Skin preparation type and post-cesarean infection with use of adjunctive azithromycin prophylaxis

To compare the frequency of postoperative surgical site infection (SSI) by type of skin preparation used for unscheduled cesarean in the setting of adjunctive azithromycin prophylaxis.

Secondary analysis of a multi-center randomized controlled trial of adjunctive azithromycin (500 mg intravenous) versus placebo in women who were ≥24 weeks gestation and undergoing unscheduled cesarean (i.e. during labor or ≥4 h after membrane rupture). Type of skin preparation used was identified based on the protocol at the hospital at the time of delivery: iodine-alcohol, chlorhexidine, chlorhexidine-alcohol, or the combination of chlorhexidine-alcohol and iodine. The primary outcome of this analysis was incidence of post-operative SSI, as defined by CDC criteria. Multivariable logistic regression was applied for adjustments.

All 2013 women in the primary trial were included in this analysis. Women were grouped according to type of skin preparation received: iodine-alcohol (n = 193), chlorhexidine (n = 733), chlorhexidine-alcohol (n = 656), and chlorhexidine-alcohol and iodine combined sequentially (n = 431). The unadjusted rates of wound infection ranged from 2.9% to 5.7%. Using iodine-alcohol as the referent, the adjusted odds ratios for wound SSI were 0.71 (95% CI 0.30-1.66) for chlorhexidine, 0.97 (95% CI 0.41-2.28) for chlorhexidine-alcohol, and 0.88 (95% CI 0.36-2.20) for chlorhexidine-alcohol with iodine combination.

In women undergoing unscheduled cesarean delivery in a trial of adjunctive azithromycin, the type of skin preparation used did not appear to be associated with the frequency of wound SSI.