TABLE 1.
Characteristics of patients with bloodstream infections caused by gram-negative organisms in low-, intermediate-, and high-MIC groups
| Characteristica | Value for patients (n = 312) grouped according to:
|
P valuee | ||
|---|---|---|---|---|
| Low MICb (n = 64) | Intermediate MICc (n = 227) | High MICd (n = 21) | ||
| Male sex | 29 (45.3) | 105 (46.3) | 13 (61.9) | 0.37 |
| Age (yr)f | 58.6 (19.2) | 61.1 (18.0) | 60.2 (16.7) | 0.62g |
| Infecting organism | ||||
| P. aeruginosa | 0 (0) | 8 (3.5) | 8 (38.1)h | <0.001 |
| E. coli | 32 (50) | 130 (57.3) | 2 (9.5)h | <0.001 |
| K. pneumoniae | 19 (29.7) | 61 (26.9) | 8 (38.1) | 0.53 |
| Other | 13 (20.3) | 28 (12.3) | 3 (14.3) | 0.27 |
| Nosocomial infection | 10 (15.6) | 37 (16.3) | 8 (38.1)h | 0.04 |
| Charlson score | 0.96 | |||
| 0 | 29 (45.8) | 104 (45.8) | 9 (42.9) | |
| 1-2 | 28 (43.8) | 91 (40.1) | 9 (42.9) | |
| ≥3 | 7 (10.9) | 32 (14.1) | 3 (14.3) | |
| ICU admission | 16 (25) | 58 (25.6) | 8 (38.1) | 0.44 |
| Surgical admission | 42 (65.6) | 136 (59.9) | 13 (61.9) | 0.71 |
| Sepsis diagnosis code | 14 (21.9) | 67 (29.5) | 6 (27.9) | 0.48 |
| Treatment with another active antimicrobial | 26 (40.6) | 98 (43.2) | 11 (52) | 0.64 |
| Preculture length of stay (days)f | 2.7 (6.9) | 2.0 (6.0) | 11.7 (25.1)h | 0.01i |
| Preculture length of levofloxacin treatment (days)f | 0.2 (0.9) | 0.5 (4.7) | 8.8 (23.8)j | 0.08i |
All data are presented as the number (percentage) of patients unless otherwise indicated.
A low MIC was defined as a levofloxacin MIC of ≤0.25 mg/liter.
An intermediate MIC was defined as a levofloxacin MIC of 0.5 mg/liter.
A high MIC was defined as a levofloxacin MIC of 1 or 2 mg/liter.
Determined by a χ2 test unless otherwise indicated.
Data are presented as the mean (standard deviation).
Determined by analysis of variance.
Results of Mann-Whitney U nonparametric test for two groups, the high-MIC group versus all others: group with infections caused by P. aeruginosa, P < 0.001; group with infections caused by E. coli, P < 0.001; and group with nosocomial infections, P < 0.011.
Determined by a Kruskal-Wallis nonparametric test for three groups.
Results of Mann-Whitney U nonparametric test for two groups, the high-MIC group versus all others: P = 0.007.