Single dose of gentamicin in combination with metronidazole versus multiple doses for prevention of post-caesarean infection at Bugando Medical Centre in Mwanza, Tanzania: a randomized, equivalence, controlled trial

BACKGROUND: Caesarean section(C/S) has been found to increase rates of maternal infectious morbidities five times more than vaginal delivery. The provision of intravenous prophylactic antibiotics 30 to 60 minutes prior to C/S has been found to substantially reduce post-caesarean infection. At Bugando Medical Centre, there is no consistent protocol for the administration of antibiotic prophylaxis to patients who are undergoing emergency C/S. Providing repeated dosages of antibiotic prophylaxis after C/S is the common practice. This study aimed to determine the comparative efficacy of a single dose of gentamicin in combination with metronidazole versus multiple doses for prevention of post-caesarean infection. METHODS: From October 2011 to May 2012, a randomized, equivalence, non-blinding clinical trial was conducted at Bugando Medical Centre in Mwanza, Tanzania. A total of 500 eligible participants were enrolled in the study and were randomly allocated into two study arms -- “A” and “B”. Participants in “A” received a single dose of gentamicin in combination with metronidazole 30 to 60 minutes prior to the operation, and participants in “B” received the same drugs prior to the operation but continued with for 24 hours. Both groups had 30 days of follow-up and were assessed for signs and symptoms of surgical-site infection as the primary outcome. The equivalence margin was set at 5%. The two-tailed equivalence was analyzed based on intention- to-treat analysis. RESULTS: The randomization was proper, as the distribution of various demographic and other baseline characteristics had a p-value of > 0.05. All 500 participants were included in our analysis; of these, no participants were lost to follow-up. Surgical-site infection occurred in 12 out of the 250 (4.8%) receiving single dose compared to 16 out of the 250 (6.4%) receiving multiple doses. There is an absolute proportion difference of 1.6% (95% Confidence interval: -2.4 – 5.6%) which lies outside the pre-specified 5% equivalence margin. CONCLUSION: We recommend the administration of pre-operative single dose antibiotic prophylaxis for emergency caesarean as this intervention proved to be not equivalent to multiple doses antibiotic prophylaxis in reducing surgical site infection. Single dose therapy also reduces staff workload along with medication costs. TRIAL REGISTRATION: Current Controlled Trials ISRCTN44462542