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United States Department of Agriculture

Agricultural Research Service

Research Project: Molecular Biology of Human Pathogens Associated with Food

Location: Produce Safety and Microbiology Research

Title: Description of Campylobacter fetus subsp. testudinum subsp. nov., isolated from humans and reptiles

Authors
item Fitzgerald, Collette -
item Tu, Zheng-Chao -
item Patrick, Mary -
item Stiles, Tracy -
item Lawson, Andrew -
item Santovenia, Monica -
item Gilbert, Maarten -
item Van Bergen, Marcel -
item Joyce, Kevin -
item Pruckler, Janet -
item Stroika, Steven -
item Duim, Brigitta -
item Miller, William
item Loparev, Vladimir -
item Sinnige, Jan -
item Fields, Patricia -
item Tauxe, Robert -
item Blaser, Martin -
item Wagenaar, Jaap -

Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 2, 2014
Publication Date: June 4, 2014
Citation: Fitzgerald, C., Tu, Z., Patrick, M., Stiles, T., Lawson, A.J., Santovenia, M., Gilbert, M., Van Bergen, M., Joyce, K., Pruckler, J., Stroika, S., Duim, B., Miller, W.G., Loparev, V., Sinnige, J.C., Fields, P.I., Tauxe, R., Blaser, M.J., Wagenaar, J.A. 2014. Description of Campylobacter fetus subsp. testudinum subsp. nov., isolated from humans and reptiles. International Journal of Systematic and Evolutionary Microbiology. 64(9):2944-2948.

Interpretive Summary: The food-borne pathogen Campylobacter is a natural contaminant of most birds and livestock. Campylobacters are generally restricted to warm-blooded animals, unlike other pathogens that can grow in the environment or on plants. However, a small subset of campylobacters, highly related to the livestock abortifacient species Campylobacter fetus, are commonly isolated from cold-blooded reptiles, for example snakes, iguanas and pet turtles. These reptile-derived campylobacters can cause illness in humans, presumably through contact and handling of reptiles, although transmission through consumption of reptile meat cannot be ruled out. This study characterizes a reptile Campylobacter strain through genome sequencing, and multiple phenotypic and molecular biological analyses. Results indicate that this strain is an example of a new Campylobacter species, related to C. fetus but distinct with usual (non C. fetus) Campylobacter membrane properties. Analysis of the gene content of this strain will hopefully reveal why this organism can grow and thrive in cold blooded animals and reveal also potential virulence mechanisms that are responsible for disease in humans.

Technical Abstract: A polyphasic study was undertaken to determine the taxonomic position of 13 Campylobacter fetus-like isolates from humans (n=8) and reptiles (n=5). Phenotypic characterization, Genusgenus-specific and sap insertion-PCR initially identified all human isolates as type A Campylobacter fetus. Phylogenetic analyseis based on 16S rRNA or hsp60 (groEL) gene sequences revealed that these isolates from humans, along with the isolates from reptiles, formed a robust cluster distinct from the two known subspecies of Campylobacter fetus and other Campylobacter species. Further characterization by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS), pulsed- field gel electrophoresis (PFGE), amplified fragment length polymorphism (AFLP) analysis , whole genome sequencing and DNA-DNA hybridization confirmed this divergence. This unique cluster of 13 isolates represents a novel subspecies within the species C. fetus, for which the name Campylobacter fetus subsp. testudinum subsp. nov. is proposed, with strain 03-427T (=ATCCxxxxT = LMGxxxxxT) as the type strain.

Last Modified: 10/1/2014
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