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Orla O'Sullivan

Research Officer

Research Interests

Orla a Senior Research Officer is a computational biologist working on the food programme in Teagasc.

  • Investigating the role of physical fitness and diet on the gut microbiome in elite athletes, and in healthy and diseased cohorts.
  • Genomics of single bacteria and phage and metagenomics of various environments including human gut and lung, rumen and food.
  • Profiling the soil microbiome and in particular antibiotic resistance genes.
  • Identification of novel probiotics for specific population groups
  • Development of “omics” tools for analysis of next generation sequencing data
  • Studying the impacts of food on the gut microbiome

Current Projects


B.Sc. (Hons.) Biochemistry 2000 National University Ireland, Cork

PhD Bioinformatics 2004 National University Ireland, Cork.


February 2020:Principle Investigator, VistaMilk

October 2019- Present: Senior Research Officer

June 2018: Funded Investigator, APC Microbiome Ireland

Feb 2017–Present: Research Officer (Computational Biologist), Teagasc

2015–2017: Faculty Member APC Microbiome Centre

Sep 2014–Feb 2017: Starting Investigator Research Grant, Fellow.

Feb 2014–August 2014: Research Fellow, Teagasc and APC Microbiome Centre

Jan 2008–Dec 2013: Research Officer, ELDERMET, Teagasc and UCC

Feb 2006–Dec 2007: Research Officer, Teagasc

Jan 2005–Jan 2006: Lecturer and Senior Demonstrator, Dept. of Biochemistry, UCC.

July 2004–Jan 2005: Postdoctoral research Conway Institute, UCD, Dublin.


  1. Barton, W., O. Cronin, I. Garcia-Perez, R. Whiston, E. Holmes, T. Woods, C. B. Molloy, M. G. Molloy, F. Shanahan, P. D. Cotter and O. O’Sullivan (2021). "The effects of sustained fitness improvement on the gut microbiome: A longitudinal, repeated measures case-study approach." Translational Sports Medicine 4: 174-192
  2. O’Donovan, C. M., B. Connor, S. M. Madigan, P. D. Cotter and O. O’Sullivan (2020). "Instances of altered gut microbiomes among Irish cricketers over periods of travel in the lead up to the 2016 World Cup: A sequencing analysis." Travel Medicine and Infectious Disease: 101553
  3. Penney N, Barton W, Posma JM, Darzi A, Frost G, Cotter PD, O’Sullivan O, Garcia-Perez. Investigating the Role of Diet and Exercise in Gut Microbe-Host Cometabolism. mSystems. 2020 Dec 1;5(6).
  4. Barton, W., N. C. Penney, O. Cronin, I. Garcia-Perez, M. G. Molloy, E. Holmes, F. Shanahan, P. D. Cotter and O. O'Sullivan (2018). "The microbiome of professional athletes differs from that of more sedentary subjects in composition and particularly at the functional metabolic level." Gut 67(4): 625-633.
  5. O’Donovan, C. M., S. M. Madigan, I. Garcia-Perez, A. Rankin, O. O’Sullivan and P. D. Cotter (2020). "Distinct microbiome composition and metabolome exists across subgroups of elite Irish athletes." Journal of Science and Medicine in Sport 23(1): 63-68.
  6. Cronin, O., W. Barton, P. Skuse, N. C. Penney, I. Garcia-Perez, E. F. Murphy, T. Woods, H. Nugent, A. Fanning, S. Melgar, E. C. Falvey, E. Holmes, P. D. Cotter, O. O'Sullivan, M. G. Molloy and F. Shanahan (2018). "A Prospective Metagenomic and Metabolomic Analysis of the Impact of Exercise and/or Whey Protein Supplementation on the Gut Microbiome of Sedentary Adults." mSystems 3(3).
  7. Cronin, O., W. Barton, C. Moran, D. Sheehan, R. Whiston, H. Nugent, Y. McCarthy, C. B. Molloy, O. O'Sullivan, P. D., M. G. Molloy and F. Shanahan (2019). "Moderate-intensity aerobic and resistance exercise is safe and favourably influences body composition in patients with quiescent Inflammatory Bowel Disease: a randomized controlled cross-over trial." BMC Gastroenterol 19(1): 29.
  8. Clarke, S. F., E. F. Murphy, O. O'Sullivan, A. J. Lucey, M. Humphreys, A. Hogan, P. Hayes, M. O'Reilly, I. B. Jeffery, R. Wood-Martin, D. M. Kerins, E. Quigley, R. P. Ross, P. W. O'Toole, M. G. Molloy, E. Falvey, F. Shanahan and P. D. Cotter (2014). "Exercise and associated dietary extremes impact on gut microbial diversity." Gut 63(12): 1913-20
  9. Walsh, A. M., F. Crispie, O. O’Sullivan, L. Finnegan, M. J. Claesson and P. D. Cotter (2018). "Species classifier choice is a key consideration when analysing low-complexity food microbiome data." Microbiome 6(1): 50.
  10. Claesson, M. J., I. B. Jeffery, S. Conde, S. E. Power, E. M. O'Connor, S. Cusack, H. M. Harris, M. Coakley, B. Lakshminarayanan, O. O'Sullivan, G. F. Fitzgerald, J. Deane, M. O'Connor, N. Harnedy, K. O'Connor, D. O'Mahony, D. van Sinderen, M. Wallace, L. Brennan, C. Stanton, J. R. Marchesi, A. P. Fitzgerald, F. Shanahan, C. Hill, R. P. Ross and P. W. O'Toole (2012). "Gut microbiota composition correlates with diet and health in the elderly." Nature 488(7410): 178-84.

Recent Key note presentations at conferences including International Olympic Councils Conference Monaco 2021, Probiotia 2020, NutraIngredients 2021,  Sports Medicine 2021. For more see twitter: @OrlaOS

Laura Wosinska, Rose Edwin, Meghana Srinivas