Bacteremic pneumonia caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: Appropriateness of empirical treatment matters

Background: Clinical information about bacteremic pneumonia caused by extended-spectrum beta-lactamase (ESBL)-producing organism is limited. Methods: A retrospective study was conducted at two medical centers in Taiwan. From May 2002 to August 2010, clinical information and outcome of adults with bacteremic pneumonia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae were analyzed. The primary outcome is the 30-day mortality. Results: A total of 111 patients with bacteremic pneumonia caused by E. coli (37 patients, 33.3%) and K. pneumoniae (74, 66.7%) were identified. Their mean age was 69.2 years and 51.4% were male patients. Fifty-seven (51.3%) episodes were classified as hospital-acquired infections, 19 (17.1%) as health-care-associated infections, and four (3.6%) as community-acquired infections. Fifty-one (45.9%) patients received appropriate empiric antimicrobial therapy. The 30-day mortality rate was 40.5% (45 patients). In the multivariate analysis, several independent risk factors, including rapidly fatal underlying disease [odds ratio (OR), 5.75; 95% confidence interval (CI), 1.54-21.48; p = 0.009], severe sepsis (OR, 4.84; 95% CI, 1.55-15.14; p = 0.007), critical illness (OR, 4.28; 95% CI, 1.35-13.57; p = 0.013), and receipt of appropriate empirical therapy (OR, 0.19; 95% CI, 0.07-0.55; p = 0.002), were associated with 30-day mortality. The survival analysis consistently found that individuals with appropriate empiric therapy had a higher survival rate (log-rank test, p < 0.001). Conclusion: ESBL-producing bacteremic pneumonia, especially health-care-associated infections, often occurred in adults with comorbidities. Appropriate empirical therapy was associated with a favorable outcome.