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

 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