Shigellosis | |
---|---|
Other names | Bacillary dysentery, Marlow syndrome |
Shigella seen in a stool sample | |
Specialty | Infectious disease |
Symptoms | Diarrhea, fever, abdominal pain [1] |
Complications | Reactive arthritis, sepsis, seizures, hemolytic uremic syndrome [1] |
Usual onset | 1–2 days post exposure [1] |
Duration | Usually 5–7 days [1] |
Causes | Shigella [1] |
Diagnostic method | Stool culture [1] |
Prevention | Handwashing [1] |
Treatment | Drinking fluids and rest [1] |
Medication | Antibiotics (severe cases) [1] |
Frequency | >80 million [2] |
Deaths | 700,000 [2] |
Shigellosis, known historically as dysentery, is an infection of the intestines caused by Shigella bacteria. [1] [3] Symptoms generally start one to two days after exposure and include diarrhea, fever, abdominal pain, and feeling the need to pass stools even when the bowels are empty. [1] The diarrhea may be bloody. [1] Symptoms typically last five to seven days and it may take several months before bowel habits return entirely to normal. [1] Complications can include reactive arthritis, sepsis, seizures, and hemolytic uremic syndrome. [1]
Shigellosis is caused by four specific types of Shigella. [2] These are typically spread by exposure to infected feces. [1] This can occur via contaminated food, water, or hands or sexual contact. [1] [4] Contamination may be spread by flies or when changing diapers (nappies). [1] Diagnosis is by stool culture. [1]
The risk of infection can be reduced by properly washing the hands. [1] There is no vaccine. [1] Shigellosis usually resolves without specific treatment. [1] Rest, and sufficient fluids by mouth, are recommended. [1] Bismuth subsalicylate may help with the symptoms; however, medications that slow the bowels such as loperamide are not recommended. [1] In severe cases antibiotics may be used but resistance is common. [1] [5] Commonly used antibiotics include ciprofloxacin and azithromycin. [1]
A 2005 report by the World Health Organization estimated that shigellosis occurs in at least 80 million people and results in about 700,000 deaths a year globally. [2] Most cases occur in the developing world. [2] Young children are most commonly affected. [1] Outbreaks of disease may occur in childcare settings and schools. [1] It is also relatively common among travelers. [1] In the United States about half a million cases occur a year. [1]
Signs and symptoms may range from mild abdominal discomfort to severe dysentery characterized by cramps, diarrhea, with slimy-consistent stools, fever, blood, pus, or mucus in stools or tenesmus. [6] [7] Onset time is 12 to 96 hours, and recovery takes 5 to 7 days. [8] Infections are associated with mucosal ulceration, rectal bleeding, and drastic dehydration. Reactive arthritis and hemolytic uremic syndrome are possible sequelae that have been reported in the aftermath of shigellosis.[ citation needed ]
Shigellosis is caused by a bacterial infection with Shigella , [1] a bacterium that is genetically similar to and was once classified as E. coli . [10] There are three serogroups and one serotype of Shigella:
The probability of being infected by any given strain of Shigella varies around the world. For instance, S. sonnei is the most common in the United States, while S. dysenteriae and S. boydii are rare there. [1]
Shigella is transmitted through the fecal-oral route of individuals infected with the disease, whether or not they are exhibiting symptoms. [1] [11] Long-term carriers of the bacteria are rare. [11] The bacteria can infect not just humans but other primates as well. [12]
Upon ingestion, the bacteria pass through the gastrointestinal tract until they reach the small intestine. There they begin to multiply until they reach the large intestine. [13] In the large intestine, the bacteria cause cell injury and the beginning stages of Shigellosis via two main mechanisms: direct invasion of epithelial cells in the large intestine and production of enterotoxin 1 and enterotoxin 2. [13]
Unlike other bacteria, Shigella is not destroyed by the gastric acid in the stomach. As a result, it takes only 10 to 200 cells to cause an infection. [13] This infectious dose is several orders of magnitude smaller than that of other species of bacteria (e.g., cholera, caused by the bacterium Vibrio cholerae , has an infectious dose between 108 and 1011 cells). [14]
The diagnosis of shigellosis is made by isolating the organism from diarrheal fecal sample cultures. Shigella species are negative for motility and are generally not lactose fermenters, but S. sonnei can ferment lactose. [15] They typically do not produce gas from carbohydrates (with the exception of certain strains of S. flexneri) and tend to be overall biochemically inert. Shigella should also be urea hydrolysis negative. When inoculated to a triple sugar iron slant, they react as follows: K/A, gas -, and H2S -. Indole reactions are mixed, positive and negative, with the exception of S. sonnei, which is always indole negative. Growth on Hektoen enteric agar produces bluish-green colonies for Shigella and bluish-green colonies with black centers for Salmonella.[ citation needed ]
Simple precautions can be taken to prevent getting shigellosis: wash hands before handling food and thoroughly cook all food before eating. The primary prevention methods are improved sanitation and personal and food hygiene, but a low-cost and efficacious vaccine would complement these methods. [16]
Since shigellosis is spread very quickly among children, keeping infected children out of daycare for 24 hours after their symptoms have disappeared, will decrease the occurrence of shigellosis in daycares. [17]
Currently, no licensed vaccine targeting Shigella exists. Several vaccine candidates for Shigella are in various stages of development including live attenuated, conjugate, ribosomal, and proteosome vaccines. [16] [18] [19] Shigella has been a longstanding World Health Organization target for vaccine development, and sharp declines in age-specific diarrhea/dysentery attack rates for this pathogen indicate that natural immunity does develop following exposure; thus, vaccination to prevent the disease should be feasible. Shigella species are resistant to many antibiotics, [1] so vaccination is an important part of the strategy to reduce morbidity and mortality. [16]
Treatment consists mainly of replacing fluids and salts lost because of diarrhea. Replacement by mouth is satisfactory for most people, but some may need to receive fluids intravenously. Antidiarrheal drugs (such as diphenoxylate or loperamide) may prolong the infection and should not be used. [20]
Antibiotics should only be used in severe cases or for certain populations with mild symptoms (elderly, immunocompromised, food service industry workers, child care workers). For Shigella-associated diarrhea, antibiotics shorten the length of infection, [21] but they are usually avoided in mild cases because many Shigella strains are becoming resistant to common antibiotics. [22] Furthermore, effective medications are often in short supply in developing countries, which carry the majority of the disease burden from Shigella. Antidiarrheal agents may worsen the sickness, and should be avoided. [23]
In most cases, the disease resolves within four to eight days without antibiotics. Severe infections may last three to six weeks. Antibiotics, such as trimethoprim-sulfamethoxazole, ciprofloxacin may be given when the person is very young or very old, when the disease is severe, or when the risk of the infection spreading to other people is high. Additionally, ampicillin (but not amoxicillin) was effective in treating this disease previously, but now the first choice of drug is pivmecillinam. [24]
Insufficient data exist, [25] but it is estimated to have caused the death of 34,000 children under the age of five in 2013, and 40,000 deaths in people over five years of age. [16] Shigella also causes about 580,000 cases annually among travelers and military personnel from industrialized countries. [26]
An estimated 500,000 cases of shigellosis occur annually in the United States. [27] Infants, the elderly, and the critically ill are susceptible to the most severe symptoms of disease, but all humans are susceptible to some degree. Individuals with acquired immune deficiency syndrome (AIDS) are more frequently infected with Shigella. [28] Shigellosis is a more common and serious condition in the developing world; fatality rates of shigellosis epidemics in developing countries can be 5–15%. [29]
Orthodox Jewish communities (OJCs) are a known risk group for shigellosis; Shigella sonnei is cyclically epidemic in these communities in Israel, with sporadic outbreaks occurring elsewhere among these communities. "Through phylogenetic and genomic analysis, we showed that strains from outbreaks in OJCs outside of Israel are distinct from strains in the general population and relate to a single multidrug-resistant sublineage of S. sonnei that prevails in Israel. Further Bayesian phylogenetic analysis showed that this strain emerged approximately 30 years ago, demonstrating the speed at which antimicrobial drug–resistant pathogens can spread widely through geographically dispersed, but internationally connected, communities." [30]
Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea lasting a few days. Vomiting and muscle cramps may also occur. Diarrhea can be so severe that it leads within hours to severe dehydration and electrolyte imbalance. This may result in sunken eyes, cold skin, decreased skin elasticity, and wrinkling of the hands and feet. Dehydration can cause the skin to turn bluish. Symptoms start two hours to five days after exposure.
Diarrhea, also spelled diarrhoea or diarrhœa, is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are exclusively breastfed, however, are normal.
Dysentery, historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications may include dehydration.
Shigella is a genus of bacteria that is Gram negative, facultatively anaerobic, non–spore-forming, nonmotile, rod shaped, and is genetically nested within Escherichia. The genus is named after Kiyoshi Shiga, who discovered it in 1897.
Campylobacter jejuni is a species of pathogenic bacteria that is commonly associated with poultry, and is also often found in animal feces. This species of microbe is one of the most common causes of food poisoning in Europe and in the US, with the vast majority of cases occurring as isolated events rather than mass outbreaks. Active surveillance through the Foodborne Diseases Active Surveillance Network (FoodNet) indicates that about 20 cases are diagnosed each year for each 100,000 people in the US, while many more cases are undiagnosed or unreported; the CDC estimates a total of 1.5 million infections every year. The European Food Safety Authority reported 246,571 cases in 2018, and estimated approximately nine million cases of human campylobacteriosis per year in the European Union. In Africa, Asia, and the Middle East, data indicates that C. jejuni infections are endemic.
Gastroenteritis, also known as infectious diarrhea, is an inflammation of the gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of energy, and dehydration may also occur. This typically lasts less than two weeks. Although it is not related to influenza, in the U.S. and U.K., it is sometimes called the "stomach flu".
Campylobacteriosis is among the most common infections caused by a bacterium in humans, often as a foodborne illness. It is caused by the Campylobacter bacterium, most commonly C. jejuni. It produces an inflammatory, sometimes bloody, diarrhea or dysentery syndrome, and usually cramps, fever and pain.
Travelers' diarrhea (TD) is a stomach and intestinal infection. TD is defined as the passage of unformed stool while traveling. It may be accompanied by abdominal cramps, nausea, fever, headache and bloating. Occasionally dysentery may occur. Most travelers recover within three to four days with little or no treatment. About 12% of people may have symptoms for a week.
Shigella dysenteriae is a species of the rod-shaped bacterial genus Shigella. Shigella species can cause shigellosis. Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, nonmotile bacteria. S. dysenteriae has the ability to invade and replicate in various species of epithelial cells and enterocytes.
Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis. It is associated with species of bacteria from the family Enterobacteriaceae. The term is usually restricted to Shigella infections.
Shigella flexneri is a species of Gram-negative bacteria in the genus Shigella that can cause diarrhea in humans. Several different serogroups of Shigella are described; S. flexneri belongs to group B. S. flexneri infections can usually be treated with antibiotics, although some strains have become resistant. Less severe cases are not usually treated because they become more resistant in the future. Shigella are closely related to Escherichia coli, but can be differentiated from E.coli based on pathogenicity, physiology and serology.
The schedule for childhood immunizations in the United States is published by the Centers for Disease Control and Prevention (CDC). The vaccination schedule is broken down by age: birth to six years of age, seven to eighteen, and adults nineteen and older. Childhood immunizations are key in preventing diseases with epidemic potential.
Paratyphoid fever, also known simply as paratyphoid, is a bacterial infection caused by one of three types of Salmonella enterica. Symptoms usually begin 6–30 days after exposure and are the same as those of typhoid fever. Often, a gradual onset of a high fever occurs over several days. Weakness, loss of appetite, and headaches also commonly occur. Some people develop a skin rash with rose-colored spots. Without treatment, symptoms may last weeks or months. Other people may carry the bacteria without being affected; however, they are still able to spread the disease to others. Typhoid and paratyphoid are of similar severity. Paratyphoid and typhoid fever are types of enteric fever.
Ehrlichiosis is a tick-borne bacterial infection, caused by bacteria of the family Anaplasmataceae, genera Ehrlichia and Anaplasma. These obligate intracellular bacteria infect and kill white blood cells.
Shigella sonnei is a species of Shigella. Together with Shigella flexneri, it is responsible for 90% of shigellosis cases. Shigella sonnei is named for the Danish bacteriologist Carl Olaf Sonne. It is a Gram-negative, rod-shaped, nonmotile, non-spore-forming bacterium.
Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba Entamoeba histolytica. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ulcerations, abdominal pain, diarrhea, or bloody diarrhea. Complications can include inflammation and ulceration of the colon with tissue death or perforation, which may result in peritonitis. Anemia may develop due to prolonged gastric bleeding.
Enteroinvasive Escherichia coli (EIEC) is a type of pathogenic bacteria whose infection causes a syndrome that is identical to shigellosis, with profuse diarrhea and high fever. EIEC are highly invasive, and they use adhesin proteins to bind to and enter intestinal cells. They produce no toxins, but severely damage the intestinal wall through mechanical cell destruction.
Escherichia coli is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but pathogenic varieties cause serious food poisoning, septic shock, meningitis, or urinary tract infections in humans. Unlike normal flora E. coli, the pathogenic varieties produce toxins and other virulence factors that enable them to reside in parts of the body normally not inhabited by E. coli, and to damage host cells. These pathogenic traits are encoded by virulence genes carried only by the pathogens.
Enteroaggregative Escherichia coli are a pathotype of Escherichia coli which cause acute and chronic diarrhea in both the developed and developing world. They may also cause urinary tract infections. EAEC are defined by their "stacked-brick" pattern of adhesion to the human laryngeal epithelial cell line HEp-2. The pathogenesis of EAEC involves the aggregation of and adherence of the bacteria to the intestinal mucosa, where they elaborate enterotoxins and cytotoxins that damage host cells and induce inflammation that results in diarrhea.