[Bacterial pneumonia in HIV-infected patients]

Patients and methods: This is a retrospective study performed on HIV-positive patients discharged from our Institution from January 1993 through December 1998 with a diagnosis of bacterial pneumonia. Cases of TB or atypical micobacterial infection were excluded from this analysis. Causative organisms were identified, when possible, by taking into account positive cultures from diverse sources (blood, sputum, pleural fluid and others). Results: In the 6-yr period we considered, 120 patients were identified. Among them, we were able to obtain clinical and imaging data on 98 cases. Focal infiltrates on chest X-ray studies were present in 87.7% of cases, 24.5% had a pleural effusion, 9.2% nodular lesions, 4.1% cavitary images and in 2 patients only hilar lymphadenopaties were noted. Causative agents resulted to be S. aureus (14 cases); P. aeruginosa (11); S. pneumoniae (6); R. equi (4); Enterobacter spp. and K. pneumoniae (3 cases each); E. coli, Peptostreptococcus spp and Enterococcus spp. (1 case each). No causative organism was isolated in 54 patients (55.1%) and the diagnosis was based on clinical and therapeutical grounds. Around half of cases (46.9%) responded well to therapy, while 11 (11.2%) died because of the lung infection. In 3 cases other opportunistic infections were the cause of death and 22 cases of relapse were recorded as well. Five patients resulted lost to follow-up. Conclusions: This retrospective study demonstrated a high prevalence of S. aureus lung infections along with the presence of otherwise rare causative organisms such as R. equi. Radiologic appearance of lung lesions did not differ substantially from the one of HIV negative patients. A relatively good response to antibiotic therapy was also noted.