BOVINE MASTITIS IN LACTATING COWS: AN INVESTIGATION OF ANTIBIOTIC-RESISTANT BACTERIA

Abstract

Milk quality and quantity is greatly affected by the high incidence of bacterial infection, bovine mastitis (BM) in lactating cows. Bacteria were isolated from mastitis infected cow. The efficacy of antibiotics against the bacteria isolates were determined by agar-well diffusion technique. Eight of the isolates were Gram-negative – Escherichia coli (2), Citrobacter freundii (3), Citrobacter diversus (1), Enterobacter aerogenes (1), Klebsiella pneumoniae (1), while ten were Gram-positive – Staphylococcus spp. (8), and Micrococcus spp. (2). Staphylococcus spp. (44.44%) had the highest percentage occurrence. Gentamicin (25±1.41 mm) and ofloxacin (27.5±0.71 mm) showed the highest zone of inhibition (ZI) against the Gram-positive isolates, but the organisms were 100% resistant to ceftazidime, cefuroxime, augmentin and cloxacillin. Ofloxacin (26.5±2.12 mm) and ciprofloxacin (30±0 mm) showed the highest ZI against the Gram-negative isolates and the organisms were 100% resistant to ceftazidime, cefuroxime, cefixime, and augmentin. Staphylococcus spp., C. freundii, E. coli and Micrococcus spp. were the predominant pathogens associated with BM in the study area. Ofloxacin is very effective against BM but all the organisms were resistant to ceftazidime, cefuroxime and augmentin. This study confirms that antibiotic resistant bacteria are present in BM infection and the antibiotics (ceftazidime, cefuroxime, cefixime, cloxacillin, and augmentin) are not effective therapies for treating BM. Therefore, indiscriminate use of these antibiotics should be discouraged in veterinary medicine.