Pneumonia due to Aeromonas hydrophila-complex: epidemiologic, clinical, and microbiologic features.

Review of published data examining the various types of infections produced by strains of the Aeromonas hydrophila-complex demonstrates a paucity of information on lower respiratory tract infections due to this organism. Although it is rarely cited as a cause of pneumonitis, we have been able to collect epidemiologic, clinical, and microbiologic data on eight patients who have had evidence of Aeromonas pneumonia. Interestingly, seven of the eight patients were male, and the average age for the group was 54.3 years. In contrast to reports showing a prevalence of other types of A hydrophila infections during the summer months, five of the pneumonitis cases occurred during late fall and early winter. Infections were both community-acquired and nosocomial. A proven or suspected history of aspiration was present in six patients. Preexisting medical conditions were noted in all patients, the majority having multiple predisposing factors, which included alcohol abuse and alcoholic liver disease, cardiovascular and cerebrovascular disease, and chronic lung disease. Three patients died of their acute pulmonary infection. Based on in vitro antimicrobial susceptibility testing, aminoglycoside therapy would seem appropriate in the treatment of these infections.