Salmonella (S.) is the genus name for a large number (over 2,500) of types of bacteria. Each type is distinctly identifiable by its specific protein coating. The types are otherwise closely related. Salmonella bacteria are rod-shaped, flagellated, Gram stain-negative and are known to cause disease in humans, animals, and birds (especially poultry) worldwide.
Salmonellosis is spread to people by ingestion of Salmonella bacteria that contaminate food. Salmonella is worldwide and can contaminate almost any food type, but recent outbreaks of the disease involve raw eggs, egg products, fresh vegetables, cereal, and contaminated water. Contamination can come from animal or human feces that contact the food during its processing or harvesting.
Potential direct sources of Salmonella are pets such as turtles, dogs, cats, most farm animals, and humans that are infected or are carriers of the organisms.
Although typhoid and paratyphoid fevers can be transmitted by the same methods as Salmonellosis listed above, the most frequent manner of transmission is by the feces of infected people contaminating the water or food source of uninfected people.
What are the symptoms of Salmonella?
Salmonellosis (gastroenteritis) is the most common disease caused by the organisms. Over 1.4 million cases per year occur in the U.S., and the rest of industrialized countries have similar rates. Countries with poor sanitation have a much higher incidence of Salmonellosis. Symptoms include:
Typhoid fever occurs when some of the Salmonella organisms are not killed by the normal human immune defenses (macrophage cells). Salmonella then survive and grow in the human spleen, liver, and other organs and may reach the blood (bacteremia). Salmonella can be shed from the liver to the gallbladder, where they can continue to survive and be secreted into the patient's feces for up to a year. Symptoms include:
High fevers up to 104 F
Inflammation of the stomach and intestines
Symptoms usually resolve but many patients become Salmonella carriers. Approximately half of patients develop slow heartbeat (bradycardia), and about 30% of patients get flat, slightly raised red or rose-colored spots on the chest and abdomen. Typhoid fever is also referred to as enteric fever. What is the treatment for Salmonella?
Treatment for enteritis or food poisoning is controversial. Some doctors recommend no antibiotics since the disease is self-limited, while others suggest using antibiotics such as ciprofloxacin for 10-14 days. Patients identified as immunosuppressed (for example, patients with AIDS or undergoing cancer chemotherapy) should receive antibiotics. Some investigators believe antibiotics prolong the carrier state.Treatment for typhoid or enteric fevers with septicemia is not controversial. Antibiotics, often given intravenously, are needed.
These S. spp also should be tested for antibiotic resistance as some Salmonella species have been reported to be resistant to multiple antibiotics.Supportive therapy for both enteritis and enteric fevers consists mainly of preventing dehydration and electrolyte abnormalities (for example, abnormal levels of potassium and sodium ions) with fluids containing electrolytes (for example, IV fluids or oral fluids like sports drinks).
Carriers of Salmonella are considered to be infected even though they may show no symptoms. Carriers can infect other people and need to be cured of the carrier state. About 85% of carriers can be cured by a combination of surgery to remove their gallbladder and antibiotic treatments.
How can you prevent infection from Salmonella?
Cleanliness is a key to prevention. Hand washing with soap and water, especially after handling eggs, poultry, and raw meat is likely to reduce the chance for infections. Chlorine-treated drinking water, washed produce, and not ingesting undercooked foods such as eggs can also reduce the chance of exposure to Salmonella. Avoiding direct contact with animal carriers of Salmonella (for example, turtles, snakes, pigs) also prevents the disease. Public-health authorities that enforce restaurant cleanliness and employee hand washing have helped in general prevention.
Human carriers of Salmonella should never work in the food-handling service industry and ideally should undergo gallbladder removal and antibiotic therapy for an attempt for a cure of the carrier state. Although some Salmonella vaccines are available for poultry and animals, human vaccines are still under development