Somasish Ghosh Dastidar Poster 2023

Dr Somasish Ghosh Dastidar

Manipal Academy of Higher Education, Manipal- India., India

Genomic and biochemical characterization of ‘novel’ Burkholderia pseudomallei clinical isolates from Melioidosis and Neuromelioidosis patients from Southern India and their virulome and phylogenomic profiling.

Poster Abstract

Varshith MR*1, 2, Dastidar RG*2, 3, Shrilaxmi MS*1, 2, Choudhary S2, 4, Bhattacharya R5, Earny V 2, 4, Jha S 2,4, Biswas SR5, Damerla RR5, Smith C6, Sundaramoorthy V7, Carvalho RA9, Herai RH1, 2, 9, Lal PB2, 4, Brett P8, Mukhopadhyay C2, 4, Dastidar SG1, 2 *.

Affiliation: 1 Centre for Molecular Neurosciences, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India. 2 Centre for Emerging Tropical Disease, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India. 3 Department of Biochemistry, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India. 4 Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India. 5 Department of Botany, Visva Bharati University, India. 6 School of Medicine, Deakin University, Australia. 7 The Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Deakin University, Geelong, Victoria, Australia.  8 School of Medicine, University of Nevada, Reno, USA. 9 Graduate Program in Health Sciences, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná, Paraná, Brazil. 

Melioidosis is typically a disease in tropical and subtropical regions. A spate of clinical studies has reported that Burkholderia pseudomallei is the causative agent of melioidosis, a neglected tropical disease that is endemic in Southeast Asian regions like Northern Australia, Thailand, & the Indian subcontinent. B. pseudomallei is a flagellated, gram-negative rod-shaped bacterium that is reported to be a facultative anaerobe and soil saprophyte having the potential to be used as bioweapon. The modes of infection are inhalation, ingestion, and inoculation through cut wounds.  B. pseudomallei has multidrug resistance, and can remain undetected in the host for decades. At present, there is no diagnostic kit for early detection of the disease or commercial vaccine available. 

 We have isolated several B. pseudomallei strains from a clinical case in India causing Melioidosis and Neuromelioidosis and characterized it for their physiological, biochemical, and genetic traits. In this study, the clinical isolates of B. pseudomallei were characterized and then investigated through whole genome sequencing and bioinformatics analysis to identify potentially novel virulent factors. We found that the strains have different colony morphotype and showed a faster doubling time with high biofilm producing capacity. Phylogenetic analysis also showed that the clinical isolates are placed close to B. pseudomallei strain Mahidol 1106a and B. mallei Turkey2 in the maximum likelihood neighbourjoining tree. The draft genome size of this clinical isolate was 7.3 Mbp, and the virulome profiling and comparative genome analysis between different species belonging to the Burkholderia genus and B. pseudomallei strains revealed that few genes related to Burkholderia virulence are considerably different. Additionally, we note the presence of genomic islands which is indicative of horizontal gene transfer. Notably, within these genome island elements, we found two virulent protein coding genes, gmhA and gmhB2, that are associated with bacterial pathogenesis during the escape of host phagosome. We have also found functionally different genes such as sugC, LPS-rfb, and cysC1 as compared to global reference strains.  Further in silico proteomic analysis indicated two other genes, lolA and ompV, as potential candidate biomarkers for vaccine development. When infected in neuronal cell lines these Burkholderia strains exhibit differential infectivity and cytotoxicity patterns. Further downstream experiments are being designed to understand the host pathogen relationship of these Indian Bp strains. 

 Key Words: Melioidosis, whole genome sequencing, virulent factors, genome islands Burkholderia pseudomallei, vaccine candidates. 

 Biography

The Dastidar lab focuses in solving molecular puzzles and mechanisms behind the etiology of Melioidosis with a focus on Neuromelioidosis. The lab collaborates with Prof. Chiranjay Mukhopadhyay lab who is the director of Centre for Emerging Tropical Disease to understand the host pathogen relationships of India specific Burkholderia pseudomallei strains using in vitro systems.

The lab is located in Kasturba Medical College, Manipal Academy of Higher Education, in southern India. The Manipal Hospital here gets on an average 40 Melioidosis patients every year. Mostly the patients are from very poor background. Hence the survivors cannot afford prolonged treatment and a cheaper vaccine alternative is the best option for India. The Dastidar lab with the mentorship of Prof. Chiranjay Mukhopadhyay and Prof. Paul Brett is focused towards host-pathogen interactions and vaccine development against Burkholderia pseudomallei.

Preliminary work from have identified that the Indian strains are different from their cousin international strains. To address questions pertaining to research the lab utilizes novel molecular and cell biology tools and technique, microbiology, biochemistry, in vitro model systems, MEFs, mice genetics, regenerative biology and CRISPR/Cas9 based functional genomics screening approaches. The Dastidar lab is highly collaborative and focused on establishing new multidisciplinary collaborative ventures nationally and internationally.

Dr. Dastidar did his Bachelors in Microbiology from the University of Pune, India and his Masters in Biotechnology from Visva Bharati University, India. Dastidar moved to the US and did a MS in Cell and Molecular biology through his integrated MS-PhD program at the University of Texas at Dallas under Prof. Santosh D’Mello. After his PhD, Dastidar joined the laboratory of Prof. Albert La Spada, to pursue his postdoctoral training in neurobiology at University of California San Diego and Duke University. Currently Dastidar is an Assistant Professor at Manipal Academy of Higher Education, India. He is also a Department of Biotechnology-India Ramalingaswami Fellow.