Download Digestive Diseases

Digestive Diseases
Shigellosis
Campylobacter jejuni
Cholera
Shigella
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Etiology
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Family: Enterobacteriaceae
Gram negative
Rod shaped
Non motile
Non spore forming
Very closely related to Escherichia coli
Shigella
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There are four species of Shigella
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S. sonnei
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S. dysenteriae
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Type 1
Is rare in the U.S. but can lead to deadly outbreaks in developing
countries
S. flexneri
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Also known as group D Shigella
Responsible for most cases of shigellosis in the United States
Group B Shigella
Accounts for almost all of the rest
S. boydii
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Is the most genetically-divergent of the Shigella genus
S. boydii is restricted to the Indian subcontinent
Shigellosis
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Shigellosis is an infectious disease caused by a group of
bacteria called Shigella
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Endemic in North America, Europe, and the tropics
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Every year, approximately 14,000 cases of Shigellosis are
reported each year in the United States
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Infection is more common in children ages 1-4 years and in the
elderly , debilitated and malnourished
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The only reservoir for Shigella organism is the human
intestinal tract, and infected feces are always the source of the
infection
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Incubation period is usually 1 to 3 days
Transmission
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Pass from one infected person to another
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Directly by fecal-oral route transmission or indirectly through
contact with contaminated objects
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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
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Food can also be contaminated by flies that carry enough of the
organism for it to multiply to an infectious dose in food
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When dogs ingest human feces, the infection can be passed by them
to children or other susceptible persons
Symptoms
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Shigellae invade the intestinal mucosa and cause
inflammation
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In children: usually produces diarrhea, high fever, nausea,
vomiting, abdominal pain with distention, irritability, and
drowsiness
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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
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Persons with mild infections usually recover quickly without antibiotic
treatment
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Resistance to traditional first-line drugs like ampicillin and
trimethoprim-sulfamethoxazole is common, and resistance to some
other antibiotics is increasing
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If an effective one can be found, then the shigellae can be eliminated quickly
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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
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No vaccine at present
Control of the human reservoir and sanitary control of
environmental sources through:
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Adequate treatment of water and sewage, fly control and
protection of food, water, and milk from human or mechanical
vectors
Campylobacter jejuni
Campylobacter jejuni
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Etiology
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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
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Epidemiology
Is prevalent in the United States and other developed
countries
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One of the most common causes of diarrheal illness in the
United States
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over 2 million cases are reported each year
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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
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Most cases of campylobacteriosis are associated with eating
raw or undercooked poultry meat or from crosscontamination of other foods by these items
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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
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characterized by bloody or mucosal diarrhea
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The diarrhea is a result of the bacteria's colonization in the
intestine and cell death due to the cytolethal toxin
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Other symptoms may include muscle pain, headache,
fever, and nausea which are due to dehydration from the
diarrhea
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most symptoms cease after five days
Treatment
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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
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Drinks such as soda and fruit juices contain too much sugar
and too few electrolytes to be considered effective treatments
for dehydration.
Prevention
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Proper food handling and hand washing skills are key practices to prevent the
spread of Campylobacter jejuni
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Make sure that the meat is cooked throughout (no longer pink in the center)
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All poultry should be cooked to at least an internal temperature of 165°F
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Prevent cross-contamination while preparing foods by using separate
cutting boards for raw meats and other foods
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Cleaning all cutting boards, kitchen countertops, and silverware with soap and hot
water
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Do not drink unpasteurized milk or untreated surface water
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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
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Etiology
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Gram-negative
Curved rod
Non-spore forming
Two serotypes
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V. cholera O1 and O139
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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
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It is rare in the United States and other industrialized
nations
Global cases of cholera have increased steadily in many
places
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U.S. travelers to areas where it is endemic may be
exposed to cholera bacterium
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CDC has an alert of an outbreak of Cholera in several areas of
central Mexico beginning in August 2013
Travelers may also bring contaminated seafood back to the U.S.
It affects both children and adults and can kill within
hours
Cholera
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Acute gastrointestinal infections caused by Vibrio cholerae
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Caused by an exotoxin produced by the organism
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Most likely to be found and spread in places with
inadequate water treatment, poor sanitation, and
inadequate.
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Humans are the only known reservoir, although there is a
possibility of environmental reservoirs
Transmission
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Person can get cholera by drinking water or eating food
contaminated with cholera bacterium
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Transmitted through feces or vomitus of carriers or persons with
active infections
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Epidemic spread usually results from contaminated water supplies
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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
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Infection is often mild or without symptoms, but can
sometimes be severe
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Incubation period is generally 2-3 days
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Communicability lasts as long as the stools are positive, usually only a
few days after recovery
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Diarrhea will be pale, white flecks appear (“rice water stools”)
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Due to massive loss of fluid, other symptoms occur:
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Thirst, weakness, sunken eyes, muscle cramps, and cardiovascular
problems
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Collapse, shock, and death may follow if the patient is not
continuously rehydrated until the infection subsides
Treatment
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Successfully treated by immediate replacement of the
fluid and salts lost through diarrhea
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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:
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Intravenous fluid replacement
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Antibiotics- to shorten the course and diminish the severity of
the illness
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Diminish duration of diarrhea, speeds the elimination of the bacteria
from the feces
Prevention
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Proper sanitation and vaccine are the best methods of
prevention
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Currently, there are two oral cholera vaccines available
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People traveling to epidemic areas in other countries may be required to
have a vaccination
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If possible drink only bottled water
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Boil water for 1 minute
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Wash your hands often with soap and clean water
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Eat foods that are packaged or are freshly cooked and served hot
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Do not eat raw and undercooked meats and seafood or unpeeled fruits
and vegetables
Dispose of feces in sanitary manner