Table 2.

Microorganism Abundance by Species

Organism	log10 cfu/ml [Median (IQR)]	Number of Studies* (Total = 3,522)
P. aeruginosa	6.7 (5.9–7.0)	2,267
S. aureus†	6.5 (5.3–7.0)	2,046
MRSA	6.6 (5.7–7.0)	1,084
MSSA	6.3 (5.0–7.0)	972
H. influenzae	6.3 (5.5–7.0)	209
Other bacteria‡	6.5 (5.8–7.0)	1,803
Fungus	3.5 (3.0–4.0)	99

Definition of abbreviations: CF = cystic fibrosis; H. influenzae = Haemophilus influenzae; IQR = interquartile range; MRSA = methicillin-resistant S. aureus; MSSA = methicillin-sensitive S. aureus; P. aeruginosa = Pseudomonas aeruginosa; S. aureus = Staphylococcus aureus.

^*Subjects with CF who had at least one quantitative culture positive for the indicated species and quantified in cfu/ml. All subjects had at least 10 quantitative culture studies between January 1, 2004, and December 31, 2017.

^†Some S. aureus cultures could not be classified as either MRSA or MSSA. Occasionally, MRSA and MSSA were present on the same culture.

^‡Sum of all bacteria other than P. aeruginosa, S. aureus, and H. influenzae.