Investigation of antibiotic resistance genes and the presence of pantone valentine leukocidin in Staphylococcus aureus strains isolated from various clinical specimens

Staphylococcus aureus is one of the most common infectious agents. In this study, wound, blood and respiratory samples isolated from S. aureus strains, is intended to be determined by the resistance status to various antibiotics phenotypic and genotypic methods identified and compared and is also aimed to detect the presence of Panton-Valentine Leukocidin (PVL) with molecular methods and resistant genes caused by resistance on this strains. Between December 2012 and September 2014, Laboratory of Microbiology in Gaziantep University Medical Faculty Hospital, 96 S. aureus strains isolated from wound, blood and respiratory samples which were sent from clinics and inpatients, are included in the study. The identification of S. aureus strains were made and methicillin resistance, cefoxitine (30μg) and oxacillin (1μg) disc diffusion test and oxacillin salt-agar screening test and chormogenic agar were used for methicillin resistance. Various antibiotics sensitivity patterns were researched with disc diffusion test. Macrolide (ermA, ermC), beta lactamase (mecA), tetracycline (tetK, tetM), kinolone (gyrA, parC), aminoglycoside (aacA) and vancomycine resistances (vanA) and PVL presence were researched by Polimerase Chain Reaction (PCR) following hyridization method. Out of the 96 S. aureus isolates, 61 were methicillin sensitive Staphylococcus aureus (MSSA, 63.5%) and 35 were methicillin resistant Staphylococcus aureus (MRSA, 36.5%). The highest resistance rates observed as; 93 (96.9%) penicillin, 91 (94.8%) ampicillin and 62 (64.6%) amoxicillin clavulanic acid. 11 (31.4%) of the MSSA isolates and 24 (68.6%) of the MRSA isolates showed the presence of the mecA gene. Out of 96 S. aureus isolates, positivity of the genes were mecA 35%, ermA 17.7%, ermC 12.5%, tetK 12.5%, tetM 19.8%, parC %15.6, aacA 30% and PVL presence was 5.4%. vanA gene positivity did not observed. In conclusion, cefoxitine (30 µg) disk diffusion test was found as the most reliable test for the detection of MRSA. Key words: S. aureus, antibiotic resistance, mecA, MRSA, PVL