Bacterial Isolation and Antimicrobial Susceptibility from Bronchoalveolar Lavage Fluids of Calves with Severe Pneumonia

Abstract

In this study, nasopharyngeal swabs (Swab) and bronchoalveolar lavage fluids (BALF) were collected from 50 Japanese black cattle diagnosed with severe chronic pneumonia, and identification of the causative bacteria of pneumonia and its antibiotic susceptibilities were investigated. Mycoplasma bovis and Pasteurella multocida were mainly isolated from Swab and BALF. However, the rates at which the same bacterial species were isolated from both specimens in the same cow were relatively low. In addition, M. bovis and P. multocida isolated from BALF were mainly sensitive to fluoroquinolones, but the antibiotic susceptibilities of the same two species isolated from Swab were low. From the above, M. bovis and P. multocida were mainly isolated from the nasopharyngeal area and bronchoalveolar area of cattle with severe chronic pneumonia, but the antibiotic susceptibility differs depending on the collection site, even if the same bacterial species is a possibility. It seems necessary to be careful about estimating the pneumonia causing bacteria by Swab in calves with severe pneumonia.