Latest Research Behind Campylobacter

Campylobacter is identified as the leading pathogen causing foodborne bacterial infections in the European Union (EU), according to the European Food Safety Authority and the European Centre for Disease Prevention and Control.

From their most recent report, in 2015 Campylobacter continued to be the most commonly reported gastrointestinal bacterial pathogen in humans in the EU, and has been so since 2005. The number of reported confirmed cases of human campylobacteriosis was 229,213, with an EU notification rate of 65.5 per 100,000 population. Despite the high number of human campylobacteriosis cases, their severity in terms of reported case fatality was low (0.03 percent).

Broiler meat is considered to be the most important single source of human campylobacteriosis in the EU.

“Some European countries, including Belgium, the Netherlands, Denmark, and the United Kingdom, set national action limits for Campylobacter in broiler carcasses or poultry meat a few years ago,” says Mieke Uyttendaele, PhD, a microbiologist in the Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, at Ghent University in Belgium. “Moreover, in August 2017 the European Commission issued an Amendment of EU regulation 2073/2005 on microbiological criteria for foods, stipulating EU-wide process hygiene criteria for broiler carcasses, with a target value of 1,000 colony forming units per gram of pooled neck skin.”

In recent years Dr. Uyttendaele has overseen a number of studies addressing Campylobacter in poultry, including at the farm, abattoir, and processing levels. She is a co-author of “Sense and Nonsense of Microbiological Analysis of Foods: Guidelines for the Interpretation of Results of Microbiological Testing of Foods.”

“Our academic department just released these guidelines in March 2018,” she relates.

Trojan Horse Research

Researchers at Kingston University, London, England, have shown how Campylobacter jejuni can infiltrate amoebae and multiply within their cells—protected inside the amoebae from harsh environmental conditions.

“This is significant since Campylobacter and amoebae often exist in the same environments, drinking water for chickens on poultry farms, for example,” says Kingston PhD student Ana Vieira, the project leader. “The amoeba may act as a protective host against some disinfection procedures, so the findings could be used to explore new ways of preventing the bacteria’s spread by breaking the chain of infection.”

The Kingston team used a modification of the gentamicin protection assay, a process that assesses a bacteria’s ability to invade cells, to confirm Campylobacter can survive and multiply while inside the amoebae.

“Being protected inside amoebae allows Campylobacter to thrive then to escape the amoebae cells in larger numbers,” says Kingston University microbiology professor Andrey Karlyshev, PhD, the study supervisor. “Because amoebae are widespread, we have shown how Campylobacter are able to use them as a Trojan horse for infection of the food chain. Otherwise Campylobacter wouldn’t survive, as they are very sensitive to the environment.”

The Kingston researchers also demonstrated how a multidrug efflux pump, which is a cellular system (consisting of three proteins) involved in elimination of toxins from bacteria, factors into Campylobacter’s ability to thrive within amoebae.

The team examined how this mechanism helps Campylobacter become resistant to antibiotics, which could lead to new methods of preventing resistance from developing, Dr. Karlyshev relates.

“Campylobacter is becoming increasingly resistant to antibiotics because of their widespread use on humans and animals,” he points out. “Because of its role in antibiotic resistance and bacterial survival in amoebae, the efflux pump could prove to be a good target for the development of antibacterial drugs. Targeting the bacterial factors required for survival within amoebae could help to prevent Campylobacter from spreading in the environment and colonizing chickens. This, in turn, holds promise for reducing this bacteria’s ability to enter the food chain and cause disease in humans.”