Antifungal susceptibility of bloodstream yeasts isolated at a public children’s hospital in Brazil: comparison of the Etest^® and the AFST–EUCAST microdilution method

Abstract

This study compared the minimum inhibitory concentration (MIC) results from the proposed standard methods of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing (AFST-EUCAST) with the commercial system Etest(R) in the evaluation of susceptibility to flucytosine, fluconazole, itraconazole, voriconazole, and amphotericin B of 136 Candida spp. isolated from the blood of hospitalized children. The results presented a greater agreement among Etest(R) MICs +/-2 log2 dilutions of AFST-EUCAST for fluconazole (98.1% and 96.3%) and voriconazole (100% and 100%) for Candida albicans and Candida parapsilosis. For Candida glabrata, the agreement was greater only for fluconazole (81.8%) and voriconazole (100%). For amphotericin B, the agreement between the methods was low for all species. The agreement percentage among the Etest(R) and AFST-EUCAST susceptibility profiles was high according to the MIC breakpoints recommended by the M27-A2 protocol for the majority of the yeasts, except for fluconazole and itraconazole against Candida tropicalis and for itraconazole against C. glabrata and Candida krusei. According to both methodologies, a great number of Candida spp. isolates showed an in vitro susceptibility to all evaluated antifungal agents. Overall, both procedures can be reliable techniques for susceptibility tests of yeasts, but the assessment of interlaboratory agreement and correlation of MICs by different methods with in vivo response are of great importance.

Candida spp. isolated from inpatients, the environment, and health practitioners in the pediatric unit at the Universitary Hospital of the Jundiaí Medical College, state of São Paulo, Brazil

“…In pediatric or neonatal units, C. parapsilosis has been marked as the second most common agent in patients with candidemia, a fact that is linked to the exogenous contamination because of the patients' manipulation by the hospital staff, the patients' exposure to invasive procedures in the ICU, prematurity, immunosuppression, and long-course antibiotic therapy 34,35,[39][40][41] . Results from many other works have evidenced C. tropicalis or C. parapsilosis as the main Candida non-albicans agent involved in the different types of candidemia around us 38,[42][43][44][45][46][47] , which is different from what has been observed in Europe and North America, where C. glabrata has been detected as the second most recurrent pathogen after C. albicans 43,44,[47][48][49] . This species was not isolated in our research.…”

“…Fifty percent to 60% of the patients who present this species are expected to develop systemic infections 38 . Other studies point to C. parapsilosis as the most prevalent species among the Candida non-albicans [1][2][3][4]18,24,34,35,39 .…”

Fenótipos e perfis de sensibilidade aos antifúngicos de leveduras isoladas da mucosa oral de cães da cidade de Campinas, São Paulo

“…Outro fator que tem dado origem a casos alarmantes de resistência aos antifúngicos, entre as espécies de Candida, é a administração por períodos prolongados do fármaco em casos de infecção e o uso profilático dos antifúngicos tais como a anfotericina B e os azóis menos tóxicos (Pfaller et al, 1995;Matsumoto et al, 2007 inkin, T. asteroides e T. cutaneum Bentubo et al, 2013).…”

“…É uma excelente técnica de determinação da sensibilidade aos antifúngicos "in vitro", simples, de fácil execução, com resultados rápidos, não necessitando de equipamentos de custos elevados ou especializados (Pfaller et al, 1995;Silva et al, 2002;Matsumoto et al, 2007;Navarini, 2007).…”

“…Figura 2.9 -"Etest" para fluconazol e itraconazol Fonte: Navarini (2007) Em um de seus estudos, Matsumoto et al (2007), comparou resultados de dois métodos de avaliação da sensibilidade aos antifúngicos, o AFST-EUCAST e o "Etest", para as mesmas cepas de leveduras. Ambos os testes mostraram confiabilidade, porém não 100% concordantes, o que demonstra uma maior necessidade de estudo e de padronização das CIMs (Matsumoto et al, 2007).…”