Volume 22, Number 11—November 2016
Letter
Shigella flexneri with Ciprofloxacin Resistance and Reduced Azithromycin Susceptibility, Canada, 2015
Table
Antimicrobial susceptibility of the Shigella flexneri,serotype 2a pulsovar 21, isolated in Montreal, Quebec, Canada, 2015*
Antimicrobial agent | Disk diffusion, mm | MIC, mg/L | Interpretation |
---|---|---|---|
Ampicillin | 6 | ≥32 | R |
TMP/SMX | 6 | ≥320 | R |
Ciprofloxacin | 12 | ≥4 and 8 | R |
Nalidixic acid | 6 | NA | R |
Ceftriaxone | 33 | ≤0.25 | S |
Cefixime | 26 | 0.25 | S |
Azithromycin† | 6 | >256 | NS |
Tetracycline | 6 | 32 | R |
Chloramphenicol | NA | >256 | R |
Amoxicillin-clavulanic acid | 14 | 16 | I |
Ertapenem | NA | ≤0.5 | S |
Gentamicin |
21 |
≤1 |
S |
*I, intermediate; NA, not available; NS, nonsusceptible; R, resistant; S, susceptible; TMP/SMX, trimethoprim/sulfamethoxazole. †Azithromycin epidemiologic cutoff values for wild-type (MIC ≤8 mg/L) and non–wild-type (MIC ≥16 mg/L) Shigella flexneri (2) and the susceptibility and resistance breakpoints for the other 11 antimicrobial agents were CLSI Enterobacteriaceae breakpoints (2). |