SCCmec typing and integron investigation of staphylococcus aureus strains isolated from clinical samples

SCCmec Typing and Integron Investigation of Staphylococcus aureus Strains Isolated from Clinical Samples Aim:Staphylococcus aureus is one of the leading human pathogens. Methicillin-resistant S. aureus strains are resistant to all beta-lactam antibiotics, and also they have potency to rapid development of resistance to other classes of antimicrobials. Therefore, typing of the mec genes which are responsible for methicillin resistance and determination of the integrons that carry the antibiotic resistance genes will be valuable for a successful treatment against this bacterium. In this study, typing of SCCmec by studying the mecA and mecC genes, and determination of the class 1-3 integrons in the S. aureus strains which were isolated from the patients' samples were aimed to be investigated. Material and Method: a total 138 S. aureus strains which were isolated from clinical samples of the patients between March 2016 and March 2017, in the central microbiology laboratory of Turgut Ozal Medical Center were included. Methicillin resistance of the identified strains was phenotypically studied with disk diffusion method. Polymerized Chain Reaction (PCR) was used for determination of mecA and mecC genes, SCCmec types, and for integrons. The clonal relationship of the isolates was studied with Pulsed Field Gel Electrophoresis (PFGE). Results: total 38 out of 138 included strains were found as methicillin-resistant, and remaining 100 were found as methicillin-susceptible. mecA gene was found in all methicillin-resistant strains, and no mecC gene was determined. Regarding the SCCmec typing of these 38 isolates, 5 (13%) were typed as SCCmecI, 5 (13%) were typed as SCCmecII, and 10 (26%) were typed as SCCmec III; however, the remaining 18 (47%) strains couldn't be typed, and classified as "ungrupped". A total 116 different genotypes were determined in PFGE, and the clusture rate was found as 13%. Among these 116 different groups,class-1 integron was determined in only 19 (16%) genotypes of which 4 were positive for mecA gene. Conclusion: according to the results of this study, almost ¼ of the S. aurues strains that were isolated from our hospital were methicillin-resistant, all which were due to mecA gene. This study is important since the fact that different integron types were investaigated in S. aureus strains, and first detection of class-1 integron in S. aureusstrains in our country. Molecular studies will provide useful data for better understanding the dynamics of the antimicrobial resistance spread, and to prevent this transmission