Salmonellosis is illness caused by Salmonella bacteria, which belong to the family Enterobacteriaceae. The bacteria are transmitted in food and water or sometimes from certain animals such as chicken, fowl, livestock, domestic pets and turtles, entering the body by the mouth then growing in the small intestine.

In people with HIV, the bacteria often spread into the blood and are transported to other parts of the body, causing recurring problems. HIV-positive people who repeatedly have salmonella bacteria in their blood (i.e. they are bacteraemic) are diagnosed as having AIDS. High bacteraemia is associated with declining CD4 cell counts in HIV-infected individuals.

People with HIV who have had salmonellosis may continue to excrete (infectious) salmonella in their urine and faeces even after treatment with antibiotics, so it may be wise to take extra care with safer sex and when preparing food to avoid infecting others. Hygienic food preparation can help to prevent infection with salmonella in the first place.

Symptoms and diagnosis

The most common symptoms of salmonellosis are non-specific problems such as fever, chills, sweats, weight loss, diarrhoea (which can be severe and bloody) and anorexia. Although bowel problems are common in AIDS, they are usually not caused by salmonella.

It is diagnosed by growing the bacteria from a sample of stool or blood.

Treatment

In people with HIV, salmonella infections are usually treated with a three-week course of antibiotics. The most commonly used is ampicillin, but the bacteria are sometimes resistant to this. Alternatives include chloramphenicol (Chloromycetin), cephalosporins, ciprofloxacin, ofloxacin and co-trimoxazole. Diarrhoea may be alleviated by standard anti-diarrhoea medicines. Salmonellosis often recurs after an episode has been successfully treated, so long-term maintenance therapy may be necessary; some research suggests that anti-HIV drugs and/or co-trimoxazole may help to prevent recurrences.

HIV-infected individuals with salmonella are more likely to have antibiotic resistance and salmonella bacteraemia, making treatment of this condition difficult (Fisk 2000).

References

Fisk T et al. Drug resistant S. typhimurium in HIV-infected persons. Seventh Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 265, 2000.

Glaser JB et al. Recurrent Salmonella typhimurium bacteremia associated with AIDS. Ann Intern Med 102: 189, 1985.

Jacobs JL et al. Salmonella infections in patients with AIDS. Ann Intern Med 102: 186, 1986.

Jacobson MA et al. Ciprofloxacin for Salmonella bacteremia in the acquired immunodeficiency syndrome (AIDS). Ann Intern Med 110: 1027-1029, 1989.

Levine WC et al. Epidemiology of nontyphoidal Salmonella bacteremia during the HIV epidemic. J Infect Dis 164: 81-87, 1991.

Nelson MR et al. Salmonella, Campylobacter and Shigella in HIV-seropositive patients. AIDS 6: 1495-1498, 1992.