Epidemic methicillin-gentamicin-resistant Staphylococcus aureus in a neonatal intensive care unit
A. C. Reboli, J. F. John Jr and A. H. Levkoff
Department of Medicine, Medical University of South Carolina, Charleston.
Between October 1985 and August 1986, 49 isolates of methicillin-resistant
Staphylococcus aureus (MRSA) were obtained from 26 neonates in the neonatal
intensive care unit (NICU) at the Medical University Hospital, Charleston,
SC. Sites of MRSA isolation were the respiratory tract (33%); nasopharynx
(12%); gastrointestinal tract (12%); eye (8%); blood (6%); and catheter
tips, wounds, or umbilicus (29%). Very low birth weight was a significant
risk factor for MRSA acquisition. All isolates had the same phage type
(47/54/75/83A), antibiogram, and whole-cell protein profile. Agarose gel
electrophoresis of all 49 isolates disclosed a plasmid level of
approximately 45 X 106 daltons (45 megadaltons) in ten different isolates
and no plasmid DNA in 39 isolates. Cultures of NICU personnel failed to
disclose MRSA carriers and environmental cultures for MRSA were negative.
Ten selected isolates showed lower minimal bactericidal concentrations for
hexachlorophene than for chlorhexidine. Standard infection-control measures
such as contact isolation, hand washing with chlorhexidine, and cohorting
(when possible) failed to contain the epidemic. Ultimately, eradication of
MRSA from the NICU was associated with the institution of hexachlorophene
hand washing.
