I. Bacterial causes of Diarrhoea

Characteristic are : gram negative; slender, spirally curved-rod, motile (single polar flagellum)

Campylobacter are important pathogens in animals and in the past 10 years have become the most frequent cause of bacterial gastroenteritis in human, the most common C.jejuni.

As with Salmonella, there is a large animal reservoir, so that infections are acquired by consumption of contaminated food, especially poultry, milk, or water

3. Campylobacter - epidemiology

3. Campylobacter PathogenesisNot all infections are symptomatic, some patients

may become asymptomatic excreters

The incubation period is usually 2-5 days (2-11 days), duration 3 days-3 weeks

Diarrhea may be preceded by fever, myalgia, and abdominal pain. Abdominal pain mimic acute peritonitis. Vomiting rare.

Diarrhea lasts about 2-3 days but abdominal pain may persist. Stool may contain fresh blood, pus or mucus, indicating colorectal inflammation

C. jejuni causes infectious proctitis in homosex. man

3. Campylobacter Lab. Diagnosis and Treatment

Direct examination of fresh by dark-field or phase contrast microscopy can be used in the diagnosis of Campylobacter enteritis.

Selective media with and without blood have been used to isolate organism from stool

Chemotherapy is not warranted, and erythromycin is the antibiotic of choice for cases of diarrhoea disease that are severe enough to treatment

Invasive infection may require treatment with an aminoglycoside

3. Campylobacter Prevention

Prevention of Campylobacter infection is possible when (like prevention salmonella):

1) water supply are purified properly

2) milk for human consumption is heat-treated

3) there is hygienic handling of raw meats, and

4) there is control of infection at all stages of poultry production

4. Vibrio cholerae IntroductionVibrio are straight or curved rods belong to

the family Vibrionaceae comma-shaped gram negative, facultative anaerobes, that are motile by a polar flagellum or flagella.

The most important of Vibrio is V. cholerae, the etiological agent of cholera

Cholera is still a major cause of gastrointestinal illness in dweveloping countries.

4. Vibrio cholerae EpidemiologyV. cholera is free-living inhabitant of fresh water but

causes infection only humans

Asymptomatic human carriers are believed to be a major reservoir

The disease is spread via contaminated food; shelfish grown in fresh waters all type of shelfish product may be the source of infection

Thus cholera continues to flourish in communities where the provision of clean dringking water and adequate sewage disposal is absent or unrealible

Cases still occur in develop countries, and drinking contaminated water is also a means of infection

4. Vibrio cholerae Epidemiology

V. cholerae can be subdevided into serotype based on somatic (O) antigen

Serotype O1 is the most important and it is further devided into 2 biotype : Classical and El Tor.

The El Tor biotype differs from classical V. cholerae is several ways.

4. Vibrio cholerae PathogenesisVibrio cholerae O1 :Cholera caused by V. cholerae O1 is spread

from person to person by ingestion of contaminated water or uncooked foods, especially fish

M.o. is very susceptible to gastric secretion. Ingestion of 109 vibrios in food or water is required to initiate disease.

If the individual ‘s gastric content have been neutralized by bicarbonate or other antacid, 106 vibrio may cause disease

4. Vibrio cholerae PathogenesisThe incubation period for cholera is

approximately 2-3 days and is followed by a period of vomiting and diarrhea up to 7 days. 10-25 liters of fluid may be lost during infection

Rapid dehydration is accompanied by loss of electrolyte such as potassium and bicarbonate. The loss of electrolytes is due to a microbial enterotoxin

Protration can occur at any time and is directly related to the amount of fluid lost

4. Vibrio cholerae PathogenesisThe major causes of death in cholera are

shock, metabolic acidosis, and renal failure

The relationship between adherence properties and pathogenesis has not been clearly it is believe that flagellum is s prerequisite to attachment to the epithelial surface

The flagellum enables the m.o. to penetrate the mucous gel covering the intestinal epithelial surface

Adherence to the epithelial surface may also be mediated by other types of surface adhesins

4. Vibrio cholerae PathogenesisOnce attached to the epithelial

surface, the m.o. can multiply and produce enterotoxin

Enterotoxin is a protein composed of A and B subunits. The subunits B attach to receptor dissociation of subunit and entry of subunit A to plasma membrane activation of subunit A cause activation of adenyl cyclase that change ATP to cAMP.

4. Vibrio cholerae Pathogenesis

Increase cAMP alters the ion transport mechanism associated with the cytoplasmic membrane.

Permeability changes involving sodium (Na+) and chlorine (CL-) cause an efflux of water from the mucosal surface and hence cause diarrhea

4. Vibrio cholerae Pathogenesis

Vibrio cholerae non-O1 :Non O1 organism produce a cholera-like

toxin that is believed to beassociate with gastrointestinal sympom,. Most cases are sporadic, and not associated with pandemics, as classic cholera is

The symptoms of non O1 disease are similar to those of classical cholera but are less severe

4. Vibrio cholerae Lab. diagnosis

In country where cholera is prevalent , diagnosis based on clinical ground. Because ETEC infection can resemble cholera an its severity, so fluid and electrolyte replacement are of important

For diagnosis of sporadic and detection of carriers , culture is required to distinguish cholera from other acute diarrhoeas

4. Vibrio cholerae TreatmentCholera is a self-limiting disease when water and

electrolytes are replaced.

Prompt oral or intravenous rehydration with fluids and electrolytes is central to the treatment of cholera.

A replacement fluid consisting of NaCl, sodium bicarbonate, and potasium chloride can be given IV for patient in severe shock

Oral rehydration therapy for patient with less severe disease includes the use of glucose or sucrose in addition to the salt just mentioned

4. Vibrio cholerae TreatmentThe addition of sugars permits fluid balance

in the gut by preventing the loss of sodium

Antibiotic are not necessaary , but tetracycline may be given as some evidence indicates that this treatment reduces the time of secretion of V. cholera thereby reducing the risk of transmission

Tetracyclin is used for adults while trimetoprim-sulfamethoxazole and furazolidone are used for childres and pregnant women respectively

4. Vibrio cholerae Prevention As with other diarrhoeal disease, a

clean drinking-water supply adequate sewage disposal are fundamental to the prevention of cholera.

Be possible to eliminate the disease because there is no animal reservoir

A killed, whole-cell vaccine is available and is given parenterally, but is only effective in about 50% of vaccinees, with protection lasting only for 3-6 months

5. Shigellosis IntroductionShigellosis is also known as

bacillary dysenthry because in its more severe form it is characterized by an invasive infection of the mucosa of large intestine, causing inflammation and resulting in pus and blood in the diarrhoeal stool

However symptoms range from mild to severe depending on the species of shigella involved and on the underlyying state of health of the host

5. Shigellosis EpidemiologyThre are 4 species, of which Shigella

dysenteriae is the most serious.

Shigellosis is primarily a paediatric disease. When associated with severe malnutrition it may precipitate complication such as the ‘kwashiorkor’

Shigella are human pathogens without animal reservoir, being spread from person-to-person by the fecal-oral route and less frequently by contaminated food and water

Shigella able to initiate infection from a small infective dose thus spread is easily in situation where sanitation / personal hygiene may be poor (nurseries, day care centre, and institution for the handycapped)

5. Shigellosis PathogenesisShigella are effective pathogen, cause

disease with doses as low as 10-100 m.o.; whereas with Salmonellae, Campylobacter, and V. cholera, higher doses are usually required

Incubation periode 1-4 days, duration 2-3 days. Vomiting rare. The m.o. attach to and invade the mucosal epithelium of the distal ileum and colon, causing inflammation and ulceration. Abdominal cramp and fever positif

However they rarely invade throught the gut wall to the bloodstream. Enterotoxin is produced but it role in pathogenesis is uncertain since toxin-negative mutants still produce disease

5. Shigellosis Clinical features, Treatment, and Prevention

Diarrhoea is usually watery at first but later contains mucus and blood. Lower abdominal cramps may be severe

The disease is usually self-limiting but dehydration can occur, especially in the young and elderly.

Complication may be associated with malnutrition.

Treatment : Rehydration may be indicated. Antibiotic not be given except in severe cases.

Prevention : education in personal hygiene and proper sewage disposal are important. Cases may continue to excrete shigellae for a few weeks. Because of no animal reservoir, the disease is potentially eradicable

6. Other bacterial causes of diarrhoeal disease Gram (-) and (+) bacteriaThe patogen described in the previous are the major bacterial causes of diarrhoeal disease

Salmonella and Campylobacter infection and some types of E. coli infections are most often food associated.

Cholera is more often waterborne and Shigellosis is usually spread by direct fecal-oral contact.

There are several other bacterial pathogens that causes food-associated infection or food poisoning.

Two Gram-negative bacteria which have been associated with food-borne outbreaks of diarrhoeal disease are : Vibrio parahaemolyticus and Yersinia enterocolitica

These Gram-negative organism previous, invade the intestinal mucosa or produce enterotoxin which cause diarrhea. None of, produce spores

Two Gram-positive species are important causes of diarrhoeal disease particulalrly in associated with spore-contaminated food, these are Clostridium perfringens and Bacillus cereus

6. Other bacterial causes of diarrhoeal disease Gram (-) and (+) bacteria

Gram NEGATIVE bacteria : 1. Vibrio parahaemolyticus

Is a halophilic (salt-loving) vibrio contaminates seafood and fish, if consume uncook causes diarrhoeal disease

Most strain associated with infection are haemolytic by production of a heat-stable cytotoxin and shown invade intestinal cell (in contrast to V. cholerae : non invasive and cholera toxin is not cytotoxic)

Incubation period 8 hours-2 days, duration 3 days. Symptom are diarrhoea, vomiting, abdominal; cramp and fever

Diagnosis laboratorium , must provide adequate information about the patient’s history and food consumption to indicate to that vibrios should be looked for.

Prevention : depends on proper cooking of fish and seafood

Gram NEGATIVE bacteria : 1. Vibrio parahaemolyticus

Member of the Enterobacteriaceae and is a cause of food-associated infection, particularly in colder parts of the world, because m.o. prefers to grow at temp. 22o - 25o C.

Yersinia enterocolitica is found in a variety of animal host (rodent, pig, rabbit, sheep, and domestic pets)

Transmission to human from household dogs has been reported.

M.o. survive and multiply, more slowly at refrigrator tem. (4o C), and has been implicated in outbreak of infection associated with contaminated milk as well as other food

Gram NEGATIVE bacteria : 2. Yersinia enterocolitica

The mechanism of pathogenesis is unknown but the clinical feature of the disease result from invasion of the terminal ileum, necrosis Peyer’s patches and an associated inflammation of the mesenterica lymph node.

Incubation periode 4-7 days, duration 1-2 weeks, symptom diarrhoea and abdominal cramp, fever, rare vomiting

Lab. Diagnosis as with V. parahaemolyticus, an indication of suspicion of Yersinia infection is useful to lab. Staff to process the specimen apropriately

Gram NEGATIVE bacteria : 2. Yersinia enterocolitica

C. perfringens (C. welchi) is associated with diarrhoeal disease in different circumstance :- enterotoxin-producing strain are a common causeof food-associated infection;- much more rarely beta-toxin producing strain produce an acute necrotizing disease of the small intestinum, accompanied by abdominal pain and diarrhoea.

This form occurs after consumption of contaminated meat by people who are unaccustomed to a high protein diet and do not have sufficient intestinal trypsin to destroy the toxin

Gram POSITIVE bacteria : 1. Clostridium perfringens

Pathogenesis C.perfringens have 2 form of food-associated infection.

1. The common, enterotoxin-mediated infetion is usually acquired by eating meat that has been cooked enough to kill vegetatif cells but not spora. As the food cools the spore germinate. If re-heating before consumption is in adequate, large number of m.o. are ingested. 2. The rare form associated with beta-toxin producing strain causes a severe necrotizing disease

Gram POSITIVE bacteria : 1. Clostridium perfringens

Antibacterial treatment of C. perfringens diarrhoea is rarely required.

Prevention depend on through re-heating of food before serving, or preferably avoiding cooking foodtoo long in advance of consumption

C. perfringens is also an important cause of infection of wound and soft tissue.

Gram POSITIVE bacteria : 1. Clostridium perfringens

Spores and vegetatif cells of Bacillus cereus contaminate many food, and food-associated infection take ones of twp form :

1. Diarrhoea resulting from the production of enterotoxin in the gut2. Vomiting due o the ingestion of enterotoxin in food (emetic toxin)

Clinical feature : incubation periode for Diarrhoea (8 hours-12 hours) and emetic (15 mins-4 hours); duration for diarrhoea 12 hors-1 day) and emetic (12 hours-2 days). In type diarrhoea, diarrhoea with abdominal cramps

Gram POSITIVE bacteria : 2. Bacillus cereus

Diagnosis labor. : requires specific media

Prevention of Bacillus food-associated infection depend on proper cooking and rapid consumption of food.

Treatment : Spesific antibacterial treatment is not indicated, cause self-limiting disease

Gram POSITIVE bacteria : 2. Bacillus cereus