Dr. Gezahegn Mamo, Dr. Teshale SoriDr. Bersissa KumsaAbebe, Wirtu2018-12-252023-11-302018-12-252023-11-302018-06http://etd.aau.edu.et/handle/123456789/15297MSc ThesisPneumonic pasteurellosis is a multifactorial respiratory disease of cattle and sheep caused by combination etiologic agents; hence, reliable information is needed on the inventory of Pasteurella species for optimum control of the disease. This study was conducted from November 2017 to May 2018 with objectives of isolation and identification of Pasteurella organisms and assessment of their antibiotic sensitivity profiles from cattle and sheep using conventional and molecular methods. A cross-sectional study was carried out on samples collected from abattoirs (Bishoftu and Sululta area) and nasal swabs from cattle and sheep brought to Sendafa veterinary clinic for various reasons. A total of 149 nasal swabs (74 cattle and 75 sheep) were collected and examined using bacteriological methods, of which 33 (22.15%) yielded positive results for Pasteurella, Mannheimia and Bibersteinia species. Out of the 33 isolates 15 (20.27%) were from cattle and 18 (24.00%) were from sheep. The species composition of the isolates showed that 15 (10.07%), 7 (4.7%) and 11 (7.38%) of them were M. haemolytica, B. trehalosi and P. multocida, respectively. Pasteurella species were more frequently isolated from pneumonic (36.84%) cattle than non-pneumonic ones (2.78%). Similarly Pasteurella species were more frequently isolated from pneumonic sheep (41.03%) than non-pneumonic counterparts (5.56%). Mannheimia haemolytica was isolated from 8.72% of the pneumonic cases, P. multocida from 7.38% and B. trehalosi from 4.02% of pneumonic cases. From 176 pneumonic lung samples (93 cattle and 83 sheep) collected from abattoirs Pasteurella species were isolated from 48 (27.27%) of them comprising 24.73% (23) from cattle and 30.12% (25) from sheep. The isolates comprised M. haemolytica (13.07%), B. trehalosi (7.39%) and P. multocida (6.83%). Molecular characterization also confirmed the identity of P. multocida and M. haemolytica. In addition, the P. multocida isolates were identified to be similar to serovars A1 and A3 found in the Gene bank. The isolates were found to be resistant to the commonly used antibiotics Cloxacillin and Ampicillin (77.78 -100%); whereas they showed sensitivity to Chloramphenicol, Norfloxacillin and Oxytetracycline (71.43 -100%). This study revealed that M. haemolytica, P. multocida and B. trehalosi are commonly circulating in cattle and sheep originated from various parts of the country.enAbattoirantibiotic susceptibilityPasteurella speciesThesis