Morello, WilliamD'Amico, FedericaSerafinelli, JessicaTurroni, SilviaAbati, IsabellaFiori, JessicaBaskin, EsraYalcinkaya, FatosJankauskiene, AugustinaPennesi, MarcoZurowska, AleksandraBecherucci, FrancescaDrozdz, DorotaMekahli, DjalilaKrzemien, GrazynaLa Scola, ClaudioTaranta Janusz, KatarzynaMehls, OttoSchaefer, FranzCandela, MarcoMontini, Giovanni2022-09-062022-09-0620212296-2360https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8247656/pdf/fped-09-674716.pdfhttp://hdl.handle.net/11727/7534Background and Objectives: Maturation of the gut microbiota (GM) in infants is critically affected by environmental factors, with potential long-lasting clinical consequences. Continuous low-dose antibiotic prophylaxis (CAP) is the standard of care for children with vesicoureteral reflux (VUR), in order to prevent recurrent urinary tract infections. We aimed to assess short-term GM modifications induced by CAP in infants. Methods: We analyzed the GM structure in 87 infants (aged 1-5 months) with high-grade VUR, previously exposed or naive to CAP. Microbial DNA was extracted from stool samples. GM profiling was achieved by 16S rRNA gene-based next-generation sequencing. Fecal levels of short- and branched-chain fatty acids were also assessed. Results: 36/87 patients had been taking daily CAP for a median time of 47 days, while 51/87 had not. In all patients, the GM was predominantly composed by Bifidobacteriaceae and Enterobacteriaceae. Subgroup comparative analysis revealed alterations in the GM composition of CAP-exposed infants at phylum, family and genus level. CAP-exposed GM was enriched in members of Enterobacteriaceae and Bacteroidetes, especially in the genera Bacteroides and Parabacteroides, and showed a trend toward increased Klebsiella, often associated with antibiotic resistance. In contrast, the GM of non-CAP children was mostly enriched in Bifidobacterium. No differences were found in fatty acid levels. Conclusions: In infants with VUR, even a short exposure to CAP definitely alters the GM composition, with increased relative abundance of opportunistic pathogens and decreased proportions of health-promoting taxa. Early low-dose antibiotic exposure might bear potential long-term clinical risks.enginfo:eu-repo/semantics/openAccessgut microbiotaantibiotic prophylaxisvesicoureteral refluxurinary tract infectionchildrenarticle9190006686220000012-s2.0-85109039921