Antifungal susceptibility of yeast bloodstream isolates collected during a 10‐year period in Austria

Abstract

Summary Background Candida‐associated infections put a significant burden on western healthcare systems. Development of (multi‐)resistant fungi can become untreatable and threaten especially vulnerable target groups, such as the immunocompromised. Objectives We assessed antifungal susceptibility and explored possible influence factors of clinical Candida isolates collected from Austrian hospitals between 2007 and 2016. Methods Thousand three hundred and sixty clinical Candida spp. isolated from blood cultures were subjected to antifungal susceptibility testing (AFST) in a liquid‐handling aided continuous microdilution assay. We tested against fluconazole, voriconazole, posaconazole, itraconazole, isavuconazole, anidulafungin, caspofungin and micafungin according to EUCAST with additional recording of growth curves. We performed rigid quality control on each assay via growth curve assessment and included two standard reference strains. Minimal inhibitory concentrations (MIC) were quantified according to EUCAST guideline E.DEF 7.3.1, and susceptibility was evaluated using EUCAST clinical breakpoints. Results The isolate collection consisted of Candida albicans (59%), C. glabrata (19%), C. parapsilosis (9%), C. tropicalis (5%) and C. krusei (3%) and few other Candida species and fungi (5%). During the observed time period, species abundance and antifungal resistance rates remained constant. Multi‐resistance was rare and we found no single isolate which was resistant to both azoles and echinocandins. Within the antifungal resistance profile of our strain collection, we observed clusters along species boundaries. Conclusions Over the last decade, the distribution of Candida species and its level of antifungal resistance remained constant in Austria. Our data compare well with other European countries. Principal component analysis of the susceptibility profile of this collection revealed species‐specific clusters and substantial intra‐species variation, especially for C. glabrata.

Multilocus Sequence Typing Reveals Clonality of Fluconazole-Nonsusceptible Candida tropicalis: A Study From Wuhan to the Global

“…The susceptibility of Asian strains to azoles is lower than that of Europe, America, and Oceania, and FNS CCs have not been seen outside Asia. This is consistent with many previous studies (Corzo-Leon et al, 2014;Huang et al, 2014;Fernández-Ruiz et al, 2015;Tan et al, 2016;Wang H. et al, 2016;Fan et al, 2017;Teo et al, 2017;Wu P. F. et al, 2017;Morris et al, 2018;Scordino et al, 2018;Beyer et al, 2019;Chen et al, 2019). Three FNS CCs from three Asian countries With pulmonary candidiasis: A total of 4 cases.…”

“…Studies in Asia have shown that the non-susceptible rate of C. tropicalis to fluconazole is around 20% (mostly cross-resistant with other azoles) and increases rapidly (Wang H. et al, 2016;Fan et al, 2017;Chen et al, 2019). However, fluconazole-nonsusceptible (FNS) C. tropicalis is relatively rare in Europe and America (Corzo-Leon et al, 2014;Scordino et al, 2018;Beyer et al, 2019). Some studies support the link between FNS C. tropicalis infections and prior antifungal exposure (Choi et al, 2016;Chen et al, 2019), whereas others suggest that FNS C. tropicalis may come from the environment (Lo et al, 2017;Wang et al, 2018).…”

Evaluation of Molecular Epidemiology, Clinical Characteristics, Antifungal Susceptibility Profiles, and Molecular Mechanisms of Antifungal Resistance of Iranian Candida parapsilosis Species Complex Blood Isolates

“…Alarmingly, in the candidemia studies conducted in South Africa (Govender et al, 2016) and Turkey (Hilmioglu-Polat et al, 2018) almost half of FLZ-R isolates were crossresistant to VRZ. Similar to South Africa (Govender et al, 2016), Turkey (Hilmioglu-Polat et al, 2018), Qatar (Taj-Aldeen et al, 2018), Asia-Pacific countries (Tan et al, 2016), Spain and Italy (Bassetti et al, 2013;Tortorano et al, 2013), and Austria (Beyer et al, 2019) that showed low levels of echinocandin resistance (except for one MCF-R isolate), our isolates were susceptible to this antifungal class. We assume that such a low level of antifungal resistance in our study might be explained by the lack of previous and prolonged antifungal exposure (Ii et al, 2013;Perlin, 2015) and the fact that prophylactic antifungal therapy is not well-exercised in many Iranian hospitals.…”

“…The overall low rate of antifungal resistance is similar to what is observed in several European countries (Austria, Italy, and Spain) and Asia Pacific countries (Bassetti et al, 2013;Tortorano et al, 2013;Tan et al, 2016;Beyer et al, 2019), but quite different from studies conducted in the USA, South Africa, and India with surprisingly high rates of azole resistance (Raghuram et al, 2012;Govender et al, 2016;Singh et al, 2019). Alarmingly, in the candidemia studies conducted in South Africa (Govender et al, 2016) and Turkey (Hilmioglu-Polat et al, 2018) almost half of FLZ-R isolates were crossresistant to VRZ.…”

Do Candida albicans Isolates with Borderline Resistant Micafungin MICs Always Harbor FKS1 Hot Spot Mutations?

“…Because all of strains published by AURES are collected at our department we retested all strains in order to confirm the published resistance data [12]. The MICs of fluconazole, voriconazole, posaconazole, itraconazole, isavuconazole, anidulafungin, caspofungin, and micafungin of all isolates were determined while using the microdilution reference method as described by EUCAST.…”