Isolation, Identification and Antimicrobial Resistance Profile of staphylococcus aureus and Occurrence of Methicillin Resistant S. aureus Isolated from Mastitic Lactating Cows in and Around Assosa Town, Benishangul Gumuz Region, Ethiopia

Abstract

A cross - sectional study was conducted from November 2016 to May 2017 in Dairy cattle in and around Asossa town in order to estimate the prevalence of mastitis, to identify S. aurues from mastitic lactating cows, to evaluate its antimicrobial resistance pattern and to identify risk factors associated with mastitis. A total of 384 Dairy cows milk samples were collected using purposive sampling techniques. The overall prevalence of mastitis at cow level was 39.32 % with 11.45 % and 27.86 % of clinical and subclinical mastitis, respectively. In this study, the subclinical mastitis was significantly higher than clinical mastitis. For all except Age and parity, the multivariable logistic regression analysis for intrinsic and extrinsic risk factors showed significant difference in the prevalence of mastitis in the study area (P˂0.05). From 151 mastitis infected lactating cows, 436 milk samples were cultured and 22.14% S.aureus were isolated. Presumptively identified S. aureus isolates were subjected to antimicrobial susceptibility test and 63(74.11%) MRSA have been identified from a total of 85 S. aureus using cefoxitin through disk diffusion method. The present result showed a significant association of resistance pattern with S.aureus isolates, particularly to penicillin G (95.55%), Cefoxitin (77.19%), Tetracycline (63.41%), Streptomycin (60.78%), Gentamycin (59.37%), Vancomycin (56.75%), Clindamycine (54.35%) and Bacitracin (53.65%). In this study, 77.19 % S.aureus isolates were found resistant against Cefoxitin. There were also observed multidrug resistance, mainly to Penicillin G, Streptomycin and Tetracycline. The present study revealed higher prevalence of mastitis and occurrence of multidrug resistance S.aureus specifically which belongs to the MRSA which are dependent on multiple associated risk factors. Hence, regular resistance follow-up, using antimicrobials sensitivity tests helps to select effective antimicrobials and to reduce the problems of drug resistance developments towards commonly used antimicrobials.

Keywords: Asossa, Antimicrobial susceptibility, Dairy cattle, milk, mastitis, Methicillin resistance, Staphylococcus aureus