Salmonellosis is a bacterial infection caused by gram-negative bacilli of the genus Salmonella. Sometimes classified as food poisoning because it is frequently acquired by ingesting food that has been contaminated with the Salmonella bacterium, salmonellosis occurs as either enterocolitis, bacteremia, localized infection, typhoid, or parathyroid fever. The most severe form of sal-monellosis is typhoid, which can cause perforation or hemorrhage of the intestines, pneumonia, toxemia, acute circulatory failure, and cerebral thrombosis.
Once the Salmonella bacterium is ingested, it multiplies rapidly in the mucosal layers of the stomach and small intestine. The greater the number of organisms ingested, the shorter the incubation period; typically, incubation is 8 to 48 hours after ingestion of contaminated food or liquid, and symptoms usually last for 3 to 5 days. An inflammatory response in the tissues produces gastroenteritis. The infection may stop there, or the salmonella organisms may travel via the lymph and vascular system throughout the body. The dissemination of organisms produces lesions in other organs or, possibly, sepsis. Systemic lesions may result in appendicitis, peritonitis, otitis media, pneumonia, osteomyelitis, or endocarditis. Symptoms of intermittent fever, chills, anorexia, and weight loss indicate sepsis.
Salmonellosis is caused by any of more than 2000 serotypes of Salmonella bacteria. Typhoid is transmitted through ingestion of water that has been contaminated with the feces of infected persons. Salmonellosis may also be contracted by eating infected raw eggs or egg products or uncooked meat or poultry, ingesting raw milk, or handling infected animals. Salmonella can survive for an extended period of time in water, sewage, ice, and food. Although cooking food thoroughly can reduce the risk of salmonellosis, it cannot eliminate it.
All people are susceptible. Although the disease is rarely fatal, severity may be pronounced in infants and persons with neoplastic, immunosuppressive, or other debilitating conditions. Enterocolitis and bacteremia are more common among infants. People in hospitals and nursing homes have a higher prevalence of this disease than does the general population. Women over 50 years of age are the most common carriers of typhoid. Acquired immunodeficiency syndrome (AIDS) patients are susceptible to recurrent bacteremia caused by Salmonella bacteria. While the disease has no predilection or a particular race, ethnicity, or sex, people in developing countries have a higher incidence and mortality rate than do people in developed countries.
HISTORY. Establish a history of fever (often 102°F and higher), nausea, abdominal pain, vomiting, anorexia, and diarrhea that has persisted for at least 4 days. Ask about headache or constipation, which are symptoms of typhoid. The first symptoms generally appear between 8 and 48 hours after ingesting the bacteria; ask the patient about possible sources of the infection. Ask if
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