Development of a stock medium for the preservation of the national collection of Leptospira spp. maintained by the Laboratory of Bacterial Zoonoses of the University of São Paulo

• Grant number: 25/12694-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Israel Barbosa Guedes
• Grantee: Gabriela Rodrigues Evangelista Brandão
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The Laboratory of Bacterial Zoonosis at the Faculty of Veterinary Medicine and Animal Science at the University of São Paulo have the largest collection of live antigens of Leptospira spp. from Brazil. These bacteria are kept for decades in the laboratory, which makes this rich collection available for genetic and microbiological studies carried out throughout the country. The conservation of this large collection is laborious and relatively expensive work, as it involves the production of large amounts of culture medium and quarterly seeds to maintain viability of these samples. However, environmental contamination and drying of the media constantly threaten the maintenance of these bacteria; in fact, Fletcher's medium, traditionally used for this purpose, has been discontinued. Therefore, the objective of this project is to develop a simple stock culture medium with the incorporation of a contamination-inhibiting agent, as an alternative to the standard Fletcher medium. To achieve this, all 151 samples in the collection will be seeded in the developed medium and incubated for five months and then seeded in a new medium for another five months, evaluating the bacterial viability, the level of the medium in the tubes and the presence of contamination, in comparison with the samples seeded in Fletcher's medium. In addition, all characterization data from the samples in the collection will be digitized and entered a website to create a digital catalog and facilitate access to information. The main expected results are the cultivation of leptospires for a longer incubation time, avoiding environmental contamination and reducing the volume of medium, favoring the compaction and optimization of the collection and savings in the production of the medium. (AU)