Determination of bacterial aetiologic factor on tracheobronchial lavage in relation to clinical signs of bovine respiratory disease França Dias de Oliveira, Bernardo Augusto and Carrillo Gaeta, Natália and Mendonça Ribeiro, Bruno Leonardo and Reyes Alemán, Mário Augusto and Miranda Marques, Lucas and Timenetsky, Jorge and Melville, Priscila Anne and Avansi Marques, Júlia and Marvulle, Valdecir and Gregory, Lilian,, 65, 1137-1142 (2016), doi = https://doi.org/10.1099/jmm.0.000345, publicationName = Microbiology Society, issn = 0022-2615, abstract= This study aimed to determine the occurrence of Mannheimia haemolytica, Pasteurella multocida and Mycoplasma spp., in relation to clinical signs of respiratory disease. Tracheobronchial lavage samples were collected from 96 (healthy and unhealthy) cattle in the State of São Paulo, Brazil. Mycoplasma spp. (12.5 %) and Pasteurella multocida (15.50 %) were the most prevalent species. Bacillus sp., Staphylococcus sp., Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa and Klebsiella pneumoniae were also isolated. Mollicutes (70.83 %), Mycoplasma bovis (2.94 %) and Mycoplasma dispar (38.23 %) were identified using conventional PCR. Submassive sound on acoustic percussion of the thorax was associated with the absence of Mollicutes (P=0.025). Whistling (P=0.076) and coarse crackle (P=0.046) were associated with the absence of Mycoplasma dispar. Clear sound on acoustic percussion of the thorax was associated with the absence of Mycoplasma bovis (P=0.007). Coughing was associated with the presence of Pasteurella multocida [P=0.035; confidence interval (CI), 1.12–26.89], but its absence was associated with mucopurulent (P=0.0215; CI, 1.55–34.5) and mucoid nasal discharge (P=0.068; CI, 19–28.5), submassive sound (P=0.031; CI, 1.23–75.5), fine crackle (P=0.058; CI, 1.23–20.1) and coarse crackle (P=0.046; CI, 2.38–70.8). The high prevalence of Pasteurella multocida and Mycoplasma spp. in unhealthy calves increases the importance of these micro-organisms in the pathogenesis of respiratory diseases. This study increases the information about the role of Mycoplasma dispar in respiratory diseases. Differences in some species in relation to clinical signs can be applied as a presumptive diagnosis., language=, type=