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Gireesh Rajashekara, DVM, PhD





  • Srivastava V, Deblais L, Huang HC, Miyazaki A, Kandasamy S, Langel SN, Paim FC, Chepngeno J, Kathayat D, Vlasova AN, Saif LJ, Rajashekara G. Reduced rotavirus vaccine efficacy in protein malnourished human-faecal-microbiota-transplanted gnotobiotic pig model is in part attributed to the gut microbiota. Beneficial Microbes. 2020 Dec 2;11(8):733-751. doi: 10.3920/BM2019.0139.
  • Rajashekara G, Deblais L, Miller SA. Impact of plant pathogens infection on  Salmonella  enterica subsp. enterica serotype Typhimurium persistence in tomato plants. J Food Prot. 2020 Nov 12. doi: 10.4315/JFP-20-291.
  • Kathayat D, Antony L, Deblais L, Helmy YA, Scaria J, Rajashekara G. 2020. Small molecule adjuvants potentiate colistin activity and attenuate resistance development against Escherichia coli by affecting pmrAB system. Infection & Drug Resistance 2020;13:2205-2222
  • Helmy YA, Kathayat D, Ghanem M, Jung K, Closs Jr G, Deblais D, Srivastava V, El-Gazzar M, and Rajashekara G. 2020. Identification and characterization of novel small molecule inhibitors to control Mycoplasma gallisepticum infection in chickens. Veterinary Microbiology 247,108799. DOI:10.1016/j.vetmic.2020.108799.
  • Lu Y, Deblais L, Rajashekara G, Miller SA, Helmy YA, Zhang H, Wu P, Qiu Y, Xu X. 2020. High-throughput screening reveals small molecule modulators inhibitory to Acidovorax citrulli. Plant Pathol. 69 (5) 818-826.
  • Michael H, Langel SN, Miyazaki A, Paim FC, Chepngeno J, Alhamo MA, Fischer DD, Srivastava V, Kathayat D, Deblais L, Rajashekara G, Saif LJ, Vlasova AN. 2020. Malnutrition Decreases Antibody Secreting Cell Numbers Induced by an Oral Attenuated Human Rotavirus Vaccine in a Human Infant Fecal Microbiota Transplanted Gnotobiotic Pig Model. Front Immunol 11.
  • Terefe Y, Deblais L, Ghanem M, Helmy YA, Mummed B, Chen D, Singh N, Ahyong V, Kalantar K, Yimer G, Yousuf Hassen J, Mohammed A, McKune SL, Manary MJ, Ordiz MI, Gebreyes W, Havelaar AH, Rajashekara G. 2020. Co-occurrence of Campylobacter Species in Children From Eastern Ethiopia, and Their Association With Environmental Enteric Dysfunction, Diarrhea, and Host Microbiome. Front Public Health 8. Front Public Health. 2020 Apr 15;8:99. doi: 10.3389/fpubh.2020.00099.
  • Vrisman CM, Deblais L, Helmy YA, Johnson R, Rajashekara G, Miller SA. 2020. Discovery and Characterization of Low-Molecular Weight Inhibitors of Erwinia tracheiphila. Phytopathology® 110:989–998.
  • Chen D, McKune SL, Singh N, Hassen JY, Gebreyes W, Manary M, Bardosh K, Yang Y, Diaz N, Mohammed A, Terefe Y, Roba KT, Ketema M, Ameha N, Assefa N, Rajashekara G, Deblais L, Ghanem M, Yimer G, Ordiz I, Havelaar AH. 2021. Campylobacter Colonization, Environmental Enteric Dysfunction, Stunting, and Associated Risk Factors among Young Children in Rural Ethiopia: a Cross-sectional Study from the Campylobacter Genomics and Environmental Enteric Dysfunction (CAGED) Project. Front. Public Health, 21 January 2021.
  • Helmy Y.A., Kassem I.I., and Rajashekara G. (2021). Immuno-modulatory effect of probiotic E. coli Nissle 1917 in polarized human colonic cells against Campylobacter jejuni infection. Gut Microbes 13 (1), 1-16.


  • Deblais L, Helmy YA, Kathayat D, Huang HC, Miller SA, Rajashekara G. Novel Imidazole and Methoxybenzylamine Growth Inhibitors Affecting Salmonella Cell Envelope Integrity and its Persistence in Chickens. Sci Rep. 2019 Nov 6;9(1):16508. doi: 10.1038/s41598-019-52826-x. PubMed PMID: 31695121; PubMed Central PMCID: PMC6834860.
  • Vlasova AN, Takanashi S, Miyazaki A, Rajashekara G, Saif LJ. How the gut microbiome regulates host immune responses to viral vaccines. Curr Opin Virol. 2019 Aug; 37:16-25. doi: 10.1016/j.coviro.2019.05.001. Epub 2019 Jun 1. Review. PubMed PMID: 31163292.
  • Deblais L, Vrisman C, Kathayat D, Helmy YA, Miller SA, Rajashekara G. Imidazole and Methoxybenzylamine Growth Inhibitors Reduce Salmonella Persistence in Tomato Plant Tissues. J Food Prot. 2019 Jun;82(6):997-1006. doi:10.4315/0362-028X. JFP-18-555. PubMed PMID: 31121102.
  • Deblais L, Helmy YA, Testen A, Vrisman C, Jimenez Madrid AM, Kathayat D, Miller SA, Rajashekara G. Specific Environmental Temperature and Relative Humidity Conditions and Grafting Affect the Persistence and Dissemination of Salmonella enterica subsp. enterica Serotype Typhimurium in Tomato Plant Tissues. Appl Environ Microbiol. 2019 May 16;85(11). pii: e00403-19. doi:10.1128/AEM.00403-19. Print 2019 Jun 1. PubMed PMID: 30926732; PubMed Central, PMCID: PMC6532026.
  • Deblais L, Helmy YA, Kumar A, Antwi J, Kathayat D, Acuna UM, Huang HC, de
  • Blanco EC, Fuchs JR, Rajashekara G. Novel narrow spectrum benzyl thiophene sulfonamide derivatives to control Campylobacter. J Antibiot (Tokyo). 2019 Jul;72(7):555-565. doi: 10.1038/s41429-019-0168-x. Epub 2019 Mar 27. PubMed PMID:30918323.


  • Miyazaki, A., Kandasamy, S., Michael, H., Langel, S.N., Paim, F.C., Chepngeno, J., Alhamo, M.A., Fischer, D.D., Huang, H.C., Srivastava, V., Kathayat, D., Deblais, L., Rajashekara, G., Saif, L.J., Vlasova, A.N. 2018. Protein deficiency reduces efficacy of oral attenuated human rotavirus vaccine in a human infant fecal microbiota transplanted gnotobiotic pig model. Submitted to Vaccine. Vaccine. 2018 Oct 8;36(42):6270-6281.
  • Kumar, A., Vlasova, A., Deblais, L., Huang, H.C., Wijeratne, A., Kandasamy, S., Fischer, D.D., Langel, S.N., Paim, F.C., Alhamo, M.A., Shao, L., Saif, L.J., Rajashekara, G. 2018. Impact of nutrition and rotavirus infection on the infant gut microbiota in a humanized pig model. BMC Gastroenterol. 2018 Jun 22;18(1):93. doi: 10.1186/s12876-018-0810-2. PMC N/A
  • Huang, H.C., Vlasova, A.N., Kumar, A., Kandasamy, S., Fischer, D.D., Deblais, L., Paim, F.C., Langel, S.N., Alhamo, M.A., Rauf, A., Shao, L., Saif, L.J., Rajashekara, G. 2018. Effect of antibiotic, probiotic, and human rotavirus infection on colonisation dynamics of defined commensal microbiota in a gnotobiotic pig model. Benef Microbes. 2017 Oct 12:1-16. doi: 10.3920/BM2016.0225.


  • Isaac P. Kashoma, Vishal Srivastava and Gireesh Rajashekara, Advances in Vaccines for controlling Campylobacter in Poultry. In, Food Safety in Poultry Meat Production. Editors: Dr. Siddhartha Thakur and Dr. Steven Ricke and Kumar Venkitanarayanan. Springer Nature. Under review

  • Issmat I. Kassem and Gireesh Rajashekara. Campylobacter in Poultry. In Diagnosis of major poultry diseases. 2017. Editors: Libro de Toro, Haroldo; Saif, Yehia Mo. Servet Publishing. ISBN: 8417225056 ISBN-13: 9788417225056

  • Heshan Du, Bin Chen, Xiaofen Zhang, and Fenglan Zhang, Sally A. Miller, Gireesh Rajashekara, Xiulan Xu and Sansheng Geng, Evaluation of Ralstonia solanacearum Infection Dynamics in Resistant and Susceptible Pepper Lines Using Bioluminescence Imaging. Plant Disease /Vol. 101 No. 2; 272-278. February 2017

  • Huang HC, Vlasova AN, Kumar A, Kandasamy S, Fischer DD, Deblais L, Paim FC, Langel SN, Alhamo MA, Rauf A, Shao L, Saif LJ, Rajashekara G. Effect of antibiotic, probiotic, and human rotavirus infection on colonisation dynamics of defined commensal microbiota in a gnotobiotic pig model. Benef Microbes. 2018 Jan 29;9(1):71-86. doi: 10.3920/BM2016.0225. Epub 2017 Oct 12.PMID: 29022385

  • Helmy YA, Kassem II, Kumar A, Rajashekara G. In Vitro Evaluation of the Impact of the Probiotic E. coli Nissle 1917 on Campylobacter jejuni's Invasion and Intracellular Survival in Human Colonic Cells.Front Microbiol. 2017 Aug 22;8:1588. doi: 10.3389/fmicb.2017.01588. eCollection 2017. PMID: 28878749

  • Amadi VA, Matthew-Belmar V, Subbarao C, Kashoma I, Rajashekara G, Sharma R, Hariharan H, Stone D. Campylobacter Species Isolated from Pigs in Grenada Exhibited Novel Clones: Genotypes and Antimicrobial Resistance Profiles of Sequence Types.Foodborne Pathog Dis. 2017 Jul;14(7):419-425. doi: 10.1089/fpd.2016.2229. Epub 2017 Jun 26. PMID: 28650672

  • Fischer DD, Kandasamy S, Paim FC, Langel SN, Alhamo MA, Shao L, Chepngeno J, Miyazaki A, Huang HC, Kumar A, Rajashekara G, Saif LJ, Vlasova AN. Protein Malnutrition Alters Tryptophan and Angiotensin-Converting Enzyme 2 Homeostasis and Adaptive Immune Responses in Human Rotavirus-Infected Gnotobiotic Pigs with Human Infant Fecal Microbiota Transplant. Clin Vaccine Immunol. 2017 Aug 4;24(8). pii: e00172-17. doi: 10.1128/CVI.00172-17. Print 2017 Aug. PMID: 28637803

  • Kassem II, Helmy YA, Kathayat D, Candelero-Rueda RA, Kumar A, Deblais L, Huang HC, Sahin O, Zhang Q, Rajashekara G. Nonculturability Might Underestimate the Occurrence of Campylobacter in Broiler Litter. Foodborne Pathog Dis. 2017 Aug;14(8):472-477. doi: 10.1089/fpd.2017.2279. Epub 2017 Jun 16. PMID: 28622473

  • Nisar M, Kassem II, Rajashekara G, Goyal SM, Lauer D, Voss S, Nagaraja KV. Genotypic relatedness and antimicrobial resistance of Salmonella Heidelberg isolated from chickens and turkeys in the midwestern United States. J Vet Diagn Invest. 2017 May;29(3):370-375. doi: 10.1177/1040638717690784. PMID: 28430086

  • Vlasova AN, Paim FC, Kandasamy S, Alhamo MA, Fischer DD, Langel SN, Deblais L, Kumar A, Chepngeno J, Shao L, Huang HC, Candelero-Rueda RA, Rajashekara G, Saif LJ. Protein Malnutrition Modifies Innate Immunity and Gene Expression by Intestinal Epithelial Cells and Human Rotavirus Infection in Neonatal Gnotobiotic Pigs. mSphere. 2017 Mar 1;2(2). pii: e00046-17. doi: 10.1128/mSphere.00046-17. eCollection 2017 Mar-Apr. PMID: 28261667

  • Kassem II, Candelero-Rueda RA, Esseili KA, Rajashekara G. Formate simultaneously reduces oxidase activity and enhances respiration in Campylobacter jejuni. Sci Rep. 2017 Jan 16;7:40117. doi: 10.1038/srep40117. PMID: 28091524

  • Vrisman, C.M., Deblais, L., Rajashekara, G., Miller, S.A. Discovery and characterization of small molecules inhibitory to Erwinia tracheiphila. Phytopathology 107:S5.42

  • Kandasamy S, Vlasova AN, Fischer DD, Chattha KS, Shao L, Kumar A, Langel SN, Rauf A, Huang HC, Rajashekara G, Saif LJ. Unraveling the Differences between Gram-Positive and Gram-Negative Probiotics in Modulating Protective Immunity to Enteric Infections. Front Immunol. 2017 Mar 27;8:334. doi: 10.3389/fimmu.2017.00334. eCollection 2017. Review. PMID: 28396664

  • Chandrashekhar K, Kassem II, Rajashekara G. Campylobacter jejuni transducer like proteins: Chemotaxis and beyond. Gut Microbes. 2017 Jul 4;8(4):323-334. doi: 10.1080/19490976.2017.1279380. Epub 2017 Jan 12. PMID:28080213.

  • Zilu Wan, Gireesh Rajashekara, James Fuchs, Esperanza Carcache de Blanco, Melvin A. Pascall. Incorporation of Selected Small Molecule Compounds into Tapioca Starch and the Effects on Thickness, Moisture and Oxygen Mass Transfer, and Mechanical Properties of the Films. Packaging Technology and Science (In Press).

  • Loïc Deblais, Yosra A. Helmy, Diapak Kathayat, Rosario A Candelero, Huang-chi Huang, Sally A. Miller, Gireesh Rajashekara. Novel Small Molecules Growth Inhibitor Affecting Salmonella Cell Membrane and Effective in Chicken Broilers. Submitted to AAC.

  • Loïc Deblais, Ben Lorentz, Joy Scaria, Kakambi V. Nagaraja, Muhammad Nisar, and Gireesh Rajashekara. Divergent Metabolic Functions in Salmonella Heidelberg Isolated from Chicken and Turkey Production Systems. Submitted to AEM.

  • Anand Kumar; Ananstasia Vlasova; Loic Deblais; Huang-Chi Huang; Asela Wijeratne; Sukumar Kandasamy; David D Fischer; Stephanie N Langel; Francine Chimelo Paim; Moyasar A. Alhamo A Alhamo; Lulu Shao; Linda J Saif; Gireesh Rajashekara. Impact of nutrition and rotavirus infection on the infant gut microbiota in a humanized pig model. BMC Gastroenterology



  • Sukumar Kandasamy. Anand Kumar, Gireesh Rajashekara, Anastasia Vlasova, Linda Saif., "Probiotics for Immunomodulation and treatment of Immunological disorders in children: Evaluation in a germ free animal model.". In "Probiotics in Children". Edited by: Marco Manfredi and Gian Luigi de'Angelis. New York: Nova Science Publishers.2015.

  • Kashoma IP, Kassem Il, Julius John J, Kessy BMs Gebreyes W, Kazwala RR, and Rajashekara G. "Prevalence and Antibiotic Resistance of Campylobacter Isolated from Dressed Cattle Carcasses and Raw Milk in Tanzania". Microbial Drug Resistance. Vol. 22, no. 1: 40-52. 2015.

  • Chandrashekhar K, Gangaiah DI Mimbela R, Kassem Il, Jeon B and Rajashekara G., 'Transducer like proteins of Campylobacter jejuni 81-176: rote in chemotaxis and colonization of the chicken gastrointestinal tract". Front. Cell. Infect. Microbiol. Vol. May 201:1-10. 2015.

  • Xu X, Kumar A. Deblais L, Pina-Mímbela R, Nistow C. Fuchs JR Miller SAI Rajashekara G., "Discovery of novel small molecule modulators of Ctavibacter michiganensis subsp. michiganensis,". Front Microbiol. Vol. 6, el 127. 2015.

  • Kashoma IP, Kassem Il, Kumar A, Kessy 8M, Gebreyes W, Kazwala RRV Rajashekara G., "Antimicrobial Resistance and Genotypic Diversity of Campylobacter Isolated from Pigst Dairy, and Beef Cattle in Tanzania.". Front Microbiol. Vol. 6, el 240. 2015.

  • Chandrashekhar K, Kassem Il, Nislow CT Gangaiah D, Candetero-Rueda RAI Rajashekara G., "Transcriptome analysis of Campylobacter jejuni polyphosphate kinase (ppkl and ppk2) Virulence. Vol. 6, no. 8: 814-8. 2015.

  • Pina-Mimbela R, Madrid JA Kumar A, Torrettes JB, Rajashekara G. "Polyphosphate kinases modulate Campylobacter jejuni outer membrane constituents and alter its capacity to invade and survive in intestinal epithelial cells in vitro.". Emerg Microbes Infect Vol 4, no, e77: e77 2015.

  • Sahin O, Kassem ll. Shen Z, Lin J. Rajashekara G, and Zhang Q, "Campylobacter in Poultry: Ecology and Potential Interventions". Avian Diseases. Vol. 59, no. 2: 185-200. (2015).