Identification and Antimicrobial Susceptibility Patterns of Aerobic Pathogenic Bacteria Isolated from Respiratory Tract of Sheep in Ethiopia.

Respiratory tract diseases, mainly of bacterial origin, have been identified as important problems accounting for up to 54% of the overall mortality of sheep in the central highlands of Ethiopia. This descriptive cross-sectional study was conducted on sheep reared at Debre Berhan Agricultural Research Centre. It is aimed at establishing the prevalence of bacterial respiratory tract infections in sheep and their susceptibility to commonly used antimicrobials. Bacteria isolated from lung samples were identified using standard procedures and subjected to in vitro susceptibility test using disc diffusion method. Out of 80 samples 70 (87.50%) yielded bacteria of which 38 (54.30%) indicated mixed infections. The most commonly isolated bacteria is Staphylococcus epidermidis (13.16%) followed by Escherichia coli (11.41%) and Staphylococcus aureus (9.65%). Antimicrobial sensitivity test revealed that Streptococcus pyogenes, S. epidermidis and Streptococcus pneumoniae were strongly sensitive to seven of the eight antimicrobials tested. Conversely, 54.55% and 50.00% of the isolates were resistant to clindamycin and penicillin G, respectively. The highest resistance was observed in Enterococcus faecalis and Streptococcus uberis. This study indicated high level of resistance to some of the commonly used antimicrobials both in human and veterinary practice. Therefore, rational use of antimicrobials should be instituted to minimize further development of resistance.Key words: respiratory tract diseases, cross-sectional study, sheep, bacterial identification, antimicrobials susceptibilit