Comparative virulence of four different Campylobacter strains in a mouse model

Cilj: Bakterije roda Campylobacter najčešći su uzročnici bakterijskog gastroenteritisa u ljudi širom svijeta. Najčešćim izvorom infekcije ljudi s C. jejuni i C. coli smatra se pileće meso. Dijelom i zbog nedostatka odgovarajućeg životinjskog modela za in vivo istraživanja, još uvijek nije objašnjeno jesu li svi izolati iz namirnica virulentni i mogu li izazvati infekciju u čovjeka. Cilj našeg istraživanja bio je utvrditi razliku u virulenciji između sojeva kampilobaktera različitog podrijetla koristeći prethodno uspostavljeni model mišje kampilobakterioze. Metode: BALB/c miševi intravenski su inficirani različitim sojevima kampilobaktera. Ispitana su tri soja C. jejuni (dva klinička izolata i jedan izolat iz pilećeg mesa) i jedan C. coli (klinički izolat). Broj bakterija u homogenatima organa (jetre i slezene) praćen je osam dana. Rezultati: Nakon inokulacije, bez obzira na ispitivani soj, uspostavljena je sustavna infekcija koja je potvrđena izolacijom bakterija iz jetre i slezene. S obzirom na razlike u broju izoliranih kampilobaktera iz homogenata ispitivanih organa, zapažena je razlika u virulenciji ispitivanih sojeva. Najveći broj bakterija dokazan je u jetri i slezeni životinja inficiranih C. jejuni izolatom iz pilećeg mesa, dok je C. coli pokazao najslabiju virulenciju. Zaključci: Bakterije roda Campylobacter pokazuju razlike u virulenciji ovisno o vrsti i podrijetlu izolata. U opisanom mišjem modelu virulencija je najsnažnije izražena u slučaju C. jejuni izolata iz namirnice, upućujući na značajnost pilećeg mesa u uspostavi humane kampilobakterioze.Aim: Campylobacter spp. is recognized as the most common bacterial cause of human gastroenteritis worldwide. Poultry meat is considered to be a major source of C. jejuni and C. coli. However, partly due to the lack of appropriate animal model of infection, it is still not clear whether all of food isolates are virulent and can cause disease in humans. The aim of this study was to affirm possible virulence differences of Campylobacter spp. from different origin in a previously established mouse model. Methods: BALB/c mice were intravenously infected with four different Campylobacter strains. Three different strains of C. jejuni (two isolates recovered from diarrhoeal patients and one poultry derived isolate), and one C. coli (human clinical isolate) were tested. Infected mice were sacrificed at different time points and the number of recovered bacteria (CFU/organ) in the organ homogenates (spleen and liver) was determined. Results: The isolates were differentially virulent for mice according to different numbers of bacteria recovered from the examined organs. The highest numbers of bacteria were recovered from livers and spleens of animals infected with food isolate of C. jejuni. C. coli showed the least virulence potential. Conclusions: Campylobacter spp., a major human enteric pathogen, exhibits significant strain-to-strain differences in pathogenic potential in a mouse model. Mouse virulence of tested strains showed a trend toward food isolate indicating chicken meat associated risk of campylobacteriosis