Shigella flexneri is a type of pathogenic bacteria. Specifically, it is a Gram-negative, rod-shaped species of Shigella, which is a genus in the family Enterobacteriaceae. It is closely related to Escherichia coli (i.e. E. coli). Shigella bacteria can cause a disease called Shigellosis. S. flexneri infection is generally not serious, and accounts for a third of all incidences of this disease in the United States.
Symptoms of Infection
Symptoms of Shigellosis are mostly gastrointestinal in nature. Diarrhea, often bloody, is a trademark symptom. The diarrhea can also be accompanied by abdominal pain and cramping and fever. Symptoms occur about one to three days after initial exposure to the bacteria, and usually resolve in five to seven days. In some patients, particularly the very young and elderly, the diarrhea may be severe enough to require hospitalization. In children younger than 2 years old, a very high fever may lead to convulsions. Some people, however, experience no symptoms at all, although they are still able to transmit the disease.
Complications
In rare cases (roughly 3 percent of those infected), an S. flexneri infection may lead to a late-onset complication called Reiter's Syndrome, which is marked by joint pain, eye problems such as conjunctivitis, painful urination and skin lesions. Arthritis is the primary symptom of the disease, and can be an isolated episode or chronic. Individuals with a certain genetic makeup are more likely to contract the disease.
Diagnosis
Diagnosis of Shigellosis involves determining whether the Shigella bacteria is responsible for the symptoms. This is done with a series of laboratory tests identifying the bacteria in the stool of the infected person. This procedure can also isolate the species responsible for the infection, and can determine which antibiotics would be best for treatment.
Treatment
Shigellosis is generally treated with antibiotics, most commonly ampicillin, trimethoprim-sulfamethoxazole (known as Bactrim) or ciprofloxacin (known as Cipro). The treatment course usually lasts for seven to ten days, and may be supplemented with treatment of dehydration or hypotension in severe cases. Antidiarrheal medication such as Imodium should not be used, as it can make the illness worse.
Some Shigella have become antibiotic-resistant due to overuse of antibiotics. In mild cases or cases in which a large number of people have been infected, antibiotics may not be used in order to prevent resistance. Non-severe cases of Shigella infection tend to clear up on their own and may not require antibiotics.
Transmission
Shigella is transmitted through the feces of an infected persons. Due to the fact that this bacteria does not need to be present in large numbers to cause an infection, it is fairly easy to transmit the disease. Most cases of infection occur as a result of poor hygiene. Young children and toddlers who have not been toilet trained, as well as their family and playmates, are at the greatest risk because of inadequate hand-washing habits. Frequent and careful hand washing is usually sufficient to prevent infection, although occasionally Shigella may be food- or waterborne.
