TABLE 1.
Phenotypic and genotypic characteristics of the fluoroquinolone-resistant strains of C. difficile studieda
| Strain | Year isolated | Hospital | Toxin production | Serotype | MIC (μg/ml)
|
Susceptibility
|
Amino acid substitution (mutation)
|
|||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CIP | MOX | CHL | ERY | TET | RIF | GyrA | GyrB | |||||
| ATCC9689 | − | G | 8 | 2 | ||||||||
| 253 | 1991 | Bichat | + | C | 64 | 16 | R | R | R | R | Asp426→Asn (GAT→AAT) | |
| 580 | 1991 | Bichat | + | C | 32 | 8 | R | R | R | R | Asp426→Asn (GAT→AAT) | |
| 602 | 1991 | Bichat | + | C | 128 | 8 | R | R | R | R | Asp426→Asn (GAT→AAT) | |
| 714 | 1991 | Bichat | − | D | 128 | 32 | S | S | R | S | Thr82→Ile (ACT→ATT) | |
| 1229 | 1991 | Bichat | + | C | 128 | 8 | S | R | R | R | Asp426→Asn (GAT→AAT) | |
| 728 | 1991 | Pitié | + | A9 | 128 | 32 | S | S | S | R | Thr82→Ile (ACT→ATT) | |
| 875 | 1991 | Saint-Joseph | + | H | 64 | 8 | S | S | S | S | Asp71→Val (GAC→GTC) | |
| 22 | 1997 | Broca | + | K | 128 | 16 | S | S | S | S | Asp426→Asn (GAT→AAT) | |
| 36 | 1997 | Cochin | + | C | 64 | 16 | S | R | R | R | Thr82→Ile (ACT→ATT) | |
| 266 | 1997 | René Muret | + | H | 128 | 32 | S | S | S | S | Thr82→Ile (ACT→ATT) | |
| 271 | 1997 | Saint-Antoine | + | H | 128 | 32 | S | S | S | S | Thr82→Ile (ACT→ATT) | |
| 302 | 1997 | Saint-Antoine | + | H | 128 | 32 | S | S | S | S | Thr82→Ile (ACT→ATT) | |
| 334 | 1997 | Institut Montsouris | + | Nt | 32 | 4 | S | S | S | S | Arg447→Leu (CGA→CTA) | |
| 358 | 1997 | Broussais | − | D | 64 | 8 | S | R | S | S | Ala118→Thr (GCT→ACT) | |
a
MICs of ciprofloxacin (CIP) and moxifloxacin (MOX) were determined by agar dilution. Susceptibility was determined in a previous study with the ATB ANA susceptibility test (7). CHL, chloramphenicol; ERY, erythromycin; TET, tetracycline; RIF, rifampin; Nt, nontypeable.