Pleuropulmonary Infections due to Nontyphoid Strains of Salmonella

Medical records of 11 patients with nontyphoid Salmonella pleuropulmonary disease studied from 1960 to 1986 in a general hospital were reviewed. Eight patients (73%) were 60 years old or older, and the median age was in the seventh decade. There was no seasonal variation in the prevalence. The infection was hospital acquired in 4 patients (36%). All patients had one or more (median, 1.5) major underlying diseases. Seven of them had previous abnormalities of the lung or pleura. Severe immunosuppression was present in 7 cases. Pneumonia occurred in 8 patients, lung abscesses in 2, and empyema in 1. All patients with pneumonia had positive blood cultures. A gastrointestinal source of pulmonary infection was not probable because only 2 patients had positive stool cultures. We suggest that the reticulo-endothelial system could be the source of hematogenous spread of nontyphoid Salmonella. The overall mortality was 63%. Pulmonary infection due to Salmonella should be considered among the pathogens associated with gram-negative bacillary pneumonia in elderly patients who are immunosuppressed and have underlying pulmonary disease. Pathogenesis of this infection remains to be clarified.