Campylobacter molothri sp. nov. isolated from wild birds

Authors: Miller, William; LOPES, BRUNO - Teesside University; Chapman, Mary; Williams, Tina; RAMJEE, MEENAKSHI - University Of Glasgow; Wood, Delilah; Bono, James; FORBES, KEN - University Of Aberdeen

Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2024
Publication Date: 2/6/2025
Citation: Miller, W.G., Lopes, B.S., Chapman, M.H., Williams, T.G., Ramjee, M., Wood, D.F., Bono, J.L., Forbes, K.J. 2025. Campylobacter molothri sp. nov. isolated from wild birds. International Journal of Systematic and Evolutionary Microbiology. 75(2). Article 006635. https://doi.org/10.1099/ijsem.0.006635.
DOI: https://doi.org/10.1099/ijsem.0.006635

Interpretive Summary: Strains of the species Campylobacter are commonly associated with human illness. Campylobacter jejuni is considered the leading cause of bacterial human gastroenteritis worldwide. Campylobacters are predominantly associated with avian hosts, both wild and domestic. Twenty-nine Campylobacter strains were recovered from both wild birds (for example, cowbirds and blackbirds) and river water. Analysis of these strains indicated that they were distinct from but closely related to species previously isolated from finches. These strains, for which the name Campylobacter molothri is proposed, have a unique genomic content. They are unable to synthesize most amino acids and presumably rely on their avian hosts for these compounds. They may also be able to use glucose and galactose as nutrients, a feature atypical of most campylobacters. Finally, several of these strains could potentially induce Guillain-Barre syndrome and thus could be of clinical importance.

Technical Abstract: Twenty-nine hippuricase positive Campylobacter strains were isolated from wild birds and river water. Previous characterization using atpA typing indicated that these strains were related to Campylobacter jejuni and Campylobacter coli but were most similar to three recently described hippuricase-positive Campylobacter species recovered from Zebra finches, i.e., C. aviculae, C. estrildidarum and C. taeniopygiae. Phylogenetic analyses using 330 core genes placed the 29 strains into a clade well separated from the other Campylobacter taxa, indicating that these strains represent a novel Campylobacter species. Pairwise digital DNA-DNA hybridization and average nucleotide identity values were below 70% and 95%, respectively, thus providing further supporting evidence of a novel taxon. Standard phenotypic testing was performed. All strains are microaerobic or anaerobic, motile, Gram-negative, spiral cells that are oxidase, catalase and nitrate reductase positive, but urease negative. Genomic analyses indicate that the 29 strains can potentially synthesize very few amino acids de novo and are auxotrophic for many amino acids and cofactors, similar to the species composing the Campylobacter lari group. In addition, these strains encode complete Entner-Doudoroff and Leloir pathways, suggesting that they may possess the ability to utilize both glucose and galactose; these pathways were also identified in the genomes of the Zebra finch-associated taxa. The data presented here show that these strains represent a novel species within Campylobacter, for which the name Campylobacter molothri sp. nov. (type strain RM10537T=LMG 32306T=CCUG 75331T) is proposed.