| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1510-1 | ||||
Resumo:The gut microbiota composition is dynamic and exerts a major influence on host immune response regulation. Changes in gut microbiota of children with acute lymphoblastic leukemia (ALL) have been described intensively not only due to the alterations induced by leukemia itself, but also to antibiotics and chemotherapy drugs administration. During chemotherapy, the minimal residual disease (MRD) assessment is used to determine the response to the ongoing treatment by checking the presence of leukemia cells within the bone marrow (BM). To endorse the benefits of gut microbiota characterization as a novel biomarker of prognosis in ALL patients and considering that many factors can impair the balance of the gut microbiota homeostasis during ALL treatment, the objective of this study was to highlight the differences in the gut microbiota of ALL children that presented distinct response to therapy according to the MRD result. We evaluated the gut microbiota composition of 12 children newly diagnosed with ALL by analyzing fecal samples collected at diagnosis. The samples were submitted to DNA extraction using a commercial kit and DNA libraries were prepared. Amplicons of the bacterial 16S rRNA gene were analyzed by high-throughput sequencing to determine the diversity and composition of the microbiota. We used Qiime2 for bioinformatics analysis and good-quality reads were grouped into amplicon sequence variants (ASVs) using the DADA2 algorithm. Bacterial taxonomic classification was done using USEARCH pipeline and SILVA database release 138. Statistical analysis was performed with STAMP 2.1.3. Clinical and epidemiological data were obtained from the institutional medical records. All patients were diagnosed with B-ALL, with age varying from 1 to 11 years (mean of 4.75 years) and categorized in two groups: negative MRD (no blasts in BM) and positive MRD (% Blasts > 0.01), paired by age. Patients with negative MRD presented a slightly more diverse microbiota when compared to those with positive MRD. Although beta diversity in both groups was similar, genera Coprobacillus was statistically more abundant in the positive MRD group (p-value 0.037). This Gram-positive anaerobic coccus is commonly found in the gut of elderly subjects and has also been related to gut microbiota frailty. Many studies have shown that having a diverse and rich microbiota is an important biomarker for gut health however, intestinal dysbiosis is related to a wide range of diseases. Our results suggest that a healthier microbiota is associated with negative MRD, while those who presented Coprobacillus were from the positive MRD group, suggesting that it could be considered as a prognostic marker, although more extensive and robust studies are needed to confirm these findings. Palavras-chave: Microbiome, Coprobacillus, Minimal residual disease, Acute lymphoblastic leukemia, 16S Agência de fomento:Programa Nacional de Apoio à Atenção Oncológica (PRONON) | |||||