TABLE 4.
Effects of subinhibitory concentrations of fluoroquinolones on the expression of genes encoding colonization factors of C. difficile in the two in vitro-selected moxifloxacin-resistant mutants and their parental strains
| Gene | Antibiotic stressa | Mean relative expression ratiob ± SD |
|||||
|---|---|---|---|---|---|---|---|
| NAP1/027 strain |
Non-NAP1/027 strain |
||||||
| CD196 | CD196-M1 | P value | ATCC 43603 | ATCC 43603-M1 | P value | ||
| cwp84 | OFX | 6.1 ± 1.3 | 11.7 ± 4.1 | 0.132c | 3.2 ± 1.1 | 67.4 ± 34.0 | 0.009c |
| MXF | 7.1 ± 4.3 | 2.9 ± 0.2 | 0.485 | 3.1 ± 1.8 | 17.3 ± 5.4 | 0.024c | |
| slpA | OFX | 2.7 ± 0.2 | 4.3 ± 2.4 | 0.610 | 3.9 ± 0.1 | 32.8 ± 24.7 | 0.114 |
| MXF | 1.8 ± 1.8 | 1.9 ± 0.8 | 0.575 | 2.9 ± 2.7 | 16.5 ± 11.8 | 0.262 | |
| fbp68 | OFX | 3.1 ± 1.3 | 2.3 ± 1.8 | 0.381 | 4.8 ± 1.7 | 2.1 ± 1.0 | 0.267 |
| MXF | 5.0 ± 2.8 | 1.1 ± 0.9 | 0.048 | 2.1 ± 1.9 | 0.8 ± 0.2 | 0.800 | |
a
OFX, ofloxacin; MXF, moxifloxacin.
b
Ratio of expression in bacteria grown with antibiotic versus expression in control grown without antibiotic. P values for the comparison of the upregulation of genes between the moxifloxacin-resistant mutant and its parental strain were derived using the Wilcoxon test.
c
The difference between expression levels in the moxifloxacin-resistant mutant and its parental strain was significant.