Haemolytic and antibiogram activities of Staphylococcus aureus isolated from cattle with mastitis in Sokoto, Northern Nigeria

Abstract

Mastitis continues to be one of the most fatal disease in dairy cattle, and it causes enormous economic losses due to decreased milk production, high treatment costs, and eventual development of antimicrobial resistance. Therefore, this study assessed the in vitro haemolytic and antimicrobial activities of Staphylococcus aureus isolated from active cases of mastitis in cattle in Sokoto metropolis. Milk samples from various sources in the study area were collected aseptically, placed in an ice-packed container, and transported to the microbiology laboratory of the Department of Veterinary Microbiology, Usmanu Danfodiyo University, Sokoto. The samples were processed according to standard laboratory methods for S. aureus isolation and identification and tested for antimicrobial susceptibility using the Kirby-Bauer qualitative disk diffusion method. The diameter zone of inhibitions of each antibiotic used was recorded and interpreted using zone diameter interpretive standards of Clinical and Laboratory Standard Institute. A total of 105 (35 %) Staphylococcus species were identified, out of which 86 (81.9 %) were confirmed to be beta-haemolytic S. aureus and only 57 (66.3%) had their susceptibility to antimicrobials evaluated. Most of the antimicrobials used were found to be effective, with Gentamicin having the highest level of susceptibility (82.5%). However, reasonable resistance against S. aureus was observed in betalactam antimicrobials, revealing 56.1% and 50.9% for Ampicillin and Amoxycillin clavulanic acid, respectively. We recommend the use of antimicrobials only where absolutely necessary and management practices that will promote wholesomeness and control antimicrobial resistance in food animals.