Escherichia coli: an unknown and infrequent cause of community acquired pneumonia

Our aim was to describe the incidence, clinical characteristics and outcome of community acquired pneumonia (CAP) caused by Escherichia coli through the analysis of a cohort of patients with this condition. This study includes all the patients who were admitted to our hospitals because of CAP caused by E. coli, diagnosed with highly reliable microbiological techniques, such as blood culture, bronchoscopic protected specimen brush (PSB) or transthoracic needle aspiration (TNA). 29 patients were enrolled, representing 0.4% of CAP cases admitted. Main symptoms were fever and dyspnoea. 18 patients were classified into class IV and class V of the Pneumonia Severity Index (PSI). Diagnosis was based on blood culture in 24 cases, PSB in 4 cases and by TNA in 1 case. Three of the patients died, the longer time evolution of the symptoms being the only factor related to higher mortality (p<0.05). Mean hospitalization time was 7.1+/-3.1 d, and correlated with severity at admission (r=0.43; p<0.003). This study demonstrates that CAP caused by E. coli is infrequent. It has an unspecific presentation and mortality rate is 10.3%, associated with longer time before admission to hospital.