The investigation of nasal MRSA carriage and clonal association PFGE in healtcare personnel and healthy individuals

The investigation of nasal MRSA carriage and clonal association PFGE in healtcare personnel and healthy individualsDespite rapid improvements in antimicrobial treatment over the years, the treatment of staphylococcus infections remains challenging. In addition, with their ability to cause hospital epidemics, they constitute an important health problem worldwide. Colonization of the anterior nasal area by MRSA is an important risk factor for nosocomial and community-acquired Staphylococcus aureus (S. aureus) infections. In patients with MRSA infection, contamination usually occurs via contagion by a carrier.This study was conducted at the laboratories of Infectious Diseases department of Firat University medical school and Microbiology and Clinical Microbiology Department of Inonu University Medical School between September, 2007 and November, 2007. The isolates collected from the healthcare personnel and in-patients at various hospitals in Elazig and healthy individuals residing at Elazig city center were evaluated for nasal S. aureus colonization and its methicilline resistance and clonal association by pulse field electrophoresis (PFGE). Description of clinical isolates, determination of their antibiotic sensitivity, and determination of MRSA were done according to the criteria of Clinical Laboratory Standards Institute (CLSI). Clonal association was studied by PFGE method at the molecular laboratory of Microbiology and Clinical Microbiology Department of Inonu University Medical School.The rate of S. aureus colonization in the doctors was 22.3% (MRSA 4.1%); in the nurses, 10.1% (MRSA 3.4%), and in the auxiliary healthcare personnel (AHP), 28% (MRSA 2.6%). The rates of S. aureus colonization in the community and in-patients were 16.7% and 22.6% (MRSA 15 and 5.8%).S. aureus and MRSA carriage were found to increase with increased use of ß-lactam and combined antibiotics as well as hospitalization time. Comparisons of the clinics from which the nasal cultures were obtained revealed that the individuals from the otolaryngology clinics had the highest rate of MRSA carriage, followed by those at intensive care units of anesthesia departments and plastic surgery clinics. The highest resistance rate of MRSA strains was to penicillin (100%), followed by resistance to ampicillin (94.2%), while no resistance to vancomycin, teicoplanin, and linezolid was detected.Through PFGE evaluation, MRSA was found to spread between in-patients, auxiliary healthcare personnel and in-patients, and between hospitals due to patient transfers. It was also found to spread from the hospitals to the community trough patient visits by the visitors.Molecular tests such as PFGE have increasingly gained importance in detection of contamination and source of MRSA strains.