EPIDEMIOLOGY OF THE COLONIZATION OF INPATIENTS AND OUTPATIENTS WITH CIPROFLOXACIN-RESISTANT COAGULASE-NEGATIVE STAPHYLOCOCCI

We tested the skin staphylococcal flora of inpatients and hospital sta ff in the orthopedic unit of Turku University Central Hospital (Turku, Finland) for susceptibility to ciprofloxacin. Ciprofloxacin-resistant coagulase-negative staphylococci were detected on the skin of 14 (61% ) of the 23 inpatients and 16 (53%) of the 30 members of the hospital staff. Plasmid profiles were highly similar for most of these resistan t isolates, thus suggesting that cross infection was responsible for t he spread of ciprofloxacin-resistant strains in the orthopedic unit. C olonization of inpatients with ciprofloxacin-resistant coagulase-negat ive staphylococci was significantly associated with hospitalization lo nger than 6 days (P = .006) and the use of antibiotics during the hosp ital stay (P = .009). Twelve of 30 outpatients with venous leg ulcers were treated with ciprofloxacin, and all of these 12 were colonized wi th ciprofloxacin-resistant coagulase-negative staphylococci; in contra st, only three (33%) of the nine outpatients who were treated with tri methoprim (P = .004) and three (33%) of the nine outpatients who were treated with placebo (P = .004) were colonized with these strains. The ciprofloxacin-resistant strains from the outpatients had distinctly d ifferent plasmid profiles, a finding that suggests that, in the commun ity, ciprofloxacin resistance may have emerged in isolates from each t reated individual.