scholarly journals Increasing Prevalence of Multidrug-Resistant Candida haemulonii Species Complex among All Yeast Cultures Collected by a Reference Laboratory over the Past 11 Years

2020 ◽  
Vol 6 (3) ◽  
pp. 110 ◽  
Author(s):  
Soraia Lopes Lima ◽  
Elaine Cristina Francisco ◽  
João Nóbrega de Almeida Júnior ◽  
Daniel Wagner de Castro Lima Santos ◽  
Fabiane Carlesse ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Species Complex ◽  
Antifungal Susceptibility ◽  
Its Region ◽  
Multidrug Resistant ◽  
Sensu Stricto ◽  
Culture Collection ◽  
Reference Laboratory ◽  
Yeast Cultures ◽  
Candida Haemulonii

There is worldwide concern with the increasing rates of infections due to multiresistant Candida isolates reported in tertiary medical centers. We checked for historical trends in terms of prevalence rates and antifungal susceptibility of the Candida haemulonii species complex in our yeast stock culture collected during the last 11 years. The isolates were identified by sequencing the rDNA internal transcribed spacer (ITS) region, and antifungal susceptibility tests for amphotericin B, voriconazole, fluconazole, anidulafungin, and 5-fluorocytosine were performed by the Clinical and Laboratory Standards Institute (CLSI) microbroth method. A total of 49 isolates were identified as Candida haemulonii sensu stricto (n = 21), followed by C. haemulonii var. vulnera (n = 15) and C. duobushaemulonii (n = 13), including 38 isolates cultured from patients with deep-seated Candida infections. The prevalence of the C. haemulonii species complex increased from 0.9% (18 isolates among 1931) in the first period (December 2008 to June 2013) to 1.7% (31 isolates among 1868) in the second period (July 2014 to December 2019) of analysis (p = 0.047). All isolates tested exhibited high minimum inhibition concentrations for amphotericin B and fluconazole, but they remained susceptible to 5-fluorocytosine and anidulafungin. We were able to demonstrate the increased isolation of the multiresistant Candida haemulonii species complex in our culture collection, where most isolates were cultured from patients with deep-seated infections.

scholarly journals Comparing Etest and Broth Microdilution for Antifungal Susceptibility Testing of the Most-Relevant Pathogenic Molds

2015 ◽  
Vol 53 (10) ◽  
pp. 3176-3181 ◽  
Author(s):  
Frédéric Lamoth ◽  
Barbara D. Alexander
Keyword(s):  
Amphotericin B ◽  
Antifungal Therapy ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Multidrug Resistant ◽  
Antifungal Susceptibility Testing ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Content Type ◽  
Broth Microdilution Method

Invasive mold infections are life-threatening diseases for which appropriate antifungal therapy is crucial. Their epidemiology is evolving, with the emergence of triazole-resistantAspergillusspp. and multidrug-resistant non-Aspergillusmolds. Despite the lack of interpretive criteria, antifungal susceptibility testing of molds may be useful in guiding antifungal therapy. The standard broth microdilution method (BMD) is demanding and requires expertise. We assessed the performance of a commercialized gradient diffusion method (Etest method) as an alternative to BMD. The MICs or minimal effective concentrations (MECs) of amphotericin B, voriconazole, posaconazole, caspofungin, and micafungin were assessed for 290 clinical isolates of the most representative pathogenic molds (154Aspergillusand 136 non-Aspergillusisolates) with the BMD and Etest methods. Essential agreements (EAs) within ±2 dilutions of ≥90% between the two methods were considered acceptable. EAs for amphotericin B and voriconazole were >90% for most potentially susceptible species. For posaconazole, the correlation was acceptable forMucoromycotinabut Etest MIC values were consistently lower forAspergillusspp. (EAs of <90%). Excellent EAs were found for echinocandins with highly susceptible (MECs of <0.015 μg/ml) or intrinsically resistant (MECs of >16 μg/ml) strains. However, MEC determinations lacked consistency between methods for strains exhibiting mid-range MECs for echinocandins. We concluded that the Etest method is an appropriate alternative to BMD for antifungal susceptibility testing of molds under specific circumstances, including testing with amphotericin B or triazoles for non-Aspergillusmolds (MucoromycotinaandFusariumspp.). Additional study of molecularly characterized triazole-resistantAspergillusisolates is required to confirm the ability of the Etest method to detect voriconazole and posaconazole resistance amongAspergillusspp.

scholarly journals Prevalence and Antifungal Susceptibility of the Emerging Fungal Species, Candida nivariensis, Isolated in a Teaching Hospital in Poland

2019 ◽  
Vol 68 (3) ◽  
pp. 303-308 ◽  
Author(s):  
MAGDALENA SIKORA ◽  
ROBERT KUTHAN ◽  
KATARZYNA PISKORSKA-MALOLEPSZA ◽  
MARLENA GOLAS-PRADZYNSKA ◽  
DARIUSZ DOMAŃSKI ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Teaching Hospital ◽  
Antifungal Susceptibility ◽  
Sensu Stricto ◽  
Fungal Species ◽  
Clinical Samples ◽  
Global Knowledge ◽  
Identification Of Species ◽  
26S Rrna

The data on susceptibility to antifungals of new specieswithin Candida glabrata complex are limited. Our study was to enrich a global knowledge of yeast epidemiology and drug resistance. The study was focused on the identification of species within clinical isolates of the C. glabrata complex and on the determination of their resistance to antifungals. Four hundred forty-five clinical C. glabrata sensu lato strains were isolated from different clinical samples at routine mycological exams at the Infant Jesus Teaching Hospital in Warsaw. The identification of the most of tested isolates to species complex level was performed using the ID 32 C system. The identification of C. nivariensisand C. bracarensis species within the C. glabrata complex was performed by DNA sequencing. The MICs of amphotericin B, fluconazole, itraconazole, posaconazole, voriconazole, caspofungin, anidulafungin, and micafungin were determined by E-test. Twenty-four isolates did not have an ITS-1 region, characteristic of C. glabrata sensu stricto and their D1/D2 regions of the 26S rRNA were 99% homologous to C. nivariensis 26S rRNA. No strains of C. bracarensis were recovered. C. nivariensis strains were very susceptible to amphotericin B, anidulafungin, micafungin, and caspofungin. Ninety-two percent of C. nivariensis were resistant to itraconazole. The halves of the strains was resistant to posaconazole. Eighty-three percent of C. nivariensis were susceptible to voriconazole. None of the tested strains were susceptible to fluconazole. In the present study, none of the C. nivariensis strains were simultaneously resistant to azoles and echinocandins. C. nivariensis should be recognized as an emerging pathogen, resistant to azoles.

scholarly journals In Vitro Interactions of Echinocandins with Triazoles Against Multidrug-Resistant Candida auris

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S82-S82
Author(s):  
Hamid Badalii
Keyword(s):  
Amphotericin B ◽  
Antifungal Susceptibility ◽  
Multidrug Resistant ◽  
In Vivo Studies ◽  
Synergistic Activity ◽  
Candida Auris ◽  
Unsuccessful Treatment ◽  
In Vitro Interactions

Abstract Background Blood stream infections due to Candida auris are related to a high mortality rate and treatment failure attributed to resistance to fluconazole, voriconazole, amphotericin B, and caspofungin. Thus, the precise identification of agents and in vitro antifungal susceptibility testing is highly recommended. Novel therapeutic strategies, such as combination therapy, are essential for increasing the efficacy and reducing the toxicity of antifungal agents. Therefore, we investigated the in vitro combination of micafungin plus voriconazole against multidrug-resistant C. auris isolated from cases of candidemia. Methods The in vitro interactions between echinocandins and azoles were determined against ten multidrug-resistant Candida auris strains by using a microdilution checkerboard technique. Results Results revealed that MICs range for voriconazole and micafungin were 0.5–8 and 0.25–8 mg/l, respectively. The checkerboard analysis revealed that the combination of micafungin with voriconazole exhibited synergistic activity against all 10 multidrug-resistant C. auris isolates (FICI range: 0.15–0.5). Overall, no antagonistic effects were observed in this experiments. Conclusion In vitro studies have previously suggested that among azoles isavuconazole and posaconazole are more active drugs against C. auris. In addition, the majority of isolates reported are resistant to fluconazole. Remarkably, unsuccessful treatment of C. auris infections with fluconazole, voriconazole, amphotericin B, caspofungin, and anidulafungin has been already on record. Here in we demonstrates that interaction between micafungin with voriconazole exhibited synergistic activity against multidrug-resistant C. auris isolates. It seems that lower concentrations of drugs cause fewer side-effects and improve the treatment outcomes. However, in vivo studies with suitable animal models of C. auris infection is highly recommended. Disclosures All authors: No reported disclosures.

scholarly journals Thermogenic Characterization and Antifungal Susceptibility of Candida auris by Microcalorimetry

2019 ◽  
Vol 5 (4) ◽  
pp. 103 ◽  
Author(s):  
Mariagrazia Di Luca ◽  
Anna Koliszak ◽  
Svetlana Karbysheva ◽  
Anuradha Chowdhary ◽  
Jacques Meis ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Heat Production ◽  
Therapeutic Option ◽  
Antifungal Susceptibility ◽  
Multidrug Resistant ◽  
Candida Auris ◽  
Candida Spp ◽  
Heat Curve ◽  
Candida Lusitaniae ◽  
Minimum Heat

Candida auris has emerged globally as a multidrug-resistant fungal pathogen. Isolates of C. auris are reported to be misidentified as Candida haemulonii. The aim of the study was to compare the heat production profiles of C. auris strains and other Candida spp. and evaluate their antifungal susceptibility using isothermal microcalorimetry. The minimum heat inhibitory concentrations (MHIC) and the minimum biofilm fungicidal concentration (MBFC) were defined as the lowest antimicrobial concentration leading to the lack of heat flow production after 24 h for planktonic cells and 48 h for biofilm-embedded cells. C. auris exhibited a peculiar heat production profile. Thermogenic parameters of C. auris suggested a slower growth rate compared to Candida lusitaniae and a different distinct heat profile compared to that of C. haemulonii species complex strains, although they all belong to the Metschnikowiaceae clade. Amphotericin B MHIC and MBFC were 0.5 µg/mL and ≥8 µg/mL, respectively. C. auris strains were non-susceptible to fluconazole at tested concentrations (MHIC > 128 µg/mL, MBFC > 256 µg/mL). The heat curve represents a fingerprint of C. auris, which distinguished it from other species. Treatment based on amphotericin B represents a potential therapeutic option for C. auris infection.

scholarly journals Antifungal Susceptibility In Vitro Determined by the Etest(r) for Candida Obtained from the Oral Cavity of Irradiated and Elderly Individuals

2015 ◽  
Vol 26 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Edimilson Martins de Freitas ◽  
Larissa Cavalcanti Monteiro ◽  
Michelle Bonfim da Silva Fernandes ◽  
Hercílio Martelli Junior ◽  
Paulo Rogério Ferreti Bonan ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Candida Species ◽  
Antifungal Susceptibility ◽  
Culture Collection ◽  
Morphological Criteria ◽  
Group 2 ◽  
In Vitro Antifungal Susceptibility ◽  
Mic Minimum Inhibitory Concentration ◽  
Dose Dependent

This study aimed to evaluate the in vitro antifungal susceptibility of Candida species of head-and-neck-irradiated patients (Group 1), non-institutionalized (Group 2) and institutionalized elders (Group 3) using Etest(r) methodology. Candida was isolated from saliva and presumptively identified by CHROMagar Candida(r), confirmed by morphological criteria, carbohydrate assimilation (API 20C AUX(r)) and genetic typing (OPE 18). The collection was made from 29, 34 and 29 individuals (Groups 1, 2 and 3, respectively) with 67 isolates. Etest(r) strips (ketoconazole, itraconazole, fluconazole, amphotericin B and flucytosine) on RPMI (Roswell Park Memorial Institute) agar, on duplicate, were used to evaluate susceptibility. ATTC (American Type Culture Collection) 10231 (Candida albicans) was used as quality control. Among the 67 isolates of Candida species, most were susceptible to azoles, flucytosine and amphotericin B. None of the isolates showed resistance and dose-dependent susceptibility to amphotericin B. There were nine strains resistant to itraconazole, six to fluconazole and two to ketoconazole and ten dose-dependent, mainly to flucytocine. The highest MIC (minimum inhibitory concentration) to C. albicans, C. tropicalis, C. parapsilosis was 2.671 μg.mL-1, 8.104 μg.mL-1, 4.429 μg.mL-1, all for flucytosine. C. krusei and C. glabrata were associated with higher MIC for azoles and C. glabrata with higher MIC to flucytosine. In summary, susceptibility to all tested antifungal agents was evident. The isolates were more resistant to itraconazole and dose-dependent to flucytosine. A comparison of C. albicans in the three groups showed no outliers. Higher MIC was associated with C. krusei and C. glabrata.

scholarly journals First Report of Colletotrichum siamense Causing Anthracnose of Guava (Psidium guajava) in Mexico

Plant Disease ◽  
2021 ◽  
Author(s):  
Edgar Edel Rodríguez-Palafox ◽  
Alfonso Vásquez-López ◽  
Guillermo Márquez-Licona ◽  
Nelson Bernardi Lima ◽  
Erika Lagunes-Fortiz ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Species Complex ◽  
Aerial Mycelium ◽  
Its Region ◽  
Psidium Guajava ◽  
Culture Collection ◽  
First Report ◽  
Colletotrichum Species ◽  
Guava Fruit ◽  
Colletotrichum Siamense

Guava (Psidium guajava L.) is a small tree belonging to the Myrtaceae family and it is distributed worldwide in the tropical and subtropical areas. During the summer of 2019, symptoms of fruit anthracnose were observed on approx. 90% of 250 guava trees located in backyards in Juan Jose Rios, Sinaloa, Mexico. Lesions on guava fruit were irregular, necrotic, and sunken. On advanced infections, acervuli containing salmon-pink masses of spores were observed on the lesions. Twenty fruits were collected from 10 trees (2 fruits per tree). Colletotrichum-like colonies were consistently isolated on PDA medium and 20 monoconidial isolates were obtained. Four isolates were selected as representatives for morphological characterization, multilocus phylogenetic analysis, and pathogenicity tests. The isolates were deposited in the Culture Collection of Phytopathogenic Fungi of the Faculty of Agriculture of El Fuerte Valley at the Sinaloa Autonomous University (Accession nos. FAVF205–FAVF208). Colonies on PDA medium were flat with an entire margin, with abundant felty and white aerial mycelium, with pink conidial masses. Conidia (n= 100) were cylindrical, hyaline, aseptate, with ends rounded, and measuring 14.8 to 18.1 × 4.4 to 5.3 μm. Based on morphological features, the isolates were tentatively allocated in the C. gloeosporioides species complex (Weir et al. 2012). For molecular identification, genomic DNA was extracted, and the internal transcribed spacer (ITS) region (White et al. 1990), as well as partial sequences of actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-tubulin (TUB2), chitin synthase (CHS-1) and glutamine synthetase (GS) genes were amplified by PCR (Weir et al. 2012), and sequenced. A phylogenetic tree based on Bayesian inference and including published ITS, GAPDH, TUB2, ACT, CHS-1, and GS data for Colletotrichum species was constructed. The multilocus phylogenetic analysis clearly distinguished the four isolates FAVF205–FAVF208 as C. siamense separating it from all other species within the C. gloeosporioides species complex. The sequences were deposited in GenBank (accessions nos. ITS: MW598512–MW598515; GAPDH: MW595216–MW595219; TUB2: MW618012–MW618015; ACT: MW595208–MW595211; CHS-1: MW595212–MW595215; and GS: MW618008–MW618011). Pathogenicity of the four isolates was verified on 40 healthy guava fruits. Twenty fruits were wounded with a sterile toothpick (2 mm in depth) and a mycelial plug (6 mm of diameter) was placed on each wound. Ten fruits inoculated with a PDA plug without mycelial growth served as controls. The fruit was kept in a moist plastic chamber at 25°C for 7 days. Pathogenicity of each isolate was tested with both non-wound and wound inoculation methods. The experiments were repeated twice with similar results. All inoculated fruits developed sunken necrotic lesions 4 days after inoculation, whereas no symptoms were observed on the control fruits. The fungi were consistently re-isolated only from the diseased fruits, fulfilling Koch´s postulates. Colletotrichum siamense has been previously reported on guava fruit in India (Sharma et al. 2015). However, to our best knowledge, this is the first report of C. siamense causing fruit anthracnose on guava in Mexico. Therefore, it is necessary to explore the diversity of Colletotrichum species on guava in detail through subsequent phylogenetic studies as well as to monitor the distribution of this pathogen into other Mexican regions.

scholarly journals Preliminary Evaluation of a Semisolid Agar Antifungal Susceptibility Test for Yeasts and Molds

2000 ◽  
Vol 38 (2) ◽  
pp. 537-541 ◽  
Author(s):  
Harriet Provine ◽  
Susan Hadley
Keyword(s):  
Amphotericin B ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Cost Effective ◽  
Culture Collection ◽  
National Committee ◽  
Preliminary Evaluation ◽  
Growth Reduction ◽  
Broth Macrodilution ◽  
Yeasts And Molds

This report presents a semisolid agar antifungal susceptibility (SAAS) method for the rapid susceptibility screening of yeasts and molds. The reproducibility and accuracy of the SAAS method were assessed by comparing the MICs of amphotericin B and fluconazole obtained for 10 candidate quality control (QC) American Type Culture Collection yeast strains in ≥15 replicates with those found by six independent laboratories using the National Committee for Clinical Laboratory Standards (NCCLS) M27-P broth macrodilution method (M. A. Pfaller et al., J. Clin. Microbiol. 33:1104–1107, 1995). Overall, 96% of MICs for both drugs fell within 1 log2dilution of the modal MIC for each strain. The MICs for amphotericin B showed 99% agreement with the NCCLS proposed QC ranges within 1 log2 dilution. Likewise, the MICs for fluconazole at ≥75% growth reduction showed 99% agreement for seven strains. Three strains, Candida albicans ATCC 24333 and ATCC 76615 and Candida tropicalis ATCC 750, showed a less sharp fluconazole endpoint at ≥75% growth reduction, but at >50% growth reduction, the agreement was 98% within 1 log2 dilution of the proposed range. The MIC agreement within the proposed range for the suggested QC strains Candida parapsilosisATCC 22019 and Candida krusei ATCC 6258 was 100% for fluconazole and 100% within 1 log2 dilution of the proposed range for amphotericin B. The SAAS method demonstrated the susceptibility or resistance of 25 clinical isolates of filamentous fungi such as Aspergillus fumigatus to amphotericin B, itraconazole, and fluconazole, usually within 48 h. Although the results are preliminary, this SAAS method is promising as a rapid and cost-effective screen and is worthy of concerted investigation.

scholarly journals Multilocus sequence typing of azole-resistant Candida auris strains, South Africa

2020 ◽  
Vol 35 (1) ◽  
Author(s):  
Rindidzani Magobo ◽  
Mabatho Mhlanga ◽  
Craig Corcoran ◽  
Nelesh P. Govender
Keyword(s):  
Multilocus Sequence Typing ◽  
Genetic Relatedness ◽  
Antifungal Susceptibility ◽  
Venous Catheter ◽  
Multidrug Resistant ◽  
Reference Laboratory ◽  
Candida Auris ◽  
Patient Demographics ◽  
Male Patients ◽  
And Cluster Analysis

Background: Candida auris is an emerging multidrug-resistant fungal pathogen associated with high mortality.Methods: We investigated the genetic relatedness of clinical C. auris isolates from patients admitted to either public- or private-sector hospitals, which were submitted to a reference laboratory from 2012 to 2015. Patient demographics and clinical details were recorded. We performed antifungal susceptibility testing, sequencing of the hotspot 1 and 2 regions of the FKS1 and FKS2 genes for all isolates with an echinocandin minimum inhibitory concentration (MIC) of ≥1 µg/mL and cluster analysis using multilocus sequence typing.Results: Eighty-five isolates were confirmed as C. auris. The median patient age was 59 years [inter-quartile range (IQR): 48–68 years], with male patients accounting for 68% of cases. Specimen types included urine (29%), blood (27%), central venous catheter tips (25%), irrigation fluid (7%), tissue (5%), respiratory tract specimens (4%) and other (3%). Ninety-seven per cent of isolates were resistant to fluconazole, 7% were resistant to both fluconazole and voriconazole, 8% were resistant to both fluconazole and echinocandins (considered multidrug resistant) and all were susceptible to amphotericin B. Of the 15 randomly selected fluconazole-resistant isolates, 14 isolates had an isavuconazole MIC ≤ 1 µg/mL. No FKS mutations were detected. Multilocus sequence typing (MLST) analysis grouped isolates into two clusters: cluster 1 and cluster 2 comprising 83 and 2 isolates, respectively.Conclusions: Azole-resistant C. auris strains circulating in South African hospitals were related by MLST, but the possibility of nosocomial transmission should be explored using a more discriminatory technique, for example, whole genome sequencing.

scholarly journals Microscopic Evaluation, Molecular Identification, Antifungal Susceptibility, and Clinical Outcomes inFusarium,Aspergillusand, Dematiaceous Keratitis

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Devarshi U. Gajjar ◽  
Anuradha K. Pal ◽  
Bharat K. Ghodadra ◽  
Abhay R. Vasavada
Keyword(s):  
Clinical Outcomes ◽  
Amphotericin B ◽  
Molecular Identification ◽  
Antifungal Agents ◽  
Antifungal Susceptibility ◽  
Its Region ◽  
Fungal Species ◽  
Fungal Keratitis ◽  
Accurate Identification ◽  
Microscopic Evaluation

Purpose.Fusarium,Aspergillus, and Dematiaceous are the most common fungal species causing keratitis in tropical countries. Herein we report a prospective study on fungal keratitis caused by these three fungal species.Methodology. A prospective investigation was undertaken to evaluate eyes with presumed fungal keratitis. All the fungal isolates (n=73) obtained from keratitis infections were identified using morphological and microscopic characters. Molecular identification using sequencing of the ITS region and antifungal susceptibility tests using microdilution method were done. The final clinical outcome was evaluated in terms of the time taken for resolution of keratitis and the final visual outcome. The results were analyzed after segregating the cases into three groups, namely,Fusarium,Aspergillus, and Dematiaceous keratitis.Results. Diagnosis of fungal keratitis was established in 73 (35.9%) cases out of 208 cases. The spectra of fungi isolated wereFusariumspp. (26.6%),Aspergillusspp. (21.6%), and Dematiaceous fungi (11.6%). The sequence of the ITS region could identify theFusariumandAspergillusspecies at the species complex level, and the Dematiaceous isolates were accurately identified. Using antifungal agents such as fluconazole, natamycin, amphotericin B, and itraconazole, the minimum inhibitory concentrations (MICs) forFusariumspp. were >32 μg/mL, 4–8 μg/mL, 0.5–1 μg/mL, and >32 μg/mL, respectively. Antifungal susceptibility data showed thatCurvulariaspp. was highly resistant to all the antifungal agents. Overall, natamycin and amphotericin B were found to be the most effective antifungal agents. The comparative clinical outcomes in all cases showed that the healing response in terms of visual acuity of the Dematiaceous group was significantly good when compared with theFusariumandAspergillusgroups (P<0.05). The time required for healing in theFusariumgroup was statistically significantly less when compared with theAspergillusand Dematiaceous groups.Conclusion. This study demonstrates important differences in microscopic features of scraping material and antifungal susceptibility between the three groups. Early and accurate identification coupled with the MIC data, and thereby appropriate treatment is crucial for complete recovery.

scholarly journals Insights into the Multi-Azole Resistance Profile in Candida haemulonii Species Complex

2020 ◽  
Vol 6 (4) ◽  
pp. 215
Author(s):  
Laura Nunes Silva ◽  
Lívia de Souza Ramos ◽  
Simone Santiago Carvalho Oliveira ◽  
Lucas Barros Magalhães ◽  
Eamim Daidrê Squizani ◽  
...  
Keyword(s):  
Species Complex ◽  
Fungal Pathogens ◽  
Rhodamine 6G ◽  
Efflux Pump ◽  
Antifungal Susceptibility ◽  
Cross Resistance ◽  
Azole Resistance ◽  
Candida Spp ◽  
Resistance Profile ◽  
Candida Haemulonii

The Candida haemulonii complex (C. duobushaemulonii, C. haemulonii, and C. haemulonii var. vulnera) is composed of emerging, opportunistic human fungal pathogens able to cause invasive infections with high rates of clinical treatment failure. This fungal complex typically demonstrates resistance to first-line antifungals, including fluconazole. In the present work, we have investigated the azole resistance mechanisms expressed in Brazilian clinical isolates forming the C. haemulonii complex. Initially, 12 isolates were subjected to an antifungal susceptibility test, and azole cross-resistance was detected in almost all isolates (91.7%). In order to understand the azole resistance mechanistic basis, the efflux pump activity was assessed by rhodamine-6G. The C. haemulonii complex exhibited a significantly higher rhodamine-6G efflux than the other non-albicans Candida species tested (C. tropicalis, C. krusei, and C. lusitaneae). Notably, the efflux pump inhibitors (Phe-Arg and FK506) reversed the fluconazole and voricolazole resistance phenotypes in the C. haemulonii species complex. Expression analysis indicated that the efflux pump (ChCDR1, ChCDR2, and ChMDR1) and ERG11 genes were not modulated by either fluconazole or voriconazole treatments. Further, ERG11 gene sequencing revealed several mutations, some of which culminated in amino acid polymorphisms, as previously reported in azole-resistant Candida spp. Collectively, these data point out the relevance of drug efflux pumps in mediating azole resistance in the C. haemulonii complex, and mutations in ERG11p may contribute to this resistance profile.

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