Abbreviations: ARI: acute respiratory illness; OR: odds ratio; CI: confidence interval.

^a Calculated using a generalized estimating equation accounting for within-patient clustering.

^b Calculated using a generalized estimating equation to control for patient-level covariates [including: number of complex chronic conditions, ventilator use, race, ethnicity, insurance type], culture-level covariates [including: age at culture acquisition, time with tracheostomy at culture acquisition, culture source (tracheostomy aspirate or bronchoalveolar lavage), department obtained], and to account for within-patient clustering.

^c versus no organism isolation.

^d versus no P. aeruginosa isolation.

^e versus no S. aureus isolation.