Species identification, antibiotic sensitivity and slime production of coagulase-negative staphylococci isolated from clinical specimens

Abstract

SUMMARYTwo hundred and seventy-five consecutive clinical isolates of coagulase-negative staphylococci, including strains associated with disease, contaminants and skin colonizers, were speciated, tested for slime production and for their sensitivity to a range of antibiotics.Staphylococcus epidermidiswas the most commonly identified species, comprising 63% of all isolates. Slime production was detected in half the strains ofStaph. epidermidis, Staph. haemolyticusandStaph. Saprophyticusbut was rare in other species. MostStaph. haemolyticusstrains and approximately half of theStaph. epidermidisstrains were resistant to five or more antibiotics. A significant association was found between slime production and multiple antibiotic resistance. For catheter-associated strains, clinical relevance was predictable by species i.e.Staph. epidermidis. Multi-resistant slime-positiveStaph. haemolyticusstrains, although infrequently associated with disease, were common skin colonizers, presumably acquired from the hospital environment. We describe a practical and inexpensive scheme for thespeciation of human coagulase-negative staphylococcal isolates.