Isolation of Actinomyces cricetomyis sp. nov from orocervicofacial abscesses of African giant pouched rats (Cricetomys ansorgei)

African giant pouched rats are notable both for their exceptional sense of smell and for how readily they can be trained, a combination that suits them to applications ranging from explosives detection to disease screening. A colony housed at a university animal care facility developed abscesses associated with the jaw and eye in multiple animals. The predominant bacterial species in each case was a catalase-positive Actinomyces-like Gram-positive bacillus. The isolates from different sites and animals matched each other genetically but had sequences and biochemical profiles inconsistent with previously described species of this group. The strains clustered together with 100% bootstrap support based on both 16S rRNA and whole genome alignment. Based on genomic metrics, the average nucleotide identity of the most closely related species is Actinomyces respiraculi ZJ750T with 90.5% average nucleotide identity. Distinguishing biochemical characteristics include lack of nitrate reduction and hydrolysis of aesculin. Based on 16S rRNA, phylogenomic metric, and biochemical characterization, a novel species of the genus Actinomyces is proposed, namely Actinomyces cricetomyis sp. nov. The type strain is 186855T (ATCC TSD-310T=LMG 32803T).