Aksoy, MuratBarkar, Saeid2022-04-202022-04-202009http://hdl.handle.net/20.500.12575/79179S. aureus is one of the major causes of infections in both communities and hospitals worldwide. It is associated with toxigenic diseases such as toxic shock syndrome, food poisoning, scalded skin syndrome; local pyogenic diseases such as impetigo, folliculitis, furuncles, carbuncles, cellulites, blepharitis, mastitis, surgical wound infections; and systemic infections such as endocarditis, osteomyelitis, arthritis, sepsis, pneumonia, urinary tract infections, metastatic abscesses and meningitis. Nasal carriage is an important risk factor for S. aureus infections. Formerly known to be a nosocomial pathogen, methicillin resistant S. aureus (MRSA) has begun to be isolated from community associated infections since the 1980s. The aim of this study is to determine the resistance profiles and virulance factors of S. aureus strains isolated from various clinical specimens and healthy carriers of different age groups, and to investigate the cassette chromosome types (SCCmec ve ccr gen complex) with PCR methods.This study was carried out at Ankara University Faculty of Medicine, Department of Microbiology and Clinical Microbiology. In order to obtain CA-MRSA strains, nasal and axillary specimen were taken from 1040 healthy individuals of ages from 4 to 85, between October 2007 and May 2008. Taken using sterile moistured swabs and carried in Stuart?s transpor media, nasal and axillary specimen were inoculated on to 5% sheep blood agar, EMB media and SDA (including antibiotics) for routine bacteriological examinations. 31 CA-MRSA strains as infectious agents were isolated from urine, uretral discharge, nasal, pus, wound, joint fluid samples of outpatients of ages from 4 to 76 who applied to Istanbul Haydarpaşa Numune, Teaching and Research Hospital between 2004-2005. For all S. aureus strains, DNA extraction was performed by phenol chloroform method and mecA, PVL, SCCmec genes and ccr gene complex was investigated by PCR and multiplex PCR methods.The rate of S. aureus carriers among 1040 healthy individuals was found to be 27,1%, while carriage rates in males and females were found to be 32,1% and 21,2% respectively (p<0,001). S. aureus nasal, axillary, and both nasal and axillary colonisation rates were found to be 91,8%, 3,9% and 4,3% respectively. Nasal carriage was higher than axillary carriage (p<0,001). S. aureus carriage rates were found to be 30,6% among medical workers, 25,4% among students and 25,5% among other occupational groups.18 MRSA strains were determined by PCR method, 12 by cefoxitin, oxacillin disc diffusion and oxacillin-salt screening agar tests and 51 by ORSAB tests. CA-MRSA carriage rates among males and females were found to be 2,3% and 1,1% respectively, while the avarage rate was 1,7%.Among CA-MRSA strains isolated from healthy individuals, highest sensivity were found against vancomycin (100%), trimethoprim/sulfamethoxazole (100%) and chloramphenicol; whereas sensivity against tetracycline and amoxycilline/clavulanic acid was found to be 16,7%. Among CA-MRSA strains isolated from outpatients, highest sensivity rates were found against vancomycin (100%), and chloramphenicol (96,8%), whereas tetracycline and ciprofloxacin sensivities were found to be 38,7% and 35,5% respectively. iMLSB, MS and S phenotypes of CA-MRSA strains isolated from healthy individuals /outpatients were found as 12,9% / 11,1%; 6,5% / 0% and 80,6% / 88,9% respectively. cMLSB phenotypes could not be detected in any of the CA-MRSA strains.SCCmec and ccr typing methods were used for type determination of 18 CA-MRSA strains isolated from healthy individuals and 31 strains isolated from outpatient. Casette chromozomal typing resulted as %5,6 (1/18) type I, %38,9 (7/18) type II, %11,1 (2/18) type III, %38,9 (7/18) type IV and %5,6 (1/18) type V in healthy individual CA-MRSA strains; and %9,7 (3/31) type I, %9,7 (3/31) type II, %48,4 (15/31) type III, %22,6 (7/31) type IV and %9,7 (3/31) type V in outpatients CA-MRSA strains. 22,2% of 18 healthy individuals CA-MRSA strains were found to be PVL positive, while the PVL gene was not found in any of the 31 outpatient CA-MRSA strains. All of 4 PVL positive strains out of 18 healthy individual MRSA strains which were typed by SCCmec and/or ccr methods where found to be type IV. The differentiation of PVL pozitivity between CA-MRSA strains isolated from healthy individuals and from outpatients was statistically found to be significant (p<0,014).When cassette types, PVL positivity and antimicrobial suseptibility test profiles of outpatient CA-MRSA strains were investigated, they were found to be more similar to HA-MRSA strains.trMetisilKromozomal kaset tipleriPolimerazdoctoralThesis