Moraxella osloensis is a Gram-negative oxidase-positive, aerobic bacterium within the family Moraxellaceae in the gamma subdivision of the purple bacteria.^[1]

Quick Facts Moraxella osloensis, Scientific classification ...

Moraxella osloensis
Scientific classification
Domain:	Bacteria
Phylum:	Pseudomonadota
Class:	Gammaproteobacteria
Order:	Pseudomonadales
Family:	Moraxellaceae
Genus:	Moraxella
Species:	M. osloensis
Binomial name
Moraxella osloensis Bøvre and Henriksen 1967 (Approved Lists 1980)

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Moraxella osloensis is a mutualistic symbiont of the slug-parasitic nematode Phasmarhabditis hermaphrodita.^[1] In nature, Phasmarhabditis hermaphrodita vectors M. osloensis into the shell cavity of the slug host in which the bacteria multiply and kill the slug.^[1]

This bacterium has been identified as one of the natural symbionts of a bacteria-feeding nematode, Phasmarhabditis hermaphrodita (Rhabditida: Rhabditidae), which is an endoparasite of slugs, including the slug Deroceras reticulatum^[1] (grey garden slug) which is one of the most serious agricultural and garden slug pests.^[2]

In nature, bacteria colonize the gut of nematode-infective juveniles which represent a specialized stage of development adapted for survival in the unfavorable environment.^[1] The infective juveniles seek out and enter the slug's shell cavity through the posterior mantle region.^[1] Once inside the shell cavity, the bacteria are released, and the infective juveniles resume growth, feeding on the multiplying bacteria.^[1] The infected slugs die in 4–10 days, and the nematodes colonize the entire carcass and produce next-generation infective juveniles, which leave the carcass to seek a new host.^[1] The bacteria are responsible for killing the slugs; nematodes without bacteria do not cause death.^[2]

The lipopolysaccharide, that is an endotoxin, from M. osloensis is a molluscicide for Deroceras reticulatum when applied by injection.^[3]

The lethality of these nematodes to slugs has been shown to correlate with the number of M. osloensis cells carried by infective juveniles.^[1] Tan and Grewal (2001)^[2] demonstrated that the 72-hour-old M. osloensis cultures inoculated into the shell cavity were highly pathogenic to the slug.^[1] They further reported that M. osloensis produced an endotoxin which was identified to be a rough type lipopolysaccharide with a molecular weight of 5300 KD, and the purified lipopolysaccharide was toxic to the slug with an estimated 50% lethal dose of 48 μg when injected into the shell cavity.^[1]

Although M. osloensis rarely infects humans, it can sometimes be found in a variety of tissues, where it sometimes causes disease.^[4][5] Antibiotics^[which?] are usually effective against such infections.^[5]

Moraxella osloensis has been found to be responsible for locker-room smell or shower-curtain odor.^[6]

The species M. osloensis was proposed in 1967; the bacteria which are now considered to be M. osloensis would previously have been considered to be Moraxella nonliquefaciens or Mima polymorpha (var.) oxidans.^[5]

• List of restriction enzyme cutting sites