Relationships between copies of 16S rRNA gene (base 10 logarithmic values) and characteristics of patients and pleural fluid (PF) samples
| Number | Copies of 16S rRNA gene, measured by qPCR | |||||
|---|---|---|---|---|---|---|
| % change per unit1 | 95% CI | Geometric mean | 95% CI | p value | ||
| PF pH | 97 | -89.6 | -97.6, -55.5 | 0.003 | ||
| PF culture status Negative Positive | 110 44 | 2.8 × 105 2.2 × 106 | 1.9 × 105, 4.0 × 105 1.2 × 106, 4.0 × 106 | <0.0001 | ||
| PF appearance Non-purulent Purulent | 74 76 | 1.9 × 105 1.4 × 106 | 1.2 × 105, 2.9 × 105 8.8 × 105, 2.2 × 106 | <0.0001 | ||
| PF LDH ≤1000 1000–5000 >5000 | 26 41 36 | 1.4 × 105 4.1 × 105 6.2 × 105 | 6.9 × 104, 2.8 × 105 2.3 × 105, 7.1 × 105 3.4 × 105, 1.1 × 106 | 0.007 | ||
| PF glucose ≤1.0 1.0–2.2 >2.2 | 43 14 35 | 5.9 × 105 2.9 × 105 1.5 × 105 | 3.4 × 105, 1.0 × 106 1.1 × 105, 7.3 × 105 8.5 × 104, 2.8 × 105 | 0.007 | ||
| Patient CRP <100 100–160 ≥160 | 28 27 87 | 3.5 × 105 3.5 × 105 5.8 × 105 | 1.6 × 105, 7.5 × 105 1.6 × 105, 7.7 × 105 3.7 × 105, 8.9 × 105 | 0.372 | ||
| Patient WCC ≤11.0 11.0–16.5 >16.5 | 41 58 53 | 3.7 × 105 4.6 × 105 7.7 × 105 | 1.9 × 105, 7.0 × 105 2.7 × 105, 7.9 × 105 4.4 × 105, 1.4 × 106 | 0.215 | ||
1% change in 16S rRNA gene copies number per unit increase in the specified variable. CI = confidence interval. p values for tests of linear trend (continuous variables) and for tests of heterogeneity (categorical variables). LDH units – IU/L; glucose units – mmol/L; CRP units – mg/L; WCC units – x 109/L