No abstract

Background and Aims: 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 methicillinresistant Staphylococcus aureus strains and Staphylococcal Chromosomal Cassette mec (SCCmec) phenotypes isolated from the intensive care unit in Hazrat Fatemeh Zahra hospital of Isfahan. Materials and Methods: 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. Results: 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%). Conclusions: 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.

Background Staphylococcus aureus has long been recognized as an important pathogen of hospital acquired infections (1). Due to the expansion of the drug resistance pattern and importance of antibiotic resistance, the study of these microbial strains is one of the major challenges which should be taken into consideration (2). Methicillin resistance in S. aureus is mediated by a penicillin binding protein (PBP2a) which is encoded by the mecA gene (2-4). According to previous studies, 50% to 90% of S. aureus strains isolated from hospital infections were resistant to methicillin (5,6). Staphylococcus aureus is the most common cause of skin and soft-tissue infections like impetigo, furunculosis, superficial and surgical wounds and abscess (7-13). PIA is a polysaccharide composed of β1-6-linked N-acetyl glucosamine with partially deacetylate residues, which encloses the human cells or medical tools and protects the microorganism against both host immune system and antibiotic treatment (6). In this study, we investigated effective MSCRAMM-encoding genes, during biofilm formation on Congo Red Agar (CRA) medium and polystyrene plates, via phenotypic and genotypic screening of methicillin resistant S. aureus strains isolated from the patients with nosocomial infections in Hazrat Fatemeh Zahra (SA) hospital, Isfahan, Iran. Methods and Materials Bacterial Isolation and Culture Conditions Sample collection and Staphylococcus identification were performed in diabetes clinic of Hazrat Fatemeh Zahra (SA) hospital, Isfahan, Iran. A total of 267 clinical samples were selected from various types of wound infections, from which 132 samples were S. aureus. The isolates were selected from infectious wounds in patients hospitalized in diabetes clinic of Hazrat Fatemeh Zahra