Community-acquired pneumonia due to Escherichia coli.

OBJECTIVE: To describe the features of community-acquired Escherichia coli pneumonia and to compare these patients with patients with pneumonia caused by other etiologic agents. PATIENTS AND METHODS: This prospective study was carried out at five medical institutions in three geographic locations---Pittsburgh, PA, Boston, MA and Halifax, NS. Pneumonia etiology was assigned, based on results of microbiological investigations, by a committee consisting of five investigators using rules established prior to the study. Demographic and clinical features and outcomes of patients with E. coli pneumonia were compared with those of pneumonia due to other microorganisms. RESULTS: Nineteen patients (9 (47.4%) blood culture positive) had pneumonia due to E. coli and 430 (69 (16.0%) blood culture positive) had pneumonia caused by other etiologic agents. E. coli was the second most common cause of bacteremic pneumonia. The E. coli patients were older, and more likely to be female, from a nursing home and confused compared with patients with pneumonia due to other microbial agents. They were more severely ill as measured by a validated pneumonia specific severity of illness scoring measure. Although there was no in-hospital mortality for the patients with E. coli pneumonia, the 90-day mortality was 21%. Thirty-two (7.4%) of the patients with pneumonia due to other agents died in hospital and the 90-day mortality rate was 13.5% (p NS). Eight of the 19 patients with E. coli pneumonia were admitted from a nursing home and an additional four patients (63.2%) were discharged to such a facility. In contrast, only 44 (10.2%) of the patients with pneumonia due to other agents were discharged to a nursing home (p<0.001). CONCLUSIONS: Patients diagnosed with E. coli pneumonia are frequently bacteremic. They are older than patients with pneumonia due to other etiologies, and more likely to be female, from a nursing home and severely ill. Despite the absence of in-hospital mortality, 21% of these patients died within 90 days of presentation.