The role of ‘atypical’<i>Brucella</i>in amphibians: are we facing novel emerging pathogens?

Mühldorfer, Kristin; Wibbelt, Gudrun; Szentiks, Claudia A.; Fischer, Dominik; Scholz, Holger C.; Zschöck, M.; Eisenberg, Tobias

doi:10.1111/jam.13326

Cited by 44 publications

(46 citation statements)

References 43 publications

(122 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The close relationship of amphibian isolates with ‘atypical’ Brucella isolates, previously been associated with severe human disease, suggests that these organisms may themselves have pathogenic potential that merits investigation. Apparently, amphibian brucellae are capable of causing disease in different anuran species ranging from localized manifestations to generalized organ infections [7–12] (this study). This indicates that they are at least facultative pathogens of veterinary importance in cold-blooded vertebrates.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The Change of a Medically Important Genus: Worldwide Occurrence of Genetically Diverse Novel Brucella Species in Exotic Frogs

et al. 2016

View full text Add to dashboard Cite

The genus Brucella comprises various species of both veterinary and human medical importance. All species are genetically highly related to each other, sharing intra-species average nucleotide identities (ANI) of > 99%. Infections occur among various warm-blooded animal species, marine mammals, and humans. Until recently, amphibians had not been recognized as a host for Brucella. In this study, however, we show that novel Brucella species are distributed among exotic frogs worldwide. Comparative recA gene analysis of 36 frog isolates from various continents and different frog species revealed an unexpected high genetic diversity, not observed among classical Brucella species. In phylogenetic reconstructions the isolates consequently formed various clusters and grouped together with atypical more distantly related brucellae, like B. inopinata, strain BO2, and Australian isolates from rodents, some of which were isolated as human pathogens. Of one frog isolate (10RB9215) the genome sequence was determined. Comparative genome analysis of this isolate and the classical Brucella species revealed additional genetic material, absent from classical Brucella species but present in Ochrobactrum, the closest genetic neighbor of Brucella, and in other soil associated genera of the Alphaproteobacteria. The presence of gene clusters encoding for additional metabolic functions, flanked by tRNAs and mobile genetic elements, as well as by bacteriophages is suggestive for a different ecology compared to classical Brucella species. Furthermore it suggests that amphibian isolates may represent a link between free living soil saprophytes and the pathogenic Brucella with a preferred intracellular habitat. We therefore assume that brucellae from frogs have a reservoir in soil and, in contrast to classical brucellae, undergo extensive horizontal gene transfer.

show abstract

Section: Discussionmentioning

confidence: 99%

“…More detailed information about pathological findings among the various frog species can be retrieved from a recent publication by Muehldorfer et al [12]. …”

Section: Methodsmentioning

confidence: 99%

The Change of a Medically Important Genus: Worldwide Occurrence of Genetically Diverse Novel Brucella Species in Exotic Frogs

et al. 2016

View full text Add to dashboard Cite

show abstract

“…A total of 21 strains (Table 1) isolated from tissue samples of various moribund or dead African bullfrogs kept in a quarantine unit of the Frankfurt Zoo (Germany) were analyzed44. The animals had been originally imported from Tanzania.…”

Section: Methodsmentioning

confidence: 99%

Brucella spp. of amphibians comprise genomically diverse motile strains competent for replication in macrophages and survival in mammalian hosts

Dahouk

Köhler

Occhialini

et al. 2017

Sci Rep

View full text Add to dashboard Cite

Twenty-one small Gram-negative motile coccobacilli were isolated from 15 systemically diseased African bullfrogs (Pyxicephalus edulis), and were initially identified as Ochrobactrum anthropi by standard microbiological identification systems. Phylogenetic reconstructions using combined molecular analyses and comparative whole genome analysis of the most diverse of the bullfrog strains verified affiliation with the genus Brucella and placed the isolates in a cluster containing B. inopinata and the other non-classical Brucella species but also revealed significant genetic differences within the group. Four representative but molecularly and phenotypically diverse strains were used for in vitro and in vivo infection experiments. All readily multiplied in macrophage-like murine J774-cells, and their overall intramacrophagic growth rate was comparable to that of B. inopinata BO1 and slightly higher than that of B. microti CCM 4915. In the BALB/c murine model of infection these strains replicated in both spleen and liver, but were less efficient than B. suis 1330. Some strains survived in the mammalian host for up to 12 weeks. The heterogeneity of these novel strains hampers a single species description but their phenotypic and genetic features suggest that they represent an evolutionary link between a soil-associated ancestor and the mammalian host-adapted pathogenic Brucella species.

show abstract

“…The first strains isolated from anurans of wild origin, kept as pets or in zoological collections, (Eisenberg et al, ; Fischer et al, ; Kimura et al, ; Mühldorfer et al, ; Soler‐Lloréns et al, ; Whatmore et al, ) are phenotypically and genetically related to the B. inopinata clade (Al Dahouk et al, ; Mühldorfer et al, ). In both wild and captive anurans, the distribution of B. inopinata has not been extensively investigated.…”

Section: Introductionmentioning

confidence: 99%

“…In both wild and captive anurans, the distribution of B. inopinata has not been extensively investigated. The Brucella transmission seems to be possible among amphibians sharing the same terrarium (Eisenberg et al, 2012;Kimura et al, 2017;Mühldorfer et al, 2017;Whatmore et al, 2015) but its pathogenicity remains controversial: most isolations have concerned animals with lesions but Brucella has also been isolated in healthy individuals (Kimura et al, 2017). The human pathogenicity of these amphibian strains has not been demonstrated but cannot be ruled out as B. inopinata was originally described in human infections (Scholz et al, 2010;Tiller et al, 2010).…”

mentioning

confidence: 99%

Brucella microti‐ like prevalence in French farms producing frogs

Jaý

Freddi

Mick

et al. 2019

Transbound Emerg Dis

View full text Add to dashboard Cite

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.

show abstract

The role of ‘atypical’Brucellain amphibians: are we facing novel emerging pathogens?

Cited by 44 publications

References 43 publications

The Change of a Medically Important Genus: Worldwide Occurrence of Genetically Diverse Novel Brucella Species in Exotic Frogs

The Change of a Medically Important Genus: Worldwide Occurrence of Genetically Diverse Novel Brucella Species in Exotic Frogs

Brucella spp. of amphibians comprise genomically diverse motile strains competent for replication in macrophages and survival in mammalian hosts

Brucella microti‐ like prevalence in French farms producing frogs

Contact Info

Product

Resources

About