Identification of persistent subtypes of Campylobacter jejuni by pulsed-field gel electrophoresis in Finland

Genotypical Relationship Between Human and Poultry Strains of Campylobacter jejuni

This study aimed to compare the genotype diversity of C. jejuni isolates. From the total of 64 C. jejuni strains evaluated, 44 were isolated from broiler carcasses (2015-2016) and 20 from hospitalized patients with gastroenteritis caused by the microorganism (2000-2006). The strains were correlated for the presence of flaA, pldA, cadF, ciaB, cdtABC, luxS, dnaJ, cbrA, htrA, pVir, Hcp, cstII, and neuA genes by PCR (polymerase chain reaction) and for phylogenetic proximity by PFGE (pulsed-field gel electrophoresis). Of the total strains studied, 28 (43.7%) presented all the studied genes, except pVir. Among these strains, 25 (89.3%) were of poultry origin. Poultry strains showed a higher prevalence (P < 0.05) of genes linked to adhesion, colonization, invasion, cytotoxicity, biofilm formation, and adaptation to adverse conditions. Additionally, the profile that denotes the presence of all genes identified in the study (P1) was identified in 56.8% of poultry strains and in 15.0% of human strains. Molecular typing analysis identified five pulsotypes, none of which grouped strains from different origins. Although human strains were from hospitalized patients, they presented limited virulence capacity and adaptability to adverse conditions compared to chicken carcasses, besides being different in molecular typing. However, the ability to cause Guillain-Barré Syndrome is equal for both strains. In general, poultry strains, being more recent, are more specialized to adapt to the environment, invade, and cause disease in the human host.

Novel microbiological and spatial statistical methods to improve strength of epidemiological evidence in a community-wide waterborne outbreak

Failures in the drinking water distribution system cause gastrointestinal outbreaks with multiple pathogens. A water distribution pipe breakage caused a community-wide waterborne outbreak in Vuorela, Finland, July 2012. We investigated this outbreak with advanced epidemiological and microbiological methods. A total of 473/2931 inhabitants (16%) responded to a web-based questionnaire. Water and patient samples were subjected to analysis of multiple microbial targets, molecular typing and microbial community analysis. Spatial analysis on the water distribution network was done and we applied a spatial logistic regression model. The course of the illness was mild. Drinking untreated tap water from the defined outbreak area was significantly associated with illness (RR 5.6, 95% CI 1.9–16.4) increasing in a dose response manner. The closer a person lived to the water distribution breakage point, the higher the risk of becoming ill. Sapovirus, enterovirus, single Campylobacter jejuni and EHEC O157:H7 findings as well as virulence genes for EPEC, EAEC and EHEC pathogroups were detected by molecular or culture methods from the faecal samples of the patients. EPEC, EAEC and EHEC virulence genes and faecal indicator bacteria were also detected in water samples. Microbial community sequencing of contaminated tap water revealed abundance of Arcobacter species. The polyphasic approach improved the understanding of the source of the infections, and aided to define the extent and magnitude of this outbreak.