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Bacterial pathogens account for a large percentage of the morbidity in HIV-infected patients. HIV-infected patients have defects in B-cell function, chemotaxis, and intracellular killing capabilities of monocytes and macrophages. These abnormalities result in an increased susceptibility to a number of organisms with a predilection to infections by S. pneumoniae, S. aureus, H. influenza, P. aeruginosa and Salmonella. In 1992, bacterial infections were associated with over 13% of all reported AIDS-related deaths.
Pneumonia
In a recent study by the Pulmonary Complications of HIV Infection Study Group, bacterial pneumonias occurred more frequently than Pneumocystis. A study by the CPCRA showed bacterial pneumonias to be the most common HIV-related complication for persons with >200 CD4 cells. It is estimated that the overall occurrence of pneumonia is up to 5-fold more common than in non-HIV-infected populations, and that certain organisms, such a S. pneumoniae occur.
The clinical presentation of bacterial pneumonia in HIV-infected persons is not unusual, with most patients having fever, cough with sputum production, and consolidation on chest X-ray. Many patients have a normal WBC, although a shift may be present. An elevated LDH may occur in persons with bacterial pneumonia and is not specific for PCP.
Treatment should be broad enough to cover S. pneumoniae and H. influenza unless a specific organism is initially identified. Penicillin-resistant pneumococci are prevalent in many areas and should be considered in selecting the initial antibiotic. One should consider the use of a third-generation cephalosporin to cover both resistant pneumococci.
All HIV-infected patients should receive pneumococcal vaccination. Several studies have proven that giving the vaccine to persons with >200 CD4 cells is associated with improved efficacy, but even persons with more advanced disease may benefit. Monthly gamma-globulin has been proven to reduce the incidence of serious bacterial infections in children, but is not routinely used in adults. Patients receiving Trimethoprim-sulfa for PCP prophylaxis.
Bacteremia
Bacteremia may occur in relation to another infection, such as pneumonia, or may represent the only site of infection. The two most common factors associated with bacteremia in HIV-infected patients are the presence of an indwelling venous catheter and neutropenia. Central catheter infections have been shown to occur more commonly in persons with HIV compared to other groups, and account for the majority of bacteremias in HIV-infected persons. The organisms associated with these infections are predominantly S. aureus and coagulase-negative Stapho These infections should be treated as in HIV-negative patients. Pseudomonas aeruginosa.
Upper Respiratory Tract Infections
(Sinusitis, Otitis)
Acute otitis media and sinusitis are more common in both HIV-infected adults and children. Studies in children have shown that 20% of all serious bacterial infections were related to sinusitis.
In both children and adults, otitis and sinusitis can be recurrent and difficult to cure. The diagnosis of sinusitis should be aggressively approached with the use of X-rays and CT scans. The use of needle aspiration for isolation of pathogens is indicated for individuals who fail.
Bartonella Infections
Bartonella (formerly Rochalimaea) henselae and B. quintana are fastidious bacteria