HOME > Research > Foodborne Pathogen
Salmonella enterica is an enteropathogenic bacterium capable of causing a wide range of illness ranging from mild food poisoning to life-threatening systemic infections. Salmonella causes much food poisoning in the world, including estimated four million cases of salmonellosis in the United States per year. To reduce this pathogenic bacteria, antibiotics have been used since the introduction of penicillin. Traditional antibiotics have been identified of their ability to kill bacteria or inhibit bacterial growth. Recently, however, clinically significant antibiotic-resistant bacteria have evolved against almost every antibiotic utilized.
Therefore, it’s important that we comprehend the mechanism of the virulence expression in Salmonella Typhimurium. This understanding of the pathogen will bring novel approaches to regulating the pathogen’s virulence. Namely, we study what is important in the virulence of Salmonella and try modulating it without the use of antibiotics.
Cronobacter sakazakii is considered an opportunistic foodborne pathogen, causing meningitis and enterocolitis in premature infants with reported mortality rates of 40 to 80%. Although, dried infant formula has been suggested as the source of this organism, in our previous work of surveying the prevalence of C. sakazakii, the pathogen was isolated from various food samples. It has been known that C. sakazakii can invade animal cell and produce enterotoxin, however little is known about genes associated with virulence of this pathogen. To elucidate genes required for the expression of virulence, random transposon mutagenesis was carried out to screen mutants which demonstrate reduced invasion ability to Caco-2 intestinal cells. Out of approximately 1200 mutants screened, several mutants showed significant reduction in invasion ability to Caco-2 compared to wild-type C. sakazakii ATCC 29544.
Campylobacter jejuni is one of the most common bacterial causes of gastroenteritis throughout the world. Infection of C. jejuni, campylobacteriosis, usually causes watery or bloody diarrhea with fever, nausea, vomiting and rarely brings on systemic post-infection, such as neuropathy, Guillain-Barre or Miller Fisher syndrome.
Major source of C. jejuni infection is from the consumption of uncooked poultry because C. jejuni is a commensal organism in avian gut. Campylobacter has to adapt and survive in the environment until infection into host can be done by changing its regulation mechanisms. However, its mechanisms of survival and virulence are poorly understood. We study the survival and virulence mechanisms of Campylobacter jejuni by understanding the genetics of this pathogen. This would ultimately be helpful in developing new control strategies applicable in food industry.
