A O S Fonseca1, D I B Pereira2, F S Maia Filho3, L G Osório4, B P Maroneze5, J S S Valente5, L Pötter6, M C A Meireles1. 1. Programa de Pós-graduação em Veterinária, Universidade Federal de Pelotas, Pelotas, Brazil Laboratório de Micologia, Departamento de Doenças Infecciosas, Faculdade de Veterinária, Universidade Federal de Pelotas, Pelotas, Brazil. 2. Programa de Pós-graduação em Parasitologia, Universidade Federal de Pelotas, Pelotas, Brazil Laboratório de Micologia, Departamento de Microbiologia e Parasitologia, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, Brazil danielabrayer@gmail.com. 3. Programa de Pós-graduação em Parasitologia, Universidade Federal de Pelotas, Pelotas, Brazil Laboratório de Micologia, Departamento de Microbiologia e Parasitologia, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, Brazil. 4. Laboratório de Micologia, Departamento de Doenças Infecciosas, Faculdade de Veterinária, Universidade Federal de Pelotas, Pelotas, Brazil. 5. Laboratório de Micologia, Departamento de Microbiologia e Parasitologia, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, Brazil. 6. Departamento de Zootecnia, Universidade Federal de Santa Maria, Santa Maria, Brazil.
Abstract
OBJECTIVES: The purpose of this study was to compare the in vitro susceptibilities of 22 Brazilian isolates of Pythium insidiosum to antifungals using a standardized inoculum of zoospores and a proposed novel inoculum prepared from cultured mycelia (hyphae) of P. insidiosum. METHODS: A zoospore suspension of P. insidiosum was obtained by the zoosporogenesis technique. The hyphal inoculum was prepared from a suspension of P. insidiosum mycelium. Susceptibility to each drug was evaluated using the CLSI M38-A2 method. RESULTS: Of the 88 MIC comparisons performed, 36 (41%) showed the same MIC value for the two inocula. The agreement (differences not greater than one dilution) between MICs obtained with both types of inocula was 39.8% (35/88). In other MIC comparisons analysed, 17 (19.3%) showed differences of two or three dilutions. CONCLUSIONS: We conclude that the use of hyphal inocula of P. insidiosum for in vitro susceptibility tests could be a suitable method for evaluating antimicrobial susceptibility, particularly when it is not possible to obtain a standardized zoospore inoculum.
OBJECTIVES: The purpose of this study was to compare the in vitro susceptibilities of 22 Brazilian isolates of Pythium insidiosum to antifungals using a standardized inoculum of zoospores and a proposed novel inoculum prepared from cultured mycelia (hyphae) of P. insidiosum. METHODS: A zoospore suspension of P. insidiosum was obtained by the zoosporogenesis technique. The hyphal inoculum was prepared from a suspension of P. insidiosum mycelium. Susceptibility to each drug was evaluated using the CLSI M38-A2 method. RESULTS: Of the 88 MIC comparisons performed, 36 (41%) showed the same MIC value for the two inocula. The agreement (differences not greater than one dilution) between MICs obtained with both types of inocula was 39.8% (35/88). In other MIC comparisons analysed, 17 (19.3%) showed differences of two or three dilutions. CONCLUSIONS: We conclude that the use of hyphal inocula of P. insidiosum for in vitro susceptibility tests could be a suitable method for evaluating antimicrobial susceptibility, particularly when it is not possible to obtain a standardized zoospore inoculum.
Authors: Aaron R Farmer; Clinton K Murray; Ian R Driscoll; Brian L Wickes; Nathan Wiederhold; Deanna A Sutton; Carmita Sanders; Katrin Mende; Brent Enniss; James Feig; Anuradha Ganesan; Elizabeth A Rini; Todd J Vento Journal: J Clin Microbiol Date: 2015-04-01 Impact factor: 5.948
Authors: Erico S Loreto; Juliana S M Tondolo; Maiara B Pilotto; Sydney H Alves; Janio M Santurio Journal: Antimicrob Agents Chemother Date: 2014-09-15 Impact factor: 5.191