Corynebacterium of thediphtheriaecomplex in companion animals: clinical and microbiological characterization of 64 cases from France

Abstract

Objectives: Corynebacteria of the diphtheriae complex (Cdc) can cause diphtheria in humans and have been reported from companion animals. We aimed to describe animal infection cases caused by Cdc isolates. Methods: 18 308 animals (dogs, cats, horses and small mammals) with rhinitis, dermatitis, non-healing wounds and otitis were sampled in metropolitan France (August 2019 to August 2021). Data on symptoms, age, breed, and the administrative region of origin were collected. Cultured bacteria were analyzed for tox gene presence, for production of the diphtheria toxin, for antimicrobial susceptibility, and genotyped by multilocus sequence typing. Results: C. ulcerans was identified in 51 cases, 24 of which were toxigenic. Rhinitis was the most frequent presentation (18/51). Eleven cases (6 cats, 4 dogs, 1 rat) were mono-infections. Large breed dogs, especially German Shepherds (9 of 28 dogs; p < 0.00001) were overrepresented. C. ulcerans isolates were susceptible to all tested antibiotics. tox-positive C. diphtheriae was identified in 2 horses. Last, 11 infections cases (9 dogs, 2 cats; mostly chronic otitis, and 2 sores) had tox-negative C. rouxii, a recently defined species. C. rouxii and C. diphtheriae isolates were susceptible to most antibiotics tested, and almost all of these infections were polymicrobial. Conclusions: Monoinfections with C. ulcerans point towards a primary pathogenic potential to animals. C. ulcerans represents an important zoonotic risk, and C. rouxii may represent a novel zoonotic agent. This case series provides novel clinical and microbiological data on Cdc infections, and underlines the need for management of animals and their human contacts.

Pastern dermatitis outbreak associated with toxigenic and non‐toxigenic Corynebacterium diphtheriae and non‐toxigenic Corynebacterium ulcerans at a horse stable in Finland, 2021

“…Based on epidemiologic studies and sequence homology, zoonotic transmission of C. ulcerans-type diphtheria between pigs and humans (Berger et al, 2013;Schuhegger et al, 2009) and between wild animals, dogs, and humans (Katsukawa et al, 2016) seems likely. Sporadically, C. ulcerans findings among game, hunting and pet dogs, cats and horses have been reported (Abbott et al, 2020;Carfora et al, 2018;Eisenberg et al, 2014;Katsukawa et al, 2016;Museux et al, 2023;Saeki et al, 2015;Zendri et al, 2021). During 2002-2008 most of the human C. ulcerans cases in France had had animal contact (dogs or cats) before infection, but animal-human transmission could not always be confirmed due to negative animal test results or lack of testing of animals (Bonmarin et al, 2009).…”

Zoonotic transmission of diphtheria toxin‐producing Corynebacterium ulcerans

“…Generally, infection is associated with mild respiratory and cutaneous manifestations with more serious manifestations thought to be linked to immunocompromise or inadequate vaccination (Gower et al, 2020). C. ulcerans has been isolated from many domesticated and wild animals (Eisenberg et al, 2015;Seto et al, 2008;Sting et al, 2023;Tejedor et al, 2000;Terriere et al, 2022;Thomas et al, 2022); the earliest reports of human infection were associated with the drinking of unpasteurised bovine products (Hacker et al, 2016), though companion animals such as cats and dogs are more frequently implicated in recent reports (Abbott et al, 2020;Carfora et al, 2018;Museux et al, 2023).…”

“…Like in humans, the burden of C. ulcerans colonization or infection in animals is sparsely described. Several prevalence studies (of between 60 and 13,310 animals, Table 1) have indicated that the bacteria may be carried by 0.4%-29% of monkeys in closed breeding colonies (Hirai-Yuki et al, 2013;Panaitescu et al, 1977), 0.07%-7.2% of dogs in shelters, local government custody, or veterinary hospitals (Museux et al, 2023;Abbott et al, 2020;Dias et al, 2010;Katsukawa et al, 2012), and 6.25% of cats in veterinary hospitals (Abbott et al, 2020). One prevalence study in farm pigs found many Corynebacterium species, but not C. ulcerans (Boschert et al, 2014).…”