UCSF

A broad-spectrum antibiotic, typically amoxicillin, is included in many country guidelines as part of the management of uncomplicated severe acute malnutrition (SAM) in children without overt clinical symptoms of infection. Alternative antibiotics may be beneficial for children with SAM without increasing selection for beta-lactam resistance. We conducted a 1:1 randomized controlled trial of single dose azithromycin versus a 7-day course of amoxicillin for SAM. Children 6-59 months of age with uncomplicated SAM (mid-upper arm circumference < 11.5 cm and/or weight-for-height Z-score < -3) were enrolled in Boromo District, Burkina Faso, from June through October 2020. Rectal swabs were collected at baseline and 8 weeks after treatment and processed using DNA-Seq. We compared the resistome at the class level in children randomized to azithromycin compared with amoxicillin. We found no evidence of a difference in the distribution of genetic antibiotic resistance determinants to any antibiotic class 8 weeks after treatment. There was no difference in genetic macrolide resistance determinants (65% azithromycin, 65% placebo, odds ratio, OR, 1.00, 95% confidence interval, CI, 0.43-2.34) or beta-lactam resistance determinants (82% azithromycin, 83% amoxicillin, OR 0.94, 95% CI, 0.33-2.68) at 8 weeks. Although presence of genetic antibiotic resistance determinants to macrolides and beta-lactams was common, we found no evidence of a difference in the gut resistome 8 weeks after treatment. If there are earlier effects of antibiotics on selection for genetic antibiotic resistance determinants, the resistome may normalize by 8 weeks.