A newly published study by Australian researchers describes how particularly virulent strains of Campylobacter jejuni are able to cause gastroenteritis in humans. It is reportedly the first time such a bacterial sensor has been identified.
Campylobacter bacteria typically have a spiral, or corkscrew, shape.
Researchers at the Griffith University Institute for Glycomics near Brisbane say that their results suggest it may be possible to create antimicrobial drugs to specifically target certain foodborne pathogens.
Their study, “A direct-sensing galactose chemoreceptor recently evolved in invasive strains of Campylobacter jejuni,” was published online Oct. 20 in the journal Nature Communications.
The team’s research showed that the ability of bacteria to cause disease stems from whether bacterial cells are able to move toward target host cells, and that movement depends on specialized structures on the cells, known as “sensory receptors,” that can sense chemicals in their environment.
Tests on chickens found that disabling just one sensor of the bacteria reduced the ability of Campylobacter to colonize and infect them.
“This is a very important finding as sensory structures are very specific to each bacteria and offer high-target specificity for design of new antimicrobial compounds,” noted research leader Victoria Korolik, a microbiology professor at Griffith University. “Essentially it should be possible to design an antimicrobial drug to target a specific pathogen that will not affect normal flora.”
She added that targeting the sensory apparatus of these microbes could reduce the chances of developing antimicrobial resistance because the bacterial cell is not killed but instead has its ability to reach host cells and cause disease disabled.
Victoria Korolik
Besides Korolik, other researchers on the team included Chrisopher Day, Rebecca King, Lucy Shewell, Greg Tram, Tahria Najnin and Lauren Hartley-Tassell, all from the Institute of Glycomics; Jennifer Wilson from the Griffith University School of Medicine; and Aaron Fleetwood and Igor Zhulin from the Department of Microbiology at the University of Tennessee in Knoxville.
Campylobacter bacteria are one of the most common causes of diarrheal illnesses in the United States, according to the Centers for Disease Control and Prevention. CDC estimates more than 1.3 million people are affected by it every year.
“Most cases of campylobacteriosis are associated with eating raw or undercooked poultry meat or from cross-contamination of other foods by these items. Outbreaks of Campylobacter have most often been associated with unpasteurized dairy products, contaminated water, poultry and produce,” CDC states.
The World Health Organization (WHO) reports that Campylobacter bacteria cause more cases of diarrhea around the world than foodborne Salmonella and that, in developing countries, infections in children younger than two are especially common and sometimes fatal.
There are currently 17 known species and six subspecies of Campylobacter, with C. jejuni and C. coli being the most frequently reported in connection with human diseases, according to WHO.
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