Introduction: Meropenem and piperacillin-tazobactam have similar indications, spectrum of antimicrobial actions, and cost. When selecting between two antibiotics with similar efficacy, one may want the antibiotic with the least harm, such as C. difficile associated diarrhea (CDAD).
Aim & Objectives: This study tested the hypothesis that patients on piperacillintazobactam had a lower incidence of CDAD than patients on meropenem.
Methods: A retrospective analysis was performed that included patients who received meropenem or piperacillin-tazobactam during their admissions to Ridge Meadows Hospital, Canada from September 2007 to August 2009. This study had a subgroup analysis on patients with risk factors of developing CDAD: male, over 65 years old, staying longer than 28 days in healthcare settings, receiving concurrent risk factor medications, not on Saccharomyces boulardii in the previous two months, and not on oral metronidazole, intravenous metronidazole, or oral vancomycin in the previous two months.
Results: There were 168 patients in the meropenem group and 122 patients in the piperacillin-tazobactam group. No significant difference was found between meropenem and piperacillin-tazobactam with respect to incidence of CDAD (3.57% and 4.92%, respectively; p=0.5676), two-month in-hospital mortality (34.52% and 36.89%, respectively; p=0.7102), and composite outcome of CDAD and two-month in-hospital mortality (37.50% and 40.16%, respectively; p=0.7142). All subgroup analyses showed no difference in incidence of CDAD between the two antibiotics.
Conclusions: There was no evidence to support patients on piperacillin-tazobactam had a lower incidence of CDAD or mortality than patients on meropenem. Further research is still needed to help selecting the safest antibiotic for patients.