Organism Isolation Outcomes
Among all cultures obtained, only 617 cultures (17.2%) demonstrated organism isolation, with 751 total organisms identified (22 unique species). Unadjusted analysis demonstrated that cultures of children with ARI had higher odds of any organism isolation compared with those from children without ARI (24.3% vs 14.8%, p<0.01,Figure 1(a) ); unadjusted odds ratio(OR) 1.83 (95% Confidence Interval(CI) 1.67-2.01, Table 2 ). The most prevalent organisms isolated in both children with and without ARI were Pseudomonas aeruginosa , Staphylococcus aureus (29% methicillin-resistant),Haemophilus influenzae , and Moraxella catarrhalis(Figure 1(b) ). On unadjusted analysis, all 4 of these organisms were significantly more frequently isolated with ARI diagnosis compared with no ARI diagnosis (Figure 1(b) ).
On adjusted analysis, ARI diagnosis continued to demonstrate increased odds of organism isolation (aOR 1.29; 95%CI 1.16-1.44, Table 2 ). ARI was not associated with P. aeruginosa or S. aureus isolation on adjusted analysis, but P. aeruginosa was associated with bARI diagnosis. Using multinomial adjusted analysis examining for the comprehensive outcome of each organism isolation, ARI diagnosis was associated with isolation of 4 organisms, H. influenzae (aOR 2.09), M. catarrhalis (aOR 1.76), S. pyogenes (aOR 1.92), and Streptococcus pneumoniae (aOR 4.04,Table 3 ), as compared with no organism isolation. Isolation of all other organisms, including P. aeruginosa and S. aureus , were not associated with ARI diagnosis at the time of culture collection.