A new strategy for healthcare-associated pneumonia: a 2-year prospective multicenter cohort study using risk factors for multidrug-resistant pathogens to select initial empiric therapy.

BACKGROUND Optimal empiric therapy for hospitalized patients with healthcare-associated pneumonia (HCAP) is uncertain. METHODS We prospectively applied a therapeutic algorithm, based on the presence of risk factors for multidrug-resistant (MDR) pathogens in a multicenter cohort study of 445 pneumonia patients, including both community-acquired pneumonia (CAP; n = 124) and HCAP (n = 321). RESULTS MDR pathogens were more common (15.3% vs 0.8%, P < .001) in HCAP patients than in CAP patients, including Staphylococcus aureus (11.5% vs 0.8%, P < .001); methicillin-resistant S. aureus (6.9% vs 0%, P = .003); Enterobacteriaceae (7.8% vs 2.4%, P = .037); and Pseudomonas aeruginosa (6.9% vs 0.8%, P = .01). Using the proposed algorithm, HCAP patients with ≥2 MDR risk factors, one of which was severity of illness (n = 170), vs HCAP patients with 0-1 risk factor (n = 151) had a significantly higher frequency of MDR pathogens (27.1% vs 2%, P < .001). In total, 93.1% of HCAP patients were treated according to the therapy algorithm, with only 53% receiving broad-spectrum empiric therapy, yet 92.9% received appropriate therapy for the identified pathogen. Thirty-day mortality was significantly higher for HCAP than for CAP (13.7% vs 5.6%, P = .017), but among HCAP patients with 0-1 MDR risk factor, mortality was lower than with ≥2 MDR risk factors (8.6% vs 18.2%, P = .012). In multivariate analysis, initial treatment failure, but not inappropriate empiric antibiotic therapy, was a mortality risk factor (odds ratio, 72.0). CONCLUSIONS Basing empiric HCAP therapy on its severity and the presence of risk factors for MDR pathogens is a potentially useful approach that achieves good outcomes without excessive use of broad-spectrum antibiotic therapy. CLINICAL TRIALS REGISTRATION Japan Medical Association Center for Clinical Trials, JMA-IIA00054.