Understanding Campylobacter — A Leading Cause of Food Poisoning

Introduction of campylobacter

Camppylobacters were first isolated in 1905 from aborting sheep in the UK. Originally taught be vibiros, they were latter placed in their own genus. Campylobacters cause both diarrheal and systemic diseases. Campylobacters are motile, curved, oxidase-positive, Gram- negative rods similar in morphology to vibrios. The cells have polar flagella and are often are attached at their ends giving pairs “S” shapes or a “seagull” appearance. C. jejuni, and C. coli are by far the most common and similar enough to be considered as one.  Some other Campylobacter species are potential causes of diarrhea. The primary reservoir is in animals and the bacteria are transmitted to humans by ingestion of contaminated food or by direct contact with pets.  Campylobacters are commonly found in the normal gastrointestinal and genitourinary flora of warm-blooded animals, including sheep, cattle, chickens, wild birds, and many others. Domestic animals such as dogs may also carry the organisms and probably play a significant role in transmission to humans.  The most common source of human infection is undercook.

What is campylobacter?

Campylobacter is a type of bacteria that can cause foodborne illness in humans. It is one of the most common causes of bacterial gastroenteritis worldwide. The species most often linked to human disease are Campylobacter jejuni and Campylobacter coli. When a person becomes infected, usually through contaminated food or water, the bacteria cause an illness called campylobacteriosis. The most common source of human infection is undercooked poultry, but outbreaks have been caused by contaminated rural water supplies and unpasteurized milk often consumed as a “natural” food.

Types of campylobacter

1. Campylobacter jejuni:

Campylobacter jejuni is a spiral-shaped bacterium that is one of the leading causes of bacterial gastroenteritis in humans. It is a Gram-negative and microaerophilic organism, meaning it requires low levels of oxygen to grow. This bacterium is commonly found in the intestines of poultry, cattle, and other animals, and infection in humans usually occurs through the consumption of undercooked chicken, unpasteurized milk, or contaminated water and food. The illness caused by Campylobacter jejuni is known as campylobacteriosis, which typically presents with symptoms such as diarrhea that can sometimes be bloody, abdominal pain, fever, nausea, and vomiting. Symptoms generally appear within two to five days after exposure and often last for about a week. While most cases resolve on their own, some infections can lead to complications including Guillain-Barré syndrome, reactive arthritis, or bloodstream infections, making Campylobacter jejuni an important public health concern.

Pathogenesis and clinical manifestations

Campylobacter jejuni accounts for 90 to 95% of human campylobacter infections in most parts of the world. Campylobacter jejuni and Campylobacter coli cause enteritis which may take the form of toxigenic watery diarrhoea or dysentery. The organisms are able to produce enterotoxins and cytotoxins. The jejunum and ileum are the firs sites to become Colonized followed by the colon and rectum. In well-developed infections, mesenteric lymph nodes are enlarged. Colonization of the intestine require factors such as chemotactic motility, iron uptake system and several potential adhesins, Diarrhoea is likely to result from disruption of intestinal mucosa due to cell invasion by campylobacters and the production of toxins.

Laboratory diagnosis

Specimen: Fresh diarrhoeal or dysenteric specimens containing blood, pus and mucus. Microscopy: Typical ‘gull-wing’ shaped gram-negative rods. Typical darting motility of the bacteria under dark field microscopy or phase contrast microscopy.

Culture: Campylobacter species are strictly micro-aerophilic,requiring incubation in an atmosphere of reduced oxygen (5–10%) with added carbon dioxide. C. jejuni and C. coli are thermophilic, i.e. they will grow at 42 43 ºC and 36–37 ºC but not at 25 ºC. Incubation at 42-43 C helps to identify C. jejuni and C. coli. Blood agar: C. jejuni and C. coli produce non-haemolytic spreading, Butzller’s medium and Charcoal - based blood -free agar containing antimicrobial agent such as vancomycin, polymyxin B, and trimethoprims are selective culture media for campylobacter species. Biochemical tests Campylobacter species are oxidase and catalase positive. A presumptive diagnosis of Campylobacter enteritis can be made by isolating oxidase and catalase positive colonies (from a selective medium or faecal suspension filtrate cultured on a non selective medium), showing typical Campylobacter morphology.

Haw to treatment campylobacter

Erythromycin or ciprofloxacin are drugs of choice for C. jejuni enterocolitis. C. jejuni is typically susceptible to macrolides and fluoroquinolones but resistant to -lactams.

Haw to prevention campylobacter

Campylobacter infection can be prevented by following simple hygiene and food safety measures. Cooking meat, especially poultry, thoroughly ensures that harmful bacteria are destroyed. It is also important to avoid drinking unpasteurized milk or untreated water, as these can carry the bacteria. Washing hands carefully with soap and water after handling raw meat, animals, or after using the toilet reduces the risk of spreading the infection. Using separate cutting boards and utensils for raw meat and ready-to-eat foods helps to prevent cross-contamination in the kitchen.

Conclusion

Campylobacter causes foodborne diarrhea, mainly from contaminated food or water. Most infections are mild and preventable through good hygiene and proper cooking.