A common infection in the United States, salmonellosis is caused by gram-negative bacilli of the genus Salmonella, a member of Enterobacteriaceae family, which includes both normal and pathogenic (disease causing) enteric (living in intestinal tract) microorganisms. It occurs as enterocolitis, bacteremia, localized infection, typhoid, or paratyphoid fever.
Typhoid, the most severe form of salmonellosis, usually lasts from 1 to 4 weks. Mortality is about 3% in persons who are treated and 10% in those untreated, usually as a result of intestinal perforation or hemorrhage, cerebral thrombosis, toxemia, pneumonia, or acute circulatory failure.
An attack of typhoid confers lifetime immunity, although the patient may become a carrier. Most typhoid patients are under age 30; most carriers are women over age 50. Incidence of typhoid in the United States is increasing as a result of travelers returning from endemic areas.
Enterocolitis (inflammation of the small and large intestine) and bacteremia (bacteria growing in the bloodstream) are more common among infants, elderly people, and people already weakened by other infections; paratyphoid fever is rare in the United States.
CAUSES
Of an estimated 1,700 serotypes of Salmonella, 10 cause the disease most common in the United States, all 10 can survive for weeks in water, ice, sewage, or food. Nontyphoidal salmonellosis usually follows the ingestion of contaminated food, especially eggs, chicken, turkey, and duck. Proper cooking reduces the risk of contracting salmonellosis.
Other causes include contact with infected people or animals or ingestion of contaminated dry milk, chocolate bars, or drugs of animal origin. Salmonellosis may occur in children under age 5 from feca-oral spread.
Typhoid results more frequently from drinking water contaminated by excretions of a carrier.
SIGNS & SYMPTOMS
Clinical manifestations of salmonellosis vary but usually include fever, abdominal pain, and severe diarrhea with enterocolitis. headaches, increasing fever, and constipation are more common with typhoidal infection.
TREATMENT
Antimicrobial therapy for typhoid, paratyphoid and bacteremia depends on the organism sensitivity. It may include amoxicillin, chloramphenicol and, in severe toxemia, cotrimoxazole, ciprofloxacin, or ceftriaxone. Localized abscesses may also need surgical dainage.
Enterocolitis requires a short course of antibiotics only if it causes septicemia (bacteria growing in the bloodstream) or prolonged fever. Other treatments include bed rest and replacement of fluids and electrolytes. Camphorated opium tincture, kaolin with pectin, diphenoxylate, hydrochloride, codeine, or small doses of morphine may be necessary to relieve diarrhea and control cramps in patients who must remain active.