- Ph.D., National Institute of Cholera & Enteric Diseases, Kolkata
- M.Sc. Microbiology, University of Calcutta
- B.Sc. Microbiology, University of Calcutta
- March 2015 – till date, Scientist C-I (G. N. Ramachandran Fellow), Rajiv Gandhi Centre for Biotechnology, Trivandrum
- September 2012 – 2015 February, Post-Doctoral Fellow, Translational Health Science and Technology Institute, Faridabad
- G. N. Ramachandran Fellowship, Rajiv Gandhi Centre for Biotechnology, Trivandrum, 2015
- Postdoctoral Fellowship (Microbiome Innovation Awardee) of the Centre for Human Microbial Ecology at Translational Health Science and Technology Institute, Faridabad, 2013
- Postdoctoral Fellowship (Innovation Awardee) of the Centre for Bio-design & Diagnostics at Translational Health Science and Technology Institute, Faridabad, 2012
- American Society for Microbiology (ASM) International Fellowship award for Asia Program, 2010
- Life member, Indian Science Congress Association (ISCA)
Role of gut microbiome in malnutrition
The blindingly obvious might not always be the truth. Malnutrition is traditionally believed to be caused by a lack of food and essential nutrients. However treating malnourished children with standardized food regimes does not ensure recovery and prevent relapse into going back to a malnourished state after completion of treatment. Increasing evidence based on studies of the human gut microbiome suggests that a 'potentially bad' assortment of microbes in the human gut can conspire with a nutrient poor diet to promote and perpetuate the variety of forms of malnutrition.
Children are the most visible victims of undernutrition. Undernutrition encompassing stunting, wasting, fetal growth restriction, and deficiencies of micronutrients (vitamin A and zinc) along with suboptimum breastfeeding is attributable to 3.1 million child deaths annually or half of all child deaths in 2011 (Black et al., 2013). Child undernutrition is assessed by measuring height and weight and screening for clinical manifestations and biochemical markers. Indicators based on weight, height and age are compared to international standards and are most commonly used to assess the nutritional status of a population. Stunting (inadequate length/height for age) captures early chronic exposure to undernutrition; wasting (inadequate weight for height) captures acute undernutrition; underweight (inadequate weight for age) is a composite indicator that includes elements of stunting and wasting. A severely stunted child faces a four times higher risk of dying, and a severely wasted child is at a nine times higher risk (Black et al., 2008).
Undernutrition magnifies the effect of every disease putting children at greater risk of dying from common infections, increasing the frequency and severity of such infections, and delayed recovery creating a potentially lethal cycle of worsening illness and deteriorating nutritional status.
At the RGCB Microbiome laboratory we intend to design intricate gut microbiome related studies to understand the dynamics of the extensive population of these gut microbial passengers in the context of nutrient assimilation, immune dysfunction and further systemic contributions. Some primary focus areas of research on gut microbiome and malnutrition at the microbiome laboratory are listed below:
- Understand geographic differences in the gut microbiome structure of malnourished and healthy children
- Understanding the functional consequences of gut microbiome immaturity and dysbiosis on nutritional status
- Studying interventions like probiotics or fecal transplantations in addition to nutritional therapy in suitable animal models to try and restore microbiome function in malnourished state
- Use gut microbiome derived metabolomics profiles to device bacterial interventions to compensate for specific nutritional deficiencies
- Black RE, Victora CG, Walker SP, Bhutta ZA, Christian P, de Onis M, Ezzati M, Grantham-McGregor S, Katz J, Martorell R, Uauy R; Maternal and Child Nutrition Study Group. 2013. Maternal and child undernutrition and overweight in low-income and middle-income countries. Lancet 382(9890):427-51.
- Black RE, Allen LH, Bhutta ZA, Caulfield LE, de Onis M, Ezzati M, Mathers C, Rivera J; Maternal and Child Undernutrition Study Group. 2008. Maternal and child undernutrition: global and regional exposures and health consequences. Lancet 371(9608):243-60.
Environmental enteropathy and infection of the gut in context of malnutrition and child health
If we could only provide clean drinking water to all and ensure proper sanitation and hygiene, we would ensure the well-being and health of the entire human race. However many governments and health workers are finding this to be an insurmountable challenge despite their best efforts. Children in developing countries are constantly exposed to unhygienic environmental conditions and contaminated food and water resulting in a state known as environmental enteropathy (tropical enteropathy). It is a subclinical condition caused by constant fecal-oral contamination resulting in blunting of intestinal villi and intestinal inflammation. Tropical enteropathy is most common in developing countries of the tropics but absent in some tropical populations of high socio-economic status such as Qatar and Singapore. Tropical enteropathy has been shown to have slowly resolved in migrants relocating to developed nations with better hygiene conditions.
There are a number of ailments associated with environmental enteropathy especially in children from developing countries although they might appear apparently healthy and asymptomatic and without any overt diarrhea. Small intestinal inflammation, reduced absorptive capacity (malabsorption), impaired gut immune function, growth faltering and increased intestinal permeability facilitating microbial translocation across the compromised intestinal barrier, leading to chronic systemic inflammation that may adversely impact health are usually consequences of environmental enteropathy. It is also believed to be the underlying reason for poor response to nutritional therapy for treatment of malnutrition and failure of oral vaccines in the developing world.
Our work here at the microbiome laboratory will focus on understanding the dynamics of these constant exposure of beneficial gut microbes to enteric fecal pathogens. We will focus on understanding the role of overt known gut pathogens which sometimes have been shown to be surprisingly present in very low numbers in our gut without causing disease and a recently described class of microbes called pathobionts, in states of health and malnourishment. It is imperative that it is critical to correct these underlying pathological conditions like environmental enteropathy for successful implementation of nutritional therapy for treatment of malnutrition. We will try to understand the intricate networks of interaction between the gut microbes and these pathogens/pathobionts and the host-microbiome cross-talk in these states of environmental enteropathy. Our aim is to ultimately design therapies targeting the reestablishment of gut microbial homeostasis by disrupting networks of deleterious microbes and restoration of normal gut functioning.
- Lindsay B.≠, Ramamurthy T.≠, Sen Gupta S., Takeda Y., Rajendran K., Nair G.B., Stine O.C. 2011. Diarrheagenic pathogens in polymicrobial infections. Emerg Infect Dis. 17(4):606-11. (≠Joint first authors)
- Gupta S.S., Mohammed M.H., Ghosh T.S., Kanungo S., Nair G.B., Mande S.S. 2011. Metagenome of the gut of a malnourished child. Gut Pathog. 3:7.
- Sinha A., SenGupta S., Guin S., Dutta S., Ghosh S., Mukherjee P., Mukhopadhyay A.K., Ramamurthy T., Takeda Y., Kurakawa T., Nomoto K., Nair G.B., Nandy R.K. 2011. Culture-independent real-time PCR reveals extensive polymicrobial infections in hospitalized diarrhoea cases in Kolkata, India. Clin Microbiol Infect. 19(2):173-80.
- Sinha A., Sengupta S., Ghosh S., Basu S., Sur D., Kanungo S., Mukhopadhyay A.K., Ramamurthy T., Nagamani K., Rao M.N., Nandy R.K. 2012. Evaluation of rapid dipstick test for identifying cholera cases during the outbreak. Indian J Med Res. 135(4):523-8.
- De R., Ghosh J.B., Sen Gupta S., Takeda Y., Nair G.B. 2013. The role of Vibrio cholerae genotyping in Africa. J Infect Dis. 208(Suppl 1):S32-8.
- Ghosh T.S., Gupta S.S., Nair G.B., Mande S.S. 2013. In silico analysis of antibiotic resistance genes in the gut microflora of individuals from diverse geographies and age-groups. PLoS One. 8(12):e83823.
- Ghosh T.S. #, Gupta S.S. #, Bhattacharya T., Yadav D., Barik A., Chowdhury A., Das B., Mande S.S., Nair G.B. 2014. Gut microbiomes of Indian children of varying nutritional status. PLoS One. 9(4):e95547. (#Contributed equally)
- Das B., Kumari R., Pant A., Sen Gupta S., Saxena S., Mehta O., Nair G.B. 2014. A Novel Broad Range CTXΦ Derived Stable Integrative Expression Vector For Functional Studies. J Bacteriol. pii: JB.01966-14.
- Hajela N., Nair G.B. and Sen Gupta S. (2013). Probiotics in the prevention of acute diarrhea. In R. Chaudhry (Ed.), Probiotics (pp. 85-97). New Delhi, India: Kontentworx, a division of KWX Communications Pvt. Ltd.
- Sen Gupta S., Das B. and Nair G.B. (2014). The “Uncultured” but significant world of the human gut microbiome- New metagenomic insights. In G. P. Talwar and L .M. Srivastava (Eds.), Textbook of Biochemistry and Human Biology (pp. 664-671). Delhi, India: PHI Learning Pvt. Ltd