@article {1381, title = {Prolonged mass azithromycin distributions and macrolide resistance determinants among preschool children in Niger: A sub-study of a cluster-randomized trial (MORDOR).}, journal = {PLoS Med}, volume = {21}, year = {2024}, month = {2024 May}, pages = {e1004386}, abstract = {

BACKGROUND: Randomized controlled trials found that twice-yearly mass azithromycin administration (MDA) reduces childhood mortality, presumably by reducing infection burden. World Health Organization (WHO) issued conditional guidelines for mass azithromycin administration in high-mortality settings in sub-Saharan Africa given concerns for antibiotic resistance. While prolonged twice-yearly MDA has been shown to increase antibiotic resistance in small randomized controlled trials, the objective of this study was to determine if macrolide and non-macrolide resistance in the gut increases with the duration of azithromycin MDA in a larger setting.

METHODS AND FINDINGS: The Macrolide Oraux pour R{\'e}duire les D{\'e}c{\`e}s avec un Oeil sur la R{\'e}sistance (MORDOR) study was conducted in Niger from December 2014 to June 2020. It was a cluster-randomized trial of azithromycin (A) versus placebo (P) aimed at evaluating childhood mortality. This is a sub-study in the MORDOR trial to track changes in antibiotic resistance after prolonged azithromycin MDA. A total of 594 communities were eligible. Children 1 to 59 months in 163 randomly chosen communities were eligible to receive treatment and included in resistance monitoring. Participants, staff, and investigators were masked to treatment allocation. At the conclusion of MORDOR Phase I, by design, all communities received an additional year of twice-yearly azithromycin treatments (Phase II). Thus, at the conclusion of Phase II, the treatment history (1 letter per 6-month period) for the participating communities was either (PP-PP-AA) or (AA-AA-AA). In Phase III, participating communities were then re-randomized to receive either another 3 rounds of azithromycin or placebo, thus resulting in 4 treatment histories: Group 1 (AA-AA-AA-AA-A, N = 51), Group 2 (PP-PP-AA-AA-A, N = 40), Group 3 (AA-AA-AA-PP-P, N = 27), and Group 4 (PP-PP-AA-PP-P, N = 32). Rectal swabs from each child (N = 5,340) were obtained 6 months after the last treatment. Each child contributed 1 rectal swab and these were pooled at the community level, processed for DNA-seq, and analyzed for genetic resistance determinants. The primary prespecified outcome was macrolide resistance determinants in the gut. Secondary outcomes were resistance to beta-lactams and other antibiotic classes. Communities recently randomized to azithromycin (groups 1 and 2) had significantly more macrolide resistance determinants than those recently randomized to placebo (groups 3 and 4) (fold change 2.18, 95\% CI 1.5 to 3.51, Punadj \< 0.001). However, there was no significant increase in macrolide resistance in communities treated 4.5 years (group 1) compared to just the most recent 2.5 years (group 2) (fold change 0.80, 95\% CI 0.50 to 1.00, Padj = 0.010), or between communities that had been treated for 3 years in the past (group 3) versus just 1 year in the past (group 4) (fold change 1.00, 95\% CI 0.78 to 2.35, Padj = 0.52). We also found no significant differences for beta-lactams or other antibiotic classes. The main limitations of our study were the absence of phenotypic characterization of resistance, no complete placebo arm, and no monitoring outside of Niger limiting generalizability.

CONCLUSIONS: In this study, we observed that mass azithromycin distribution for childhood mortality among preschool children in Niger increased macrolide resistance determinants in the gut but that resistance may plateau after 2 to 3 years of treatment. Co-selection to other classes needs to be monitored.

TRIAL REGISTRATION: NCT02047981 https://classic.clinicaltrials.gov/ct2/show/NCT02047981.

}, keywords = {Anti-Bacterial Agents, Azithromycin, Child Mortality, Child, Preschool, Drug Resistance, Bacterial, Female, Humans, Infant, Macrolides, Male, Mass Drug Administration, Niger}, issn = {1549-1676}, doi = {10.1371/journal.pmed.1004386}, author = {Arzika, Ahmed M and Abdou, Amza and Maliki, Ramatou and Beido, Nassirou and Kadri, Boubacar and Harouna, Abdoul N and Galo, Abdoul N and Alio, Mankara K and Lebas, Elodie and Oldenburg, Catherine E and O{\textquoteright}Brien, Kieran S and Chen, Cindi and Zhong, Lina and Zhou, Zhaoxia and Yan, Daisy and Hinterwirth, Armin and Keenan, Jeremy D and Porco, Travis C and Lietman, Thomas M and Doan, Thuy} } @article {71, title = {Macrolide and Nonmacrolide Resistance with Mass Azithromycin Distribution.}, journal = {N Engl J Med}, volume = {383}, year = {2020}, month = {2020 11 12}, pages = {1941-1950}, abstract = {

BACKGROUND: Mass distribution of azithromycin to preschool children twice yearly for 2 years has been shown to reduce childhood mortality in sub-Saharan Africa but at the cost of amplifying macrolide resistance. The effects on the gut resistome, a reservoir of antimicrobial resistance genes in the body, of twice-yearly administration of azithromycin for a longer period are unclear.

METHODS: We investigated the gut resistome of children after they received twice-yearly distributions of azithromycin for 4 years. In the Niger site of the MORDOR trial, we enrolled 30 villages in a concurrent trial in which they were randomly assigned to receive mass distribution of either azithromycin or placebo, offered to all children 1 to 59 months of age every 6 months for 4 years. Rectal swabs were collected at baseline, 36 months, and 48 months for analysis of the participants{\textquoteright} gut resistome. The primary outcome was the ratio of macrolide-resistance determinants in the azithromycin group to those in the placebo group at 48 months.

RESULTS: Over the entire 48-month period, the mean ({\textpm}SD) coverage was 86.6{\textpm}12\% in the villages that received placebo and 83.2{\textpm}16.4\% in the villages that received azithromycin. A total of 3232 samples were collected during the entire trial period; of the samples obtained at the 48-month monitoring visit, 546 samples from 15 villages that received placebo and 504 from 14 villages that received azithromycin were analyzed. Determinants of macrolide resistance were higher in the azithromycin group than in the placebo group: 7.4 times as high (95\% confidence interval [CI], 4.0 to 16.7) at 36 months and 7.5 times as high (95\% CI, 3.8 to 23.1) at 48 months. Continued mass azithromycin distributions also selected for determinants of nonmacrolide resistance, including resistance to beta-lactam antibiotics, an antibiotic class prescribed frequently in this region of Africa.

CONCLUSIONS: Among villages assigned to receive mass distributions of azithromycin or placebo twice yearly for 4 years, antibiotic resistance was more common in the villages that received azithromycin than in those that received placebo. This trial showed that mass azithromycin distributions may propagate antibiotic resistance. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT02047981.).

}, keywords = {Anti-Bacterial Agents, Azithromycin, Child Mortality, Child, Preschool, Drug Resistance, Bacterial, Female, Gastrointestinal Microbiome, Humans, Infant, Macrolides, Male, Mass Drug Administration, Metagenome, Niger, Sequence Analysis, DNA}, issn = {1533-4406}, doi = {10.1056/NEJMoa2002606}, author = {Doan, Thuy and Worden, Lee and Hinterwirth, Armin and Arzika, Ahmed M and Maliki, Ramatou and Abdou, Amza and Zhong, Lina and Chen, Cindi and Cook, Catherine and Lebas, Elodie and O{\textquoteright}Brien, Kieran S and Oldenburg, Catherine E and Chow, Eric D and Porco, Travis C and Lipsitch, Marc and Keenan, Jeremy D and Lietman, Thomas M} }