Salmonellosis

What is Salmonellosis?

Salmonellosis is an infection caused by certain species of Salmonella, a gram-negative rod-shaped bacterium. There are three forms of Salmonella infection that occur in man: typhoid (enteric) fever, bacteremia (bacteria in the blood stream), and acute gastroenteritis (also known as "food poisoning") which is by far the most common form.

All types of Salmonella infection can be acquired by ingestion of contaminated food or water. Some animals harbor Salmonella bacteria in their tissues. Salmonella infections can result if meat, poultry, or milk is consumed raw or improperly cooked. Infections may be spread person to person if organisms in feces contaminate food, directly or indirectly. This can occur if vegetable or fruit crops are sprayed with sewage, if flies settle on feces and then on food, or if food is handled by a person who has not washed his or her hands. Contaminated food that is left out in warm conditions for any length of time can rapidly develop a large colony of bacteria without signs of food spoilage.

There is some risk of transmission from an infected mother or family member to newborns and infants. Individuals with depressed immune systems (such as AIDS) are at increased risk. Salmonellosis is the most common organism isolated from individuals with sickle cell anemia.

How is it diagnosed?

History: When caused by Salmonella, symptoms of acute gastroenteritis (food poisoning) usually occur within eight to 48 hours after ingestion of the contaminated food or liquid. Symptoms, which last three to five days, may include fever, chills, nausea, vomiting, painful abdominal cramps, and diarrhea. The diarrhea may be bloody. If the infection enters the blood stream (bacteremia), it can localize, causing aching in the joints or bones.

Physical exam: The physical findings in acute gastroenteritis may include fever and abdominal tenderness, but are usually nonspecific (could apply to any number of conditions). Individual may have signs of dehydration including: orthostatic blood pressure (blood pressure that changes with body position changes), dry mucous membranes, sunken eyes, and decreased skin tension (turgor).

Tests: Stools are examined for the presence of white blood cells. If present, a stool culture is indicated to identify the organism. A complete blood count (CBC) or blood culture may be done if infection is suspected to have entered the blood stream (bacteremia).

How is Salmonella infection treated?

Salmonella infections are usually time-limited so treatment is primarily supportive. Avoiding dehydration by replacing fluids and electrolytes is the most important aspect of treatment. Severely ill individuals, those with sickle cell disease, and those with suspected bacteremia are treated with antibiotics.

Medications

Information	Brand	Generic	Label	Rating
	Bactrim	Co-trimoxazole
	Cipro	Ciprofloxacin
	Principen	Ampicillin
	Augmentin	Amoxicillin/Clavulanate
	Noroxin	Norfloxacin

Activity

Stay in bed, except for trips to the bathroom, until at least 3 days after diarrhea, fever and other symptoms disappear. Then resume normal activities gradually. Flex the legs regularly in bed to prevent formation of blood clots.

Diet

Drink diluted electrolyte solutions, such as Gatorade or Pedialyte, until diarrhea stops. Then eat a bland but high-calorie, well-balanced diet. Vitamin and mineral supplements may be helpful after prolonged illness.

What might complicate it?

Complications include severe dehydration, shock, or collapse. Septicemia, a life-threatening illness, can occur when bacteria multiply rapidly in the blood stream.

Predicted outcome

Salmonellosis is usually a self-limited disease, meaning that most cases resolve within 48 to 72 hours. This may be life threatening in immunocompromised individuals.

Alternatives

Conditions with similar symptoms include inflammatory bowel disease, irritable bowel syndrome, or other forms of infective gastroenteritis.

Appropriate specialists

Internist and infectious disease specialist.

Last updated 18 December 2011