INVESTIGATION INTO THE REPEATED RECOVERY OF COAGULASE-NEGATIVE STAPHYLOCOCCI FROM BLOOD TAKEN AT THE END OF CARDIOPULMONARY BYPASS

Forty-six strains of coagulase-negative staphylococci (CNS) were typed by biochemical reactivity, antibiotic susceptibility pattern, macrore striction analysis by pulsed-field gel electrophoresis (PFGE) and arbi trary primed polymerase chain reaction (AP PCR). Twenty-four strains w ere obtained in 1993 from blood cultures of as many patients coupled t o a heart-lung machine during cardiac surgery. Since over 30% of the l atter belonged to a single type, it was concluded that during the year of analysis a single clone of CNS persisted in this hospital setting. Subsequent epidemiological surveillance putatively identified four po ssible carriers among surgical personnel. For this reason, 22 strains collected from the bands and nose of two cardiac surgeons and two perf usionists were also tested; none were identical to the persistent clon e. Thus either the operation equipment was colonized longitudinally or the causative CNS had disappeared from the suspect individuals' flora . Longitudinal monitoring of CNS infections by various techniques give s a valuable insight into nosocomial epidemiology and elucidates the c omplexity of the CNS colonization.