Current Members

Marie-Claire Arrieta, Ph.D, PI

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Dr. Marie-Claire Arrieta an Associate Professor at the University of Calgary in Canada. She received her undergraduate degree in Microbiology from Universidad de Costa Rica, and later received MSc and PhD degrees from the University of Alberta. Following her postdoctoral training at the University of British Columbia (Brett Finlay’s group), she joined the departments of Physiology, Pharmacology and Pediatrics of the University of Calgary in 2016.

Her contributions as first or senior author have been published in leading journals such as Gut, Science Translational Medicine, Cell Host and Microbe and Nature Communications. She was awarded the CIHR-Sick Kids New Investigator Award in 2018, which is given to a select group of Canadian young investigators with outstanding contributions to children’s health. In 2020, she received the Killam Emerging Research Leader and the Peter Lougheed Research awards, given to top researchers at UCalgary, as well being named one of Calgary’s top 40 under 40 in 2017, and a UCalgary Peak Scholar in 2018. In 2023, she was selected as one of UCalgary Research Excellence Chairs and she was invited to join the Academy of Science of the Royal Society of Canada.

As an advocate of science communication to the public, Dr. Arrieta has written a best-selling public book, Let Them Eat Dirt, and is involved in several science communication initiatives within Canada and abroad, including public talks, a second book and a documentary film project.  

Julie Groizeleau, Ph.D, Research Associate


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, Laboratory Research Assistant



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.

Michel Emond, Laboratory Research Assistant


Michel graduated in the field of Wildlife Management at the CEGEP of St-Anne-De-La Pocatière, Québec. His career path changed when an opportunity opened up for him to work at McGill University. While there, he gained skills as a lab animal technician and a tissue culture specialist. He was eventually offered a position as a Research Assistant at AstraZeneca R&D Montréal. More recently, he moved to Calgary with his wife and kids to work at the Clara Christie Centre for Mouse Genomics (University of Calgary). With his extensive experience within the field of laboratory animal research, both in the private industry and the public sector, Michel is a great asset to the team of the Arrieta Lab!

William Nguyen, M.Sc, Laboratory Research Assistant

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William joined the Arrieta lab as a Research Assistant upon obtaining his M.Sc. in Medical Sciences at the University of Calgary. His thesis examined eosinophil recruitment in a TNBS model of ulcerative colitis, employing a variety of microscopy techniques including whole body imaging, thin and thick tissue immunofluorescence, as well as intravital microscopy. He also obtained his Bachelor of Science in Zoology from the University of Calgary. His honors thesis focused on free fatty acid (FFA) accumulation in aging neurons, utilizing electrophysiology and fluorescence microscopy to quantify FFAs in a snail model. With extensive microscopy, image analysis, and surgical experience he is assisting on several different projects, adding an imaging component to the Arrieta lab’s broad microbiology repertoire. Furthermore, he is developing new imaging and staining protocols for future studies. Outside the lab William actively engages in adventure and photography (Website :

Andrea Guedez, Lead Clinical Study Coordinator


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. 

Fatimoh Kasaba, PHD STUDENT


After obtaining my MSc in Nutritional Sciences at the University of Nottingham, I developed a strong interest in public health research. As part of my MAS in Nutrition and Health at ETH Zurich, I participated in research aimed at directly informing national health policy in Jamaica and developed an interest in microbiome research.  Particularly, I have a strong interest in understanding the interplay between our diet, microbiome, and other factors, notably their roles in the development of chronic diseases but also how these can be modulated to promote health and prevent diseases. I also find the prospective of  influencing health policies very enticing. As a BLOOM clinical research assistant, I enjoy meeting and interacting with the study participants, who I am helping to recruit as well as following-up our data collection. 

Allie McCreight, Clinical Administrative Assistant 


Allie is our Clinical Administrative Assistant and is 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.

Alma Tariro Muropa, Bioinformatician & Data analyst


Alma is our bioinformatician and data analyst. Her professional background notably lies in health research, working with others on health innovations, making data-driven decisions about how to implement them in both public and private health institutions. Her extensive experience in conducting routine and research health data collection, management, are instrumental to generate meaningful discoveries from our clinical Alberta BLOOM study. Alma investigates data from the study to enable visualization, and decipher predictions, that will advance the field of child health research. Alma thrives on having the chance to improve children's health.

robin knol, BLOOM registered research nurse


Robin is a Registered Nurse who does research with a background in Labor & Delivery and NICU nursing. She has a strong passion for research, which dates back to her nursing school days. Her interest in research was further fueled during her time as a NICU nurse, particularly with the BLOOM study. 

In her role in the BLOOM study, Robin carries out potential participant requitement, following up with those families whilst collecting data for the study, addressing any questions or concerns families may have.  

Robin's dedication to working with families and her desire to improve outcomes for premature infants makes her an asset to the BLOOM study. Her combination of nursing expertise and research interest allows her to bridge the gap between clinical practice and scientific inquiry for the benefit of future generations. 

Thaís Glatthardt, Ph.D, PDF


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. 

Mona Parizadeh, Ph.D, PDF

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Mona is a postdoctoral fellow specialized in microbial ecology, community ecology, computational biology, and bioinformatics. She holds a Ph.D. in Biology and a DESS (diplôme d'études supérieures spécialisées) in bioinformatics from the Université du Québec à Montréal (UQAM), Canada. Her doctoral research focused on the drivers of plant and soil microbiome diversity and composition in agro-ecosystems and their variation in response to perturbations. This work was funded by Agriculture and Agri-Food Canada. She also has an M.Sc. in Horticulture from the University of Tehran, Iran, where she studied the genetic diversity of Iranian Basil populations. Mona is interested in environmental effects on microbiomes, host-microbe and microbe-microbe interactions, and drivers of microbial community assembly in different environments, including humans, plants and soil. She addresses these objectives by applying ecological theory and using different high-throughput sequencing approaches, including meta-barcoding and meta-omics.

Other than research, Mona enjoys cooking new recipes, traveling and living in different places around the world, learning about different cultures and languages, and exploring science and art integration.

Michelle Asbury, Ph.d, PDF

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Michelle is a Postdoctoral Associate in the Departments of Physiology & Pharmacology and Pediatrics at the University of Calgary, as part of the Arrieta lab. She holds MSc and PhD degrees in Nutritional Sciences from the University of Toronto (Dr. Deborah O’Connor’s lab) where she studied the role of early-life nutrition for growth and microbiome development of very-low-birth-weight infants. Building upon her prior research, Michelle is now focused on characterizing the complex nutritional and immunological “system” of human milk and its importance for orchestrating microbiome assembly and immune system development in preterm infants as part of the Alberta BLOOM study. Michelle’s research is generously supported by postdoctoral fellowships from the Killam Laureates, Molly Towell Perinatal Research Foundation, and L’Oreal Canada-UNESCO. 

Emily Mercer, Ph.D student

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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, Ph.D student



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 CIHR- PhD student in the lab and is exploring the contributions of the microbiome in metabolic development and inflammation. 

Kaetlyn Phillips, M.Sc  student


Kaetlyn is currently completing her M.Sc. thesis in the Arrieta Lab. She achieved her B.Sc. in Honors Biology from the University of Waterloo where participation in the co-op stream provided her with multidisciplinary research experiences and an NSERC Undergraduate Student Research Award in 2018. Her decision to study the microbiome became the bridge between her childhood passion for health sciences, her preferred coursework in molecular and microbiology, and her avid engagement in research to date. Her thesis will focus on the gut-brain axis by investigating the relationship between gut microbiome immaturity in premature infants and neurodevelopmental outcomes using gnotobiotic mouse models. In her personal time, she enjoys hiking, libraries, art galleries and museums.

Van Ortega, Ph.D, PDF



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.

Ellen ren, Coop student


Ellen is a Co-op student from UBC working as an undergraduate research assistant at the Arrieta lab. She has completed her 3rd year at UBC studying Biology. Ellen is excited to learn about immunology, microbiology, adipose tissue, lab techniques, and everything else! Outside of the lab, She enjoys cooking, piano, badminton, and video games. 

Simrit Rai, Summer Student

Simrit is going into her fourth year studying Psychology and Cellular Molecular Microbial Biology at the University of Calgary. Through both her neuropsychology and immunology classes she became interested in the microbiome and the gut-brain axis. Simrit joined the Arrieta team as a volunteer in November 2021. She is currently working on determining the role of microglia on gut microbiota and its influence on stress and immunity.

Erik van Tilburg Bernardes, M.Sc, Ph.D student

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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.