Changes in the gastrointestinal microbiota of children with acute lymphoblastic leukaemia and its association with antibiotics in the short term.

Purpose. To detect the alteration of gut bacteria in children with ALL and analyse the impact of short-term-use of antibiotics on the changes caused by ALL.Methodology. We collected faecal samples from both children with ALL and healthy children. According to their medication history with antibiotics, we classified the samples into ALL+ATBx, ALL, CON+ATBx and CON groups. Next-generation sequencing was performed to identify the gut bacteria according to the MiSeq platform. The Shannon index, Simpson index, Chao index and Ace index were used to represent the alpha diversity of gut bacteria. The beta diversity was estimated using the principles of co-ordinate analysis and non-metric multi-dimensional scaling. The taxon composition and presence of biomarkers were then determined through bioinformatics.Results. With regard to alpha diversity, the Shannon index and Simpson index differed significantly between the ALL and CON groups, as well as the CON+ATBx and CON groups, but not the ALL+ATBx and CON+ATBx groups. With regard to beta diversity, the ALL and CON separated clearly into clusters, as did ALL+ATBx and CON+ATBx. There were differences in composition among the four groups at different taxonomy hierarchies. More bacteria showed an obvious difference between the paired groups ALL and CON than did for the paired groups ALL+ATBx and CON+ATBx. The area under the receiver operating characteristic curves for Bacteroidales and Enterococcaceae used to predict ALL were 0.735 and 0.724, respectively.Conclusion. ALL induced structural changes of the gut microbiota, with the alpha diversity being significantly weakened by antibiotics, but not beta diversity. Bacteroidales and Enterococcaceae can be referred to as biomarkers for ALL.