Potential role of Staphylococcus cohnii in a hospital environment

Abstract

We have analysed the isolates of Staphylococcus cohnii found in the intensive care unit of a pediatric teaching hospital: in the environment, 159 isolates; on the skin of hospitalized premature infants, 26; and on the skin of ward personnel, 49. Sixteen phenotypic features were used to characterize the isolates at metabolic, biologic and antibiotic resistance level. All selected attributes were treated as equivalent, and numerical analysis of all isolates was performed on this basis. Each isolate was described with a zero-one sequence, then dendrograms were created, indicating similarities inside the group of isolates. This method proved the phenotypic diversity of S. cohnii isolated in the hospital. Among them, almost 65% showed distinct patterns (on the basis of 16 traits) and there were no large clusters created by identical or very similar isolates. The results of these investigations suggest that owing to its diversity S. cohnii may be perfectly adaptive to hospital habitat conditions, and undergoes alteration in the hospital environment by an exchange of genetic material with species selected under the effect of antibiotic pressure. In this way this species, which is rarely associated with human infections, becomes a reservoir of antibiotic resistance genes in the hospital environment.