Collection of human bacteria at University of Tartu, Estonia.

In 1889, Franz Kral founded the “Kral Bacteriological Museum” in Prague, pioneering microbial culture collections ( 1 ). In the University of Tartu (UT), Estonia, studies on human microbial ecology began during the 1960s under Prof. Akivo Lenzner, including research on Soviet cosmonauts’ lactobiota. The cosmonauts received lyophilized strains of their own beneficial lactobacilli, marking the emergence of personalized medicine. During the 1990s, the collected lactobacilli were transferred to a partner institute in Moscow ( 2 ). The Human Microbiota Biobank (HUMB) in UT was established by Prof. Marika Mikelsaar in 1994 during the Estonian-Swedish allergy study ( 3 ). In addition to lactobacilli, opportunistic bacteria were added to collection through several national and EU projects ( 4 – 7 ). In 2010, the HUMB joined the World Data Center for Microorganisms (WDCM), and in 2012, the European Cultural Collections Organization (ECCO). As of 2025, the collection holds nearly 20,000 human-derived microbial strains from over 120 genera and 350 species ( Fig. 1 ). The HUMB contains both lactic acid bacteria and opportunistic bacteria, many of which have been characterized for properties and genetic traits. Number of strains of the most numerous genera in the HUMB collection. Lactic acid bacteria in the HUMB form an important basis for probiotic development. Patented strains (deposited also in DSMZ) include L. fermentum ME-3 ( 8 – 14 ) developed in University of Tartu and L. plantarum Tensia ( 15 ) and L. plantarum Inducia ( 16 ) developed in a competence center, BioCC. ME-3 is an antioxidant and anti-inflammatory strain; Tensia lowers diastolic blood pressure through various mechanisms; and Inducia lowers total and ox-LDL cholesterol levels. These strains are available in several food and pharmaceutical products. Opportunistic bacteria in the HUMB originate from different specimens of healthy and diseased subjects ( Table 1 ). In the majority of them, properties have been detected like antibiotic susceptibility, resistance-associated genes, or typing patterns ( 17 – 19 ). Subcollections of bacteria in the HUMB collection Only a few examples of references are given in the table. More references can be seen on the HUMB website. Collection supports continuing research. Lactic acid bacteria are tested in vitro and in vivo to develop novel probiotics and functional foods ( 48 , 49 ). Drug resistance and virulence markers are monitored in opportunistic bacteria. Over 40 PhD and MSc theses have been defended and over 400 papers published using and/or supplementing the collection. The development of modern database and website was initiated in 2010. The information platform is based on MySQL. The database was developed using dbForge Studio (Devart). PHPRunner (Xlinesoft) was used to create a web-based user interface that is managed by cPanel platform (cPanel, L.L.C.) on a webserver of UT. The HUMB webpage is hosted by Estonian Electronic Microbial DataBase (EEMB). The other collections within EEMB (CELMS, CREP) are not associated with the HUMB. Guest users can view basic catalog data, while registered users have access to full structure with editing capabilities. New strains are obtained into collection according to Material Deposit Agreement (MDA) in accordance with ECCO suggestions ( 50 , 51 ). Strains are available for academic research under Material Transfer Agreement (MTA). Eligible collaborators include accredited academic institutions, publicly funded research organizations, and non-profit entities engaged in scientific research. Commercial entities may be considered on a case-by-case basis, subject to separate agreements. All collaborations are expected to result in shared scientific outputs, such as publications, dissertations, or patents.