Peron Isabela Haddad, Reichert-Lima Franqueline, Busso-Lopes Ariane Fidelis, Nagasako Cristiane Kibune, Lyra Luzia, Moretti Maria Luiza, Schreiber Angelica Zaninelli
Clinical Pathology Department Faculty of Medical Sciences, University of Campinas, Campinas, Sao Paulo, Brazil.
Internal Medicine Department, Faculty of Medical Sciences, University of Campinas, Campinas, Sao Paulo, Brazil.
PLoS One. 2016 Jul 14;11(7):e0158126. doi: 10.1371/journal.pone.0158126. eCollection 2016.
Candida albicans caused 44% of the overall candidemia episodes from 2006 to 2010 in our university tertiary care hospital. As different antifungal agents are used in therapy and also immunocompromised patients receive fluconazole prophylaxis in our institution, this study aimed to perform an antifungal susceptibility surveillance with the C.albicans bloodstream isolates and to characterize the fluconazole resistance in 2 non-blood C.albicans isolates by sequencing ERG11 gene. The study included 147 C. albicans bloodstream samples and 2 fluconazole resistant isolates: one from oral cavity (LIF 12560 fluconazole MIC: 8μg/mL) and one from esophageal cavity (LIF-E10 fluconazole MIC: 64μg/mL) of two different patients previously treated with oral fluconazole. The in vitro antifungal susceptibility to amphotericin B (AMB), 5-flucytosine (5FC), fluconazole (FLC), itraconazole (ITC), voriconazole (VRC), caspofungin (CASP) was performed by broth microdilution methodology recommended by the Clinical and Laboratory Standards Institute documents (M27-A3 and M27-S4, CLSI). All blood isolates were classified as susceptible according to CLSI guidelines for all evaluated antifungal agents (MIC range: 0,125-1.00 μg/mL for AMB, ≤0.125-1.00 μg/mL for 5FC, ≤0.125-0.5 μg/mL for FLC, ≤0.015-0.125 μg/mL for ITC, ≤0.015-0.06 μg/mL for VRC and ≤0.015-0.125 μg/mL for CASP). In this study, we also amplified and sequenced the ERG11 gene of LIF 12560 and LIF-E10 C.albicans isolates. Six mutations encoding distinct amino acid substitutions were found (E116D, T128K, E266D, A298V, G448V and G464S) and these mutations were previously described as associated with fluconazole resistance. Despite the large consumption of antifungals in our institution, resistant blood isolates were not found over the trial period. Further studies should be conducted, but it may be that the very prolonged direct contact with the oral antifungal agent administered to the patient from which was isolated LIF E-10, may have contributed to the development of resistance.
在我们大学的三级护理医院中，2006年至2010年期间，白色念珠菌导致了44%的念珠菌血症发作。由于在治疗中使用了不同的抗真菌药物，并且在我们机构免疫功能低下的患者接受氟康唑预防，本研究旨在对白色念珠菌血流分离株进行抗真菌药敏监测，并通过对ERG11基因进行测序来鉴定2株非血液白色念珠菌分离株中的氟康唑耐药性。该研究包括147份白色念珠菌血流样本和2株氟康唑耐药分离株：一株来自两名不同患者的口腔（LIF 12560，氟康唑MIC：8μg/mL），另一株来自食管腔（LIF-E10，氟康唑MIC：64μg/mL），这两名患者之前均接受过口服氟康唑治疗。通过临床和实验室标准协会文件（M27-A3和M27-S4，CLSI）推荐的肉汤微量稀释法，对两性霉素B（AMB）、5-氟胞嘧啶（5FC）、氟康唑（FLC）、伊曲康唑（ITC）、伏立康唑（VRC）、卡泊芬净（CASP）进行体外抗真菌药敏试验。根据CLSI指南，所有评估的抗真菌药物（AMB的MIC范围：0.125 - 1.00μg/mL，5FC的MIC范围：≤0.125 - 1.00μg/mL，FLC的MIC范围：≤0.125 - 0.5μg/mL，ITC的MIC范围：≤0.015 - 0.125μg/mL，VRC的MIC范围：≤0.015 - 0.06μg/mL，CASP的MIC范围：≤0.015 - 0.125μg/mL），所有血液分离株均被分类为敏感。在本研究中，我们还对LIF 12560和LIF-E10白色念珠菌分离株的ERG11基因进行了扩增和测序。发现了6个编码不同氨基酸替代的突变（E116D、T128K、E266D、A298V、G448V和G464S），这些突变之前被描述为与氟康唑耐药性相关。尽管我们机构大量使用抗真菌药物，但在试验期间未发现耐药血液分离株。应进行进一步研究，但可能是与从其分离出LIF E-10的患者所服用的口服抗真菌药物的长时间直接接触，导致了耐药性的产生。
