Table 1. Demographic data of bronchoalveolar lavage samples stratified by traditional culture results.

Variable	C- (n = 7) Median (IQR); Count (Percentage)	C+ (n = 7) Median (IQR); Count (Percentage)	RTF (n = 8) Median (IQR); Count (Percentage)	P value
Age (years)	40 (26–54)	51 (32–73)	47 (29–57)	0.27
Male gender	6 (86%)	6 (86%)	7 (87%)	0.99
Days Post Injury of BAL	4 (2–11)	2 (2–6)	3 (2–4.5)	0.80
Reason for BAL Collection
--Diagnostic	2 (28%)	0 (0%)	1 (12.5%)	<0.0001
--Screening	5 (72%)	7 (100%)	7 (87.5%)
Reason for ICU admission
Trauma	4	6	5	0.51
Oncology	2	0	2
CNS	0	1	1
Other	1	0	0
Antibiotics at time of BAL	5 (71%)	1 (14%)	1 (12.5%)	0.028
16s Copy Number	24,266(10,860–134,000)*	434,600(134,200–912,000)	343,000(126,866–720,850)	0.006

Quantitative data is presented as median and interquartile range, whereas qualitative data is presented as count and percentage of samples analyzed. Age, gender and days post injury for BAL collection were not significantly different between groups. Kruskal-Wallis test was utilized to compare 16s copy number in GraphPad Prism 7 (p = 0.0057).

Dunn’s post-hoc multiple comparison test was utilized to adjust P-values to determine statistical significance at *P < 0.05.

Culture negative 16s copy numbers were statistically significant between culture positive (adjusted P = 0.0154) and respiratory tract flora samples (adjusted P = 0.0442). 16s copy numbers were not statistically significant between respiratory tract flora and culture positive samples (adjusted P>0.999). Abbreviations: RTF = respiratory tract flora