Ali Asghar Masihi Nezhad - Department of Health and Food Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran
Mojtaba Boniadian - Department of Health and Food Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran
Mohammad Motamedifar - Department of Bacteriology and Virology, School of Medicine HIV/AIDS Research Center, Research Institute for Health, Shiraz University of Medical Sciences
Zahra Naziri - Department of Pathobiology, School of Veterinary Medicine, Shiraz University.

Staphylococcus aureus (S. aureus) is responsible for most cases of food poisoning all around the world. These carriers and manipulated foodstuffs are the main sources of bacteria transmission to ready-to-eat food. This study aims to determine the genetic affinity of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from cream pastries and workers, nasal of Shiraz city confectioneries.  Methods: ۳۰ MRSA strains (۷ nasal carriers, ۲۳ food isolates) were selected from the bank of bacteria at Shiraz medical faculty. To determine the genetic affinity of the isolates, RAPD-PCR technique was performed using OLP۶, OLP۱۱, and OLP۱۳ primers. RAPD-PCR patterns were analyzed using the software GelJ. Results: By using primer OLP۶ only ۵ RAPD-PCR patterns were produced from DNA ampliqons of creamy pastry isolates and were not enough to compare the genetic affinity of all the isolates. Based on ۱۰۰% similarity, OLP۱۳ primer produced ۲۰ different patterns with some bands in the range of ۱ to ۱۱, and the OLP۱۱ primer produced ۲۲ patterns with some bands from ۳ to ۱۱ bands. At closely and possibly genetically related levels, the isolates are categorized into (۱۳-۱۵) and (۱-۵) clusters. In general, all the isolates are classified into human and food isolates. Conclusions: There was no genetic affinity of MDSA isolates regarding human and food samples; but, a high percentage of close genetic relationship between the isolates increases the possibility of bacteria transfer from humans to pastries and food poisoning

Methicillin-resistant Staphylococcus aureus, Genetic affinity, Nasal carriers, Cream Pastry, RAPD-PCR.