Foodborne pathogens and diseases

1. FOODBORNE DISEASE CAUSED BY Clostridium Species: A REVIEW
Sanjogta Thapa Magar1
1 Department of Microbiology , St Xavier’s College, Kathmandu
ABSTRACT
Foodborne diseases can be defined as those conditions that are commonly transmitted through
ingested food. The two most common types of food borne diseases are intoxication and infection.
Intoxication occurs when toxin produced by the pathogens cause food poisoning, while infection
is caused by the ingestion of food containing pathogens. Some microorganisms can use our food
as a source of nutrients for their growth. By growing on the food, metabolizing them and
producing byproducts, they not only render the food inedible but also pose health problems upon
consumption. Clostridia produce the highest number of toxins of any type of bacteria. Among
Clostridium species, Clostridium perfringens and Clostridium botulinm are the largest toxin
producer and also the most widespread, being found as part of the microbiota of animals and
humans and in the soil. In most cases, Clostridium perfringens food poisoning results by eating
improperly cooked and stored foods. C. perfringens food poisoning is quite common and it is an
important cause of outbreaks worldwide. The prevention of growth of this organism is best
accomplished by following the standard food service practices of rapidly chilling prepared foods
in shallow containers and keeping cold food cold and hot food hot. Botulinum toxin, one of the
most poisonous biological substances known, is a neurotoxin produced by the
bacterium Clostridium botulinum. C. botulinum elaborates eight antigenically distinguishable
exotoxins (A, B, C1, C2, D, E, F and G). Botulinum toxins now play a very significant role in the
management of a wide variety of medical conditions, especially strabismus and focal dystonias,
hemifacial spasm, and various spastic movement disorders, headaches, hypersalivation,
hyperhidrosis, and some chronic conditions that respond only partially to medical treatment
Keywords: Foodborne diseases ,Clostridium perfringens , Clostridium botulinum, Intoxication,
Poisoning ,Botulinum toxin, clinical applications, adverse effects
Introduction
Foodborne pathogens are the infection causing microorganism that are usually found in foods
as a contaminants. As we know foods are the one of the vehicles for transmission of many
diseases. When a person consumes the contaminated foods , he/she is likely to be infected with
the disease. The most common cause for the food contamination is faecal-oral route because of
the poor hygiene habits. The foodborne pathogens includes pathogenic bacteria ,virus and
parasites that causes food poisoning, intoxication and disease which may be acute or chronic
that may lead to death. The first symptoms of food poisoning is usually diarrhea. Other
symptoms are stomach cramping, vomiting , high fever and blood in stool, dehydration etc.
One of the bacteria causing foodborne disease is Clostridium species. Clostridium is
gram positive rod shaped anaerobic spore forming bacteria. There are two types of Clostridium
that causes foodborne disease – Clostridium perfringens and Clostridium botulinum.

2. 1. Clostridium perfringens : Clostridium perfringens was discovered in 1892 by two men:
George Nuttall and William Welch which were and still are two well respected men in there
field. C. perfringens is a spore-forming gram-positive anaerobic bacteria that is found in many
environmental sources as well as in the intestines of humans and animals. C. perfringens is
commonly found on raw meat and poultry. Some strains of C. perfringens produce a toxin in the
intestine that causes illness.The main causes of food poisoning by C. perfringens are dried or
pre-cooked meat and meat products, soup and sauces or gravy. Although C. perfringens are
found in the human intestine, illness is caused by eating food contaminated with large numbers
of C. perfringens bacteria that produce toxin in the intestines to cause illness.. C. perfringens is
divided into 5 toxovars A, B, C, D, and E based on the synthesis of four major lethal toxins:
alpha(cpa), beta (cpb), epsilon (etx), and iota (iap) . Along with these four major toxins, some
other toxins like enterotoxin (cpe) and beta2 (cpb2) toxin produced by C. perfringens are
considered as important toxins for enteric diseases . C. perfringens can survive high temperatures
During cooling and holding of food at temperatures from 54°F–140°F (12°C–60°C), the
bacteria grows. It can grow very rapidly between 109°F–117°F (43°C–47°C). The bacteria
produce a toxin inside the intestine that causes illness. The person infected with C.
perfringens by ingesting larger amount of it will develop diarrhea and abdominal cramps
within 6 to 24 hours (usually 8 to 12 hours). The disease is usually over within 24 hours. Less
severe symptoms may last for 1 or 2 weeks. It doesnot causes fever and vomiting.
.
2. Clostridium botulinm: A description is given of a food intoxication in 1895 at Ellezelles, a
village in Belgium. As a result 3 persons died within a few days and others became seriously ill.
An investigation by E. van Ermengem led to the discovery of Clostridium botulinum and
botulinum toxin. C.botulinm is gram positive rod shaped anaerobic spore forming motile
bacteria which has ability to produce neurotoxin known as botulinum. C.botulinum is
commonly found in canned foods and fruits. This causes botulism in human. Botulism is a rare
but life threatening illness. There are 7 distinct forms of botulinum toxin, types A–G. Four of
these (types A, B, E and rarely F) cause human botulism. Types C, D and E cause illness in other
mammals, birds and fish. Only botulinum toxin types A, B, E, and F cause disease in humans.
Types A, B, and E are associated with foodborne illness, with type E specifically associated with
fish products. Type C produces limberneck in birds and type D causes botulism in other
mammals. No disease is associated with type G.
EPIDEMIOLOGY
1.C. perfringens: C. perfringens is the leading cause of food poisoning in
the UnitedStates and Canada. Contaminated meats in stews, soups and gravies are usually
responsible for outbreak. C.Perfringens poisoning is one of the most commonly reported
foodborne illnesses in the U.S. There were 1,162 cases in 1981, in 28 separate outbreaks.It
causes about 250,000 cases of foodborne illnesses in the United States every year. Deaths due to
the disease are rare and mostly occurs in elderly and people who are predisposed to the
disease. From 1998–2010, 289 confirmed outbreaks of C. perfringens illness were reported with
15,208 illnesses, 82 hospitalizations, and 8 deaths. Outbreaks can cause regularly and can cause
substantial morbidity but it can be prevented by avoiding the contamination of meats that were
coming from the slaughterhouses and farms.

3. . Typically, dozens or even hundreds of person are affected. It is probable that many outbreaks
go unreported because the implicated foods or patient feces are not tested routinely for C.
perfringens or its toxin. CDC estimates that about 10,000 actual cases occur annually in the U.S.
2. Clostridium botulinm : Food-borne botulism, the first form of the disease to be identified, is
responsible for approximately 1000 reported annual cases worldwide. While European cases
most commonly are associated with type B contamination of home-processed meats, Alaskan,
Canadian, and Japanese outbreaks often involve type E toxin in preserved seafood. Chinese
cases involve type A toxin in home-processed bean products. A recently described case in
Thailand was associated with ingestion of home-preserved bamboo shoots.
Most cases in the continental US are associated with home-canned vegetable products
such as asparagus, green beans, and peppers. Of the average 20 - 30 food-borne US cases yearly,
approximately 60% are type A, 18% type B, and 22% type E. Alaska, California, Michigan,
Washington, New Mexico, Illinois, Oregon, and Colorado have the highest incidences of food-
borne botulism. Between 1990 and 2000, Alaska accounted for 39% of the US cases.
The toxin type most is often responsible for food-borne illness corresponds well with the
geographic distribution of the toxigenic species. Type A is most common west of the
Mississippi, type B east of the Mississippi, and type E in Alaska. Toxin type A produces a more
severe illness than type B, which in turn is more severe than type E.
By far, home-processed foods are responsible for most (94%) outbreaks of food-borne
botulism in the continental US. In fact, of the 6% of outbreaks caused by mass-produced
commercial foods, most cases were attributed to consumer mishandling of commercial products.
Infant botulism occurs in children younger than 1 year, with 95% of the cases occurring in
patients younger than 6 months. Peak susceptibility is in the 2- to 4-month range. In the 16 years
following its identification in 1976, 1134 cases of infant botulism have been recorded in the
United States. With approximately 60 cases of infant botulism reported each year, it is now the
most frequently occurring form of botulism. The disease is most common in the western part of
the United States. One half of all annual cases are reported in California, where the frequency of
the toxin responsible is distributed equally between types A and B.
While the toxin types of food-borne botulism seem to reflect the distribution of toxigenic
strains in the environment, the frequency of type B toxin in infantile botulism is
disproportionately high. Although the case-fatality ratio for infant botulism in the US is less than
2%, the disease is suspected to be responsible for up to 5% of sudden infant death syndrome
cases in California.
Although the ingestion of honey has been identified as a strong risk factor for the disease, it
is found in fewer than 20% of case histories (and only 5% of case histories in California in recent
years).
Other risk factors that have been reported include infants with higher birth weights and
mothers who were older and better educated than the general population. Another reported risk
factor was a decreased frequency of bowel movements (< 1/d) for at least 2 months.
Breastfeeding was associated with older age at onset of illness in type B cases.
Through 1992, only 1-3 cases of wound botulism were reported in the US each year. Two thirds
of these cases were type A and almost one third were type B. One half of all cases were reported
from California. In recent years, the number of reported cases of wound botulism has risen
dramatically, with 11 cases in California in 1994 and 19 cases confirmed by the State
Department of Health Services during the first 11 months of 1995. All but 1 of 40 cases reported

4. in California, at this writing, involved drug abusers, many with subcutaneous injection or skin-
popping of heroin.
Cases of adult colonization botulism have been increasingly reported in the literature. In
some of these cases, C botulinum organisms, but no preformed toxin, could be found in foods the
patients had ingested. These cases were associated with a prolonged latent period of up to 47
days postingestion before onset of symptoms. In one study, 2 of 4 patients had surgical
alterations of the gastrointestinal tract that may have promoted colonization. Jejunoileal bypass,
surgery of the small intestine, and Crohn disease are among other reported factors predisposing
adult patients for intestinal colonization.
Only rare cases of injection-related botulism have been reported, despite the increasingly
common use of botulinum neurotoxin in neurology, ophthalmology, and dermatology practices.
The standard packaging mandated by the FDA contains doses that are well below the human
toxic level.
Symptoms
1. Clostridium perfringens : Clostridium perfringens ,food poisoning is the term used to
describe the common foodborne illness caused by C. perfringens. A more serious but rare illness
is also caused by ingesting food contaminated with Type C strains. The latter illness is known as
enteritis necroticans or pig-bel disease. The common form of C. perfringens poisoning is
characterized by intense abdominal cramps and diarrhea which begin 8-22 hours after
consumption of foods containing large numbers of those C. perfringens bacteria capable of
producing the food poisoning toxin. The illness is usually over within 24 hours but less severe
symptoms may persist in some individuals for 1 or 2 weeks. A few deaths have been reported as
a result of dehydration and other complications.
Necrotic enteritis (pig-bel) caused by C. perfringens is often fatal. This disease also begins as a
result of ingesting large numbers of the causative bacteria in contaminated foods. Deaths from
necrotic enteritis (pig-bel syndrome) are caused by infection and necrosis of the intestines and
from resulting septicemia. The symptoms are caused by ingestion of large numbers (greater than
10 to the 8th) vegetative cells. Toxin production in the digestive tract (or in test tubes) is
associated with sporulation. This disease is a food infection; only one episode has ever implied
the possibility of intoxication (i.e., disease from preformed toxin).
2.Clostridium botulinm : Botulinum toxins are neurotoxic and therefore affect the nervous
system. Foodborne botulism is characterized by descending, flaccid paralysis that can cause
respiratory failure. Early symptoms include marked fatigue, weakness and vertigo, usually
followed by blurred vision, dry mouth and difficulty in swallowing and speaking. Vomiting,
diarrhoea, constipation and abdominal swelling may also occur. The disease can progress to
weakness in the neck and arms, after which the respiratory muscles and muscles of the lower
body are affected. There is no fever and no loss of consciousness.
The symptoms are not caused by the bacterium itself, but by the toxin produced by
the bacterium. Symptoms usually appear within 12 to 36 hours (within a minimum and
maximum range of 4 hours to 8 days) after exposure. Incidence of botulism is low, but the
mortality rate is high if prompt diagnosis and appropriate, immediate treatment (early

5. administration of antitoxin and intensive respiratory care) are not given. The disease can be
fatal in 5 to 10% of cases.
PREVENTION
1. Clostridium perfringens : The growth of C. perfringens spores can be prevented by most
importantly cooking food, especially beef and poultry, thoroughly to the recommended
temperatures. Leftover food should be refrigerated to a temperature below 40 °F (4 °C) within
two hours of preparation. Large pots of food like soup or stew with meats should be divided
in small quantities and covered for refrigeration. Leftovers should be reheated to at least
165 °F (74 °C) before serving. A general rule of thumb is that if the food tastes, smells, or
looks different from what it is supposed to then the food should be avoided. Even if it looks
okay, a food that has been out for a long time can also be dangerous to eat.
2. Clostridium botulinm:
The control of food-borne botulism caused by C. botulinum is based almost entirely on
thermal destruction (heating) of the spores or inhibiting spore germination into bacteria and
allowing cells to grow and produce toxins in foods. The FDA and CDC give the following
guidelines for preventing foodborne botulism:
 Use approved heat processes for commercially and home-canned foods (i.e., pressure-can
low-acid foods such as corn or green beans, meat, or poultry).
 Discard all swollen, gassy, or spoiled canned foods. Double bag the cans or jars with plastic
bags that are tightly closed. Then place the bags in a trash receptacle for non-recyclable trash
outside the home. Keep it out of the reach of humans and pets.
 Do not taste or eat foods from containers that are leaking, have bulges or are swollen, look
damaged or cracked, or seem abnormal in appearance. Do not use products that spurt liquid
or foam when the container is opened.
 Boil home-processed, low-acid canned foods for 10 minutes prior to serving. For higher
altitudes, add 1 minute for each 300 meters of elevation.
 Refrigerate all leftovers and cooked foods within 2 hours after cooking (1 hour if the
temperature is above 30 °C).
 One of the most common causes of foodborne botulism is improperly home-canned food,
especially low-acid foods such as vegetables and meats. Only a pressure cooker/canner
allows water to reach 115 to 120 °C, a temperature that can kill the spores.[37]
 Follow strict hygienic procedures to reduce contamination for at home canning. Use of
pressure canners and .Keep oils infused with garlic or herbs refrigerated. Keep potatoes
which have been baked while wrapped in aluminum foil hot until served or refrigerated. Boil
home-processed, low-acid and tomato foods canned foods in a saucepan for 10 minutes
before serving, even if you detect no signs of spoilage.
 Wound botulism can be prevented by promptly seeking medical care for infected wounds,
and by not using injectable street drugs.
 Most infant botulism cases cannot be prevented because the bacteria that causes this disease
is in soil and dust. The bacteria can be found inside homes on floors, carpet, and countertops
even after cleaning.

6.  Honey can contain the bacteria that causes infant botulism, so children younger than 12
months old should not be fed honey. Honey is safe for people 1 year of age and older.
DIAGNOSIS
1.Clostridium perfringens: C. perfringens can be diagnosed by Nagler's reaction where the
suspect organism is cultured on an egg yolk media plate. One side of the plate contains anti-
alpha-toxin, while the other side does not. A streak of suspect organism is placed through both
sides. An area of turbidity will form around the side that does not have the anti-alpha-toxin,
indicating uninhibited lecithinase activity. In addition, laboratories can diagnose the bacteria by
determining the number of bacteria in the feces. Within the 48 hours from when the disease
began, if the individual has more than 106 spores of the bacteria per gram of stool, then the
illness is diagnosed as C. perfringens food poisoning.
Typically, the symptoms of C. perfingens poisoning are used to diagnose it. However,
diagnosis can be made using a stool culture test, in which the feces is tested for toxins produced
by the bacteria.
2. Clostridium botulinm: Diagnosis is usually based on clinical history and clinical examination
followed by laboratory confirmation including demonstrating the presence of botulinum toxin in
serum, stool or food, or a culture of C. botulinum from stool, wound or food. Misdiagnosis of
botulism sometimes occurs as it is often confused with stroke, Guillain-Barré syndrome, or
myasthenia gravis special tests may be needed to exclude these other conditions. These tests
may include a brain scan, spinal fluid examination, nerve conduction test (electromyography, or
EMG), and a tensilon test for myasthenia gravis
TREATMENT
1. Clostridium perfringens : The person is given fluids and is encouraged to rest. Antibiotics are
not given.
2. Clostridium botulinm:
 Foodborne botulism - If diagnosed early, antitoxin should be administered to block the
actions of the exotoxin. If respiratory failure has set in, mechanical ventilator and
intensive care is required.
 Infant botulism - Remove the contaminated food by inducing vomiting and enemas.
Good supportive care is further required for recovery.
 Wound botulism - Administration of antitoxins to neutralize the exotoxin, surgical
debridement and excision of the effected area, followed by the required supportive
treatment.
RESULT AND DISCUSSION
C. Perfringens are ubiquitous and are impossible to eliminate from the environment. Many
foods such as meat and poultry may carry the organism, but the mere presence of C. perfringens
in food is not enough to cause illness. Millions of growing cells are needed. The total

7. destruction or significant reduction in the bacterial load in foods during growth, harvesting,
processing, packaging, and storage prior to consumption has always been a general goal.
However, the wide array of parameters for proliferation of foodborne pathogens is staggering.
Some of the same methods for the control of organisms in the food supply are used separately
or in combination in the preservation of foods .The prevention of growth of this organism is
best accomplished by following the standard food service practices of rapidly chilling prepared
foods in shallow containers and keeping cold food cold and hot food hot. Remember, always
reduce the level of contamination by keeping all work areas clean and sanitary .Prevention of C.
perfringens infections/intoxication requires strategies to interrupt various modes of
transmission. Essentially these control programs include improvements in personal hygiene
practices among healthcare workers and food handlers, decontamination of equipment, surfaces,
and clothing, proper cooking and storage of foods, and screening programs.
On the basis of strong evidence, botulism is a rare, severe, and potentially lethal illness that
is caused by the botulinum toxin, which is produced by Clostridium botulinum . All forms of
botulism (foodborne, infant, wound, iatrogenic, and inhalational) produce the same neurologic
syndrome characterized by symmetric cranial nerve palsy, commonly followed by afebrile,
symmetric descending flaccid paralysis of involuntary muscles, which may result in respiratory
compromise and death.. The mainstays of treatment are early diagnosis, intensive supportive
care, and timely botulinum antitoxin administration. Strong research evidence supports the
urgent administration of human-derived botulinum antitoxin in suspected infant botulism cases,
which has been shown to decrease the length of hospitalization, intensive care unit admission,
and mechanical ventilation. Some research and expert consensus advocate the use of
heptavalent antitoxin type A to G in noninfant botulism cases.O n the basis of consensus,
prevention strategies include education about safe food preparation and home canning
techniques, keeping wounds clean, and monitoring for signs of infection. The use of
aminoglycosides in infants with suspected sepsis or possible botulism should be avoided
because aminoglycoside administration might exacerbate paralysis.
CONCLUSION
C. perfringens is an important causative agent for food poisoning outbreaks and major
concern in public health programs worldwide. C. Perfringens poisoning is one of the most
commonly reported foodborne illnesses. In most cases, C. perfringens food poisoning results by
eating improperly cooked and stored foods. Normally, bacteria are found on food after cooking,
and these bacteria can multiply and cause C. perfringens food poisoning if the foods sit out and
cool before refrigerating.
Botulism, although rare, can present in multiple forms. The history and physical examination
are essential to making the diagnosis. The signs and symptoms usually include constipation,
weakness, hypotonia, cranial nerve abnormalities, and often respiratory depression. Loss of
airway control or respiratory failure from diaphragmatic weakness is insidious. Treatment is
supportive. Hospitalizations are often prolonged, but regardless of the severity of disease, the
outcome is usually complete recovery. Botulism a food borne disease is still a very rare
condition, yet when it does occur; it requires a full range of potential public health emergency
ACKNOWLEGDEMENT

8. I wish to express my sincere gratitude to Mr.Sagar Aryal sir for your guidance and
encouragement in carrying out this article.
I also wish to express my gratitude to other teachers of Microbiology department who
rendered their help during the period of my article.
I also thank Mr Sudhagar Pant sir for providing me the opportunity to embark on this
article.