Moraxellaceae

Moraxellaceae is a family of Gram-negative, non-spore-forming bacteria in the order Pseudomonadales, class Gammaproteobacteria. Members are found in soil, water, and host-associated habitats, ranging from environmental saprophytes to opportunistic pathogens. The family includes several genera, notably Acinetobacter and Moraxella, with Enhydrobacter and Psychrobacter among others.

Morphology and physiology: Cells are typically non-motile or variably motile, with shapes ranging from coccobacilli to rods. They are generally aerobic or facultatively aerobic and do not form spores. Metabolic traits vary; Acinetobacter is non-fermenting, Moraxella species are often diplococci, and oxidase activity can vary across the family.

Clinical relevance: Several members are human pathogens. Moraxella catarrhalis is a common cause of otitis media, sinusitis, and lower respiratory infections. Acinetobacter baumannii and related species are associated with healthcare-associated infections and can be multidrug resistant, posing challenges in clinical care.

Ecology and diversity: Outside clinical contexts, Moraxellaceae contribute to nutrient cycling in soils and aquatic environments. Psychrobacter species are adapted to cold environments, while Enhydrobacter has been isolated from human skin and other sources. Taxonomy within the family continues to evolve as genomic data refine relationships among genera.