Class of 2012 Abstract / Specific Aims: The incidence of non-response, recurrence, relapse, and rate of complications of Clostridium difficile infections treated with combination of metronidazole and vancomycin versus vancomycin or metronidazole alone over a one-year period by treatment and strain type (i.e. NAP1/BI/027) were evaluated. The incidence of mortality in patients with moderate to severe Clostridium difficile associated diarrhea prescribed metronidazole, vancomycin, or combination metronidazole plus vancomycin as initial therapy was also determined. Additionally, significant factors associated with the use of combination vancomycin-metronidazole as initial therapy for moderate to severe CDAD were characterized. Methods: T This retrospective medical record review has been approved by the Institutional Review Board. Adult patients with stool specimens tested for detection of Clostridium difficile toxin B by PCR between April 2010 and March 2011 at a tertiary care, academic medical center were evaluated. Patients were included in the study if diagnosed with moderate to severe disease and received either monotherapy with metronidazole, monotherapy with oral vancomycin, or combination therapy with metronidazole and oral vancomycin for at least 80% of the first 10 days of treatment. Patients who are discharged alive within 72 hours of admission or who received therapy for less than 48 hours were excluded. Main Results: All patients (N=411) with laboratory evidence of Clostridium difficile during the study time period were evaluated. A total of 26 subjects who received oral vancomycin monotherapy and 56 subjects who received oral vancomycin along with metronidazole for at least 80% of the first 10 days of treatment were identified. Of the subjects who received oral vancomycin monotherapy during the first ten days of therapy, 5 (19%) were classified has a treatment failure or died within the first 21 days of therapy and 5 (19%) had either a recurrence or reappearance of Clostridium difficile associated diarrhea between 22 and 65 days post start of therapy. Of the subjects who received a combination of oral vancomycin and metronidazole during the first 10 days of therapy, 14 (25%) were classified has a treatment failure or died within the first 21 days of therapy and 22 (39%) had either a recurrence or reappearance of Clostridium difficile associated diarrhea between 22 and 65 days post start of therapy. In the combination therapy group, 5 (9%) were reported to have an ileus, toxic megacolon, or necrotic bowel during the first 10 days of therapy. Conclusions: In this study, the subjects who received a combination of oral vancomycin and metronidazole had higher rates of clinical failure, death, and recurrence than subjects who received monotherapy. Current guideline statements recommend combination therapy only in patients with an ileus with Clostridium difficile-associated diarrhea.

Class of 2014 Abstract / Specific Aims: The incidence of Clostridium difficile (C. Diff) infections in pediatric patients has continually risen, which could be caused by the emergence of a hyper virulent strain, specifically NAP1/B1/027. The objectives of the study were to evaluate the incidence of strain type, compare treatment(s) prescribed, treatment duration, rate of infection recurrence based on strain and severity, rates of re-infection or recurrence, and treatment failures for patients less than 6 months and up to 18 years of age. Methods: A retrospective study of patients admitted to an academic medical center with detection of C. diff toxin was performed. Data analyses included descriptive and inferential statistics to examine demographics, strain type, infection severity, and treatment failure. Main Results: Fourty-five patients with C. Diff toxin detection were included in study analyses and the median age was 6.2 [0.31- 17.9 years]. Oral or intravenous metronidazole was prescribed as initial therapy in 89% of the patients. Strain type was available in 77% of patients, with NAP1/B1/027 detected in 31% of stool samples tested. Within 21 days after initial toxin detection, there was a 13% rate of clinical failure or death, although none directly associated with C. Diff. Within days 22 - 65 after initial toxin detection, there was a 16% rate of recurrence or reinfection. Initial therapy selection, therapy duration, and rate of recurrence or reinfection were not significantly associated with NAP1/B1/027 strain type. Conclusion: Despite variability in severity of infection, the majority of pediatric patients with C. Diff were treated with metronidazole and were infected with a non-B1/NAP1/027 strain.

Class of 2006 Abstract / Background: The processes’ underlying a recent rise in the rate of Clostridium difficile associated diarrhea (CDAD) at the Southern Arizona Veterans Administration Health Care System (SAVAHS) is unclear. Past changes to formulary in workhorse oral flouroquinolone from levofloxacin to gatifloxacin are under scrutiny. An infection-control component was also possible. Methods: 142 patients suspected of having CDAD had stool specimens submitted for toxin assay from late July to late Oct of 2004. A retrospective chart review was performed using the Veterans Administration Computerized Patient Record System (CPRS) to examine total antibiotic use in the three months prior to having specimens submitted for laboratory toxin analysis. A subset-analysis was performed on 100 specimens submitted for toxin analysis. Parallel culture was performed and 9 isolates of C. difficile were obtained for molecular analysis and fingerprinting. Results: Of the 142 patients sampled, 20 tested positive for C. difficile toxin with the remaining 122 patients testing negative. Antibiotic usage was categorized by total antibiotic use and gatifloxacin use. 98 patients received at least 1 antibiotic within the preceding 3 months with 44 patients receiving no antibiotic therapy of any kind. Of the 98 patients that received antibiotic therapy, 44 received gatifloxacin, however, all of these patients also received at least one other antibiotic. Of the nine isolates fingerprinted, two distinct genetic clusters were identified.