Time to Result for Pathogen Identification and Antimicrobial Susceptibility Testing of Bronchoalveolar Lavage and Endotracheal Aspirate Specimens in US Acute Care Hospitals

Identification (ID) and antimicrobial susceptibility testing (AST) of respiratory pathogens are critical to the management of patients with pneumonia to facilitate optimal antibiotic therapy selection. Few studies have examined the time to results (TTR) for this critical specimen, and such data can be valuable for benchmarking the current paradigm of diagnostic approaches. 'TTR for bronchoalveolar lavage (BAL) and endotracheal aspirate (ETA) specimens from hospitalized patients was evaluated using the Premier Healthcare Database, a comprehensive database of 194 U.S. hospitals. Times from specimen collection to reporting of organism ID/AST were evaluated and compared by specimen types and characteristics. A total of 79,662 (43,129 BAL; 36,533 ETA) specimens were included, of which 19.3% harbored no growth, 47.1% contained normal respiratory flora alone (including yeast), and 0.6% contained mycobacteria/molds. Potential bacterial pathogens (PBP) were recovered from 33.0%. ETA specimens had a higher proportion of specimens with isolation of PBP (39.2% versus 27.7%) and with normal respiratory flora (52.0% versus 43.0%) and were less likely to be negative (8.2% versus 28.6%) than BAL specimens (all P < 0.0001). Staphylococcus aureus and Pseudomonas aeruginosa were isolated in 10.5 and 6.4% of the specimens, respectively, and were the most common organisms identified. Median (interquartile range) TTR were 37.0 h (21.8 to 51.7 h) and 60.5 h (46.6 to 72.4 h) for ID and AST, respectively. Median TTR for major respiratory pathogens by organism ranged from 29.2 to 43.9 h for ID and from 47.9 to 73.9 h for AST. Organism type, specimen collection time, and hospital teaching status influenced TTR. Mechanically vented patients and ETA specimens were more likely to recover PBP.