Multi-virulence and phenotypic spread of Campylobacter jejuni carried by chicken meat in Brazil

Abstract

Campylobacter jejuni is the most incriminated pathogen in bacterial gastroenteritis, and therefore, characteristics of its epidemiology must be continuously investigated to support possible mitigating measures. This is particularly important when evaluating representative strains of the worlds leading chicken meat exporter, Brazil. We evaluated a panel of 14 virulence genes in 359 strains of C. jejuni isolated from chilled broiler carcasses of Brazil. The genes were classified into five virulence categories (B: biofilm/motility; SS: secretion/cytotoxicity system; CI: invasion/colonization; GB: Guillain-Barre and AE: adaptation to stress). The percentage of strains with stress adaptation genes (86.07%) indicates the potential to adapt to unfavorable environmental conditions and hcp gene in 97.77%, indicates the ability to cause serious infections in humans. Genes related to GBS in 77.44% of strains are an additional concern, which must be monitored. The gene panel showed the presence of 124 virulence profiles. Individual analyzes by carcass, slaughter establishment, and municipalities where they were located showed high I.Var., of 0.82, 0.87 and 0.78, respectively. Georeferencing indicated state A as a hotspot for virulent strains. Higher levels of isolation and multi-virulence were identified in the summer, which in Brazil is hot and humid. Proteomics was able to discriminate the strains, but due to the high heterogeneity between them, it did not allow to explain their dissemination. Together, our results showed that the studied strains are a potential danger to public health and that there is an urgent need for their surveillance and the adoption of control measures, especially in state A. AUTHOR SUMMARYCampylobacter jejuni is a bacterium considered one of the main causes of foodborne illnesses and the consumption of undercooked chicken meat is one of the main sources of human infection. In Brazil, epidemiological studies of this pathogen are still scarce, when compared to countries with structured surveillance, as well as, its analysis is not required by public health agencies in any group of foods intended for human consumption. Here we investigate the epidemiology of C. jejuni strains isolated from chilled chicken carcasses in Brazil, determining virulent and multivirulent strains, by the origin of the sample and its phenotypic patterns. The strains showed a high potential for adaptation to the environment, being classified as virulent and multivirulent, with a seasonal pattern in the hottest and humid periods of the year. In state A, the strains with the highest evolutionary level were isolated, when compared to the other states in the region. We hope that this study will help to better understand the potential risks that C. jejuni poses to the population and support surveillance agencies in tracking and adopting measures to minimize the dangers that this pathogen poses to public health.