reaction (PCR) for detecting MRSA nasal colonization of infants was evaluated and compared to culture-based methods. The effect of skin decolonization in affected infants was studied.


METHODS
Paired nasal swabs were collected from infants in our neonatal unit over a 12-month period (September 2007-2008). Colonization with MRSA was determined with a commercially available PCR method and compared to culture.


RESULTS
A total of 696 paired nasal swabs were taken. Three infants were colonized at the beginning and were included. There were positive PCRs in 12 infants. Five infants cultured MRSA from a nasal swab at the same time. No infants were culture-positive when PCR was negative (sensitivity 100%, specificity 99% compared to culture). PCR results were available within 24 h. Five infants were PCR+ and isolated meticillin-sensitive Staphylococcus aureus. This organism gave a false-positive PCR result. Two infants transferred in on broad-spectrum antibiotics were PCR+ and negative by culture. Decolonization led to negative nasal PCR and culture in 4/5 infants to discharge.


CONCLUSIONS
PCR methods are sensitive and specific for detection of MRSA colonization in newborn infants of all gestations with results 1-2 days before culture.
Regional Neonatal Unit, St George's Hospital, London, UK.
S T
ST
Francis
S
S
Rawal
H
H
Roberts
P
P
Riley
T
T
Planche
N L
NL
Kennea
D015169:Colony Count, Microbial; D046508:Culture Techniques / Q000379:methods; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000175:diagnosis; D007363:Intensive Care Units, Neonatal; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification*; D009297:Nasal Mucosa / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000175:diagnosis*