Molecular Investigation of Staphylococcal Cassette Chromosome mec (SCCmec) Elements Isolated from Intensive Care Unit

Based on the results, Staphylococcus aureus is one of the serious infectious agents found in community and hospitals with remarkable potential for high morbidity and mortality around the globe. The present study was carried out for molecular investigation of methicillin-resistant Staphylococcus aureus strains and Staphylococcal Chromosomal Cassette mec (SCCmec) phenotypes isolated from the intensive care unit in Hazrat Fatemeh Zahra hospital of Isfahan.

A total of 76 clinical wound samples were collected from Hazrat Fatemeh Zahra Hospital in Isfahan and evaluated by polymerase chain reaction (PCR) methods. The Methicillin resistance Staphylococcus aureus (MRSA) screening was performed by genotypic and phenotypic methods; also antibiotic resistance pattern was determined by using the disk diffusion method and related genes by PCR.

Totally, 53 (69.7%) out of 76 clinical samples were positive for MRSA. Of the 76 MRSA strains, 39 (63.51%) were PVL positive (51.3%). The most commonly infected samples were collected from wounds (40.8%). The most commonly detected antibiotic resistance genes were mecA (89.61%), tetK (88.23%), tetM (49.15%) and msrA (46.93%). Resultantly, it was shown that MRSA has the highest level of resistance against methicillin (98%), penicillin (97.24%), tetracycline (89.64%). It was also revealed that the most commonly detected SCCmec types in the MRSA strains are types II (14.53%) and III (16.82%).

In summary, this paper argues that the orderly surveillance of hospital-associated infections and initial management and supervision of the antibiotic resistance patterns are required to control the prevalence of MRSA.