Emergence of Vibrio cincinnatiensis, a Rare Human Pathogen, in Urban Crows

Currently, the genus Vibrio consists of 137 identified species (www.bacterio.net/ vibrio.html [accessed 26 September 2022]); among them, Vibrio cincinnatiensis is one of the 12 Vibrio species that are considered potential human pathogens (1). To date, three cases of V. cincinnatiensis infections have been reported in humans (2–4). However, because of the diversity of disease presentation of V. cincinnatiensis, including septicemia and meningitis, enteritis, and skin and soft tissue infections in immunocompromised and immunocompetent elderly patients with no history of marine exposure, knowledge of the prevalence of this rare organism in environmental settings is essential (2–4). Here, V. cincinnatiensis strains C6-3 and C12-3 were detected using CHROMagar mSuperCARBA (Kanto Chemical Co., Tokyo, Japan). They were isolated from fresh droppings from two different crows, collected from below the roosting trees in a public park of Suwa City in October 2021. The geographic location of the sampling site was more than 110 km from the sea; therefore, the crows, which commonly migrate 10 to 20 km outward from their roosts to forage, were not likely to be associated with seawater exposure. The V. cincinnatiensis strains C6-3 and C12-3 grew on thiosulfate-citrate-bile salts-sucrose agar, exhibiting yellow colonies indicative of sucrose utilization. They were comma-shaped Gram-negative rods that were halophilic, oxidase positive, and motile. Matrix-assisted laser desorption ionization–time of flight mass spectrometry-based identification (BioTyper v3.1; Bruker Daltonics, Bremen, German) yielded low confidence values for V. cincinnatiensis (scores of 1.74 and 1.79 for C6-3 and C12-3, respectively). The assigned species were verified on the basis of biochemical properties, such as positivity for acid production from arabinose, inositol, salicin, and sucrose determined by using the Vitek 2 Compact system (v07.01 software; bioMérieux, Tokyo, Japan) with Vitek 2 GN ID cards and API 50 CH kits (bioMérieux). Whole-genome sequencing was performed using the DNBSEQ-G400 platform (MGI Tech, Shenzhen, China). Sequence reads were assembled de novo using SPAdes v3.12.0 (https://cab .spbu.ru/software/spades). Strains C6-3 and C12-3 had genome average nucleotide identity values of 99.35% and 99.40% (JSpeciesWS [http://jspecies.ribohost.com/ jspeciesws]) and digital DNA-DNA hybridization values of 93.7% and 94.4% (TYGS [https://tygs.dsmz.de]), respectively, compared with the V. cincinnatiensis type strain NCTC12012 (GenBank assembly accession number GCA_900460255.1), and were confirmed as V. cincinnatiensis strains. A whole-genome multilocus sequence typing tree constructed using PGAdb-builder (http://wgmlstdb.imst.nsysu.edu.tw), with the addition of the genomes of 15 V. cincinnatiensis strains obtained from the NCBI database (see Table S2 in the supplemental material), classified the strains broadly into three Editor Sadjia Bekal, Institut National de Santé Publique du Québec Copyright © 2022 Soga et al. This is an openaccess article distributed under the terms of the Creative Commons Attribution 4.0 International license. Address correspondence to Noriyuki Nagano, naganon@shinshu-u.ac.jp. *Present address: Wataru Hayashi, Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan. The authors declare no conflict of interest.