Bacteriology of Clinical Mastitis in Sheep and Goats and In Vitro Antibiogram of the Isolates

Abstract

This study was carried out to report on the microbial causes and the sensitivity of the isolates obtained from clinical mastitis cases in ewes and does to antibiotics. A total of fifty one mastitic milk samples (41 from ewes and 10 from does) were collected during December 2014 and April 2015, from mutton-type sheep flocks and lactating goat flocks. General clinical examination of animals was conducted (including udder palpation) to detect clinical mastitis. California mastitis test (CMT) was used to determine clinical mastitis. Results obtained showed that 39 (76.47%) of samples were positive in CMT test. Bacteriological examination resulted in 16 isolates obtained from CMT positive cultured samples out of 39 positive samples (41%) Then, the isolates were confirmed using VITEK2 system for identifying sub-species genera. Bacteriological examination resulted in occurrence rate of 40%, and 29.26% in goats and sheep, respectively. The Pathogenic bacteria organisms were isolated from 31.37 % of all mastitic mammary glands secretion (51 samples). The main identified bacterial species were: Enterobacter aerogenes 31.25% (the highest incidence rate), Staphylococcus aureus (6.25%), Streptococcus ssp (12.5%) and Escherichia coli (6.25%), these organisms considered as predominant causative agents, in addition to other less common causative agents. On the basis of sensitive, moderate sensitivity and resistance nature sensitivity test of the causative bacteria isolated to ten different antibiotics (available in the market and commonly used by veterinarians and owners in the treatment in field) was done. Nine out of eleven examined isolates (81.8%) were sensitive to Gentamicin with moderate sensitivity to only two isolates (18.2%) and no resistance detected to all examined isolates(0%), the two strains (5 isolates) of Enterobacter aerogenes were found to be sensitive to Gentamicin and Trimethoprim but the majority (Four isolates) of them showed