Methicillin resistance and selective genetic determinants of isolates with bovine mastitis milk origin.

BACKGROUND AND OBJECTIVES

is one of the major causes of bovine mastitis, which can be transmitted from animals to humans. Methicillin-resistant (MRSA) isolates are more attentive and if not treated promptly, they can cause death. The aim of this study was to determine the prevalence of methicillin resistance and frequency of selected virulence factors of isolates with bovine mastitis milk origin in Ahvaz, southwest of Iran.

MATERIALS AND METHODS

During a two-year period (2014-2015), 75 isolates were recovered from referred clinical and sub-clinical bovine mastitis milk samples. The isolates were phenotypically investigated for resistance to cefoxitin by Kirby-Bauer method. DNA were analyzed by PCR for and selected genes that encode the virulence factors.

RESULTS

According to the results, the , S, , , A, B, and genes were detected in 98.7, 97.3, 97.3, 86.7, 84, 84 and 65.3% of the isolates, respectively. Among the 75 isolates, only one (1.3%) isolate was methicillin-resistant. Totally, 39 isolates (50.7%) had all of these virulence factors except . The results showed that 96% of the isolates had at least the , S and genes, signifying the noteworthy role of these genes in the pathogenesis of bovine intra-mammary infection in this area.

CONCLUSION

In the present study, the prevalence of was relatively low, possibly indicating that cows do not play a significant role in community-acquired MRSA infection in this area. According to the results, studied virulence factors were somewhat prevalent, bearing in mind the probable risk of transmission of these isolates from cows to humans, especially those that are in close contact with infected cattle. The data presented here can be used for the introduction of a protective vaccine against this infection.