[Investigation of the clonality and Panton-Valentine leukocidin toxin among nosocomial methicillin-resistant Staphylococcus aureus strains].

Abstract

Methicillin-resistant Stapyhlococcus aureus (MRSA) is one of the major causes of morbidity and mortality in hospitalized patients. This study was aimed to investigate the clonality of the MRSA strains isolated from patients with nosocomial infection and also to determine the presence of Panton-Valentine leukocidin (PVL) toxin in these isolates. A total of 37 samples (31 isolated from surgical wound samples, 2 them from abscess and 4 from drainage samples) obtained from patients hospitalized at surgery, internal medicine and intensive care units, were included to the study. The clonality among MRSA strains was demonstrated by pulsed-field gel electrophoresis (PFGE) and the presence of PVL by polymerase chain reaction using luk-PV-1 and luk-PV-2 primers. PFGE revealed that 31 of 37 strains were A pulsotype and subtypes, 3 strains were B pulsotype and the last 3 were C pulsotype. Pulsotype A has been isolated especially from cardiovascular surgery and other surgery departments and intensive care units, pulsotype B from orthopedic and pulsotype C from neurology and neurosurgery wards. PVL gene was not identified in any of the isolates. These results indicated the presence of a dominant clone among MRSA strains in our hospital, however, different pulsotypes may also be present in different surgery units. Continuous molecular epidemiological surveillance of nosocomial MRSA strains and their PVL positivity supply valuable clinical and epidemiological data for infection control and patient follow-up.