Clinical, Epidemiological, Bacteriological and Antimicrobial Resistance Studies on Bovine Mastitis in Menoufia Governorate

Bovine mastitis globally is considered one of the most important diseases within dairy herds, mainly due to the associated economic losses. Mastitis can be classified as contagious and environmental mastitis. Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae are the most common pathogens associated with mastitis cases. In this study, risk factors affecting the prevalence rate of clinical and subclinical mastitis were studied in 300 dairy cows. The clinical examination of 300 cows from El-Menoufia governorate revealed that 150 and 90 cows showed the clinical signs of acute and chronic mastitis, respectively. On the other hand, 60 cows showed no clinical signs and were positive in CMT and classified as subclinical mastitis. Bacteriological examination of 300 mastitis milk samples showed that 210 samples were positive in bacteriological culture (70 %). Staphylococcus aureus isolates are the most prevalent in clinical and subclinical mastitis cases. Sixty-two isolates were obtained from acute mastitis, 40 isolates from chronic mastitis, and 24 isolates from subclinical mastitis. On the other hand, 66 isolates of E. coli were obtained (52 isolates from acute mastitis, 11 isolates from chronic mastitis, and 3 from subclinical mastitis). The least causative agent isolates were Klebsiella species (a total of 18 isolates, from which 6 isolates were from acute mastitis, 9 isolates from chronic mastitis, and 3 from subclinical mastitis). Risk factor analysis showed that the El-Bagour region was the highest area affected by mastitis. The bacterial isolation percentages in relation to the stage of lactation showed the highest percentage at early lactation (31%), while the percentage of middle stage of lactation (22%), late stage of lactation (13%), and at the dry period (4%). From different breeds, the mixed breed was highly affected. The detection of antimicrobial resistance of the different isolates had been carried out in this study revealed that, among the randomly selected 126 Staphylococcus aureus isolates, showed high resistance to penicillin G, 66.6%, sulfamethoxazole/trimethoprim 57.1%, gentamicin 53.9%, chloramphenicol 51.5%. The highest rate of sensitivity was observed for spiramycin 80.1%, norfloxacin 59.5%, amoxicillin + clavulinic acid 57.1%, and ciprofloxacin 53.9%. Among the randomly selected 66 E. coli isolates, showed resistance to penicillin G by 86.3%, sulfamethoxazole/trimethoprim 57.5%, Tetracycline 56.06%. The highest rate of sensitivity observed was to Ciprofloxacin 84.8%, Norfloxacin 80.3%, Spiramycin 69.6%, chloramphenicol 62.1%, and amoxicillin+clavulinic acid 53%. On the other hand, among the randomly selected 18 Klebsiella species, these isolates showed resistance to amoxicillin + clavulinic acid 77.7%, Penicillin 72.2%, Spiramycin 72.2%, and Tetracycline 66.6%. The highest rate of sensitivity was observed for sulfamethoxazole/ trimethoprim, 72.2%, gentamycin, 61.1%, and Norfloxacin, 66.6%.