We are exposed to millions of bacteria in our environment everyday. Some species are harmful, while others are less so. The skin and the various defense mechanisms at the different entry points in the body ensure that these bacteria do not enter the body. One of the common ways to get an infection caused by bacteria is through food. Here the bacteria may thrive within the food and eventually the contaminated food may contain millions of bacteria that will be subsequently consumed during a meal.
Once these bacteria are within the gut, it has essentially bypassed the defensive capabilities of the skin and entry points. The bacteria could be destroyed by the body but it may also cause disease. Sometimes the bacteria are neutralized but the toxins it had produced can still cause disease. An infection with foodborne bacteria tends to affect the gut only and is restricted by the immune system from penetrating further into the body. It typically causes diarrhea but may also cause vomiting, fever and abdominal pain.
Bacterial gastroenteritis is inflammation of the stomach and bowels from consuming disease-causing bacteria or bacterial toxins. It is a very common gastrointestinal disease. While there are millions of bacteria that can be harmful to humans and could enter through contaminated food, some are more commonly responsible for bacterial gastroenteritis. It is important to remember that bacteria are not the only microbes responsible for gastroenteritis. Viruses and protozoa are other biological agents that may cause gastroenteritis and the symptoms largely overlaps, irrespective of the causative organism.
Aeromonas species of bacteria is more commonly found in seafood, meat and sometimes in vegetables. Symptoms tend to arise shortly after consuming the contaminated food. The illness can last anywhere from a few days to up to 2 weeks. Apart from diarrhea, there generally is no abdominal pain. Vomiting and fever may or may not be present.
Bacillus species of bacteria is found in foods like fried rice. The incubation period is between 1 to 16 hours meaning that only after this period does the symptoms become evident. It is a short-lived illness lasting only about 1 to 2 days. Apart from profuse diarrhea, there is vomiting and abdominal pain. A fever does not usually occur with bacterial gastroenteritis caused by Baccillus species of bacteria.
Campylobacter bacteria can be commonly found in dairy, different meats and poultry. The incubation period is between 2 to 4 days with symptoms arising thereafter. The entire length of the illness spans between 5 to 7 days. Vomiting does not usually occur. However, there is a fever with abdominal pain that accompanies the diarrhea.
Two strains of Clostridium bacteria that are commonly associated with foodborne infections are C.difficile and C.perfringens. The incubation period of C.difficile infections are variable while with C.perfringens it is usually not more than 1 day but can be as short as just a few hours. The duration of the illness with C.difficile also varies greatly while with C.perfringens the illness lasts for only about 1 day. Vomiting is usually not present with C.difficile infection and a minority of patients may experience fever and abdominal pain along with diarrhea. With C.perfringens, the vomiting is generally mild, a fever is usually absent but abdominal pain does occur with the diarrhea.
Although Escherichia coli bacteria naturally resides in the bowels of humans, some strains can cause serious disease. In food, it is usually sourced from ground beef but can also be found on vegetables, particularly when the irrigation water was contaminated with human or animal feces. Enterohemorrhagic E.coli has an incubation period of 1 to 8 days and the illness typically lasts for about 3 to 6 days.
Vomiting is usually absent, there may or may not be a fever present but abdominal pain is pronounced with diarrhea. With enterotoxigenic E.coli the incubation period is from 1 to 3 days and the illness lasts for around 3 to 5 days. There is a low grade fever with vomiting, abdominal pain and diarrhea.
The Listeria species of bacteria is commonly found in milk and dairy products. The incubation period is about 1 day, during which there are no symptoms. The illness tends to last for about 3 days. Some people do experience vomiting but it is usually uncommon. A fever is present and abdominal pain may or may not occur along with the diarrhea.
The Plesiomonas species is more commonly found in seafood and infection tends to arise after consuming oysters. The illness tends to start a short while after consuming the contaminated food and it can persist for as long as 2 weeks. Apart from diarrhea, other symptoms like vomiting, fever and abdominal pain may or may not be present.
The Salmonella species are common bacteria found in a number of different foods including dairy, eggs, meats and some vegetables like alfalfa sprouts. The incubation period can be just a few hours to up to 3 days. The illness, known as salmonellosis, can last from about 2 to 7 days. Along with the diarrhea, there is vomiting, fever and abdominal pain.
The Shigella species of bacteria causes a severe disease known as shigellosis which is one of the common types of bacillary dysentery. It can be found in any food if it was handled by a person who has the disease and does not practice good hygiene. Uncooked foods prepared with contaminated water or vegetables irrigated with water tainted by sewage may also be a problem. The incubation period can last for up to 2 days. Shigellosis typically lasts between 2 to 7 days. It presents with a high fever and abdominal pain along with diarrhea. Vomiting does not usually occur.
Staphylococci in food may be found in dairy and meats. It may also be found in foods such as custard and mayonnaise. The incubation period is very short, about 2 to 6 hours. The illness is short lived lasting only about 1 day. There is usually no fever. Vomiting and abdominal pain is present along with diarrhea.
The Vibrio species of bacteria are usually found in seafood like oysters. The more well known of the Vibrio species is Vibrio cholerae which is the cause of cholera. It is usually transmitted through contaminated water. The incubation period of an infection with the Vibrio species is very short. At most it lasts about 1 day. The illness can last for 5 to 7 days. There is typically no fever but vomiting, abdominal pain and diarrhea are pronounced.
Yersinia enterocolitica is transmitted to humans through pork that is not cooked sufficiently. It may also be spread through contaminated water. The incubation period can last anywhere from a few hours to up to 6 days. The illness can last as short as 1 day to be as long as 45 days. Typically the symptoms include fever, vomiting and abdominal pain with diarrhea.