Infections due to encapsulated bacteria, Salmonella, Shigella, and Campylobacter.

Bacterial infections occur often in HIV-infected patients. Defects in both cell-mediated and humoral immunity are associated with an increased frequency of infections due to encapsulated and enteric bacteria. Pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae, and other pathogens may occur early in the course of AIDS and have typical clinical presentations. Bacteremia is extremely common, and patients frequently fail to develop protective elevations in specific antibodies following infection. Recurrences are noted in up to one third of patients, and suppressive antimicrobial therapy may be required. The frequency of salmonellosis is increased as much as 20-fold in AIDS patients and is associated with bacteremia in more than 40 per cent of cases. Salmonella, Shigella, and Campylobacter infections in HIV-infected individuals may precede an AIDS diagnosis, may fail to respond to appropriate therapy, or may recur after completion of treatment. Prevention of bacterial infections with antibiotics or immunotherapy, or both, is recommended for children with AIDS or ARC.