Table 2

Colony-forming unit (CFU) counts of Pseudomonas aeruginosa isolated from the cough aerosol cultures of subjects with cystic fibrosis (CFUs in total aerosol, and in large and small particle fractions are shown)*

Distance	1 m	2 m	4 m	ANOVA p value†
Total‡	52.6 (40.9–67.6)^a	37.3 (28.9–48.0)^a	24.8 (19.2–32.0)^b	0.001
Large fraction§	27.4 (21.4–34.9)^a	19.9 (15.5–25.5)^a	12.6 (9.7–16.2)^b	<0.001
Small fraction¶	27.6 (21.2–35.9)^a	19.6 (15.0–25.5)^ab	14.3 (10.9–18.7)^b	0.005

Duration	5 min	15 min	45 min

Total‡	14.6 (11.0–19.2)^a	11.9 (8.9–15.7)^a	7.7 (5.4–11.0)^b	0.046
Large fraction§	4.2 (3.1–5.5)^a	3.9 (2.9–5.2)^a	2.3 (1.5–3.4)^a	0.074
Small fraction¶	11.9 (9.1–15.6)^a	9.0 (6.7–11.8)^ab	6.2 (4.3–8.8)^b	0.031

*Values are means (95% CI). Within sets and rows, a different superscript letter (^a or ^b) denotes a significant difference (p<0.05) between other distances or durations.
†ANOVA for trend across distance or duration.
‡Total CFU counts represent the P aeruginosa CFUs isolated from all six Andersen Impactor stages (aerosol particles sizes 0.65 to >7.0 µm).
§Large particle fraction CFU counts represent the P aeruginosa CFUs isolated from stages 1, 2 and 3 (aerosol particle sizes >7, 4.7–7.0 and 3.3–4.7 µm, respectively) of the Andersen Impactor.
¶Small particle fraction CFU counts represent the P aeruginosa CFUs isolated from stages 4, 5 and 6 (aerosol particle sizes 2.1–3.3, 1.1–2.1 and 0.65–1.1 µm, respectively) of the Andersen Impactor.