Brucella microti‐ like prevalence in French farms producing frogs

Abstract

In the last 10 years, many atypical novel members of Brucella species have been reported, including several Brucella inopinata‐like strains in wild‐caught and “exotic” amphibians from various continents. In 2017, a strain of Brucella was isolated for the first time in animals from a French farm producing frogs—Pelophylax ridibundus—for human consumption and identified as B. microti‐like. Following this first isolation, investigations were performed in this farm as well as in the farm of the research unit that provided the domestic frog strain to estimate the prevalence of B. microti‐like infection and its presence in the surrounding environment. Farming practices were investigated and samples including frogs at different development stages, surface tank swabs, water, feed and soil were analysed by real‐time PCR and bacteriological methods. High B. microti‐like prevalence values (higher than 90%) were obtained in frog samples in the commercial farm, and its presence was highlighted in the environmental samples except feed. In the research unit farm, B. microti‐like species was also isolated and detected in frog and environmental samples. These results show that B. microti‐like organisms are able to colonize amphibians and persist in their environment. Its presence could constitute a possible risk for consumers and workers proving the importance of assessing the zoonotic and pathogenic potentials of these new and atypical Brucella species.

The European Union One Health 2018 Zoonoses Report

“…These results showed that B. microti ‐like organisms are able to colonise amphibians and persist in their environment. Its presence could constitute a possible risk for consumers and workers proving the importance of assessing (Jaÿ et al., ).…”

Brucella: Reservoirs and Niches in Animals and Humans

“…Other species genetically related to an atypical group within the genus have been described in different host species: Brucella microti-like in marsh frogs (Pelophylax ridibundus) [11]; Brucella vulpis in the red fox (V. vulpes) [13]; Brucella inopinata in White's and Denny's tree frogs, (Ranoidea caerulea and Zhangixalus dennysi) [169] and humans; Brucella papionis in baboons (Papio spp.) [15], without mentioning Brucella strains isolates from lungworms in porpoise (Phocoena phocoena) [170], blue-spotted ribbontail ray (Taeniura lymma) [171] and reptile panther chameleon (Furcifer pardalis) [172].…”

“…In 2017, a B. microti-like strain was identified in internal organs (heart, lung, spleen, kidney, liver, and reproductive organs) and sometimes in hind limb muscles of marsh frogs in a French farm producing frogs for human consumption [11]. The human pathogenicity of amphibian strains has not been formally demonstrated but cannot be ruled out because the pathogenicity of B. microti in wild rodents has been confirmed experimentally in a mouse infection model, with high replication rates in murine macrophages [173].…”

“…Brucella melitensis, Brucella abortus, and Brucella suis are the most important members of the genus because they are responsible for the human disease [5,6] and for significant economic losses in livestock [7,8], while Brucella canis, Brucella neotomae, and Brucella ovis display less or non-zoonotic potential [9]. Recently, many other species have been described in aquatic mammals (like Brucella pinnipedialis and Brucella ceti) and other wildlife such as Brucella papionis, Brucella microti, Brucella inopinata, and Brucella vulpis [10][11][12][13][14][15][16].…”

Susceptibility of Avian Species to Brucella Infection: A Hypothesis-Driven Study

“…Furthermore, B. abortus was recovered from a dog and a cat after ingestion of infected placenta materials and ingestion of milk from Brucella-positive cows [13]. A B. microti-like organism was isolated from a domestic marsh frog (Pelophylax ridibundus) and the surrounding environment in a commercial farm in France [14,15]. A novel Brucella strain similar to a B. inopinata-like sp.…”