Investigation of the nontypical Pasteurella multocida strains obtained from multiple sources, regions, and times: an unexpected increase was detected

In this study, it was aimed to isolate Pasteurella multocida from 1250 lung samples (calf, sheep, and goat), with respiratory system infection, such as nasal discharge, cough, fever, and to investigate the phenotypic and genotypic properties of this bacteria. As a result, a total of 92 P. multocida were obtained, of which 66 (71.73%) were from calf, 19 (20.65%) from sheep, and 7 (7.6%) from goat. The A:3A type was the most common type with 34 isolates (36.95%), including 30 from calves (45.45%), and 4 from sheep (21.05%). An alternate mPCR protocol was developed to determine capB and capE genes and 5 from 41 nontypical strains were detected as type B (n = 3; 3.26%) and type E (n = 2; 2.17%) via this novel protocol. Twenty-six nontypical strains presented nonmucoid colonies. The serotype of 11 typical and 13 nontypical strains was not able to be determined by mPCR. The prevalences of nontypical P. multocida were significantly (p < 0.01) different by determinants. Nineteen virulence-associated gene profiles were determined, and the highest percentages of genes were ompA (70.65%), ptfA (69.56%), and tadD (64.13%). Also, there was a higher rate of similarity between calf and sheep strains. In conclusion, nontypical strains may commonly cause pneumonia in farm animals. These results may be considered for future vaccine studies.