Introduction Pneumonic pasteurellosis mainly caused by bacterial species of Mannheimia, Pasteurella , and Bibersteinia causes a significant financial loss to the sheep production sector through reduced productivity and high mortality. There is a dearth of information on the major agents involved in the disease in the Amhara region, Ethiopia. Therefore, the aim of this study was to isolate and molecularly confirm Mannheimia, Pasteurella , and Bibersteinia from nasal swabs of sheep suspected of pneumonic pasteurellosis in selected areas of the Amhara region. Methods Isolation and phenotypic characterization were performed using microbiological and biochemical testing according to standard methods. Molecular confirmation of isolates was done through amplification of virulence associated genes, PHSAA and Rpt2 , of Mannheimia hemolytica using multiplex PCR. Results Accordingly, 46 out of 141 (32.62%) samples were presumably identified as M. hemolytica with no Pasteurella multocida and Bibersteinia trehalosi . Seven (n=7) out of the 46 isolates tested positive for either of the two virulence genes. Discussion and conclusion The finding of this study is indicative that M. hemolytica is the main bacteria linked with pneumonic pasteurellosis in the study area which suggests the need to develop a polyvalent vaccine including strains of M. hemolytica or its antigenic determinants. However, the role of other bacterial, viral, and parasitic agents in the cases investigated should also be considered.

A longitudinal study was undertaken to investigate E. coli using standard biochemical and sugar fermentation tests. Faecal samples were taken from calves purposively from three selected dairy farms in Bishoftu Ethiopia. Four different sampling times were used to observe the detection rate of E. coli. The overall detection of E. coli was 84/104 (80.70%). The detection of E. coli isolates in different sampling points ranged from 16.34% to 25.00% in which the occurrence of E.coli has a significant association. All E. coli isolated showed different sugar fermentation patterns. E. coli was biotyped into 14 biotypes and variation occurred for samples taken during the first to fourth sampling points, the pattern ranging from 20.20% to 31.00%. Among 14 biotypes, biotypes VI and III dominate with 55.95% and 16.67% respectively. E. coli biotype (predominantly group VI) distribution concerning sampling time points have a significant association (p=0.039).Diverse natures and variations of E. coli were observed in calves with different sampling points as the main determinant. Farm management practice could reduce the occurrence of the pathogen in farm animals, particularly neonatal calves.