Genotyping and phylogenetic analysis of Mannheimia haemolytica isolates from cattle and buffaloes of West Azerbaijan, Iran

This study was conducted in West Azerbaijan province, Iran (۳۷°۲۷'۱۸.۰۲۲" N, ۴۵°۰'۰" E) to investigate the genotyping and phylogenetic characterization of Mannheimia haemolytica in cattle and buffaloes from November ۲۰۲۲ to January ۲۰۲۴. Mannheimia haemolytica is a bacterium known to cause pasteurellosis pneumonia, a respiratory disease in ruminants, such as cattle and sheep. This is one of the main causes of economic losses in the feedlot industry. In addition to the deaths, treatment costs are also significant. The lung and nasal swab samples were collected from ۳۷۸ cattle and buffaloes. The M. haemolytica was detected in ۳۲ (۸.۴۶%) of the samples, with a notably higher isolation rate from lung tissue (۵۶.۲۵%; n = ۱۸) compared to the nasal swabs (۴۳.۷۵%; n = ۱۴). Interestingly, the study also revealed a seasonal pattern, with the highest isolation rates observed during January, February, and March. Multi-locus sequence typing demonstrated that all isolates belonged to sequence type ۱ (ST۱) within clonal complex ۲۸. This finding is consistent with the global prevalence of ST۱ in bovine isolates, indicating widespread distribution. Phylogenetic analysis revealed a strong correlation between ST۱ and STs ۳۰ and ۵۴, highlighting the prevalence of ST۱ in M. haemolytica among ruminants in West Azerbaijan, Iran. Further research is needed to investigate its potential for causing disease and its transmission pattern.

کلیدواژه ها:

Genetic diversity ، Molecular typing ، Multi-locus sequence typing ، Phylogenetic analysis ، Ruminant