USE OF GAS-LIQUID-CHROMATOGRAPHY FOR SUBGROUPING COAGULASE-NEGATIVE STAPHYLOCOCCI DURING A NOSOCOMIAL SEPSIS OUTBREAK

Gas-liquid chromatographic (GLC) fatty acid profile correlation analys is was applied for the subgrouping of 169 coagulase-negative staphyloc occi collected during an outbreak of nosocomial sepsis in a hematologi c unit. The fatty acid profile similarity index between six ciprofloxa cin-resistant Staphylococcus epidermidis septicemia strains was as hig h as 98.39 +/- 0.68, indicating a high degree of resemblance. This fin ding corroborated the finding by conventional typing methods that the isolates shared the same strain characteristics and, therefore, could be derived from the same epidemiological origin. Further, the GLC fatt y acid profiles were analyzed for coagulase-negative staphylococcal cu taneous isolates recovered from colonization cultures of the patients and personnel in that same unit. The similarity index between 88 cipro floxacin-resistant Staphylococcus epidermidis skin isolates with simil ar plasmid profiles was as high as 95.47 +/- 3.78, whereas the correla tion coefficient between 45 ciprofloxacin-susceptible Staphylococcus e pidermidis skin isolates with different plasmid profiles was only 85.2 3 +/- 10.82. Cluster analysis grouped the ciprofloxacin-resistant Stap hylococcus epidermidis isolates into one distinct cluster, while most of the ciprofloxacin-susceptible Staphylococcus epidermidis isolates w ere grouped into two separate clusters. When compared with the plasmid profiling, the GLC method congruously grouped 127 (87 %) of the 146 S taphylococcus epidermidis isolates, thereby suggesting its potential v alue in subgrouping coagulase-negative staphylococci during nosocomial outbreaks.