Introduction

Campylobacter is a motile, gram-negative bacteria, which causes diarrhoea.​​ The most common type is C. jejuni, which establishes infection by the destruction of epithelial cells and the production of enterotoxins that induce diarrhoea.¹ Many other pathogens may also cause diarrhoea such as E. coli, Salmonella, Listeria, Shigella, and Vibrio cholerae. It is important to be able to distinguish the causative bacterium to provide targeted treatment to prevent antibiotic resistance, improve symptom management, and decrease the risk of complications. 

Aetiology, transmission, and at-risk groups

Campylobacter 

Campylobacter tends to be found in animals such as chickens, pigs, cows, cats, and dogs, with most cases being linked to poultry. The bacterium may be spread from animal faeces to meat during slaughter, which could lead to infection, especially if the meat is undercooked as Campylobacter is quite heat resistant. It may also be found in raw milk and contaminated ice, and may be transmitted from pet (cat/dog) to human. This bacterium is more likely to cause complications in the elderly, young children, or those with other serious conditions like AIDS.² 

Other bacterial infections 

E. coli

E. coli is often found as a commensal (bacteria which lives on our skin or mucosal surfaces but causes no harm) in the gut. However, certain strains may be pathogenic such as O157:H7, which is a Shiga-toxin producer. Shiga toxins are enterotoxins, meaning they are toxic to the gut, which is the reason for many food poisoning symptoms like diarrhoea or cramping. This pathogen is often found in cows and may be transmitted via the following: 

• Raw or undercooked meat 
• Cross-contamination via contaminated food preparation surfaces or utensils 
• Contaminated vegetables 
• Raw milk 
• Water/food contaminated by faecal matter 

Groups most at risk of serious disease include young children due to their immature immune systems, and the elderly or immunodeficient individuals due to lower immune protection.³ 

Salmonella

Salmonella is a pathogen commonly found in multiple types of animals like chickens, pigs, cows, cats, dogs, birds, and even reptiles. Transmission is common by contaminated meat or animal products like eggs or milk, but it may also be found in vegetables if they were grown in contaminated manure. Transmission may also occur by contact with pets, especially because infected pets tend to be asymptomatic. The pathogen tends to cause self-limiting infection, however may lead to more significant issues in the young and elderly, especially through extreme dehydration.⁴

Listeria 

Listeria is another pathogen which causes diarrhoea. It can be found all over the place, in soils, water, plants, and animals and so may be transmitted during harvesting, butchering, as well as during transportation/storage in a contaminated environment. Pets may also harbour the disease, passing it on to humans. Listeria is particularly dangerous for the elderly and immunocompromised, as well as pregnant women and their babies.⁵

Others 

Other bacteria which may cause diarrhoea are Shigella and Vibrio cholerae. Shigella may be transmitted in many different ways, through the faecal-oral route by contaminated food or water, person-to-person, and through sexual contact. Again, it poses the biggest risk to the elderly, young children, and the immunocompromised.⁶ 

Vibrio cholerae is a bacterium which causes the commonly known disease, cholera. It is a waterborne disease often prevalent in areas with low sanitation. Disease presentation ranges from mild to severe, with more severe infections being associated with lower gastric acidity and being blood type O (reasons for the link between type O blood and more severe cholera are not yet known).⁷

Clinical presentation and symptoms

Campylobacter 

Campylobacter tends to have an incubation period of 2 to 5 days but this may increase to up to 10 days. The most common symptoms experienced are:

• Diarrhoea (which may be bloody)
• Cramps
• Abdominal pain
• Fever
• Feeling nauseous/vomiting
• Headache

The infection tends to be self-limiting with recovery taking approximately 3 to 6 days.²

Other bacterial infections 

E. coli 

The incubation period of E. coli may range from 3 to 8 days. It most often causes symptoms like:

• Severe abdominal cramping
• Diarrhoea which may become bloody
• Vomiting
• Low-grade fever

As with Campylobacter, this infection tends to be self-limiting. Recovery does take longer though, with most patients recovering within 10 days.³ 

Salmonella 

Salmonella has a very short incubation time, with symptoms developing 6-72 hours after infection. It causes typical digestive system upset with symptoms such as:

• Fever
• Abdominal pain
• Diarrhoea
• Nausea and at times vomiting

Salmonella causes quite mild disease, which tends to pass on its own within 2 to 7 days.⁴ 

Listeria 

Listeria has varying incubation periods. Typically, symptoms show within a few hours or up to 3 days after infection. However, in more serious cases, this incubation may even last up to 3 months. It causes symptoms like:

• Fever
• Muscle pain
• Diarrhoea
• Nausea and vomiting

In some, more severe cases it may also lead to:

• Neck stiffness
• Confusion
• Convulsions.
• Headache
• Loss of balance 

For people who have a functioning and healthy immune system, Listeria tends to be cleared in around 2 days.⁵

Others

Shigella has an incubation period of 1 to 4 days, causing a self-limiting infection cleared within 5 to 7 days. It may cause symptoms such as:

• Bloody and mucoid (has lots of mucus) diarrhoea
• Fever
• Malaise
• Vomiting
• Abdominal pain⁶

The incubation of Vibrio is usually 12 hours to 5 days, the symptoms tend to be mild with the biggest issue being extreme dehydration, which is often the cause of more serious complications. Cholera symptoms include:

• Voluminous rice-water diarrhoea (pale, milky diarrhoea)
• Being very thirsty
• Peeing less
• Vomiting
• Weakness
• Muscle cramps⁸ 

Comparison of symptom patterns with Campylobacter

It is quite simple to distinguish Campylobacter from cholera by observing for either blood or rice-water-looking diarrhoea. For Shigella, there will also be a lot of mucus in the stool. For bacteria that also cause bloody diarrhoea, may be distinguished from Campylobacter by either symptom duration or additional distinguishing symptoms like the additional neurological symptoms caused by Listeria. For, E. coli symptom clearance will take longer, whilst for Listeria they should pass much sooner. 

Diagnosis

Most bacterial diarrhoeal infections are diagnosed via stool samples. For Listeria, blood or cerebrospinal fluids may be obtained. These samples are then analysed either under a microscope or using polymerase chain reaction (PCR) (a laboratory technique). 

Treatment and management

Most of the infections are mild in individuals with healthy immune systems and so no antibiotic treatment is recommended. Instead, it is key to avoid dehydration by drinking plenty of fluids and replenishing electrolytes, using sports drinks or powdered electrolytes added to water. 

People experiencing extreme dehydration may have to be taken to the hospital for intravenous fluid administration. For more severe cases affecting at-risk individuals, antibiotics would be provided. 

Prevention 

The best ways to prevent the aforementioned diarrhoeal infections are hygienic food preparation methods, including the following: 

• Using separate utensils and surfaces for meat versus other ingredients to prevent cross-contamination 
• Being careful when handling raw meat, i.e., preventing spraying or leaking of meat juice onto any areas 
• Cooking meat thoroughly 
• Vegetables and fruits should be thoroughly washed using clean water 
• Hand washing before and after preparing food, after touching pets and their items like toys, bed, water and food, their faeces, urine, or vomit 
• Drinking clean water is also important as is drinking pasteurised milk to avoid ingesting pathogenic bacteria 
• Vaccines are not typically given for prevention of infection for any of the bacteria apart from Vibrio cholerae, for which a vaccine exists that is recommended to tourists travelling to cholera-endemic areas

Complications and long-term effects

Campylobacter 

Serious Campylobacter may lead to complications like irritable bowel syndrome (IBS), reactive arthritis (inflammation of the joints caused by bacterial infection), and Guillain-Barré syndrome. 

IBS is usually associated with symptoms including constipation, gas, bloating, or diarrhoea, causing digestive discomfort.⁹ Guillain-Barré is an autoimmune condition, where your immune system attacks peripheral nerve cells (nerves outside the central nervous system) causing symptoms like numbness and tingling, which may develop to paralysis. It may also cause bacteraemia (infection of the blood), causing sepsis.¹⁰ 

Other bacterial infections 

E. coli

Some severe cases may develop into haemolytic uremic syndrome, which may lead to kidney failure, which may cause neurological issues like seizures or strokes, or death. Some individuals may also develop sepsis.³

Salmonella

Complications of Salmonella infection include sepsis, reactive arthritis and salmonella osteomyelitis (a rare bone infection which mostly occurs in individuals with haemoglobinopathies).¹¹

Listeria

Listeria is especially dangerous in pregnant women, possibly leading to miscarriages or stillbirths. It may also infect the newborn, leading to long-term health issues, or death.⁵

Others

Shigellosis and Cholera may progress by causing sepsis. Shigella may also cause haemolytic uremic syndrome, seizures, reactive arthritis, toxic megacolon (colon becomes big, weak, and floppy, increasing the chance of intestinal perturbations), colon perforations and intestinal obstructions⁶. Cholera may lead to severe dehydration, which may result in kidney failure, coma, and death.⁷

Comparison

The complications of Campylobacter vs other bacterial infections do share some similarity with reactive arthritis resulting from Salmonella and Shigella. There is a major difference in that no other bacteria cause Guillain-Barré, making this complication unique to Campylobacter out of the diarrhoea-causing bacteria such as Salmonella and Shigella. 

Summary

Campylobacter are bacteria which causes diarrhoeal disease. It may be distinguished from other bacteria, which cause digestive infection by looking for distinguishing symptoms related to the diarrhoea appearance or for neurological symptoms not common in Campylobacter infection. The complications also tend to differ with Campylobacter being the only one possibly causing Guillain-Barré.