Resistance of Clostridium difficile to antibiotics in a teaching hospital in Madrid: current situation

Abstract number: P1262

Bernaola C., Perez J., Amor E., Betriu C., Picazo J.

Objectives: Metronidazole and vancomycin are the drugs of choice for treatment of Clostridium difficile (CD)-associated disease. In Spain, there have been reports of resistance of CD to metronidazole and intermediate resistance to vancomycin. This study aims to determine the frequency of these resistant isolates in our hospital.

Methods: We studied the sensitivity of 100 non duplicate toxigenic strains of CD obtained between October 2007 and October 2008 against 14 antimicrobial drugs using the microdilution method according to CSLI guidelines. We compared the results with those from a similar study carried out 10 years ago. We also studied sensitivity to metronidazole, vancomycin, daptomycin, and tigecycline using the E-test.

Results: We found 2 isolates with an MIC of 16 mg/L (2%) by both methods. All the isolates were uniformly sensitive to vancomycin, amoxicillin-clavulanic acid, piperacillin, and piperacillin-tazobactam. Resistance to amoxicillin, imipenem, tetracycline, and clindamycin was greater than in the previous study. Moxifloxacin showed 40% resistance. Both tigecycline and daptomycin showed good activity, although that of tigecycline was superior (MIC50/MIC90, 0.06/0.12 mg/L and 0.25/1 mg/L, respectively).

Conclusion: The finding in our hospital of 2 strains with an MIC of 16 mg/L to metronidazole confirms the need for surveillance of resistance by CD to antibiotics – especially to the drugs of choice – reported in other Spanish hospitals. Alternative drugs should be studied.