Emergence of ciprofloxacin-resistant coagulase-negative staphylococcal skin flora in immunocompromised patients receiving ciprofloxacin.

Seven septicemias in neutropenic leukemia patients (two with fatal outcome) caused by ciprofloxacin-resistant coagulase-negative staphylococci were diagnosed in the hematologic unit of Turku University Central Hospital in 1988 soon after the introduction of the drug. Coagulase-negative staphylococcal skin flora of 28 neutropenic patients receiving ciprofloxacin prophylaxis and therapy for gram-negative bacterial infections were compared with those of 31 untreated patients and 33 hospital personnel working in the same unit. In ciprofloxacin-treated patients the flora were almost completely ciprofloxacin-resistant, whereas in the control groups resistant flora were detected only occasionally. Similarities in the plasmid profile patterns were found in 91% of the ciprofloxacin-resistant coagulase-negative staphylococci, suggesting an epidemiologic relation between these strains. It seems evident that cross-infection is responsible for the spread of ciprofloxacin-resistant coagulase-negative staphylococci in these patients.