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. 2025 Mar;44(3):559-569.
doi: 10.1007/s10096-024-05025-0. Epub 2024 Dec 20.

Investigation of antimicrobial susceptibility and resistance gene prevalence in Capnocytophaga spp. isolated from dogs and cats and characterization of novel class A β-lactamase CST-1

Kaoru Umeda  1 , Michio Suzuki  2 , Koichi Imaoka  2   3
Affiliations

Investigation of antimicrobial susceptibility and resistance gene prevalence in Capnocytophaga spp. isolated from dogs and cats and characterization of novel class A β-lactamase CST-1

Kaoru Umeda et al. Eur J Clin Microbiol Infect Dis. 2025 Mar.

Abstract

Purpose: Capnocytophaga spp., common inhabitants of the animal oral cavity, are zoonotic pathogens transmitted to humans through dog/cat bites and cat scratches. Appropriate antimicrobial therapy is essential for treatment this zoonotic disease because of the rapid deterioration of systemic symptoms at disease onset; however, antimicrobial resistance of animal bite-associated Capnocytophaga spp. has not been fully investigated. We sought to understand the antimicrobial susceptibility and prevalence of resistance genes among Capnocytophaga sp. isolates obtained from dogs and cats.

Method: Minimum inhibitory concentrations (MICs) of nine antibiotics for a total of 57 isolates belonging to 6 species (C. canimorsus, C. cynodegmi, C. canis, C. felis, C. stomatis, and C. catalasegens) were assayed using E-test. Resistance genes were detected using polymerase chain reaction, nucleotide sequencing, and whole-genome sequencing.

Results: The MICs of penicillin, ceftriaxone, cefepime, clindamycin, minocycline, nalidixic acid, and ciprofloxacin were high for some isolates. The MICs of imipenem and amoxicillin/clavulanic acid were low for all isolates. Known resistance genes blacfxA2, blaOXA-347, emrF, and tetQ were detected using polymerase chain reaction. Mutation in the quinolone resistance-determining region of gyrA was also detected. Cst-1, a previously unreported gene, was identified using whole-genome analysis of two C. stomatis isolates. CST-1 was proposed as a class A, subclass A2, β-lactamase based on amino acid sequence and phylogenetic relationship. In recombination experiments, CST-1 inactivated penicillin and first- and second-generation cephems; however, sulbactam inhibited it.

Conclusion: Known and novel resistance genes are prevalent among Capnocytophaga spp. in animal oral cavities. The findings have clinical implications, especially in antimicrobial treatment.

Keywords: Capnocytophaga spp.; Antimicrobial resistance; CST-1; Zoonosis; β-lactamase.

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Conflict of interest statement

Declarations. Competing interests: The authors declare no competing interests. Ethics approval: Cloning experiments were approved by the Recombinant DNA Experiments Safety Management Committee, Osaka Institute of Public Health, Japan. Ethics application was not required according to the guidelines of the Ethical Committee, Osaka Institute of Public Health, Japan. Consent to participate: Not applicable. Consent to publish: Not applicable.

References

    1. Gaastra W, Lipman LJA (2010) Capnocytophaga canimorsus. Vet Microbiol 140:339–346. https://doi.org/10.1016/j.vetmic.2009.01.040 - DOI - PubMed
    1. Butler T (2015) Capnocytophaga canimorsus: an emerging cause of sepsis, meningitis, and post-splenectomy infection after dog bites. Eur J Clin Microbiol Infect Dis 34:1271–1280. https://doi.org/10.1007/s10096-015-2360-7 - DOI - PubMed
    1. Renzi F, Hess E, Dol M, Koudad D, Carlier E, Ohlén M, Moore E, Cornelis GR (2018) Capsular serovars of virulent Capnocytophaga canimorsus are shared by the closely related species C. canis and C. cynodegmi. Emerg Microbes Infect 7:1–12. https://doi.org/10.1038/s41426-018-0126-x - DOI
    1. Suzuki M, Imaoka K, Kimura M, Morikawa S, Maeda K (2020) Capnocytophaga felis sp. nov. isolated from the feline oral cavity. Int J Syst Evol Microbiol 70:3355–3360. https://doi.org/10.1099/ijsem.0.004176 - DOI - PubMed
    1. Suzuki M, Imaoka K, Kimura M, Morikawa S, Maeda K (2023) Capnocytophaga catalasegens sp. nov., isolated from feline oral cavities. Int J Syst Evol Microbiol 73. https://doi.org/10.1099/ijsem.0.005731

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