An Overview of Salmonella

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Salmonella bacterium. Science Picture Company/Getty Images

Salmonella is a type of bacteria that can produce a diarrheal illness called salmonellosis. Salmonella illness is typically caused by food contaminated with animal or human waste, or contact with animals that carry the bacteria. The illness usually runs its course in a few days with only supportive care needed. However, dehydration or invasive salmonella infection can be seen, especially in high-risk age groups and people with weakened immune systems.

Causes

Salmonella illness caused by strains of the Salmonella bacteria that is present in animal feces and the feces of people with salmonellosis. Most people associate foodborne salmonella infection with raw or undercooked poultry or meat, but the bacteria can also be present on fruits and vegetables that are not cooked, prepared, or washed properly.

Food handlers and home cooks may spread salmonella to food if they do not properly wash their hands after using the bathroom. A person who has been sick with salmonellosis can spread it to others until 48 hours have passed without symptoms.

Large foodborne outbreaks of salmonella infection result in contaminated food being recalled, but you may already have bought it and eaten it.  A wide variety of products can be contaminated, with past recalls including nut butter, pistachios, sprouts, coconut, organic shakes, cucumbers, chicken, shell eggs, and pork.

Salmonella may be found in the feces many animals, including farm animals and pets. Reptiles, amphibians, and birds are the most likely pets to carry salmonella.

People who are at the highest risk of salmonellosis and serious complications including babies, children age 5 and under, adults over age 65, and people with weakened immune systems.

Symptoms 

The symptoms of salmonellosis are similar to those of a stomach virus. They include:

  • Diarrhea
  • Fever
  • Stomach cramps
  • Vomiting (occasionally)

If you become infected with salmonella, these symptoms typically appear between 12 and 72 hours after exposure to the bacteria. The symptoms usually last four to seven days and resolve on their own without treatment.

Occasionally—especially in infants, the elderly or those with compromised immune systems—a more serious illness may result from salmonella infection. Diarrhea may become so severe that the person needs to be hospitalized for dehydration. Invasive salmonella infection can be seen in the bloodstream and may spread to the brain, bones, or joints.

Rarely, people who have had salmonellosis can develop reactive arthritis (Reiter’s syndrome). Symptoms of Reiter’s syndrome include pain in the joints, painful urination and irritation of the eyes.

Diagnosis

Many people do not see their doctor for uncomplicated salmonellosis. If you suspect that you have a salmonella infection after eating food that may have been contaminated, it is important to see your health care provider. Tests including a stool culture can determine if salmonella is the cause of your symptoms.

Your doctor will report the infection to your local health department and the CDC so outbreaks can be identified.

People in high-risk groups or with symptoms of dehydration or severe illness should see a doctor. In cases where it is suspected that you have a blood infection, your doctor may take blood specimen for culture and antibiotic sensitivity testing.

Treatment

Usually, no treatment is necessary for salmonella other than staying hydrated. Drinking plenty of water or an electrolyte solution (such as Pedialyte for children and infants or Gatorade for adults) is important when you have diarrhea to be sure you do not become dehydrated.

Fruit juices and sodas should be avoided because they can possibly make diarrhea worse. Antibiotics are typically not necessary unless the bacteria enter the bloodstream.​

Prevention

Because salmonella is in the environment and even in our own bodies, it is important to follow some basic steps to prevent infection with the bacteria. Some things you can do include:

  • Do not eat raw or undercooked eggs, meat or poultry. Egg yolks should be cooked until firm and meat (especially ground meats) and poultry should not be pink in the middle.
  • Do not consume raw or unpasteurized milk or dairy products.
  • Thoroughly wash all produce.
  • Keep uncooked meats separated from produce and other foods so cross contamination does not occur.
  • Thoroughly wash all cutting boards and food preparation materials after preparing uncooked foods.
  • Wash your hands before you handle food and between handling different food items.
  • Always wash your hands after using the bathroom or touching pets, especially reptiles.
  • Never keep reptiles (including turtles), amphibians, or poultry as pets in the same house with infants, young children, people over age 65, or those with compromised immune systems.
  • Wash your hands immediately after touching or holding chicks, ducklings, or other birds, and do not let children handle them at all.

Sources:

Salmonella. CDC. https://www.cdc.gov/salmonella/

Salmonella Infection. CDC. https://www.cdc.gov/healthypets/diseases/salmonella.html.

Salmonella Questions and Answers. USDA Food Safety and Inspection Service. https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/foodborne-illness-and-disease/salmonella-questions-and-answers.

Salmonella Outbreak Investigations. CDC. https://www.cdc.gov/salmonella/outbreaks.html.