Mannheimia pernigra is a species of Gram-negative bacterium in the family Pasteurellaceae. It was first described in 2021 following the isolation of multiple strains from the upper respiratory tracts of veal calves in Switzerland.[1]
M. pernigra was previously referred to as "Taxon 39" of Bisgaard. Phylogenetic analyses based on 16S rRNA, recN, and rpoB gene sequences revealed that these isolates form a distinct cluster within the genus Mannheimia.[1]
Morphology and physiology
M. pernigra is a non-motile, Gram-negative coccobacillus. It grows aerobically on blood agar, forming small, grayish, non-hemolytic colonies. The major fatty acids are C14:0, C16:0, C16:1 ω7c, and C18:1 ω7c. The predominant respiratory quinones are ubiquinone-7 and ubiquinone-8.[1]
Isolation and habitat
The type strain, 17CN0883T, was isolated from the nasopharynx of a veal calf in Switzerland. Additional isolates were obtained from the upper respiratory tracts of calves at various Swiss fattening farms, indicating that M. pernigra is part of the bovine upper respiratory tract microbiota.[1]
Clinical significance
While M. pernigra has been isolated from the respiratory tracts of healthy calves, its role in bovine respiratory disease remains unclear. Further studies are needed to determine its pathogenic potential.[1]
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