Digestive Diseases

ShigellosisCampylobacter 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