Highlighting on the Incidence of Antimicrobial Resistance among Mastitic Buffaloes in Some Dairy Farms in Qalubiya governorate

This study aimed to investigate somatic cell count (SCC) levels, and foodborne pathogenic bacteria in buffalo milk beside their antibiogram characteristics. Raw buffalo milk samples (n = 600) were randomly collected from Benha, Toukh, Kafr shokr and shebin elqanater provinces of Qalubiya Governorate, Egypt, during summer and winter seasons (75 of each/season). Results revealed the higher incidence of mastitis during summer season represented by higher SCC, with higher incidence of bacteria causing mastitis. Antibiotic resistant patterns and the presence of antibiotic resistance genes were evaluated in the isolates. Results revealed isolation of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Klebsiella spp. and Enterococcus fecalis from 59.3%, 44.0%, 35.8%, 10.8%, 6.7% and 4.3% of the examined samples, respectively. All isolates showed high rates of resistance to different antibiotics, and β-lactams particularly. The blaZ and tetK genes were detected in all of the examined S. aureus isolates, while mecA was detected in 66.6% only. In addition, blaTEM and tetA genes were detected in all of the examined E. coli and Ps. aeruginosa isolates; whereas, aadB gene was detected in 66.6% of the examined Ps. aeruginosa isolates. Moreover, bla gene was detected in all of the examined B. cereus isolates; while, ermA and tetA genes were detected in 33.3 and 66.6% of the examined isolates, respectively. On the other hand, higher level of somatic cell counts (SCC), and foodborne bacteria were determined in summer season than winter season indicating higher susceptibility of buffalo herds to acquire different degrees of mastitis during humid and tropical weather (summer season) than cold weather (winter season). The high prevalence of bovine milk contamination with antimicrobial-resistant species in this study necessitates precise control on antibiotic prescription in veterinary medicine.