Genotyping pattern of Staphylococcus aureus isolated from nasal carriers among health care workers in two hospitals (Imam Sajjad and Shahid Beheshti) in Yasuj city using coa-typing method.

Background and aim: Staphylococcus aureus can colonizes variety of body sites such as skin, coetaneous membrane and especially anterior nares.  The coagulase gene (coa) typing is a technique in which the organism is typed based on the polymorphic region of the coa gene. The aim of the present study was to determine the coa based typing of S. aureus isolates from health care workers in two teaching hospitals in Yasuj city. Methods:  In this cross- sectional study a total of 125 S. aureus isolates were collected from the nasal nares of healthcare workers in Shahid Beheshti and Imam Sajjad Hospitals in Yasuj city. For typing of S. aureus isolates, amplification of the 3'-end region of the coa gene was performed. Finally PCR products were digested with HaeIII restriction enzymes and then were electrophoresed on 1.2% agarose gel, and visualized under UV illumination. Bacterial strains were typed according to the DNA bands with diverse size and numbers in each strain. Data were analyzed by descriptive statistics tests.   Results:  Amplification of the coa gene showed single band in nine different patterns ranging approximately from 400 to 860 base pair. The coa gene with 610 bp size was seen in 36 isolates and was considered a predominant type. After digestion of PCR products with HaeIII restriction enzymes, totally 15 distinct coa gene RFLP patterns, numbered C1 to C15, were observed. The C3 was the most frequent coa type with 24 isolates. There is no specific coa types belong to wards or professions in each hospitals. Conclusion: S. aureus  isolated from anterior nares of HCWs  showed genetic diversity in their coa gene, but only a few coa gene variants were predominant. Hence no prominent coa type was detected according to the wards or types of profession, the sources of bacteria for colonization in anterior nares of HCWs may be related to the  hospital environmental outside.