WIDESPREAD COLONIZATION OF PERSONNEL AT A VETERANS AFFAIRS MEDICAL-CENTER BY METHICILLIN-RESISTANT, COAGULASE-NEGATIVE STAPHYLOCOCCUS

A serial prospective survey of nasal colonization of hospital personne l by methicillin-resistant coagulase-negative staphylococci (MRCNS) wa s conducted at a Veterans Affairs medical center on three occasions ov er a 16-month period. The epidemiological typing systems used to asses s relatedness included antimicrobial susceptibility profiles; biotypin g; phage typing; plasmid profiles; restriction fragment length polymor phism (RFLP) analysis with ribosomal RNA; and plasmid hybridization wi th a 1.68-MD plasmid as the DNA probe. Forty-three percent of all pers onnel and 62% of all nurses were colonized with MRCNS. Nurses on the w ards (72%) and in the intensive care unit (73%) were significantly mor e likely to be colonized with MRCNS than nurses who had less contact w ith patients or those who worked in the operating room. The molecular epidemiological typing systems indicated some degree of relatedness am ong the strains. Specifically, riboprobe analysis revealed a Dice coef ficient of >90%. However, each typing system detected dissimilarity am ong strains. Further studies are needed to determine the role that suc h human reservoirs of MRCNS serve in horizontal transmission to and su bsequent infection of hospitalized patients.