Corynebacterium uberis sp. nov. frequently isolated from bovine mastitis

Elsevier

Available online 5 May 2022, 126325

Systematic and Applied MicrobiologyAbstract

Several strains belonging to the genus Corynebacterium, but not to any described species of the genus were isolated from bovine mastitic milk samples over the past five years in the diagnostic unit of the University of Bern. Six of these strains (18M0132T, 17M2518, 18M0913, 19M0083, 20M1046 and 20M1090) that were phenotypically similar were further characterized genotypically. Gram-positive coryneform rods were catalase positive, facultative anaerobe and CAMP-test negative. Whole genome sequencing and subsequent phylogenetic analysis revealed their genome size to be 2.53 Mb and their G+C content to be between 65.4-65.5 mol%. Digital DNA-DNA hybridisation (dDDH) showed the highest similarity of only less than 20% with Corynebacterium mastitidis and Corynebacterium frankenforstense, which indicated that the isolates belong to an undescribed Corynebacterium species. This was confirmed by studying the average nucleotide identity (ANI) where the accepted species boundary is around 95% and which ranged between 70.3% and 74.9% with the most closely related species C. mastitidis. We established MALDI-TOF fingerprints of the species, which allows a clear separation from related species and can be used by other laboratories for diagnostic purposes.

Based on our analyses we conclude that the selected strains belong to a previously undescribed species and propose the name Corynebacterium uberis sp. nov. The proposed type strain is 18M0132T (=DSM 111922T, = CCOS 1972T).

AbbreviationsANI

average nucleotide identity

dDDH

digital DNA-DNA hybridization

MALDI-TOF

matrix-assisted laser desorption/ionization – time of flight

MIC

minimal inhibitory concentration

TSA SB

Trypticase Soy Agar with 5% sheep blood

Keywords

Corynebacterium uberis sp. nov.

Bovine mastitis

Corynebacteriaceae

Phylogeny

© 2022 The Author(s). Published by Elsevier GmbH.

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