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.

Julie Groizleau, Ph.D


Julie is a Research Associate in the Arrieta lab. Originally from France, Julie obtained her MSc from the Pasteur Institute - Université de Paris in Immunology, Microbiology, and Infectious Diseases. She obtained her PhD in Microbiology from the University of Copenhagen in Denmark. She then moved to Calgary as a postdoctoral fellow in the Harrison Lab. As a microbiologist, Julie’s expertise lies in bacterial biofilms and molecular genetics. After her PDF, Julie worked as the coordinator for the Pan- Canadian Microbiome Research Core, IMPACTT. There she gained extensive experience on science communication and project management. Owing to her career path, Julie has acquired a diverse set of skills that makes her a polyvalent asset. As a member of the Arrieta Lab, Julie is helping with various projects. She assists the team with grant managements and really enjoys giving a hand in the lab. Outside of the lab, Julie keeps her balance by staying active outdoor and exploring the Canadian Rockies.

Sunita Sharma, M.Sc



I have been working in the field of Biochemistry & Molecular Biology for many years at the University of Calgary. I am skilled in conducting experiments, employing varied models both in vivo as well as in vitro. I have a MSc in Life Sciences (Botany) from India where I worked as a research fellow at the CSIR-Indian Institute of Integrative Medicine. I have also recently obtained a Certificate in Pharmacy Assistant from SAIT, Alberta. I am always open to challenge myself to learn new techniques and methodologies. Apart from research, I have an interest in activities such as cooking, baking, gardening, and hiking.

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 and probiotic data sets. She has two publications. The name of one publication is “Estimating parameters of two-level individual level models of COVID-19 Epidemic Using Ensemble Learning Classifiers” which is published in Frontiers of Physics. Where she conceived and designed the experiments. She has another 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. As a member of the Alberta BLOOM Study Team and Arrieta lab, Andrea is responsible for recruitment, follow up, building relationships with participants and if she’s lucky, also getting to know babies who are on study! Outside of the lab, Andrea enjoys hiking, the outdoors and getting together with family and friends.

Nikki Sivakumar


I got my bachelor of science honors degree with a major in life sciences at Queen’s University. During my time here, I developed a strong passion for immunology and physiology, specifically in exploring the disease development of certain immunologic conditions. This led me to work at an asthma and allergy clinic, where I got to observe these clinical manifestations in real life. I also applied my passion for research development working as a summer student in the community health sciences department at the University of Calgary, where I got to explore novel interventions that may help improve long-term health outcomes of those suffering from diabetes and food insecurity. My hobbies include swimming, traveling, and spending time with my friends and family.

Allie McCreight


Allie is our new Clinical Administrative Assistant and will be working closely with our BLOOM studies teams. With an Earth Sciences background (Honours BES’08 in Geography – Biophysical Specialization, University of Waterloo & Environmental Technologist (ET’11) Advanced Diploma, Fleming College), she is very interested in learning more about microbiology and the immune system from her brilliant team. Using her recent business experience and strong organizational skills, Allie aims to support the Arrieta Lab’s operational goals of growth and efficiency. Outside of work, Allie plays rec hockey and loves camping, hiking, yoga and entertaining friends, while her two young children keep her busy.

Van Ortega, Ph.D



Van is an NSERC and MITACS-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 combining his experience in stress and immune research to investigate the early-life role of gut bacterial communities (i.e. the gut microbiome) on the developmental outcomes of neuroendocrine stress-axis systems that are integral for maintaining immune health and physiological homeostasis later in life. 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.

Thaís Glatthardt, Ph.D


Thaís Glatthardt joined the Arrieta lab in July 2020 as a Postdoctoral Fellow in the Department of Physiology and Pharmacology. She holds a B.Sc., M.Sc., and Ph.D. in Microbiology from Federal University of Rio de Janeiro, Brazil. During her master and doctoral research, she investigated the effect of metabolites produced by skin microbiome against multiresistant pathogens, focusing in antivirulence molecules that could be helpful in the development of new therapeutical approaches. She was also awarded the Rising Star Fellowship from the Beverly Phillips Rising Star Program. Remaining in the microbiome derived bioactive metabolites field, in the Arrieta lab she is investigating the role of some novel microbiome-produced small aromatic molecules (MPSAMs) against Salmonella and EPEC virulence factors and infection.

Erik van Tilburg Bernardes, M.Sc

Linkedin, Pubmed, Google Scholar


Erik is a CIHR- and Eyes High-funded PhD student in the Arrieta lab. Erik holds 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).

Erik’s 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. His previous experience includes 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 gut fungi shape the host’s immune system and finally prevent/predispose individuals to developing diseases.

Emily Mercer

LinkedIn, Google Scholar, Research Gate


Emily is a Ph.D. student in the Arrieta lab, holding a Bachelor of Science in Microbiology from the University of Guelph. 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 life adversity in our lifelong health trajectories. In her Ph.D. thesis, Emily will explore interkingdom assembly dynamics in the infant gut microbiome and examine the relationship between early life stress and the establishment of the gut microbiome and stress-related brain circuitry in premature infants. Her research interests include microbial ecology, metabolomics, host-microbe interactions, the gut-brain axis, and brain development. 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.

David Girgis


David is a grade 12 student at St. Francis High School volunteering in the Arrieta lab this year. He was first exposed to health research last year, and found an interest in the human microbiome and its larger effect on the body. David hopes to learn more about these topics at the lab. In the future, he wishes to pursue a career in healthcare and health research. In his free time, he enjoys playing basketball, skiing, and hiking.

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.