Current Members

Marie-Claire Arrieta, Ph.D

Linkedin, ResearchGate, Pubmed


Originally trained as a medical microbiologist in San José, Costa Rica, Claire moved to Canada to pursue graduate studies. She completed M.Sc and PhD programs at the University of Alberta in Edmonton, Alberta. Her doctoral work explored the role of intestinal permeability (leaky gut) in the pathogenesis of inflammatory bowel disease. Through her work, she became very interested in the concept of the gut as the engine of diseases that occur in organs far away from the gut. Following this, she completed a postdoctoral fellowship in the laboratory of Dr. Brett Finlay's, a prominent molecular microbiologist that has pioneered many studies in the field of the human microbiome. During her postdoctoral stay, Claire studied the relationship between the gut microbiome, the gut's immune system and asthma, a disease of the lungs. Besides her time spent in research, Claire is also very interested in science communication to the public. She has written one public book (Let Them Eat Dirt), and is currently working on a second book (a children's book), as well as on a documentary film project.

Tahsin Ferdous, M.Sc


Tahsin Ferdous is a data analyst in the Department of Physiology and Pharmacology of the University of Calgary. In March 2020, she joined Dr. Marie-Claire Arrieta’s lab as a Biostatistician. There, Tahsin Ferdous is applying her expertise to perform statistical analysis of microbiome data and write supporting documents. She graduated from the University of Calgary with a Master of Science in Biostatistics. She received BSc (Hons) and another MSc degree in Statistics from Shahjalal University of Science & Technology, Sylhet, Bangladesh. She has applied statistical packages for simulated health data representing infectious persons in a sequence of hypothetical cities as well as RNA-sequencing data. She has a publication named “An Overview of RNA-seq Data Analysis” in the Journal of Biology and Life Science. She got “Queen Elizabeth II Diamond Jubilee Scholarship” and “Research scholarship at University of Calgary” in 2017. Tahsin Ferdous has great enthusiasm for working with microbiome data and in the field of Bioinformatics.

Andrea Guedez


Andrea Guedez is a Research Assistant for the BLOOM study within the Arrieta lab. She obtained her Bachelor of Medical Sciences with an Honors Double Major in Physiology and Pharmacology from the University of Western Ontario. It was here where Andrea developed a strong interest in pediatric and neonatal research, specifically in exploring the short and long-term effects of early life adversities on disease development. Her eagerness to learn led her to volunteer as a Clinical Research Assistant for the Development Neuroimaging lab, where she conducted MRI scans, managed sensitive situations and analyzed data for the Prenatal Alcohol Exposure study. As a member of the Arrieta lab, Andrea is looking forward to utilizing her experience and skills to positively contribute to the lab's success. Outside of the lab, Andrea enjoys hiking, the outdoors and getting together with family and friends.

Van Ortega, Ph.D



Van is an NSERC-funded Post Doctoral Fellow in the Arrieta lab. He obtained his PhD from the University of Alberta where his research focused on the potential for metal-based nanoparticles to inadvertently modulate immune responses, using model systems such as cell lines, primary cell cultures, and whole animals. Van also has a MSc from the University of Guelph where he examined changes in behavioral and physiological stress in fish when exposed to environmental contaminants. Van also has several years working as a risk assessment toxicologist in the turbid waters of environmental consulting. His interest in environmental health stems primarily from a fundamental curiosity in the science of environmental contamination and its effects on biological systems. For his PDF, Van is combing his experience in stress and immune research to investigate the role of commensal gut bacterial communities on the developmental outcomes of stress-axis systems that are integral for maintaining immune health and physiological homeostasis. When not in the lab, Van enjoys traveling, the outdoors and training for endurance races.

Shirin Moossavi, M.D, Ph.D

Website, Google Scholar


Shirin Moossavi is a CIHR Postdoctoral Fellow in the Department of Physiology and Pharmacology and Biomedical Engineering jointly supervised by Dr Marie-Claire Arrieta and Dr Amir Sanati-Nezhad. Shirin obtained her Medical Doctorate from Tehran University of Medical Sciences, Iran; her MSc in Genetic Manipulation and Molecular Biology from University of Sussex, UK; and PhD in Medical Microbiology from the University of Manitoba. She is the Early-Mid Career Ambassador of International Society of Microbial Ecology, the Founding Director of Microbiome and Microbial Ecology Interest Group at Universal Scientific Education and Research Network, and a contributor to Microbiome Digest.

Erik van Tilburg Bernardes, M.Sc

Linkedin, Pubmed, Google Scholar


After working for two years as the Research Associate in the Arrieta lab, Erik is changing his role in the lab and starting his Ph.D under Dr. Marie-Claire Arrieta's supervision. As the first addition to the lab, he has helped Claire immensely to set up the space and get the laboratory up and running. Erik holds both a Masters of Science in Microbiology and Infectious Diseases (2014-2017), from the University of Calgary, and a Bachelor in Pharmacy (2008-2014), by the Federal University of Alfenas (Unifal-MG, Brazil). His scientific career started in his undergraduate years in Brazil and later brought him to Calgary, working in different projects that aimed to study/identify alternative treatment options for the bacterial pathogen Pseudomonas aeruginosa. Erik's previous experience include different molecular, physiological and immunological techniques, which combined with his expertise in pharmacology and microbiology make him an invaluable asset for the team. His interests include the interactions between host and microorganisms, and Erik is keen to learn more on how these interactions shape the host's immune system and finally prevent/predispose individuals to developing diseases.

Emily Mercer



Emily is a Masters student in the Arrieta lab, holding a Bachelor of Science in Microbiology from the University of Guelph (2012-2017). She completed her undergraduate thesis under the supervision of Dr. Emma Allen-Vercoe, a prominent gut microbiome researcher, which utilized 'Robogut' technology to explore gut microbial community assembly dynamics in naturally depleted ecosystems, such as in inflammatory bowel disease. Emily's interest in the gut microbiome initially stemmed from her passion for travel and experiences abroad, but further evolved as she became curious about the role of early childhood adversity in our lifelong health trajectories. In her Masters, Emily will examine the relationship between the early-life gut microbiome and the development of stress response networks in premature infants. Her research interests include microbial ecology, metabolomics, microbial community dynamics, host-microbe interactions, microbiome-based therapeutics and the gut-brain axis. Outside of the lab, Emily enjoys hiking, traveling, and the outdoors.

Mackenzie Gutierrez



Mackenzie initially joined the lab as a co-op student in 2019 while completing her Bachelor of Science in Microbiology and Immunology from the University of British Columbia (2015-2020). During her stay she was involved in a number of projects, though her focus project, funded by Alberta Innovates, explored the role of different microbiome populations in modulating the pathology of acute inflammation in the gastro intestinal tract. This strongly reinforced her passion for investigating the role of the microbiome in immunological development, chronic diseases and how novel therapeutics can be used to manage such diseases. Mackenzie is now a Masters student in the lab and is exploring the contributions of the microbiome in metabolic development and inflammation.

Ali Javed


Ali is an undergraduate student at the University of Calgary, in his second year of the Biological Sciences program. He will be contributing to the Arrieta Lab as a summer undergraduate research student, and will be conducting an individual research project. Ali is very interested in cellular biology, as well as the effects of the environment in the development of human health and the immune system.

Julia Gorospe

Julia is in her fourth year of studying Biomedical Sciences at the University of Calgary. She joined the Arrieta Lab this summer as a recipient of an Alberta Innovates Summer Studentship. Once she has completed her summer student placement, she will be working on an independent thesis project focusing on the effects of preterm infant early nutrition on microbial composition. In the future, Julia hopes to study the connection between nutrition, the microbiome, and autoimmune disorders.

Kristen Kalbfleisch

LinkedIn, Pubmed


Kristen Kalbfleisch is embracing her role as the Arrieta Lab Manager. Here, she hopes to apply her dedication to integrity, HSE and her inquisitive mind to help the Arrieta Lab achieve their expanding research goals. In 2021, Kristen completed her Occupational Health and Safety Fundamentals certificate through the University of Calgary, and is continuing to pursue further HSE and Project Management certifications.

Kristen obtained her B.Sc. in Honors Biology from the University of Waterloo (2011), and returned for post-degree studies and a Teaching Assistant position centered in her passion - disease and microbiology - after spending some time teaching in Ilsan, South Korea. In 2017, she worked in R&D at Sanofi Pasteur in Toronto, Ontario (through Seneca College) where she helped develop novel characterization methods and the teams first GMP protocol, within Analytical R&D.

In 2018, Kristen made the difficult, but rewarding decision to move to Calgary, Alberta and now she calls the city - and the Arrieta lab - home, applying her love of science to all aspects of her life including gardening, baking, fermenting, staying present in nature and living life to the fullest.