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A. marginale susceptibility assessment to antimicrobials used on Bovine Anaplasmosis control

Grant number: 16/00035-7
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): March 01, 2016
Effective date (End): February 28, 2017
Field of knowledge:Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
Principal Investigator:Sirlei Daffre
Grantee:Elisa Silva Ventura
Home Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated research grant:13/26450-2 - Molecular characterization of the interactions among ticks, rickettsiae and vertebrate hosts, AP.TEM


Anaplasma marginale is an obligate gram-negative alpha-proteobacterium that causes bovine anaplasmosis, a very important rickettsiosis in Brazil. In the host, it infects bovine erythrocytes and on its biological vector, the tick, the bacteria infects intestinal endothelium and salivary glands. Treatment for the clinical disease has long been the use of antibiotics such as oxytetracycline, dipropionate imidocarb, and enroflaxyn. However, this long-term use of antimicrobials on sub-therapeutic doses may lead to resistant variants of A. maginale that difficult treatment in situ of sick animals. Therefore, the main objectives of the current study are to develop an in vitro test with bovine erythrocytes to evaluate antimicrobials sensibility from ten cryopreserved field strains from different regions from the south of Brazil. Then the resistant factors of such strains will also be determined.