Lack of association of outcomes with treatment duration and microbiologic susceptibility data in Clostridium difficile infections in a non-NAP1/BI/027 setting

Background: Concerns regarding the poor response of severe Clostridium difficile infection (CDI) treated with metronidazole have arisen over the last 5 y. Methods: We conducted a prospective, non-interventional study of CDI cases at our institution to evaluate the role of drug resistance, co-morbidities, and the emergence of hypervirulent strains on patient outcomes. A total of 118 adult inpatients with diarrhea and a positive stool for C. difficile toxin immunoassay had positive stool cultures and were included in the study. All 118 isolates had vancomycin and metronidazole susceptibility testing via the E-test method; rep-PCR was performed on 47 isolates. Of the 118 study patients, 107 were treated with either metronidazole or vancomycin. Results: Initial therapy was metronidazole in 98.1% (n = 105) and vancomycin in 1.9% (n = 2) patients. Evaluable clinical response within 5 days of treatment was noted in 52.5% (52/99) of cases. The mean duration of treatment was 11.7 +/- 7.2 days. The 30-day all-cause mortality rate was 24.6% (29/118). Recurrence occurred in 23.6% (21/89). A recent stay in the intensive care unit was associated with increased 30-day mortality (odds ratio 3.58, p = 0.012). There were no isolates resistant to metronidazole or vancomycin. Only 1 isolate was possibly related to the NAP1/BI/027 reference strain. No strain-related differences in deaths or recurrence were noted. Conclusions: Deaths related to CDI in our study appear to be related to multiple factors and did not appear to be independently related to antibiotic susceptibility, strain type, or treatment duration.