Determination of the staphylococcal cassette chromosome in methicillin-resistant Staphylococcus aureus strains isolated from various clinical samples

Abstract

Aim - the present study aimed to detect mecA and staphylococcal cassette chromosome mec (SCCmec) types in methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained from various clinical samples in two university hospitals. It was also aimed to make comparison amongst the isolates. Materials and Methods - A total of 99 MRSA strains isolated from various clinical samples between 2011-2015 were included in the study. Bacterial deoxyribonucleic acid (DNA) was extracted from Staphylococcus aureus strains using GF-1 DNA extraction Kit (Vivantis, Malaysia). mecA gene were detected, and SCCmec cassette types were determined by multiplex polymerase chain reaction (PCR) first, and following specific PCR. Specific MRSA strains such as COL type I, PER3 type Ia, and HU25 type IIIa were used as the quality control strains for optimization of multiplex PCR. the amplification products were electrophoresed using agarose gel electrophoresis in TAE buffer (mixture of tris base, acetic acid and ethylenediaminetetraacetic acid). Results - mecA gene was detected in 60 Staphylococcus aureus isolates, and these were identificated as MRSA. Amongst the MRSA strains, SCCmec type III was the most frequent cassette type (42 isolates, 70.0%). SCCmec type I was detected in 27 isolates (45.0%), type II was in 26 isolates (43.3%), and type V in 23 isolates (38.3%). Conclusion - in the present study, the most frequent cassette was detected as SCCmec type III in concordance with the studies conducted in Turkey and in some regions in the world. in conclusion, determination of epidemiological and molecular characteristics of MRSA strains has critical importance because of the difficulties in the treatment and of the nosocomial infections and epidemics they caused. the data obtained would contribute to the preventions in terms of epidemiology.