This unit is working with foodborne pathogens including diarrheagenic Escherichia coli, Campylobacter, and Salmonella. These pathogens sometimes colonize intestine of food animals without any symptoms and ingested by humans through various animal products.
E. coli O157 is one of the most important foodborne pathogens worldwide. Genome size of this bacteria is about 900 kb larger than non-pathogenic E. coli strain K-12. E. coli O157 is believed to become highly-virulent by acquisition of various pathogenic factor genes laterally in the course of evolution. We reported a novel factor involving lateral gene transfer of E. coli O157 for the first time. We also found that a novel linage of pathogenic E. coli showing resistance to multiple antimicrobials among pig population in Japan.
Campylobacter colonizes chicken intestine, and humans are mainly infected by this pathogen through ingestion of under-cooked chicken meats. We found several factors of Campylobacter involving intestinal colonization. These results may lead to a development of novel countermeasures to reduce the prevalence of this pathogen among chicken population. We also trying to develop a novel isolation technique to detect injured Campylobacter cells effectively.
We found that molecular types of Salmonella isolated from cattle drastically changed in the last three decades. DT104 type of Salmonella were dominant from 1990s to mid-2000s. We found that DT104 harbor a novel toxin, ArtAB for the first time. Expression mechanisms, biochemical properties, and pathogenesis of this toxin will be investigated in this unit.