An epidemiological assessment of coagulase-negative staphylococci from an intensive care unit

Detection of an unusual combination of four resistance markers among coagulase-negative staphylococci (CNS) isolated in the same intensive care unit led to the undertaking of an epidemiological assessment. Seventeen CNS isolates from the same unit and 38 epidemiologically unrelated Staphylococcus epidermidis isolates were typed by eight methods, including analysis of immunoblot patterns and hybridisation patterns (HP) obtained with three probes. The probes comprised plasmids carrying the genes encoding 16S rRNA (pBA2), aacA-aphD (pSF815A), and aacA-aphD with part of IS256 (pIP1307). Immunoblot patterns and HP with pIP1307 indicated that 14 of the 17 CNS isolates from the same unit resulted from the spread of an epidemic strain.