Dr. Siddhartha Thakur
Assistant Professor, Pig Health & Production

ORAU Research Fellow
Centre for Veterinary Medicine, FDA
Maryland, USA
2007

Doctor of Philosophy
Population Medicine, NC State University
North Carolina, USA
2005

Master of Veterinary Science
Veterinary Public Health, Indian Vet. Research Institute
India
2000

Bachelor of Veterinary Science & Animal Husbandry
G.B Pant University Ag. & Tech. India
1998

Phone: (919) 513-0729
Fax: (919) 515-3044
Email: sid_thakur@ncsu.edu

Research Focus

My research focus is to understand the molecular epidemiology of important multidrug resistant food borne pathogens in animals, food and humans. There is tremendous economic burden of treating animals and human patients affected by antimicrobial resistant pathogens. However, there is no clear consensus on the significance of ecological and management factors in the dissemination of such antimicrobial resistant strains in humans. In addition, characterizing the pathogen to specific strain level is time consuming and very costly. Thus, the molecular characterization of antimicrobial resistance and development of effective detection system for food borne pathogens are the two most important goals of my research. Through my research, I plan to address several questions that underlie the mechanisms of antimicrobial resistance and genotypic diversity of food borne pathogens including 1) Molecular characterization of antimicrobial resistance in food borne pathogens; 2) Phylogenetic analysis of Campylobacter and Salmonella and determine their clonal complexes that exist in the swine production systems, the retail market and in the human population; 3) Develop methods that will aid in the rapid identification and characterization of bacterial pathogens; and 4) Determine the risk factors that transmit Campylobacter and Salmonella among swine at farm, slaughter and retail meat.

Genotypic characterization of antimicrobial resistance is very important as it helps to determine the resistance genes, their location either on a plasmid or chromosome and other novel resistance mechanisms that might be present. Recently, I have characterized Class-I integrons in different Salmonella serovars and identified evidence of resistance gene transfer between different serotypes of Salmonella in swine and humans. In addition, I have characterized chromosomal mutations responsible for fluoroquinolone and erythromycin resistance in Campylobacter isolated from swine. Genotyping is important to identify and differentiate sources of food borne pathogens in animals, humans and the environment. For this purpose, I have used methods including Multilocus sequence typing (MLST), Pulse field gel electrophoresis (PFGE), amplified fragment length polymorphism (AFLP) for fingerprinting food borne pathogens. To elucidate the phylogenetic make up of bacterial pathogens, I have genotyped Campylobacter using MLST and successfully defined a clonal complex which is in addition to the 51 new sequence types that were reported for the first time. These findings have helped researchers in comparison of isolates from different sources and in determining the dissemination of this important food borne pathogen in humans and animals.

Current standard protocols for the isolation and detection procedures of these pathogens are laborious and have low sensitivity. Therefore, development of a sensitive and rapid method with low detection limit and cost is essential. I am currently involved in developing a multi-pathogen detection microarray for targeting important food borne pathogens including Salmonella, Campylobacter, and Yersinia and a common viral agent, Norovirus. In addition, I am also developing a real time PCR based method that is aimed at rapid and sensitive detection of Salmonella and will be of tremendous help in laboratories that do not have access to the microarray technology.

Professional Experience

North Carolina State University, Raleigh, North Carolina.................2007 - present
Assistant Professor, Department of Population Health & Pathobiology

Centre for Veterinary Medicine, Laurel, Maryland.................2005-2007
Oakridge Research Associated Universities Research Fellow

North Carolina State University, Raleigh, North Carolina.................2001-2005
Graduate Research Assistant, Department of Population Health & Pathobiology

Indian Veterinary Research Institute, Izzatnagar, India.................1998 - 2000
Junior Research Fellow, Department of Veterinary Public Health

Gobind Ballabh Pant University of Agriculture & Technology, Pantnagar, India.................1993 - 1998

Selected Publications

Thakur, S., Tadesse, D. A., Morrow, W. E. M., and Gebreyes, W. A. (2007). Occurrence of multidrug resistant Salmonella in antimicrobial-free (ABF) swine production systems. Veterinary Microbiology. June 13th

Thakur, S., Morrow, W. E. M., Funk, J. A., Bahnson, P. B. and Gebreyes, W. A. (2006). Molecular Epidemiologic investigation of Campylobacter coli in swine production systems using Multi-Locus Sequence Typing (MLST). Applied Environmental Microbiology. Aug.72(8): 5666-69.

Harbottle, H., Thakur, S., Zhao, S. and White, D. G. (2006). Genetics of antimicrobial resistance. Animal Biotechnology. 17: 1-12.

Gebreyes, W. A., Thakur, S. and Morrow, W. E. M. (2006). Comparison of prevalence, antimicrobial resistance and occurrence of multi-drug resistant Salmonella in antimicrobial-free and conventional pig production. Journal of Food Protection. April; 69(4): 743-8.

Thakur, S., and Gebreyes, W. A. (2005). Campylobacter coli in Swine Production: Antimicrobial Resistance Mechanisms and Molecular Epidemiology. Journal of Clinical Microbiology. November; 43 (11): 5705-14.

Thakur, S., and Gebreyes, W. A. (2005). Prevalence and Antimicrobial resistance of Campylobacter in antimicrobial-free and conventional pig production systems. Journal of Food Protection. November; 68 (11): 2402-10.

Gebreyes, W. A., Thakur, S. and Morrow, W. E. M. (2005). Campylobacter coli: Prevalence and Antimicrobial Resistance in Antimicrobial Free (ABF) Swine Production Systems. Journal of Antimicrobial Chemotherapy. October; 56 (4): 765-768.

Gebreyes, W. A. and Thakur, S. (2005). Multi-drug Resistant Salmonella enterica serovar Muenchen from Pigs and Humans and Evidence of Inter-serovar Transfer of Antimicrobial Resistance. Antimicrobial Agents and Chemotherapy. February; 49 (2): 503-511.

Gebreyes, W. A., Thakur, S., Davies, P. R., Funk, J. A. and Altier, C. (2004). Trends in antimicrobial resistance, phage types and integrons among Salmonella serotypes from pigs, 1997-2000. Journal of Antimicrobial Chemotherapy. June; 53 (6): 997-1003.

Gebreyes, W. A., Davies, P. R., Turkson, P. K., Morrow, W. E., Funk, J. A., Altier, C. and Thakur, S. (2004). Characterization of antimicrobial-resistant phenotypes and genotypes among Salmonella enterica recovered from pigs on farms, from transport trucks, and from pigs after slaughter. Journal of Food Protection. April; 67 (4): 698-705.

Gebreyes, W. A. and Thakur, S. (2003). Molecular Epidemiology of Multi-drug resistant Salmonella enterica serovar Typhimurium isolated from Swine and Humans. Infection, Genetics and Evolution. 2: 43.