Database of Food Borne Human Pathogens
Bacteria, Virus, Fungi, Protozoa, Helminths
Bacterial Food Pathogen
Bacteria are microscopic single-celled organisms that thrive in diverse environments.
They can live within soil, in the ocean and inside the human gut. Human's relationship with bacteria is complex. Sometimes they lend a helping hand, by curdling milk into yogurt, or helping with our digestion. At other times they are destructive, causing diseases like pneumonia and food poisoning.
In a 2012, David A. Relman, a microbiologist at Stanford University, states that there are about 10 times more microbial cells than human cells in the human body. The highest numbers of microbial species are found in the gut.
Some bacteria has an ability to cause diseases in humans. These pathogens express a wide range of toxic molecules that binds with the host's cell and facilitates different harmful responses.
The human gut is most suitable place for bacteria, where they get plenty of nutrients available for their sustenance.
Generally, they cause food poisoning, diarrhea or other gastrointestinal diseases. Bacteria enters into the host organism through contaminated food. After ingestion, they get colonize and start affecting the host's metabolism. These pathogens need oxygen, moisture, warm temperature and pH for growth and colonization and human body provide them favourable conditions to bloom inside when ingested.
Most common bacterial foodborne pathogens are: Campylobacter jejuni, Clostridium perfringens, Salmonella spp., Escherichia coli O157:H7. Other common bacterial foodborne pathogens are: Bacillus cereus, Escherichia coli, Listeria monocytogenes, Shigella spp.,Staphylococcus aureus, Staphylococcal enteritis , Streptococcus , Vibrio cholerae, including O1 and non-O1, Vibrio parahaemolyticus, Vibrio vulnificus, Yersinia enterocolitica and Yersinia pseudotuberculosis. Brucella spp., Corynebacterium ulcerans, Coxiella burnetii or Q fever and Plesiomonas shigelloides. Bacterial cell produce toxins in response to outer stimulus. Exotoxins are usually heat labile proteins secreted by certain species of bacteria which diffuse into the surrounding medium. Endotoxins are heat stable lipopolysaccharide-protein complexes which form structural components of cell wall of Gram Negative Bacteria and liberated only on cell lysis or death of bacteria.
Clostridium perfringens are non-motile rod-shaped bacteria and that produce endospores. C. perfringens is a member of the family Clostridiaceae of the Clostridiales, and is subdivided into five distanct serotypes, (A to E), on the basis of four toxins (alpha, beta, epsilon, and iota).
Francisella tularensis is a nonmotile and non-spore forming bacteria. In nature, it can survive up to weeks at low temperatures in water, soil, and animal carcasses. It is one of the most infectious pathogenic bacteria known. A small number can cause disease.
Vibrio cholerae is a Gram-negative bacteria with a single, polar flagellum for movement. The most wide sweeping pathogenic strain is the Vibrio cholerae serotype O1 El Tor N16961 strain that causes the pandemic disease cholera.2 The latest pathogenic serotype O139 was discovered in 1992. The El Tor strain was active in the seventh and most recent pandemic of cholera from 1960's-1970's, as well as in the early 1990's along with serotype O139, both displaying resistance to multiple drugs.
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A. hydrophila are rod-shaped, non- spore forming, oxidase- positive, glucose- fermenting, facultative anaerobic, gram- negative bacterium. They are motile by a single polar flagellum. The bacteria can produce heat-labile enterotoxins, which can be associated with haemolysin and cytotoxin production.
It is a marine bacterium that causes septicemia in marine animals and in humans. This pathogen is of special concern for humans, since it can cause a highly severe necrotizing fasciitis that may lead to a fatal outcome.
Plesiomonas shigelloides is a motile with polar flagella, non-spore-producing, and facultatively anaerobic bacteria. It was formerly classified in the Vibrionaceae family, but is now a part of the Enterobacteriaceae family. They are able to grow at salt concentrations of 0-5%, at a pH of 4.0-8.0, and at temperatures of 8-44 C.
Blastocystis hominis parasite lives in the intestine of infected humans or animals. It is found in four different forms: Vacuolar, Granular, Amoeboid and Cyst forms and found in the intestines of humans and other primates.
Bacillus cereus is a endospore forming, motile bacterium and was first successfully isolated in 1969 from a case of fatal pneumonia. B. cereus is mesophilic, distributed widely in nature and is commonly found in the soil as a saprophytic organism. The bacteria are able to produce six types of toxins: five enterotoxins and an emetic toxin, which can be heat-stable or heat-labile depending on the strain.
Brucella is non-spore-forming and is non-motile bacterium. Brucella melitensis is one of the six species that causes Brucellosis. Brucella melitensis are coccobacillus gram-negative, facultative, interacellular bacteria which is non-motile, non-encapsulated and non-spore-forming. In infected tissue it normally occurs singly or in small groups that can infect human and many species of aninmals. Brucella melitensis is one of the six species that causes Brucellosis, which can be described as a fatal zoonotic disease that affects multiple body system. Brucellosis infection mainly occur through the consumption of infected food (vegetables), unpasteurized dairy products contaminated goat milk. .
Clostridium botulinum is a rod-shaped, mesophilic bacteria and arranged as singles, pairs, or chains. C. botulinum lies dormant in the form of spores until the right environmental conditions are met. These spores are very resistant to adverse environmental effects, making them amenable to most environments and very hard to kill. The spores will grow under favorable conditions and will begin to produce their toxins as they rapidly propagate. They mainly in the soil and possibly food products.
E. coli commonly found in the lower intestine of warm-blooded organisms. Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in their hosts. It constitute about 0.1% of human gut flora.
Salmonella belongs to same proteobacterial family as Escherichia coli, the family Enterobacteriaceae also known as "enteric" bacteria commonly associated with food poisoning in countries all over the world.The most common cause of food poisoning is associated with the serovar S. Enteritidis.The principal habitat of the salmonellae is the intestinal tract of humans .Outbreaks associated with salmonella are attributed to contaminated poultry, chicken eggs, and products that contain eggs. Salmonella is the second most common intestinal infection in the United States. More than 7,000 cases of Salmonella were confirmed in 2009; however the majority of cases go unreported. The Centers for Disease Control and Prevention estimates that over 1 million people in the U.S. contract Salmonella each year, and that an average of 20,000 hospitalizations and almost 400 deaths occur from Salmonella poisoning, according to a 2011 report.
S. aureus is non-motile and does not form spores. It also known as "golden staph" and Oro staphira. S. aureus is one of the most common causes of bacteremia and infective endocarditis. It is frequently found in the nose, respiratory tract, and on the skin.
Streptococcus pyogenes is an important cause of throat infection that may be transmitted by food. S. pyogenes is a catalase-negative aerobic Gram-positive coccus have chain like arrangement.S.pyogenes, is one of the most virulent species causing human infections. S. pyogenes is a prototype bacterium that causes exotoxin-mediated infections. One important feature of the S. pyogenes genome is that its genetic variation is largely determined by the presence of prophages or prophage-like elements.These prophage-like elements frequently carry virulence mechanisms such as exotoxin,endotoxin adhesin,and superantigen genes There are at least 517,000 deaths globally each year due to severe S. pyogenes infections and rheumatic fever disease alone causes 233,000 deaths.
Vibrio bacteria are largely halophilic and motile with single flagellum. They are heterotrophic organisms, obtaining nutrients from their mutualistic, parasitic, or pathogenic relationships with other organisms.