Antifungal susceptibility profile of Candida clinical isolates from 22 hospitals of São Paulo State, Brazil.

This study aimed to evaluate the frequency of cryptic Candida species from candidemia cases in 22 public hospitals in São Paulo State, Brazil, and their antifungal susceptibility profiles. During 2017 and 2018, 144 isolates were molecularly identified as 14 species; C. parapsilosis (32.6%), C. albicans (27.7%), C. tropicalis (14.6%), C. glabrata (9.7%), C. krusei (2.8%), C. orthopsilosis (2.8%), C. haemulonii var. vulnera (2.1%), C. haemulonii (1.4%), C. metapsilosis (1.4%), C. dubliniensis (1.4%), C. guilliermondii (1.4%), C. duobushaemulonii (0.7%), C. kefyr (0.7%), and C. pelliculosa (0.7%). Poor susceptibility to fluconazole was identified in 6.4% of C. parapsilosis isolates (0.12 to >64 µg/mL), 50% of C. guilliermondii (64 µg/mL), 66.6% of C. haemulonii var. vulnera (16-32 µg/mL), and C. duobushaemulonii strain (MIC 64 µg/mL). Our results corroborated the emergence of C. glabrata in Brazilian cases of candidemia as previously reported. Importantly, we observed a large proportion of non-wild type C. glabrata isolates to voriconazole (28.6%; <0.015 to 4 µg/mL) all of which were also resistant to fluconazole (28.6%). Of note, C. haemulonii, a multidrug resistant species, has emerged in the Southeast region of Brazil. Our findings suggested a possible epidemiologic change in the region with an increase in fluconazole-resistant species causing candidemia. We stress the relevance of routine accurate identification to properly manage therapy and monitor epidemiologic trends.

Antifungal susceptibility profile of Candida clinical isolates from 22 hospitals of São Paulo State, Brazil

This study aimed to evaluate the frequency of cryptic Candida species from candidemia cases in 22 public hospitals in São Paulo State, Brazil, and their antifungal susceptibility profiles. During 2017 and 2018, 144 isolates were molecularly identified as 14 species; C. parapsilosis (32.6%), C. albicans (27.7%), C. tropicalis (14.6%), C. glabrata (9.7%), C. krusei (2.8%), C. orthopsilosis (2.8%), C. haemulonii var. vulnera (2.1%), C. haemulonii (1.4%), C. metapsilosis (1.4%), C. dubliniensis (1.4%), C. guilliermondii (1.4%), C. duobushaemulonii (0.7%), C. kefyr (0.7%), and C. pelliculosa (0.7%). Poor susceptibility to fluconazole was identified in 6.4% of C. parapsilosis isolates (0.12 to >64 µg/mL), 50% of C. guilliermondii (64 µg/mL), 66.6% of C. haemulonii var. vulnera (16-32 µg/mL), and C. duobushaemulonii strain (MIC 64 µg/mL). Our results corroborated the emergence of C. glabrata in Brazilian cases of candidemia as previously reported. Importantly, we observed a large proportion of non-wild type C. glabrata isolates to voriconazole (28.6%; <0.015 to 4 µg/mL) all of which were also resistant to fluconazole (28.6%). Of note, C. haemulonii, a multidrug resistant species, has emerged in the Southeast region of Brazil. Our findings suggested a possible epidemiologic change in the region with an increase in fluconazole-resistant species causing candidemia. We stress the relevance of routine accurate identification to properly manage therapy and monitor epidemiologic trends.

Multicenter, International Study of MIC/MEC Distributions for Definition of Epidemiological Cutoff Values for Sporothrix Species Identified by Molecular Methods.

Clinical and Laboratory Standards Institute (CLSI) conditions for testing the susceptibilities of pathogenic Sporothrix species to antifungal agents are based on a collaborative study that evaluated five clinically relevant isolates of Sporothrixschenckii sensu lato and some antifungal agents. With the advent of molecular identification, there are two basic needs: to confirm the suitability of these testing conditions for all agents and Sporothrix species and to establish species-specific epidemiologic cutoff values (ECVs) or breakpoints (BPs) for the species. We collected available CLSI MICs/minimal effective concentrations (MECs) of amphotericin B, five triazoles, terbinafine, flucytosine, and caspofungin for 301 Sporothrix schenckii sensu stricto, 486 S. brasiliensis, 75 S. globosa, and 13 S. mexicana molecularly identified isolates. Data were obtained in 17 independent laboratories (Australia, Europe, India, South Africa, and South and North America) using conidial inoculum suspensions and 48 to 72 h of incubation at 35°C. Sufficient and suitable data (modal MICs within 2-fold concentrations) allowed the proposal of the following ECVs for S. schenckii and S. brasiliensis, respectively: amphotericin B, 4 and 4 µg/ml; itraconazole, 2 and 2 µg/ml; posaconazole, 2 and 2 µg/ml; and voriconazole, 64 and 32 µg/ml. Ketoconazole and terbinafine ECVs for S. brasiliensis were 2 and 0.12 µg/ml, respectively. Insufficient or unsuitable data precluded the calculation of ketoconazole and terbinafine (or any other antifungal agent) ECVs for S. schenckii, as well as ECVs for S. globosa and S. mexicana These ECVs could aid the clinician in identifying potentially resistant isolates (non-wild type) less likely to respond to therapy.

Species distribution and antifungal susceptibility profile of Candida isolates from bloodstream infections in Lima, Peru.

Yeast identification and in vitro susceptibility testing provide helpful information for appropriate administration of antifungal treatments; however, few reports from the Latin American region have been published. The aim of this study was to identify the species present in isolates from bloodstream infections diagnosed in nine hospitals in Lima, Peru and to determine their in vitro susceptibility to four antifungal drugs. We tested and identified 153 isolates collected between October 2009 and August 2011 using standard methods. PCR and PCR-RFLP assays were performed to distinguish Candida albicans from Candida dubliniensis and to identify species of the Candida parapsilosis and Candida glabrata complexes. Antifungal susceptibility testing for fluconazole, anidulafungin and voriconazole was performed using the CSLI M27-A3 method, and amphotericin B susceptibility was determined using the Etest method. The most frequently isolated species were: C. albicans (61; 39.9 %), C. parapsilosis (43; 28.1 %), C. tropicalis (36; 23.5%) and C. glabrata (8; 5.2 %). The overall susceptibility rates were 98.0 %, 98.7 %, 98.0 % and 97.4 % for amphotericin B, fluconazole, voriconazole and anidulafungin, respectively. No isolate was resistant to more than one drug. These results showed that the rate of resistance to four antifungal drugs was low among Candida bloodstream isolates in Lima, Peru.

Multilaboratory study of epidemiological cutoff values for detection of resistance in eight Candida species to fluconazole, posaconazole, and voriconazole.

Although epidemiological cutoff values (ECVs) have been established for Candida spp. and the triazoles, they are based on MIC data from a single laboratory. We have established ECVs for eight Candida species and fluconazole, posaconazole, and voriconazole based on wild-type (WT) MIC distributions for isolates of C. albicans (n=11,241 isolates), C. glabrata (7,538), C. parapsilosis (6,023), C. tropicalis (3,748), C. krusei (1,073), C. lusitaniae (574), C. guilliermondii (373), and C. dubliniensis (162). The 24-h CLSI broth microdilution MICs were collated from multiple laboratories (in Canada, Brazil, Europe, Mexico, Peru, and the United States). The ECVs for distributions originating from ≥6 laboratories, which included ≥95% of the modeled WT population, for fluconazole, posaconazole, and voriconazole were, respectively, 0.5, 0.06 and 0.03 µg/ml for C. albicans, 0.5, 0.25, and 0.03 µg/ml for C. dubliniensis, 8, 1, and 0.25 µg/ml for C. glabrata, 8, 0.5, and 0.12 µg/ml for C. guilliermondii, 32, 0.5, and 0.25 µg/ml for C. krusei, 1, 0.06, and 0.06 µg/ml for C. lusitaniae, 1, 0.25, and 0.03 µg/ml for C. parapsilosis, and 1, 0.12, and 0.06 µg/ml for C. tropicalis. The low number of MICs (<100) for other less prevalent species (C. famata, C. kefyr, C. orthopsilosis, C. rugosa) precluded ECV definition, but their MIC distributions are documented. Evaluation of our ECVs for some species/agent combinations using published individual MICs for 136 isolates (harboring mutations in or upregulation of ERG11, MDR1, CDR1, or CDR2) and 64 WT isolates indicated that our ECVs may be useful in distinguishing WT from non-WT isolates.

Interlaboratory variability of Caspofungin MICs for Candida spp. Using CLSI and EUCAST methods: should the clinical laboratory be testing this agent?

Although Clinical and Laboratory Standards Institute (CLSI) clinical breakpoints (CBPs) are available for interpreting echinocandin MICs for Candida spp., epidemiologic cutoff values (ECVs) based on collective MIC data from multiple laboratories have not been defined. While collating CLSI caspofungin MICs for 145 to 11,550 Candida isolates from 17 laboratories (Brazil, Canada, Europe, Mexico, Peru, and the United States), we observed an extraordinary amount of modal variability (wide ranges) among laboratories as well as truncated and bimodal MIC distributions. The species-specific modes across different laboratories ranged from 0.016 to 0.5 µg/ml for C. albicans and C. tropicalis, 0.031 to 0.5 µg/ml for C. glabrata, and 0.063 to 1 µg/ml for C. krusei. Variability was also similar among MIC distributions for C. dubliniensis and C. lusitaniae. The exceptions were C. parapsilosis and C. guilliermondii MIC distributions, where most modes were within one 2-fold dilution of each other. These findings were consistent with available data from the European Committee on Antimicrobial Susceptibility Testing (EUCAST) (403 to 2,556 MICs) for C. albicans, C. glabrata, C. krusei, and C. tropicalis. Although many factors (caspofungin powder source, stock solution solvent, powder storage time length and temperature, and MIC determination testing parameters) were examined as a potential cause of such unprecedented variability, a single specific cause was not identified. Therefore, it seems highly likely that the use of the CLSI species-specific caspofungin CBPs could lead to reporting an excessive number of wild-type (WT) isolates (e.g., C. glabrata and C. krusei) as either non-WT or resistant isolates. Until this problem is resolved, routine testing or reporting of CLSI caspofungin MICs for Candida is not recommended; micafungin or anidulafungin data could be used instead.

Ten-year study of species distribution and antifungal susceptibilities of Candida bloodstream isolates at a Brazilian tertiary hospital.

To describe the incidence and susceptibility profile of Candida bloodstream infections in a tertiary-care hospital, we performed a retrospective observational study from 1998 to 2007. Comorbidities and risk factors were compiled from all cases. In vitro susceptibility testing to fluconazole, itraconazole, voriconazole, and amphotericin B was performed for 100 isolates, and caspofungin was tested for C. parapsilosis complex. In a ten-year evaluation of candidemias, 44 % were caused by C. albicans, and species of the C. parapsilosis complex were the second most frequent agents (37 %). Other species presented lower incidences (C. tropicalis, 13 %, C. glabrata, 5 %, and C. krusei, 1 %). Neither C. dubliniensis nor C. metapsilosis were observed in this study. C. orthopsilosis (3 %) and C. parapsilosis stricto sensu (34 %) were also found. Species distribution was independent of catheterization, mechanical ventilation, or previous use of antifungals or corticoids. Parenteral nutrition administration was strongly related to C. glabrata infection, and the highest mortality (80 %) was observed in patients infected by this species. All C. albicans isolates showed high susceptibility to all tested drugs. However, two C. parapsilosis stricto sensu isolates presented high minimum inhibitory concentration (MIC) (4 mg/L each) to fluconazole, and one exhibited voriconazole MIC of 0.25 mg/L, highlighting the cross-resistance to these azoles. All isolates of C. tropicalis and C. glabrata showed no resistance to any drug tested. No difference was noted between C. parapsilosis and C. orthopsilosis susceptibilities to caspofungin. Our results suggest that resistance to amphotericin B, fluconazole, voriconazole, itraconazole, and caspofungin in Brazilian Candida bloodstream isolates is still uncommon.