''Mannheimia'' is a genus of

Gram-negative bacteria Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the Crystal violet, crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelo ...

in the family ''

Pasteurellaceae The Pasteurellaceae comprise a large family of Gram-negative bacteria. Most members live as commensals on mucosal surfaces of birds and mammals, especially in the upper respiratory tract. Pasteurellaceae are typically rod-shaped, and are a notabl ...

''. Members of this genus are typically

facultatively anaerobic A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are ''Staphylococcus' ...

, non-

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

-forming, and non-motile

coccobacilli Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archaea ...

. Species of ''Mannheimia'' are primarily associated with mucosal surfaces of domestic and wild animals, especially ruminants. The most well-known species, ''

Mannheimia haemolytica ''Mannheimia haemolytica'' is a species of Gram-negative bacteria belonging to the family Pasteurellaceae. It is a facultatively anaerobic, non-spore-forming, and non-motile coccobacillus. ''M. haemolytica'' is a primary bacterial pathogen implic ...

'', is an important pathogen in veterinary medicine and is a leading cause of bovine respiratory disease complex (BRDC).

History

The genus ''Mannheimia'' was proposed in 1999 by Danish microbiologist Ole Angen and colleagues. It was created to resolve taxonomic confusion within the former '' Pasteurella haemolytica'' complex based on results from

DNA–DNA hybridization In genomics, DNA–DNA hybridization is a molecular biology technique that measures the degree of genetic similarity between DNA sequences. It is used to determine the genetic distance between two organisms and has been used extensively in phylo ...

and

16S rRNA 16S ribosomal RNA (or 16Svedberg, S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome (SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The genes coding for it are referred to as ...

gene sequencing. The authors transferred several species to this new genus, including the newly defined ''M. ruminalis'', ''M. varigena'', and ''M. glucosida''. The genus was named in honor of Walter Mannheim, a German microbiologist who contributed significantly to the taxonomy of the family ''Pasteurellaceae''. The type species is ''Mannheimia haemolytica''.

Species

As of 2025, the genus includes the following validly published species:

History

Species

References

Further reading