Possible Seasonality of Clostridium difficile in Retail Meat, Canada
Figure 2. Pulsed-field gel electrophoresis (PFGE)–SmaI dendogram of Clostridium difficile isolates of meat and human origin in Canada. Representative PCR ribotypes 077, 014, M31, and M26 are of meat origin from 2005 (4,11). PCR ribotype designations are described in Table 2. Note the genetic similarity (94.1%–100%) and antimicrobial resistance profiles between human and meat isolates, especially PCR ribotypes 014 and J. Also note the genetic similarity (81.8%–100%) between meat isolates from 2005 and 2006 for multidrug-resistant epidemic PCR ribotype 077, clindamycin-variable, PCR ribotype 014, and nontoxigenic PCR ribotype M26. Resistance to all 4 antimicrobial drugs was observed in meat isolates of ribotypes 077 and F, which also yielded the highest level of clindamycin resistance (>256 µL/mL; breakpoint: >6 µL/mL). The breakpoints for moxifloxacin (12) were also used for levofloxacin and gatifloxacin. R (resistant), S (susceptible), and I (intermediate) represent antimicrobial profiles. CDC, Centers for Disease Control and Prevention; NAP, North America PFGE type; NAP1-r, NAP-related strain; Tox, toxinotyping nomenclature (M. Rupnik, Maribor, Slovenia); U, unnamed.