Clinical characteristics and outcomes of patients with Escherichia coli in airway samples.

Purposes: Escherichia coli is one of the most common pathogens in nosocomial and community-acquired infections, but is an uncommon respiratory pathogen. However, this pathogen may at times be seen in respiratory secretions. The study aims to determine the clinical and prognostic value of E. coli in respiratory secretions.

Methods: Cultures of respiratory secretions from hospitalized and outpatients between 2009 and 2016 were screened for isolation of E. coli. We defined three groups of patients: "Sensitive (S)"-growth of E. coli sensitive to all antimicrobials tested; Intermediate (I)-resistant to 1-2 antimicrobial classes; and "Resistant (R)"-resistant to at least three antibiotic classes. We compared factors associated with resistant strains and outcomes between the groups.

Results: Eighty patients with E. coli isolates from respiratory secretions were identified while screening 177 712 (4.5: 10 000 samples). Of the E. Coli-positive cultures, 11 were from ambulatory patients, 31 patients were hospitalized and 37 were hospitalized and intubated. Ten people had bronchiectasis and 29 had COPD. Patients with resistant E. coli had significantly more hospitalization days prior to positive culture (S = 1.2 ± 1.89 days, I = 1.23 ± 1.5 days and R = 3.7 ± 5.4 days, respectively; P = 0.002). Mortality was higher in patients with a resistant strain (R) versus (I) or (S) (76.7%, 31.8% and 26.7%, respectively; P < 0.0001) and remained significantly elevated after correction for prior hospital days.

Conclusions: Pulmonary infection due to E. coli is uncommon. Isolation of resistant E. coli is associated with length of previous hospitalization, elevated mortality and may be viewed as a nosocomial pathogen.