The phenotypically indistinguishable Acinetobacter baumannii and Acinetobacter nosocomialis have become leading pathogens causing nosocomial pneumonia in critically ill patients. A. baumannii and A. nosocomialis nosocomial pneumonias were grouped as a single clinical entity previously. This study aimed to determine whether they are the same or different clinical entity. A total of 121 patients with A. baumannii and 131 with A. nosocomialis bacteremic nosocomial pneumonia were included during an 8-year period. Despite the similar Charlson comorbidity scores at admission, patients with A. baumannii pneumonia were more likely to have abnormal hematologic findings, lobar pneumonia, significantly higher Acute Physiology and Chronic Health Evaluation II scores and higher frequency of shock at the onset of bacteremia than those with A. nosocomialis pneumonia. A. baumannii isolates were resistant to more classes of antimicrobials except colistin, and therefore the patients with A. baumannii pneumonia were more likely to receive inappropriate antimicrobial therapy. The 14-day mortality was significantly higher in patients with A. baumannii pneumonia (34.7% vs. 15.3%, p 0.001). A. baumannii was an independent risk factor for mortality (OR 2.03, 95% CI 1.05-3.90, p 0.035) in the overall cohort after adjustment to other risk factors for death, including inappropriate antimicrobial therapy. The results demonstrated the difference in clinical presentation, microbial characteristics and outcomes between A. baumannii and A. nosocomialis nosocomial pneumonia, and supported that they are two distinct clinical entities.
Date:
2013-07
Relation:
Clinical Microbiology and Infection. 2013 Jul;19(7):640-645.
