Bacillus cereus toxin

Bacillus cereus-triggered food poisoning manifests suddenly as the microorganism releases toxins, leading to two distinct categories of gastrointestinal disorders: an emetic syndrome characterized by vomiting, and a diarrheal syndrome.

In the emetic phase, individuals undergo severe and prolonged nausea, accompanied by recurring vomiting that usually persists for hours to days. This emetic syndrome occurs due to the ingestion of a cyclic peptide toxin called cereulide, which forms within the food during the growth of B. cereus.

Symptoms of diarrheal-type food poisoning caused by B. cereus encompass abdominal discomfort, watery diarrhea, rectal tenesmus, moderate nausea often accompanying diarrhea, sporadic vomiting, and the absence of fever.

B. cereus has the potential to flourish in improperly stored food. Hence, it becomes imperative to adopt suitable food handling practices, especially post-cooking, to prevent illnesses arising from this microorganism.

The diarrheal form of food poisoning arises from the presence of complex enterotoxins emerging during the vegetative growth of B. cereus in the small intestine. In contrast, the emetic toxin is produced by multiplying cells present in the food itself. In both variations of food poisoning, the implicated food generally undergoes heat treatment, with the enduring spores acting as the source of the poisoning.

Uncooked rice can house B. cereus spores, which can persist even through the cooking process. When rice is left at room temperature, these spores can activate and develop into bacteria.
Bacillus cereus toxin

What is diarrhea?

Diarrhea is the passage of loose or watery stools at least 3 times in a 24-hour period. Acute diarrhea may be caused by different viruses, bacteria, and parasites. Rotavirus and Norwalk-like virus are the most common agents, causing up to 50% of acute diarrhea cases during the high-incidence seasons. Increases in travel, comorbidities, and foodborne illness lead to more bacteria-related cases of acute diarrhea.

Children in day care, nursing home resi-dents, food handlers, and recently hospitalized patients are at high risk of infectious diarrheal illness. Pregnant women have a 12-fold increased risk of listeriosis, which is primarily contracted by consuming cold meats, soft cheeses, and raw milk.

In a disaster scenario a child with diarrhea may present with three potentially severe or very severe clinical conditions:
(1) acute watery diarrhea (including cholera), which lasts several hours or days, and can cause dehydration
(2) acute bloody diar-rhea or dysentery, which may cause intes-tinal damage, sepsis, malnutrition and dehydration, and
(3) persistent diarrhea (diarrhea that lasts more than 14 days). Most diarrheal germs are spread from the stool of one person to the mouth of another.

These germs are usually spread through contaminated water, food, or objects. Water, food, and objects become contaminated with stool in many ways:
◊ People and animals defecate in or near water sources that people drink.
◊ Contaminated water is used to irrigate crops.
◊ Food preparers do not wash their hands before cooking.
◊ People with contaminated hands touch objects, such as doorknobs, tools, or cooking utensils.

Diarrheal illness accounts for 2.5 million deaths per year worldwide. In the United States, an estimated 48 mil-lion foodborne diarrheal illnesses occur annually, resulting in more than 128,000 hospitalizations and 3,000 deaths.
What is diarrhea?

Cyclosporiasis

Cyclosporiasis is an intestinal illness caused by a microscopic parasite. The parasite is endemic in tropical areas but reported worldwide. Humans are the only hosts known. Cyclospora cayetanensis is a unicellular parasite that causes an intestinal infection called cyclosporiasis. Because Cyclospora is a coccidian parasite, infected people shed oocysts (rather than cysts) in their feces.

People can become infected by consuming food or water contaminated with feces (stool) that contains the parasite. It is an infection of the upper small bowel that is usually self-limited. Watery diarrhea is the most common symptom of cyclosporiasis and can be profuse and protracted.

Oocysts must mature (sporulate) in the environment for days to weeks to become infective; therefore, direct person-to person (fecal-oral) transmission is unlikely. Cyclosporiasis is acquired through drinking or swimming in water contaminated with C. cayetanensis or from ingestion of contaminated produce.

It is found in many countries. But it’s most common in tropical and subtropical regions. In the United States, foodborne outbreaks of cyclosporiasis have been linked to various types of imported fresh produce, including raspberries, basil, snow peas, and mesclun lettuce; no commercially frozen or canned produce has been implicated. Most reported cases have occurred during the months of May through August, peaking in June and July.

Cyclosporiasis is characterized by watery diarrhea, loss of appetite, weight loss, abnormal bloating and cramping, increased flatus, nausea, fatigue and low-grade fever.

How to prevent cyclosporiasis?
• Avoid food or water that may have been contaminated with stool.
• When traveling, follow safe food and water habits.
Cyclosporiasis

What are the symptoms of cryptosporidiosis?

Long term sequelae resulting from infection can be common and van cause non-intestinal symptoms. The first signs and symptoms of cryptosporidium infection usually appear within a week after infection and may include:
*Watery diarrhea
*Dehydration
*Lack of appetite
*Weight loss
*Abdominal pain
*Mild Fever
*Nausea
*Anorexia
*Vomiting
*Respiratory problems

As might be expected, many individuals experienced multiple symptoms. In people with a profound immunodeficiency, there can be symptoms that are different and more prolonged, and disease can result in an earlier death than would be the case of the patient had not been infected.

Symptomatic diarrhea may be marked by stool volumes that exceed 6 liters per day. Intestinal infections may extend from the small intestine into then colon, stomach, and esophagus and may involved a variety of extra-intestinal organs and tissues.
What are the symptoms of cryptosporidiosis?

Cryptosporidiosis: History, definition, outbreak

Cryptosporidiosis
The protozoan Cryptosporidium parvum was first described in 1907 in asymmetric mice, and for decades now it has been known to be a pathogen of at least 40 mammals and varying numbers of reptiles and birds.

Although the first documented human case was not recorded until 1976, this disease has a worldwide prevalence of 1-4% among patients with diarrhea, and it appears to be increasing.

It is estimated to cause infections in from 7 to 38% of AIDS patients in some hospitals.

The prevalence of C. parvum is diarrheal stools is similar to that of Giardia lamblia.

In human disease is self limiting in immunocompetent individuals, but it is a serious infection in the immunocompromised, such as AIDS patients.

The protozoan is known to be present in at least some bodies of water and this exist the potential for food transmission.

The fecal-oral route of transmission is the most important, but indirect transmission by food and milk is known occur.

C. parvum is an obligate intracellular coccidian parasite that carries out its life cycle in one host. Following ingestion of the thick-walled oocystsm, they excyst in the small intestine and free sporozoites and penetrate the microvillous region of host enterocytes, where sexual reproduction leads to the development of zygotes.

They invade host cells by disrupting their own membrane as well as that of their host.

Host cell acting polymerization at the interface between the parasite and the host cell cytoplasm has been found to be necessary for infection.

The first demonstrated waterborne outbreak of cryptosporidiosis occurred in Braun Station, Texas, in 1984 following the consumption of artesian well water.

There were actually two outbreaks – one in May and the other in July, with 79 victims. A second outbreaks with 13,000 victims occurred in Carrolton, Georgia in 1987 and oocysts were found in the tools of 58 of 147 victims.

The clinical course of cryptosporidiosis in human depends on the immune state, with the most severe cases occurring in the immunocompromised.

In immunocompetent individuals, the organism primarily parasitizes the intestinal epithelium and causes diarrhea.

The disease is it self-limiting, with an incubation period of 6-14 days and symptoms typically last 9-23 days.

In the immunocompromised diarrhea is profuse and watery with as many as 71 stools per day and up to 171 per day reported.

Diarrhea is sometimes accompanied by mucus but rarely blood.
Cryptosporidiosis: History, definition, outbreak

Common symptoms of shigellosis

Shigellosis is often found in child care centers, nursing homes, refugee camps and other places where conditions are crowded and sanitation is poor.

Studies conducted on adult volunteers have established that the first symptom of shigellosis usually occurs within 12 to 48 hours of exposure but symptoms can be delayed for up to 1 week.

In mild infection, the only complaints may be development of watery or loose stools for a few days with minimal or no constitutional symptoms. But in severe cases symptoms can linger for 2-3 weeks.

The most common symptoms of shigellosis are watery diarrhea, sudden fever, nausea, vomiting, abdominal pain, flatulence, tenesmus, lassitude, and prostration, 1-5 days after ingestion of contaminated food and drinks.

Generally, children are more susceptible to shigellosis than adults and it is fatal in children especially when children suffer from malnourishment. Children with malnourished conditions show dehydration, magacolon, rectal prolapse, and intestinal perforation and infection is life-threatening.
Common symptoms of shigellosis

Traveler’s diarrhea

Ingestion of contaminated food or water makes travel-associated diarrhea the most common health complaint among international travelers.

The early history of the topic of traveler’s diarrhea is tied up with military campaigns, where soldiers classically have suffered more losses from diarrhea and dysentery than from war-related injury. The later history related more to international travelers, expatriates and short-term students spending time in high-risk areas.

 It has been estimated that 30% - 40% of the 50 million people who travel to developing countries every years from the developed parts of the world will experience classic symptoms of traveler’s diarrhea.

Traveler’s diarrhea characterized by a 2 fold or greater increase in the frequency of unformed bowel movement, occurs in as many as 40% of all travelers overseas.

The classical clinical picture in traveler’s diarrhea is the sudden onset of profuse, water diarrhea. The stools are watery, perhaps yellow at the beginning, but later almost colorless and relatively odorless.

The diarrhea may accompanied by cramping, nausea, vomiting and chills. The patients may also complain of muscle and joint pain. Illness was generally seen within the first week of arrival to the high-risk area, with nearly all cases occurring within the first 2 weeks.

The illness lasted between 2 to 5 days and was self limiting, the younger travelers were at greatest risk, and recurrences occurred in about 15% of travelers remaining in the area of risk for 5 weeks.

Children, especially those less than 3 year of age, have a higher incidence of diarrhea, more-severe symptoms and more-prolonged symptoms than adults, with a reported attack rate of 60% for those less than 3 year of age in one study.
Traveler’s diarrhea

Yersiniosis caused by Yersinia enterocolitica

Yersinia enterocolitica belongs to a family of Gram-negative, rod-shaped bacteria. Other species of bacteria in this family group may include Yersinia pseudotuberculosis, which causes illness similar to Yersinia enterocolitica, and Yersinia pestis, which causes Plaque.

Yersiniosis caused by Yersinia enterocolitica commonly causes sporadic infections in industrialized countries, but may also occur in developing countries. The incidence of Yersinia enterocolitica infections is highest among children under 5 and particular in 1-year-old infants.

Symptoms typically develop four to seven days after exposure and may last one to three weeks or longer. In older children and adults, right-sided abdominal pain and fever may the predominant symptoms, and often confused with appendicitis. Occasionally sepsis may lead to severe post-infection sequence such as reactive arthritis, erythema nodosum, meningitis and endocarditis.

Complications such as skin rash, joint pains or spread of bacteria to the bloodstream can occur.

The infection of Yersiniosis is most often acquired by drinking water contaminated unpasteurized milk or by eating food contaminated with the organism.
Yersiniosis caused by Yersinia enterocolitica 

Vomiting due to food poisoning

Diarrhea, vomiting and abdominal pain are probably the most common symptoms of food poisoning. Food poisoning is a general term referring to illness, usually, vomiting, caused by contaminated food or water.

Vomiting or emesis is the forceful expulsion of gastric and intestinal contents through the mouth. The emetic type of food poisoning is characterized by nausea excessive salivation, pallor and sweating and vomiting within 0.5 – 6 hours after consumption of contaminated foods.

Occasionally, abdominal cramps and/or diarrhea may also occur. Duration of symptoms is generally less than 24 hours.

In the vomiting process the stomach divides into two sections and a deep inspiration is taken; then with a strong contraction of the diaphragm and abdominal muscles the stomach contents are regurgitated up via the esophagus.

If vomiting occurs only an hour or so after food consumption, it may be caused by Staphylococcus aureus or Bacillus cereus toxins. These enterotoxins are absorbed in the stomach and act via the central vomiting center.

Vomiting from gastro-enteric infections, for example salmonella or typhoid, can also be classed as food poisoning.
Vomiting due to food poisoning

Diarrhea due to food contamination

Diarrhea is a symptom, not a disease. Usually resulted from an infection in the intestines, through in some cases it may arise from a more serious problem.

Diarrhea may be due to a variety of causes. Spoiled food in one of the culprits. Food poisoning is a common flu-like typically characterized by nausea, vomiting and diarrhea, due to something the victim ate or drank.

In food poisoning, bacteria grow on flyblown, producing toxins, or poisons, that may lead to diarrhea and stomach upsets.

Sometimes illness is caused not y the bacteria themselves but by the toxins they produce, either before or after ingestion.

Excessive consumption of alcohol or fatty and spicy food, or ingestion of food that too hot or too cold in temperature also can cause diarrhea.

Diarrhea due to excesses in respect to general dietary norms is classed as food damage diarrhea. Food damage diarrhea includes some forms of stomach, large intestinal and small intestinal diarrhea.

More than 200 diseases can be transmitted though food. Infectious organisms, present in food though poor hygiene, practices, are responsible for most cases of food poisoning.

Symptoms which usually diarrhea and vomiting, tend to occur suddenly and disappeared rapidly.

The onset of watery diarrhea, abdominal cramps, and pain occurs 6 to 15 hours after consumption of contaminated food.

Diarrhea due to food contamination

Calicivirus or Norwalk-like Virus

Calicivirus or Norwalk-like Virus
Diagnosis

• Diarrhea occurring in an outbreak especially in a closed environment
• Tends to infect older children and adults rather than infants
• Nausea and vomiting are common; bloody stools are rare
• Incubation period 1 – 2 days; illness: 1- 4 days
  

Epidemiology
Even in developed countries, antibodies to calicivirus are nearly universal by age 5. Infections tend to occur in family or community outbreaks. In undeveloped countries, infection by these viruses occurs presumably as a result of poor sanitation. In developed countries, outbreaks that occur year round have been describe in school, resorts, hospital , nursing homes, restaurants and cruise ships.

The primary method of spread is fecal-oral but contaminated water or shell fish has accounted for common source of outbreak. A measure of the importance of these agents is that – 10% of all gastroenteritis outbreaks and up to 90 – 95% of those that are non-bacterial are attributed to them. In contrast to infants, who are more often infected by rotavirus, calicivirus cause disease primarily in older children and adults. Immunity is probably short lived at best, suggesting that humoral antibody is not adequately protective. The incubation period is 1 – 2 days, and shedding can persist for 1- 2 weeks.

The Norwalk agent and related viruses are classified as caliciviruses, although they are also similar in appearance to parvoviruses and hepatitis A virus. Among the other human enteric caliciviruses which are named for where these strains were first detected. The human enteric calicivirus are now divided into two genera, provisionally named “Norwalk like virus” and “Sapporo like virus”.

Symptoms
Although calicilike viruses are typically associated with diarrheal illness, nausea and vomiting may occur frequently, especially in children. Bloody stools do not occur. Fever may be present in up to one third of patients. The incubations period in 24 – 48 hrs and the illness lasts 1 – 4 days.
Calicivirus or Norwalk-like Virus

Amebiasis

Amebiasis
Amebiasis, as trichinosis, is not a bacterial disease. A single-celled animal (an ameba) cause amebic dysentery in humans. The organism is called Endamoeba histolytica.

Amebiasis varies greatly in symptoms from patients to patient and periodically in severity in the same patient. Diarrhea is a common symptom of the diseases, and it may be persistent and severe, mild and occasional. Abdominal pain, fatigue and fever are sometimes encountered. Incubation lasts from 2 days to several months, but it usually 3-4 weeks.

The control of Amebiasis is essentially matter of good sanitary procedures.

1. Drinking water, water added to foods, and used for washing and sanitizing of equipment and utensils and for irrigation of crops should be portable.
2. Drinking water to be used for foods or for equipment or utensils that contact foods, taken form deep wells, lakes, or ponds, should be tested periodically for bacteriological safety. Although this is not a bacterial disease, it appears to occur when bacteria indicative of pollution with human discharge are present.
   
3. Persons known to have had amebic dysentery should be rigidly excluded from food handling of any kind.

Amebiasis

Foodborne illness bacteria: Clostridium perfringes

Foodborne illness bacteria: Clostridium perfringens Clostridium perfringens contamination Clostridium perfringens (both vegetative cells and spores) is found in soil, sewage, manure, water, and dust. It has been found in the intestinal tract of healthy humans and animals. 

Many raw foods, particularly meats and vegetables, are likely to be contaminated with Clostridium perfringens when they reach food preparation areas. Outbreaks of illness usually involve foods high in protein. Clostridium has a requirement for 12 to 13 amino acids.) The foods include: meats, poultry, soups, gravies, sauces, stews, and casseroles. 

When food is cooked, the vegetative cells are destroyed. However, spores survive if protein-rich foods, such as roast beef, turkey, gravies,, and sauces are allowed to cool slowly and remain at temperatures that allow outgrowth of the surviving spores, vegetative cells will multiply rapidly to large numbers in the food and create a significant hazard. 

Foodborne illness 

Foodborne illness due to Clostridium perfringens usually occurs to 24 hours after ingestion. The illness is caused by ingestion of a large number of vegetative cells. When the vegetative cells reach the intestine, they form spores and release an enterotoxin that causes diarrhea and severe abdominal pain. Nausea is uncommon; fever and vomiting are unusual. 

Fatalities can occur in the very young and elderly. The infective dose is a cell population of 500,000 cells or more per gram of food. This number of cells can form rapidly in foods because Clostridium perfringens has a very rapid generation time and can double ion number every 7 minutes at 42 C. Clostridium perfringes grows at temperatures between 15 C and 53 C. 

Foodborne illness bacteria: Clostridium perfringens

Bacillus cereus: Toxin and Spore Producing Bacteria

Bacillus cereus: Toxin and Spore Producing Bacteria
Bacillus cereus, a spore forming microorganisms, is present in soil and can be isolated from a wide variety of vegetation and food. It has been found to be present in the intestinal tract of 10 percent of healthy adults. It is often present in dairy products, meats, spices, dried products, and cereals (particularly rice). Food products implicated in this type of illness have included: cereal dishes containing corn and cornstarch, potatoes, vegetables, meat product, puddings, soups, sauces, fried rice, and ilk and dairy products. Vegetative cells of Bacillus cereus are destroyed by most cooking processes, but heat resistant spores survive.

When cooked food containing spores of Bacillus cereus is cooled and allowed to remain at warm kitchen temperatures, the spores germinate to form viable cells. The population of cells increases in the food. Illness results form ingestion of food containing a large number of cells of Bacillus cereus, that then produce toxin in intestine.
There are two types of Bacillus cereus foodborne illness:

Diarrheal illness
The Diarrheal illness is most often associated with meat product, soups, potatoes and starchy vegetables, puddings, and sauces. The onset of symptoms occurs 8 to 16 hours after ingestion of food containing the microorganisms or toxin. Symptoms include abdominal pain and diarrhea and occasionally, nausea and vomiting.

Emetic illness
The emetic form of illness may result in diarrhea and abdominal cramps, but is most often characterized by nausea and vomiting. Its onset occurs 1 to 5 hours after ingestion. The duration of illness is from 6 to 24 hours. These types of illness is most often associated with the rice dishes and pasta products that were held at improper temperatures and slow cooling of large quantities of foods.

Critical problems in today’s food supply that lead to illness caused by Bacillus cereus are:

• Holding cooked foods at room temperatures for along periods of time prior to reheating or serving them.

• Cooling foods at temperatures that allow the germination and growth of cells of Bacillus cereus.

• Failure of foodservice personnel to use good personal hygiene when working on foodservice facilities. People can be carriers of this microorganism. If they do not wash their hands and under their fingernails after defecating, they can transmit this pathogen to anything they touch or handle.

Bacillus cereus: Toxin and Spore Producing Bacteria

Food Borne illnesses

Food Borne illnesses
Since food is biological in nature and is capable of supplying consumers with nutrition, it is equally capable of supporting the growth of contaminating microorganisms. Two types of bacterial food borne disease are recognized: intoxications and infections.

Food borne bacterial intoxication is caused by the ingestion of food containing preformed bacterial toxin resulting from bacterial growth in food.

Food borne infection, on the other hand, is caused by the ingestion of food containing viable bacteria which then grow and establish themselves in host, resulting in illness. Some pathogens occur in normal, healthy animals and in some instances man. Certain microorganisms are thus ubiquitous in nature, occurring on soil and vegetation, in animal wastes, and on animal carcasses. Human skin surfaces and nasal passages harbor staphylococci. Water supply may contain pathogens when contaminated with fecal mater.

Coastal waters in particularly may also naturally harbor recognized as pathogen Vibrio vulnificus. It is thus obvious how difficult to prevent one or more pathogens from entering raw foods.

The most common symptoms associated with food borne illness is diarrhea. Depending on the pathogenicity of the organisms and the susceptibility or health status of the host, the illness may be acute and self-limiting, or it may lead to other serious chronic and life threatening sequellae. Food borne illnesses are more likely to be life-threatening for the immune compromised, the aged , and those individuals debilitated by underlying health problems such as cirrhosis, hepatitis, hemachromatosis. The increase number of sporadic outbreaks of hemorrhagic colitis and the sequella hemolytic uremic syndrome has caused health officials to speculate that Escherichia coli serotypes may be the source of many diarrheal disease of unknown etiology. Food borne disease however, may not necessarily manifest itself in diarrheal illness but may illicit other symptoms such as abdominal cramps or pseudo appendicitis. Although a number of unusual outbreaks related to processed foods have occurred on the past few years , the majority of food borne illnesses are attributable to improper handling , cooking , and syirage practices on food service operations pr in the home.
Food Borne illnesses