Microbiota and SCFA in Lean and Overweight Healthy Subjects

Obesity has recently been linked to the composition of human microbiota and the production of short chain fatty acids (SCFAs). However, these findings rely on experimental studies carried out using rather small and defined groups of volunteers or model animals. Our aim was to evaluate differences within the human intestinal microbiota and fecal SCFA concentration of lean and obese subjects. A total of 98 subjects volunteered to take part in this study. The BMI in kg/m² of 30 volunteers was within the lean range, 35 were overweight and 33 were obese. The fecal microbiota was characterized by real‐time PCR analyses. With the primers used herein we were able to cover 82.3% (interquartile range of 68.3–91.4%) of the total microbiota detectable with a universal primer. In addition, the concentration of SCFA was evaluated. The total amount of SCFA was higher in the obese subject group (P = 0.024) than in the lean subject group. The proportion of individual SCFA changed in favor of propionate in overweight (P = 0.019) and obese subjects (P = 0.028). The most abundant bacterial groups in faeces of lean and obese subjects belonged to the phyla Firmicutes and Bacteroidetes. The ratio of Firmicutes to Bacteroidetes changed in favor of the Bacteroidetes in overweight (P = 0.001) and obese subjects (P = 0.005). Our results are in line with previous reports suggesting that SCFA metabolism might play a considerable role in obesity. However, our results contradict previous reports with regard to the contribution of various bacterial groups to the development of obesity and this issue remains controversial.     

Development of a real‐time PCR method for Firmicutes and Bacteroidetes in faeces and its application to quantify intestinal population of obese and lean pigs

Aims: To investigate whether the relative abundance of the Bacteroidetes and Firmicutes divisions in pigs is different between obese and lean animals. Methods and Results: Group‐specific primers were designed to target the 16S rRNA genes of Bacteroidetes and Firmicutes present in the gut. After the validation of their specificity, these primers were used in the real‐time PCR quantification of all Bacteria, Firmicutes division, Bacteroidetes division and Bacteroides spp. in the faecal samples of obese and lean pigs from Banna mini‐pig inbred line. The obese pigs had a ～61% fewer percentage (based on all Bacteria) of Bacteroidetes division (P = 0·033) and a ～56% fewer proportion of Bacteroides spp. (P = 0·047) than the lean pigs. The proportions of both Bacteroidetes and Bacteroides had a negative correlation (P < 0·01) with the body weight. Conclusion: The results suggested that the fat storage might affect the proportion of Bacteroidetes division in the gut. Significance and Impact of the Study: The real‐time PCR assays developed for Firmicutes and Bacteroidetes will be useful for investigating the composition of gut microbiota.     

The Microbiota of the Gut in Preschool Children With Normal and Excessive Body Weight

The aim of this study was to investigate the gut microbiota in preschool children with and without overweight and obesity. Twenty overweight or obese children and twenty children with BMI within the normal range (age: 4–5 years) were recruited from the south of Sweden. The gut microbiota was accessed by quantitative PCR (qPCR) and terminal restriction fragment length polymorphism and calprotectin was measured in feces. Liver enzymes were quantified in obese/overweight children. The concentration of the gram‐negative family Enterobacteriaceae was significantly higher in the obese/overweight children (P = 0.036), whereas levels of Desulfovibrio and Akkermansia muciniphila‐like bacteria were significantly lower in the obese/overweight children (P = 0.027 and P = 0.030, respectively). No significant differences were found in content of Lactobacillus, Bifidobacterium or the Bacteroides fragilis group. The diversity of the dominating bacterial community tended to be less diverse in the obese/overweight group, but the difference was not statistically significant. Concentration of Bifidobacterium was inversely correlated to alanine aminotransferase (ALT) in obese/overweight children. The fecal levels of calprotectin did not differ between the study groups. These findings indicate that the gut microbiota differed among preschool children with obesity/overweight compared with children with BMI within the normal range.     

不同身体质量指数人群肠道菌群结构及共存网络解析

[背景] 人体能量稳态失衡表现为体重过轻、超重和肥胖,肠道菌群与人体能量稳态的维持有关,但不同身体质量指数（Body Mass Index,BMI）人群的肠道菌群特征仍需进一步探究。[目的] 基于美国肠道计划公开数据库,解析4类BMI人群肠道菌群的特征,并探究4类BMI人群肠道菌群共存网络特征及差异,为基于肠道菌群来干预肥胖及体重过轻等不健康状态提供新的理论依据。[方法] 从美国肠道计划数据集中筛选具有BMI信息的肠道菌群样本,并根据世界卫生组织规定的BMI划分标准将筛选后的样本分为4类：体重过轻（BMI<18.5 kg/m²）,正常体重（18.5 kg/m²2）,超重（25 kg/m²2）,肥胖（BMI>30 kg/m²）;通过计算和比较肠道菌群的α多样性和β多样性探究4类BMI人群肠道菌群的整体结构特征及差异;通过多元线性回归模型对不同BMI分类与肠道菌群进行相关性分析,并且将地域、年龄、性别因素作为混杂因素加入到模型中进行校正;采用SparCC分别计算4类BMI人群肠道菌群中菌属相关性,并分别构建肠道菌群共存网络。[结果] 经过Wilcoxon秩和检验,发现体重过轻、超重、肥胖人群的肠道菌群α多样性都显著低于正常体重人群;β多样性分析结果表明4类BMI人群肠道菌群的整体结构存在显著差异;4类BMI人群肠道中厚壁菌门（Firmicutes）和拟杆菌门（Bacteroidetes）的相对含量无显著差异;通过MaAsLin分析,并且将地域、年龄、性别因素作为混杂因素加入到模型中进行校正,共得到49个与BMI类型显著相关的物种;4类BMI人群肠道菌群共存网络的拓扑结构具有一定差异,体重过轻和正常体重人群肠道菌群共存网络的复杂度较高,超重和肥胖人群肠道菌群共存网络的复杂度较低。[结论] 4类BMI人群肠道菌群的多样性、整体结构和共存网络间均存在差异。     

海拔高度对青藏高原放牧牦牛肠道菌群多样性的影响

[背景]肠道菌群与宿主健康及环境适应性密切相关,牦牛为青藏高原特有的草食性反刍动物,不同海拔高度如何影响牦牛肠道菌群组成及肠道菌群在牦牛适应高海拔生境中的作用尚不清楚.[目的]探究青藏高原放牧牦牛肠道菌群多样性及其与海拔高度间的关系.[方法]采集青海省玛沁县(海拔4220 m)和乐都县(2745 m)2个海拔高度放牧牦...     

Parental obesity moderates the relationship between childhood appetitive traits and weight

Objective:

In this study, the independent and combined associations between childhood appetitive traits and parental obesity on weight gain from 0 to 24 months and body mass index (BMI) z‐score at 24 months in a diverse community‐based sample of dual parent families (n = 213) were examined.

Design and Methods:

Participants were mothers who had recently completed a randomized trial of weight loss for overweight/obese postpartum women. As measures of childhood appetitive traits, mothers completed subscales of the Children's Eating Behavior Questionnaire, including Desire to Drink (DD), Enjoyment of Food (EF), and Satiety Responsiveness (SR), and a 24‐h dietary recall for their child. Heights and weights were measured for all children and mothers and self‐reported for mothers' partners. The relationship between children's appetitive traits and parental obesity on toddler weight gain and BMI z‐score were evaluated using multivariate linear regression models, controlling for a number of potential confounders.

Results:

Having two obese parents was related to greater weight gain from birth to 24 months independent of childhood appetitive traits, and although significant associations were found between appetitive traits (DD and SR) and child BMI z‐score at 24 months, these associations were observed only among children who had two obese parents. When both parents were obese, increasing DD and decreasing SR were associated with a higher BMI z‐score.

Conclusions:

The results highlight the importance of considering familial risk factors when examining the relationship between childhood appetitive traits on childhood obesity.     

The influence of diet and environment on the gut microbial community of field crickets

The extent to which diet and environment influence gut community membership (presence or absence of taxa) and structure (individual taxon abundance) is the subject of growing interest in microbiome research. Here, we examined the gut bacterial communities of three cricket groups: (1) wild caught field crickets, (2) laboratory‐reared crickets fed cat chow, and (3) laboratory‐reared crickets fed chemically defined diets. We found that both environment and diet greatly altered the structure of the gut bacterial community. Wild crickets had greater gut microbial diversity and higher Firmicutes to Bacteroidetes ratios, in contrast to laboratory‐reared crickets. Predictive metagenomes revealed that laboratory‐reared crickets were significantly enriched in amino acid degradation pathways, while wild crickets had a higher relative abundance of peptidases that would aid in amino acid release. Although wild and laboratory animals differ greatly in their bacterial communities, we show that the community proportional membership remains stable from Phylum to Family taxonomic levels regardless of differences in environment and diet, suggesting that endogenous factors, such as host genetics, have greater control in shaping gut community membership.     

Childhood Obesity Prevention: An Intervention Targeting Primary Caregivers of School Children

Community‐based participatory research (CBPR) was used to design and evaluate the effectiveness of a culturally relevant, science‐based intervention for the prevention of childhood obesity in the Commonwealth of the Northern Mariana Islands (CNMI), a US Commonwealth in the western Pacific. This cognitive behavioral lifestyle intervention, Project Familia Giya Marianas (PFGM), was offered during the 2005–2007 school years in all CNMI public elementary schools over eight sessions to primary caregivers of 3rd grade children (N = 407). A crossover design was utilized with half of the schools offering the intervention in the Fall term, while the other half delivered the sessions in the Spring term. The primary outcome measure was change in BMI z‐score. There was an intervention‐dependent effect on BMI z‐score, with program impact being a function of baseline BMI and the number of lessons attended. This effect was most apparent in students whose baseline BMI z‐score was in healthy range (≥5 to <85 percentile). In both Asian and Pacific Island groups, children whose caregivers completed 5–8 lessons experienced a significant change in BMI z‐score as compared to those with 0 lessons (P < 0.05). Research that integrates multidisciplinary and multimethod approaches is effective in identifying and/or devising solutions to address a complex condition such as childhood obesity. PFGM demonstrated that community participation can be successfully utilized in the development and implementation of childhood obesity prevention programs.     

Metagenomic assessment of the Cebus apella gut microbiota

Cebus Apella (C. apella) is a species of Nonhuman Primate (NHP) used for biomedical research because it is phylogenetically similar and shares anatomical commonalities with humans. Here, the gut microbiota of three C. apella were examined in the different regions of the intestinal tract. Using metagenomics, the gut microbiota associated with the luminal content and mucus layer for each intestinal region was identified, and functionality was investigated by quantifying the levels of short chain fatty acids (SCFAs) produced. The results of this study show a high degree of similarity in the intestinal communities among C. apella subjects, with multiple shared characteristics. First, the communities in the lumen were more phylogenetically diverse and rich compared to the mucus layer communities throughout the entire intestinal tract. The small intestine communities in the lumen displayed a higher Shannon diversity index compared to the colon communities. Second, all the communities were dominated by aero‐tolerant taxa such as Streptococcus, Enterococcus, Abiotrophia, and Lactobacillus, although there was preferential colonization of specific taxa observed. Finally, the primary SCFA produced throughout the intestinal tract was acetic acid, with some propionic acid and butyric acid detected in the colon regions. The small intestine microbiota produced significantly less SCFAs compared to the communities in the colon. Collectively, these data provide an in‐depth report on the composition, distribution, and SCFA production of the gut microbiota along the intestinal tract of the C. apella NHP animal model.     

Adiposity in Childhood Is Related to C‐Reactive Protein and Adiponectin in Young Adulthood: From the Bogalusa Heart Study

To determine the association between cardiovascular (CV) risk factors in childhood and high‐sensitivity C‐reactive protein (hsCRP) and adiponectin in adulthood, 835 eligible white and African‐American young adult subjects (age range 24–42 years, average 34 years, 43% men, 31% African Americans) who had CV risk‐factor variable data from their childhood (20 years earlier, age range 5–18 years, average 14 years) were selected. Stepwise linear regression models revealed that mean logarithmic hsCRP level in adulthood was 0.02 greater with every increase of 1 mm in skinfold thickness in childhood, 0.25 greater for African Americans than whites, 0.36 greater for girls than boys, and 0.15 greater for every unit increase in BMI z score. Mean logarithmic adiponectin level in adulthood was 0.36 greater for girls than boys, 0.22 greater for whites than African Americans, and 0.01 less with every increase of 1 mm of childhood skinfold thickness. Seventy participants (8%) were overweight or obese in their childhood, and 64 of these (91%) remained obese in their young adulthood. In conclusion, childhood adiposity and African‐American race were associated with higher hsCRP and lower adiponectin levels in their adulthood. Skinfold thickness and BMI z score in childhood were the main obesity determinants for higher hsCRP and lower adiponectin levels in young adulthood.     

Diet and phylogeny shape the gut microbiota of Antarctic seals: a comparison of wild and captive animals

The gut microbiota of mammals underpins the metabolic capacity and health of the host. Our understanding of what influences the composition of this community has been limited primarily to evidence from captive and terrestrial mammals. Therefore, the gut microbiota of southern elephant seals, Mirounga leonina, and leopard seals, Hydrurga leptonyx, inhabiting Antarctica were compared with captive leopard seals. Each seal exhibited a gut microbiota dominated by four phyla: Firmicutes (41.5 ± 4.0%), Fusobacteria (25.6 ± 3.9%), Proteobacteria (17.0 ± 3.2%) and Bacteroidetes (14.1 ± 1.7%). Species, age, sex and captivity were strong drivers of the composition of the gut microbiota, which can be attributed to differences in diet, gut length and physiology and social interactions. Differences in particular prey items consumed by seal species could contribute to the observed differences in the gut microbiota. The longer gut of the southern elephant seal provides a habitat reduced in available oxygen and more suitable to members of the phyla Bacteroidetes compared with other hosts. Among wild seals, 16 ‘core’ bacterial community members were present in the gut of at least 50% of individuals. As identified between southern elephant seal mother–pup pairs, ‘core’ members are passed on via vertical transmission from a young age and persist through to adulthood. Our study suggests that these hosts have co‐evolved with their gut microbiota and core members may provide some benefit to the host, such as developing the immune system. Further evidence of their strong evolutionary history is provided with the presence of 18 shared ‘core’ members in the gut microbiota of related seals living in the Arctic. The influence of diet and other factors, particularly in captivity, influences the composition of the community considerably. This study suggests that the gut microbiota has co‐evolved with wild mammals as is evident in the shared presence of ‘core’ members.     

Additive Interactions of Maternal Prepregnancy BMI and Breast‐feeding on Childhood Overweight

Objective: To examine the interactions of maternal prepregnancy BMI and breast‐feeding on the risk of overweight among children 2 to 14 years of age. Research Methods and Procedures: The 1996 National Longitudinal Survey of Youth, Child and Young Adult data in the United States were analyzed (n = 2636). The weighted sample represented 51.3% boys, 78.0% whites, 15.0% blacks, and 7.0% Hispanics. Childhood overweight was defined as BMI ≥95th percentile for age and sex. Maternal prepregnancy obesity was determined as BMI ≥30 kg/m². The duration of breast‐feeding was measured as the weeks of age from birth when breast‐feeding ended. Results: After adjusting for potential confounders, children whose mothers were obese before pregnancy were at a greater risk of becoming overweight [adjusted odds ratio (OR), 4.1; 95% confidence interval (CI), 2.6, 6.4] than children whose mothers had normal BMI (<25 kg/m²; p < 0.001 for linear trend). Breast‐feeding for ≥4 months was associated with a lower risk of childhood overweight (OR, 0.6; 95% CI, 0.4, 1.0; p = 0.06 for linear trend). The additive interaction between maternal prepregnancy obesity and lack of breast‐feeding was detected (p < 0.05), such that children whose mothers were obese and who were never breast‐fed had the greatest risk of becoming overweight (OR, 6.1; 95% CI, 2.9, 13.1). Discussion: The combination of maternal prepregnancy obesity and lack of breast‐feeding may be associated with a greater risk of childhood overweight. Special attention may be needed for children with obese mothers and lack of breast‐feeding in developing childhood obesity intervention programs.     

Gender specific effect of LIPC C‐514T polymorphism on obesity and relationship with plasma lipid levels in Chinese children

Hepatic lipase (LIPC) is a key rate‐limiting enzyme in lipoprotein catabolism pathways involved in the development of obesity. The C‐514T polymorphism in the promoter region is associated with decreased LIPC activity. We performed a case‐controlled study (850 obese children and 2119 controls) and evaluated the association between LIPC C‐514T polymorphism, obesity and plasma lipid profile in Chinese children and adolescents. Additionally, we conducted a meta‐analysis of all results from published studies as well as our own data. A significant association between the polymorphism and obesity is observed in boys (P = 0.042), but not in girls. And we observed a significant relationship of the polymorphism with total cholesterol (TC) and high density lipoprotein cholesterol (HDL‐C) independent of obesity in boys. The T allele carriers have higher levels of low density lipoprotein cholesterol (LDL‐C) in obese boys, and triglyceride (TG), TC and LDL‐C in non‐obese girls (all P < 0.05). In the meta‐analysis, under dominant model the T allele increased body mass index (BMI) level in boys, while it decreased BMI in girls, and increased the levels of TC both in the overall and subgroups, TG and HDL‐C in the overall and boys, and LDL‐C in the overall (all P < 0.05). Our results suggest that the T allele might carry an increased risk of obesity in Chinese boys. The meta‐analysis suggests that T allele acts as a risk allele for higher BMI levels in male childhood, while it is a protective allele in female childhood. And the polymorphism is associated with the levels of plasma lipids, which may be modulated by obesity and gender.     

Racial Differences in the Tracking of Childhood BMI to Adulthood

Objective: The possibility that there are racial differences in the patterns of BMI (kilograms per meter squared) change throughout life has not been examined. For example, the high prevalence of obesity among black women could result from a higher prevalence of obesity among black girls or because normal‐weight black girls experience larger BMI increases in adolescence or adulthood than do their white counterparts. Therefore, we examined the tracking of childhood BMI into adulthood in a biracial (36% black) sample. Research Methods and Procedures: Five‐ to 14‐year‐old children (2392) were followed for (mean) 17 years. Childhood overweight was defined as BMI ≥ 95th percentile, and adult obesity was defined as BMI ≥ 30 kg/m². Results: The tracking of childhood BMI differed between whites and blacks. Among overweight children, 65% of white girls vs. 84% of black girls became obese adults, and predictive values among boys were 71% (whites) vs. 82% (blacks). These racial differences reflected contrasting patterns in the rate of BMI change. Although the initial BMI of black children was not higher than that of white children, BMI increases with age were larger among black girls and overweight black boys than among their white counterparts. In contrast, relatively thin (BMI < 50th percentile) white boys were more likely to become overweight adults than were their black counterparts. Discussion: These findings emphasize the black/white differences in BMI changes with age. Because of the adult health consequences of childhood‐onset obesity, early prevention should be given additional emphasis.     

Utility of Childhood BMI in the Prediction of Adulthood Disease: Comparison of National and International References

Objective: To determine whether the U.S. Centers for Disease Control and Prevention (CDC; CDC Reference) or International Obesity Task Force (IOTF; IOTF Reference) BMI cut‐off points for classifying adiposity status in children are more effective at predicting future health risk. Research Methods and Procedures: The sample (N = 1709) included 4‐ to 15‐year‐old (at baseline) boys and girls from the Bogalusa Heart Study. Overweight and obesity status were determined using both the CDC Reference and IOTF Reference BMI cut‐off points at baseline. The ability of childhood overweight and obesity, determined from the two BMI classification systems, to predict obesity and metabolic disorders in young adulthood (after a 13‐ to 24‐year follow‐up) was then compared. Results: Independently of the classification system employed to determine adiposity based on childhood BMI, the odds of being obese and having all of the metabolic disorders in young adulthood were significantly (p < 0.05) higher in the overweight and obese groups by comparison with the nonoverweight groups. Childhood overweight and obesity, determined by both the CDC Reference and IOTF Reference, had a low sensitivity and a high specificity for predicting obesity and metabolic disorders in young adulthood. Overweight and obesity as determined by the CDC Reference were slightly more sensitive and slightly less specific than the corresponding values based on the IOTF Reference. Discussion: Overweight and obesity during childhood, as determined by both the CDC and IOTF BMI cut‐off points, are strong predictors of obesity and coronary heart disease risk factors in young adulthood. The differences in the predictive capacity of the CDC Reference and IOTF Reference are, however, minimal.     

Analysis of the gut microbiota in the old order amish and its relation to the metabolic syndrome

Obesity has been linked to the human gut microbiota; however, the contribution of gut bacterial species to the obese phenotype remains controversial because of conflicting results from studies in different populations. To explore the possible dysbiosis of gut microbiota in obesity and its metabolic complications, we studied men and women over a range of body mass indices from the Old Order Amish sect, a culturally homogeneous Caucasian population of Central European ancestry. We characterized the gut microbiota in 310 subjects by deep pyrosequencing of bar-coded PCR amplicons from the V1-V3 region of the 16S rRNA gene. Three communities of interacting bacteria were identified in the gut microbiota, analogous to previously identified gut enterotypes. Neither BMI nor any metabolic syndrome trait was associated with a particular gut community. Network analysis identified twenty-two bacterial species and four OTUs that were either positively or inversely correlated with metabolic syndrome traits, suggesting that certain members of the gut microbiota may play a role in these metabolic derangements.     

A community intervention reduces BMI z-score in children: Shape Up Somerville first year results

Objective: The objective was to test the hypothesis that a community‐based environmental change intervention could prevent weight gain in young children (7.6 ± 1.0 years). Research Methods and Procedures: A non‐randomized controlled trial was conducted in three culturally diverse urban cities in Massachusetts. Somerville was the intervention community; two socio‐demographically‐matched cities were control communities. Children (n = 1178) in grades 1 to 3 attending public elementary schools participated in an intervention designed to bring the energy equation into balance by increasing physical activity options and availability of healthful foods within the before‐, during‐, after‐school, home, and community environments. Many groups and individuals within the community (including children, parents, teachers, school food service providers, city departments, policy makers, healthcare providers, before‐ and after‐school programs, restaurants, and the media) were engaged in the intervention. The main outcome measure was change in BMI z‐score. Results: At baseline, 44% (n = 385), 36% (n = 561), and 43% (n = 232) of children were above the 85th percentile for BMI z‐score in the intervention and the two control communities, respectively. In the intervention community, BMI z‐score decreased by ?0.1005 (p = 0.001, 95% confidence interval, ?0.1151 to ?0.0859) compared with children in the control communities after controlling for baseline covariates. Discussion: A community‐based environmental change intervention decreased BMI z‐score in children at high risk for obesity. These results are significant given the obesigenic environmental backdrop against which the intervention occurred. This model demonstrates promise for communities throughout the country confronted with escalating childhood obesity rates.     

Long‐term monitoring of the human intestinal microbiota composition

The microbiota that colonizes the human intestinal tract is complex and its structure is specific for each of us. In this study we expand the knowledge about the stability of the subject‐specific microbiota and show that this ecosystem is stable in short‐term intervals (< 1 year) but also during long periods of time (> 10 years). The faecal microbiota composition of five unrelated and healthy subjects was analysed using a comprehensive and highly reproducible phylogenetic microarray, the HITChip. The results show that the use of antibiotics, application of specific dietary regimes and distant travelling have limited impact on the microbiota composition. Several anaerobic genera, including Bifidobacterium and a number of genera within the Bacteroidetes and the Firmicutes phylum, exhibit significantly higher similarity than the total microbiota. Although the gut microbiota contains subject‐specific species, the presence of which is preserved throughout the years, their relative abundance changes considerably. Consequently, the recently proposed enterotype status appears to be a varying characteristic of the microbiota. Our data show that the intestinal microbiota contains a core community of permanent colonizers, and that environmentally introduced changes of the microbiota throughout adulthood are primarily affecting the abundance but not the presence of specific microbial species.     

Monitoring Bacterial Community of Human Gut Microbiota Reveals an Increase in Lactobacillus in Obese Patients and Methanogens in Anorexic Patients

Background

Studies of the bacterial communities of the gut microbiota have revealed a shift in the ratio of Firmicutes and Bacteroidetes in obese patients. Determining the variations of microbial communities in feces may be beneficial for the identification of specific profiles in patients with abnormal weights. The roles of the archaeon Methanobrevibacter smithii and Lactobacillus species have not been described in these studies.

Methods and Findings

We developed an efficient and robust real-time PCR tool that includes a plasmid-based internal control and allows for quantification of the bacterial divisions Bacteroidetes, Firmicutes, and Lactobacillus as well as the methanogen M. smithii. We applied this technique to the feces of 20 obese subjects, 9 patients with anorexia nervosa, and 20 normal-weight healthy controls. Our results confirmed a reduction in the Bacteroidetes community in obese patients (p<0.01). We found a significantly higher Lactobacillus species concentration in obese patients than in lean controls (p = 0.0197) or anorexic patients (p = 0.0332). The M. smithii concentration was much higher in anorexic patients than in the lean population (p = 0.0171).

Conclusions

Lactobacillus species are widely used as growth promoters in the farm industry and are now linked to obesity in humans. The study of the bacterial flora in anorexic patients revealed an increase in M. smithii. This increase might represent an adaptive use of nutrients in this population.     

Molecular analysis of gut microbiota in obesity among Indian individuals

Obesity is a consequence of a complex interplay between the host genome and the prevalent obesogenic factors among the modern communities. The role of gut microbiota in the pathogenesis of the disorder was recently discovered; however, 16S-rRNA-based surveys revealed compelling but community-specific data. Considering this, despite unique diets, dietary habits and an uprising trend in obesity, the Indian counterparts are poorly studied. Here, we report a comparative analysis and quantification of dominant gut microbiota of lean, normal, obese and surgically treated obese individuals of Indian origin. Representative gut microbial diversity was assessed by sequencing fecal 16S rRNA libraries for each group (n=5) with a total of over 3000 sequences. We detected no evident trend in the distribution of the predominant bacterial phyla, Bacteroidetes and Firmicutes. At the genus level, the bacteria of genus Bacteroides were prominent among the obese individuals, which was further confirmed by qPCR (P less than 0.05). In addition, a remarkably high archaeal density with elevated fecal SCFA levels was also noted in the obese group. On the contrary, the treated-obese individuals exhibited comparatively reduced Bacteroides and archaeal counts along with reduced fecal SCFAs. In conclusion, the study successfully identified a representative microbial diversity in the Indian subjects and demonstrated the prominence of certain bacterial groups in obese individuals; nevertheless, further studies are essential to understand their role in obesity.