Immunity to Salmonella

Immunity to Salmonella
Circulating antibodies to O and Vi are related to resistance to infection and disease. However, relapses may occur in 2–3 weeks after recovery in spite of antibodies. Secretory IgA antibodies may prevent attachment of salmonellae to intestinal epithelium.
Persons with S/S hemoglobin (sickle cell disease) are exceedingly susceptible to salmonella infections, particularly osteomyelitis. Persons with A/S hemoglobin (sickle cell trait) may be more susceptible than normal individuals (those with A/A hemoglobin).
Treatment
In enterocolitis, clinical symptoms and excretion of the salmonellae may be prolonged by antimicrobial therapy. In severe diarrhea, replacement of fluids and electrolytes is essential.
Antimicrobial therapy of invasive salmonella infections is with ampicillin, trimethoprim-sulfamethoxazole, or a third-generation cephalosporin. Multiple drug resistance transmitted genetically by plasmids among enteric bacteria is a problem in salmonella infections. Susceptibility testing is an important adjunct to selecting a proper antibiotic.
Carriers
After manifest or subclinical infection, some individuals continue to harbor salmonellae in their tissues for variable lengths of time (convalescent carriers or healthy permanent carriers). Three percent of survivors of typhoid become permanent carriers, harboring the organisms in the gallbladder, biliary tract, or, rarely, the intestine or urinary tract.
Sources of Infection
The sources of infection are food and drink that have been contaminated with salmonellae. The following sources are important:
-Water
-Contamination with feces often results in explosive epidemics.
-Milk and Other Dairy Products (Ice Cream, Cheese, Custard)
-Contamination with feces and inadequate pasteurization or improper handling. Some outbreaks are traceable to the source of supply.
-Shellfish
-From contaminated water.
-Dried or Frozen Eggs
-From infected fowl or contaminated during processing.
-Meats and Meat Products
From infected animals (poultry) or contamination with feces by rodents or humans.
"Recreational" Drugs
Marijuana and other drugs.
Animal Dyes
Dyes (eg, carmine) used in drugs, foods, and cosmetics.
Household Pets
Turtles, dogs, cats, etc.

Prevention & Control
Two injections of acetone-killed bacterial suspensions of Salmonella Typhi, followed by a booster injection some months later, give partial resistance to small infectious inocula of typhoid bacilli but not to large ones. Oral administration of a live avirulent mutant strain of Salmonella Typhi has given significant protection in areas of high endemicity. Vaccines against other salmonellae give less protection and are not recommended.