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Objectives We examined the changes in the developing gut microbiota of Indian infants enrolled in a colonization study of an oral synbiotic (L. plantarum and fructo-oligosaccharides) preparation. Methods Frozen stool samples were available from a previously published clinical study of the synbiotic preparation administered daily for seven days to full term Indian infants delivered by C-section. 16S rRNA gene sequencing of fecal bacterial community-DNA was done in 11 infants sampled at Day-7 and Day-60 of life. Results All infants showed changes in bacterial diversity with age. While Firmicutes and Proteobacteria were predominant in all, Actinobacteria and Bacteroidetes were initially low at day-7. In control infants, we observed a significant increase (p=0.012) in the proportions of Actinobacteria at day-60. In the treated group, over the 60-day period, there was a 10-fold increase in Bacteroidetes, a somewhat smaller increase in Firmicutes, and a reduction in Proteobacteria. Compared to controls, treated infants were increasingly colonized by different Gram positive genera including Enterococcus, Lactobacillus and Bifidobacteria. Relatively less known taxa and some unassigned sequence reads added to enriched diversity observed in the treated group. Conclusions There was a high level of bacterial diversity among infants examined in this study. Synbiotic treatment induced an increase in overall taxa and Gram positive diversity, especially in the first week of life. Changes in the microbiota during early infancy should be used as a rationale for selecting probiotics in diverse clinical settings.

Lung cancer is the leading cause of cancer death. Better 24 understanding of factors and pathways involved in lung cancer is needed to improve 25 diagnose and treatment strategies. Recent studies have provided insights into the 26 possible correlation between intestinal dysbiosis and cancer development. Although 27 the immunological relationship between gut and lung had been suggested by many 28 researches, however, to date, no study had investigated the characterization of gut 29 microbiome in treatment naïve lung cancer patients, whether it is distinct from that of 30 health individuals and contribute to the onset and development of lung cancer remain 31 unclear. In this study, we investigated whether gut microbiome of lung cancer patients 32 (LC, n=28) is altered compare with that of matched healthy individuals (HC, n=19) by 33 high throughout sequencing of the V3-V4 regions of 16S rDNA in their fecal samples. 34 We also identified microbiota signatures specific for different histological types of 35 lung cancer, including SSC, ADC, and SCLC. The gut microbiome of lung cancer 36 patients is characterized by decreased relative abundance of Prevotella, and increased 37 bacteria groups such as Actinomyces, and Streptococcus, etc. We also detected a mild 38 structural shift in gut microbiome between ADC and SCLC patients. Our results 39 showed that the gut microbiome of lung cancer patients altered significantly 40 compared with healthy individuals. However, the association between microbial 41 dysbiosis and lung cancer is not clearly understood, future studies involving larger 42 cohorts and metagenomics, or metabolomics, may elucidate the correlations between 43 gut microbiota and lung cancer development. 44 IMPORTANCE This is the first report to show the alteration of gut microbiome in 45 4 lung cancer patients. Our results showed that the gut microbiome of lung cancer 46 patients altered significantly compared with healthy individuals. 47 48

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