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Streptococcus pyogenes is a leading cause of human morbidity and mortality, especially in resource-limited settings. The development of a vaccine against S. pyogenes is a global health priority to reduce the burden of postinfection rheumatic heart disease. To support this, molecular characterization of circulating S. pyogenes isolates is needed. We performed whole-genome analyses of S. pyogenes isolates from skin and soft tissue infections in Sukuta, The Gambia, a low-income country (LIC) in West Africa where there is a high burden of such infections. To act as a comparator to these LIC isolates, skin infection isolates from Sheffield, United Kingdom (a high-income country [HIC]), were also sequenced. The LIC isolates from The Gambia were genetically more diverse (46

Background Group A Streptococcus (GAS) is a major human pathogen and an important cause of maternal and neonatal sepsis. Asymptomatic bacterial colonization is considered a necessary step towards sepsis. Intra-partum azithromycin may reduce GAS carriage. Methods A posthoc analysis of a double-blind, placebo-controlled randomized-trial was performed to determine the impact of 2 g oral dose of intra-partum azithromycin on maternal and neonatal GAS carriage and antibiotic resistance. Following screening, 829 mothers were randomized who delivered 843 babies. GAS was determined by obtaining samples from the maternal and newborn nasopharynx, maternal vaginal tract and breastmilk. Whole Genome Sequencing (WGS) of GAS isolates was performed using the Illumina Miseq platform. Results GAS carriage was lower in the nasopharynx of both mothers and babies and breast milk among participants in the azithromycin arm. No differences in GAS carriage were found between groups in the vaginal tract. The occurrence of azithromycin-resistant GAS was similar in both arms, except for a higher prevalence in the vaginal tract among women in the azithromycin arm. WGS revealed all macrolide-resistant vaginal tract isolates from the azithromycin arm were Streptococcus dysgalactiae subspecies equisimilis expressing Lancefield group A carbohydrate (SDSE(A)) harbouring macrolide resistant genes msr(D) and mef(A). Ten of the 45 GAS isolates (22.2%) were SDSE(A). Conclusions Oral intra-partum azithromycin reduced GAS carriage among Gambian mothers and neonates however carriage in the maternal vaginal tract was not affected by the intervention due to azithromycin resistant SDSE(A). SDSE(A) resistance must be closely monitored to fully assess the public health impact of intrapartum azithromycin on GAS. Trial registration ClinicalTrials.gov Identifier NCT01800942

Objectives To evaluate the impact of one oral dose of intrapartum azithromycin (2 g) on the carriage and antibiotic resistance of Escherichia coli and Klebsiella pneumoniae in the nasopharynx, breast milk and vaginal swabs of mothers and K. pneumoniae in the nasopharynx of their newborns. Methods We performed a post hoc analysis of a double-blind, placebo-controlled randomized-trial (ratio 1:1) conducted in The Gambia. Breast milk (BM) and vaginal swabs (VS) from mothers and nasopharyngeal swabs (NPS) from mother–newborn pairs were collected at different timepoints during the 4 week follow-up. Samples were processed using standard microbiological procedures. For BM and NPS post-intervention results were combined for analysis. Results In the original trial 829 mothers were randomized. In this analysis, complete sample sets were available for 630 mothers for E. coli analysis (76.0%) and 564 mother–newborn pairs for K. pneumoniae analysis (68.0%). For E. coli, carriage prevalence in BM and VS was similar in both arms but resistance was higher in the azithromycin arm in VS (2.6% versus 0%, P = 0.004). For K. pneumoniae, carriage prevalence was higher in the azithromycin arm for BM (13.8% versus 8.7%, P = 0.055) but not for VS or NPS. Prevalence of azithromycin resistant K. pneumoniae was higher in the azithromycin arm for BM (3.6% versus 1.0%, P = 0.050) and VS (1.5% versus 0% P = 0.057). Conclusions Oral intrapartum azithromycin did not reduce carriage of E. coli and K. pneumoniae and was associated with an increase in the prevalence of azithromycin-resistant E. coli and K. pneumoniae isolates in BM and VS.

BackgroundGroup A Streptococcus (GAS) is a major human pathogen and an important cause of maternal and neonatal sepsis.MethodsWe performed a posthoc analysis of a double-blind, placebo-controlled randomized-trial (ratio 1:1) carried out in The Gambia to determine the impact of one oral dose (2g) of intra-partum azithromycin on maternal and neonatal GAS carriage. Breast milk, nasopharyngeal and vaginal swabs were collected at different time points during 4 weeks post-treatment. All samples were processed using conventional microbiology techniques. Whole genome sequencing (WGS) of GAS isolates was performed by Illumina MiSeq platform.ResultsWe randomized 829 mothers who delivered 843 babies. GAS carriage in mothers in the azithromycin arm was lower in breast milk (0.28% vs 2.48%, Prevalence Ratio (PR)=0.11, 95% CI 0.01-0.90) and the nasopharynx (0.28% vs 1.93%, PR=0.15, 95% CI 0.02-1.19), but not in the vaginal tract (1.99% vs 1.93%, PR=1.03, 95% CI 0.37-2.91). Among neonates, GAS carriage in the nasopharynx was slightly lower in the azithromycin arm (0.57% vs 1.91%, PR=0.30, 95% CI 0.06-1.42). Prevalence of azithromycin-resistant GAS was similar in both arms, except for a higher prevalence in the vaginal tract among women in the azithromycin arm (1.99% vs 0.28%, PR=7.24, 95% CI 0.87-56.92). WGS revealed ten of the 45 GAS isolates (22.2%) were Streptococcus dysgalactiae subspecies equisimilis expressing Lancefield group A carbohydrate (SDSE(A)). All SDSE(A) isolates were azithromycin-resistant, harbouring macrolide resistant genes msrD and mefA.ConclusionsOral intra-partum azithromycin reduced prevalence of GAS carriage among mothers and neonates. Azithromycin-resistant SDSE(A) carriage was observed among participants treated with azithromycin.Short SummaryGroup A streptococcus (GAS) is an important cause of sepsis. One oral dose (2g) of intra-partum azithromycin reduced maternal and neonatal GAS carriage. However, azithromycin-resistant Streptococcus dysgalactiae subspecies equisimilis expressing Lancefield group A carbohydrate was detected in women receiving azithromycin.