Salmonella

Salmonella, (genus Salmonella), group of rod-shaped, gram-negative, facultatively anaerobic bacteria in the family Enterobacteriaceae. Salmonella bacteria inhabit the intestinal tract of humans and many other animals, including birds, reptiles, and mammals. Although many animals carry the bacteria without showing signs of illness, Salmonella is one of the leading causes of foodborne illness worldwide.

Human infection with Salmonella, known as salmonellosis, most commonly occurs through the consumption of contaminated food or water. Raw or undercooked poultry, eggs, meat, unpasteurized dairy products, fresh produce, and contaminated water are frequent sources of infection. Salmonella also can be transmitted through direct contact with infected animals, particularly reptiles, amphibians, and young poultry.

Most cases of salmonellosis are caused by nontyphoidal Salmonella, particularly S. enterica serovars Enteritidis and Typhimurium. Symptoms typically develop within 6 to 72 hours after exposure and include diarrhea, fever, abdominal cramps, nausea, and vomiting. In healthy individuals, illness usually resolves within several days, although severe dehydration or bloodstream infections may occur, especially in infants, older adults, and people with weakened immune systems.

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A smaller group of Salmonella, including S. enterica serovars Typhi and Paratyphi, S. typhi causes typhoid fever and paratyphoid fever. Unlike nontyphoidal salmonellosis, these illnesses are spread primarily through food or water contaminated with human waste and can produce prolonged fever and life-threatening complications if left untreated.

Refrigeration slows or prevents the growth of Salmonella but does not destroy the bacteria. Effective prevention depends on proper food handling, including cooking meat and poultry thoroughly, avoiding cross-contamination between raw and cooked foods, consuming pasteurized dairy products, washing hands after handling animals, and maintaining safe drinking water. Certain Salmonella strains have developed resistance to multiple antibiotics, making some infections more difficult to treat. Consequently, food safety measures, surveillance programs, and responsible antibiotic use in both medicine and agriculture remain important components of public health efforts to reduce salmonellosis.