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Digestive Diseases
Shigellosis
Campylobacter jejuni
Cholera
Shigella Etiology
Family: Enterobacteriaceae Gram negative Rod shaped Non motile Non spore forming Very closely related to Escherichia coli
Shigella There are four species of Shigella
S. sonnei Also known as group D Shigella Responsible for most cases of shigellosis in the United States
S. dysenteriae Type 1 Is rare in the U.S. but can lead to deadly outbreaks in
developing countries S. flexneri
Group B Shigella Accounts for almost all of the rest
S. boydii Is the most genetically-divergent of the Shigella genus S. boydii is restricted to the Indian subcontinent
Shigellosis Shigellosis is an infectious disease caused by a group of
bacteria called Shigella
Endemic in North America, Europe, and the tropics
Every year, approximately 14,000 cases of Shigellosis are reported each year in the United States
Infection is more common in children ages 1-4 years and in the elderly , debilitated and malnourished
The only reservoir for Shigella organism is the human intestinal tract, and infected feces are always the source of the infection
Incubation period is usually 1 to 3 days
Transmission Pass from one infected person to another
Directly by fecal-oral route transmission or indirectly through contact with contaminated objects
Shigella are present in the diarrheal stools of infected persons while they are sick and for up to a week or two afterwards
Widest distribution of the organism is through contaminated water or food
Transmission occurs primarily through individual who fail to wash their hands or clean their fingernails after defecation
Food can also be contaminated by flies that carry enough of the organism for it to multiply to an infectious dose in food
When dogs ingest human feces, the infection can be passed by them to children or other susceptible persons
Symptoms Shigellae invade the intestinal mucosa and
cause inflammation
In children: usually produces diarrhea, high fever, nausea, vomiting, abdominal pain with distention, irritability, and drowsiness Pus, mucus, and blood may appear in stools as a
result of the intestinal ulceration (typical of this infection)
In adults: produces many of the same symptoms except that adults generally do not have fever
Treatment
Persons with mild infections usually recover quickly without antibiotic treatment
Resistance to traditional first-line drugs like ampicillin and trimethoprim-sulfamethoxazole is common, and resistance to some other antibiotics is increasing
If an effective one can be found, then the shigellae can be eliminated quickly
When many persons in a community are affected by shigellosis, antibiotics are sometimes used to treat only the most severe cases
Some antidiarrheal drugs can make the illness worse and should be avoided
Prevention No vaccine at present Control of the human reservoir and sanitary
control of environmental sources through: Adequate treatment of water and sewage, fly
control and protection of food, water, and milk from human or mechanical vectors
Campylobacter jejuni
Campylobacter jejuni Etiology
Gram negative S- shaped or spiral rods Non-spore forming A polar tail at one or both ends propels the
bacteria through liquid They cannot tolerate drying and can be killed by
oxygen Freezing reduces the number of Campylobacter
bacteria on raw meat (They are thermophiles) Damages the small intestine and the colon
Campylobacter jejuni Epidemiology Is prevalent in the United States and other
developed countries One of the most common causes of diarrheal
illness in the United States over 2 million cases are reported each year
it is estimated that approximately 100 persons with Campylobacter infections die each year
occurs much more frequently in the summer months than in the winter
isolated from infants and young adults more frequently than from persons in other age groups and from males more frequently than females
As low as 500 organisms can cause infection
Transmission
Most cases of campylobacteriosis are associated with eating raw or undercooked poultry meat or from cross-contamination of other foods by these items
Roughly 57% of cases can be traced to chickens and 35% to cattle
to cut poultry meat on a cutting board, and then use the unwashed cutting board or utensil to prepare vegetables or other raw or lightly cooked foods
Unpasteurized milk also transmits Campylobacter through utter infection and contact with milk
some people get infected from contact with the stool of an ill dog or cat
Symptoms
characterized by bloody or mucosal diarrhea
The diarrhea is a result of the bacteria's colonization in the intestine and cell death due to the cytolethal toxin
Other symptoms may include muscle pain, headache, fever, and nausea which are due to dehydration from the diarrhea
most symptoms cease after five days
Treatment Done by managing the symptoms and any
complications until the symptoms subside Antibiotics can be used but are not usually
administered unless serious complications arise
Replacement of fluids and electrolytes lost during diarrhea and vomiting are keys to recovery and preventing symptoms from being prolonged Drinks such as soda and fruit juices contain too
much sugar and too few electrolytes to be considered effective treatments for dehydration.
Prevention Proper food handling and hand washing skills are key practices to
prevent the spread of Campylobacter jejuni
Make sure that the meat is cooked throughout (no longer pink in the center) All poultry should be cooked to at least an internal temperature of 165°F
Prevent cross-contamination while preparing foods by using separate cutting boards for raw meats and other foods
Cleaning all cutting boards, kitchen countertops, and silverware with soap and hot water
Do not drink unpasteurized milk or untreated surface water
Be sure that persons with diarrhea wash their hands carefully and frequently with soap to help reduce the risk of spreading the infection
Cholera
Vibrio cholerae Etiology
Gram-negative Curved rod Non-spore forming Two serotypes
V. cholera O1 and O139 These cause outbreaks O1 causes the majority of causes O139 confined to South east Asia
Other non O1 and non O139 can cause diarrhea but do not cause epidemics
Cholera It is rare in the United States and other
industrialized nations Global cases of cholera have increased steadily
in many places CDC has an alert of an outbreak of Cholera in several
areas of central Mexico beginning in August 2013 U.S. travelers to areas where it is endemic may
be exposed to cholera bacterium Travelers may also bring contaminated seafood back
to the U.S. It affects both children and adults and can kill
within hours
Cholera
Acute gastrointestinal infections caused by Vibrio cholerae
Caused by an exotoxin produced by the organism
Most likely to be found and spread in places with inadequate water treatment, poor sanitation, and inadequate.
Humans are the only known reservoir, although there is a possibility of environmental reservoirs
Transmission Person can get cholera by drinking water or eating
food contaminated with cholera bacterium
Transmitted through feces or vomitus of carriers or persons with active infections
Epidemic spread usually results from contaminated water supplies
Food is involved more often in sporadic cases in endemic areas
Hands, utensils, clothing, and flies may contaminate food or carry the infection directly to the mouth
Symptoms
Infection is often mild or without symptoms, but can sometimes be severe
Incubation period is generally 2-3 days Communicability lasts as long as the stools are positive,
usually only a few days after recovery
Diarrhea will be pale, white flecks appear (“rice water stools”)
Due to massive loss of fluid, other symptoms occur: Thirst, weakness, sunken eyes, muscle cramps, and
cardiovascular problems
Collapse, shock, and death may follow if the patient is not continuously rehydrated until the infection subsides
Treatment Successfully treated by immediate replacement of
the fluid and salts lost through diarrhea
Patients can be treated with oral rehydration solution, a prepackaged mixture of sugar and salts to be mixed with water and drunk in large amounts
Severe cases also require:
Intravenous fluid replacement
Antibiotics- to shorten the course and diminish the severity of the illness
Diminish duration of diarrhea, speeds the elimination of the bacteria from the feces
Prevention
Proper sanitation and vaccine are the best methods of prevention
Currently, there are two oral cholera vaccines available People traveling to epidemic areas in other countries may be required
to have a vaccination
If possible drink only bottled water
Boil water for 1 minute
Wash your hands often with soap and clean water
Eat foods that are packaged or are freshly cooked and served hot Do not eat raw and undercooked meats and seafood or unpeeled
fruits and vegetables
Dispose of feces in sanitary manner