scholarly journals Epidemiology and Molecular Characterizations of Azole Resistance in Clinical and Environmental Aspergillus fumigatus Isolates from China

2016 ◽  
Vol 60 (10) ◽  
pp. 5878-5884 ◽  
Author(s):  
Yong Chen ◽  
Zhongyi Lu ◽  
Jingjun Zhao ◽  
Ziying Zou ◽  
Yanwen Gong ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Antifungal Susceptibility ◽  
Public Health Problem ◽  
Wide Distribution ◽  
Resistance Mechanisms ◽  
Azole Resistance ◽  
Common Mutation ◽  
Content Type ◽  
Environmental Resistance ◽  
Resistant Strains

ABSTRACTAzole resistance inAspergillus fumigatushas emerged as a worldwide public health problem. We sought here to demonstrate the occurrence and characteristics of azole resistance inA. fumigatusfrom different parts of China. A total of 317 clinical and 144 environmentalA. fumigatusisolates from 12 provinces were collected and subjected to screening for azole resistance. Antifungal susceptibility,cyp51Agene sequencing, and genotyping were carried out for all suspected azole-resistant isolates and a subset of azole-susceptible isolates. As a result, 8 (2.5%) clinical and 2 (1.4%) environmentalA. fumigatusisolates were identified as azole resistant. Five azole-resistant strains exhibit the TR34/L98H mutation, whereas four carry the TR34/L98H/S297T/F495I mutation in thecyp51Agene. Genetic typing and phylogenetic analysis showed that there was a worldwide clonal expansion of the TR34/L98H isolates, while the TR34/L98H/S297T/F495I isolates from China harbored a distinct genetic background with resistant isolates from other countries. High polymorphisms existed in thecyp51Agene that produced amino acid changes among azole-susceptibleA. fumigatusisolates, with N248K being the most common mutation. These data suggest that the wide distribution of azole-resistantA. fumigatusmight be attributed to the environmental resistance mechanisms in China.

scholarly journals Elevated MIC Values of Imidazole Drugs against Aspergillus fumigatus Isolates with TR 34 /L98H/S297T/F495I Mutation

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Yong Chen ◽  
Zongwei Li ◽  
Xuelin Han ◽  
Shuguang Tian ◽  
Jingya Zhao ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Azole Resistance ◽  
Pyrenophora Teres ◽  
Str Typing ◽  
Content Type ◽  
Resistant Strains ◽  
Short Tandem

ABSTRACT The use of azole fungicides in agriculture is believed to be one of the main reasons for the emergence of azole resistance in Aspergillus fumigatus . Though widely used in agriculture, imidazole fungicides have not been linked to resistance in A. fumigatus . This study showed that elevated MIC values of imidazole drugs were observed against A. fumigatus isolates with TR 34 /L98H/S297T/F495I mutation, but not among isolates with TR 34 /L98H mutation. Short-tandem-repeat (STR) typing analysis of 580 A. fumigatus isolates from 20 countries suggested that the majority of TR 34 /L98H/S297T/F495I strains from China were genetically different from the predominant major clade comprising most of the azole-resistant strains and the strains with the same mutation from the Netherlands and Denmark. Alignments of sterol 14α-demethylase sequences suggested that F495I in A. fumigatus was orthologous to F506I in Penicillium digitatum and F489L in Pyrenophora teres , which have been reported to be associated with imidazole resistance. In vitro antifungal susceptibility testing of different recombinants with cyp51A mutations further confirmed the association of the F495I mutation with imidazole resistance. In conclusion, this study suggested that environmental use of imidazole fungicides might confer selection pressure for the emergence of azole resistance in A. fumigatus .

scholarly journals Multiplecyp51A-Based Mechanisms Identified in Azole-Resistant Isolates of Aspergillus fumigatus from China

2015 ◽  
Vol 59 (7) ◽  
pp. 4321-4325 ◽  
Author(s):  
Musang Liu ◽  
Rong Zeng ◽  
Lili Zhang ◽  
Dongmei Li ◽  
Guixia Lv ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Clinical Isolates ◽  
Resistant Isolate ◽  
Azole Resistance ◽  
Content Type ◽  
Resistant Strains

ABSTRACTSeventy-twoA. fumigatusclinical isolates from China were investigated for azole resistance based on mutations ofcyp51A. We identified four azole-resistant strains, among which we found three strains highly resistant to itraconazole, two of which exhibit the TR34/L98H/S297T/F495I mutation, while one carries only the TR34/L98H mutation. To our knowledge, the latter has not been found previously in China. The fourth multiazole-resistant isolate (with only moderate itraconazole resistance) carries a new G432A mutation.

scholarly journals Single-Center Evaluation of an Agar-Based Screening for Azole Resistance in Aspergillus fumigatus by Using VIPcheck

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
J. B. Buil ◽  
H. A. L. van der Lee ◽  
A. J. M. M. Rijs ◽  
J. Zoll ◽  
J. A. M. F. Hovestadt ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Sensitivity And Specificity ◽  
Antifungal Susceptibility ◽  
Screening Method ◽  
Point Mutations ◽  
Azole Resistance ◽  
Minimal Growth ◽  
Content Type ◽  
Mean Sensitivity ◽  
Selection Of

ABSTRACT Antifungal susceptibility testing is an essential tool for guiding therapy, although EUCAST and CLSI reference methods are often available only in specialized centers. We studied the performance of an agar-based screening method for the detection of azole resistance in Aspergillus fumigatus cultures. The VIPcheck consists of four wells containing voriconazole, itraconazole, posaconazole, or a growth control. Ninety-six A. fumigatus isolates were used. Thirty-three isolates harbored a known resistance mechanism: TR34/L98H (11 isolates), TR46/Y121F/T289A (6 isolates), TR53 (2 isolates), and 14 isolates with other cyp51A gene point mutations. Eighteen resistant isolates had no cyp51A-mediated azole resistance. Forty-five isolates had a wild-type (WT) azole phenotype. Four technicians and two inexperienced interns, blinded to the genotype/phenotype, read the plates visually after 24 h and 48 h and documented minimal growth, uninhibited growth, and no growth. The performance was compared to the EUCAST method. After 24 h of incubation, the mean sensitivity and specificity were 0.54 and 1.00, respectively, with uninhibited growth as the threshold. After 48 h of incubation, the performance mean sensitivity and specificity were 0.98 and 0.93, respectively, with minimal growth. The performance was not affected by observer experience in mycology. The interclass correlation coefficient was 0.87 after 24 h and 0.85 after 48 h. VIPcheck enabled the selection of azole-resistant A. fumigatus colonies, with a mean sensitivity and specificity of 0.98 and 0.93, respectively. Uninhibited growth on any azole-containing well after 24 h and minimal growth after 48 h were indicative of resistance. These results indicate that the VIPcheck is an easy-to-use tool for azole resistance screening and the selection of colonies that require MIC testing.

scholarly journals Multi-resistance to non-azole fungicides in Aspergillus fumigatus TR 34 /L98H azole resistant isolates.

2021 ◽  
Author(s):  
I Gonzalez-Jimenez ◽  
R Garcia-Rubio ◽  
S Monzon ◽  
J Lucio ◽  
I Cuesta ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Plant Pathogens ◽  
Crop Protection ◽  
Resistance Mechanisms ◽  
Azole Resistance ◽  
Sequencing Analysis ◽  
Human Fungal Pathogen ◽  
Evolution Pattern ◽  
Environmental Setting ◽  
Resistant Strains

Drug resistance is a worldwide problem affecting all pathogens. The human fungal pathogen Aspergillus fumigatus coexists in the environment with other fungi targeted by crop protection compounds being unintentionally exposed to the selective pressure of multiple antifungal classes leading to the selection of resistant strains. A. fumigatus azole resistant isolates are emerging in both the clinical and environmental setting. Since their approval, azole drugs have dominated the clinical treatment for aspergillosis infections, and the agriculture fungicide market. However, other antifungal classes are used for crop protection including benzimidazoles (MBC), strobilurins (QoIs) and succinate dehydrogenase inhibitors (SDHIs). Mutations responsible for resistance to these fungicides have been widely researched in plant pathogens, but it has not been explored in A. fumigatus . In this work, the genetic basis underlying resistance to MBCs, QoIs and SDHIs were studied in azole susceptible and resistant A. fumigatus strains. E198A/Q and F200Y mutations in the β-tubulin conferred resistance to MBCs, G143A and F129L substitutions in the Cytochrome b to QoIs and H270R/Y mutations in SdhB to SDHIs. Characterization of the susceptibility to azoles showed a correlation between strains resistant to these fungicides and the ones with TR-based azole resistance mechanisms. Whole genome sequencing analysis showed a genetic relationship among fungicide multi resistant strains, which grouped together into subclusters that only included strains carrying the TR-based azole resistance mechanisms, indicating a common ancestor/evolution pattern and confirming the environmental origin of this type of azole resistant A. fumigatus .

scholarly journals Is Azole Resistance in Aspergillus fumigatus a Problem in Spain?

2013 ◽  
Vol 57 (6) ◽  
pp. 2815-2820 ◽  
Author(s):  
Pilar Escribano ◽  
Teresa Peláez ◽  
Patricia Muñoz ◽  
Emilio Bouza ◽  
Jesús Guinea
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Cryptic Species ◽  
Antifungal Susceptibility ◽  
Single Species ◽  
Azole Resistance ◽  
Tubulin Gene ◽  
Complex Species ◽  
Content Type ◽  
Β Tubulin

ABSTRACTAspergillus fumigatuscomplex comprisesA. fumigatusand other morphologically indistinguishable cryptic species. We retrospectively studied 362A. fumigatuscomplex isolates (353 samples) from 150 patients with proven or probable invasive aspergillosis or aspergilloma (2, 121, and 6 samples, respectively) admitted to the hospital from 1999 to 2011. Isolates were identified using the β-tubulin gene, and only 1 isolate per species found in each sample was selected. Antifungal susceptibility to azoles was determined using the CLSI M38-A2 procedure. Isolates were considered resistant if they showed an MIC above the breakpoints for itraconazole, voriconazole, or posaconazole (>2, >2, or >0.5 μg/ml). Most of the samples yielded only 1 species (A. fumigatus[n= 335],A. novofumigatus[n= 4],A. lentulus[n= 3],A. viridinutans[n= 1], andNeosartorya udagawae[n= 1]). The remaining samples yielded a combination of 2 species. Most of the patients were infected by a single species (A. fumigatus[n= 143] orA. lentulus[n= 2]). The remaining 5 patients were coinfected with multipleA. fumigatuscomplex species, althoughA. fumigatuswas always involved; 4 of the 5 patients were diagnosed in 2009 or later. Cryptic species were less susceptible thanA. fumigatus. The frequency of resistance amongA. fumigatuscomplex andA. fumigatusto itraconazole, voriconazole, and posaconazole was 2.5 and 0.3%, 3.1 and 0.3%, and 4.2 and 1.8%, respectively, in the per-isolate analysis and 1.3 and 0.7%, 2.6 and 0.7%, and 6 and 4% in the per-patient analysis. Only 1 of the 6A. fumigatusisolates in which thecyp51Agene was sequenced had a mutation at position G448. The proportion of patients infected by azole-resistantA. fumigatusisolates was low.

scholarly journals First Clinical Isolation of an Azole-Resistant Aspergillus fumigatus Isolate Harboring a TR46 Y121F T289A Mutation in South America

2018 ◽  
Vol 62 (10) ◽  
Author(s):  
Guillermina Isla ◽  
Florencia Leonardelli ◽  
Iris N. Tiraboschi ◽  
Nicolás Refojo ◽  
Alejandra Hevia ◽  
...  
Keyword(s):  
United States ◽  
South America ◽  
Aspergillus Fumigatus ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Azole Resistance ◽  
Content Type

ABSTRACT One of the most recently described Aspergillus fumigatus CYP51A-mediated azole resistance mechanisms is TR46 Y121F T289A. Clinical A. fumigatus strains harboring these substitutions have been reported worldwide, with the exception of South America. We describe the first clinical A. fumigatus strain with this resistance mechanism isolated from an Argentinian patient. The strain was isolated in 2009 (1 year after the first-described mutant in United States), demonstrating that these alleles were scattered worldwide earlier than previously thought.

scholarly journals Triazole Resistance Is Still Not Emerging in Aspergillus fumigatus Isolates Causing Invasive Aspergillosis in Brazilian Patients

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Clara E. Negri ◽  
Sarah S. Gonçalves ◽  
Ana Cristina P. Sousa ◽  
Maria Daniela Bergamasco ◽  
Marinês D. V. Martino ◽  
...  
Keyword(s):  
Global Health ◽  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Health Problem ◽  
Antifungal Susceptibility ◽  
Azole Resistance ◽  
Cutoff Value ◽  
Content Type ◽  
Global Health Problem

ABSTRACT Aspergillus fumigatus azole resistance has emerged as a global health problem. We evaluated the in vitro antifungal susceptibility of 221 clinical A. fumigatus isolates according to CLSI guidelines. Sixty-one isolates exhibiting MICs at the epidemiological cutoff value (ECV) for itraconazole or above the ECV for any triazole were checked for CYP51A mutations. No mutations were documented, even for the isolates (1.8%) with high voriconazole MICs, indicating that triazoles may be used safely to treat aspergillosis in Brazil.

scholarly journals The Strength of Synergistic Interaction between Posaconazole and Caspofungin Depends on the Underlying Azole Resistance Mechanism of Aspergillus fumigatus

2015 ◽  
Vol 59 (3) ◽  
pp. 1738-1744 ◽  
Author(s):  
Eleftheria Mavridou ◽  
Joseph Meletiadis ◽  
Antony Rijs ◽  
Johan W. Mouton ◽  
Paul E. Verweij
Keyword(s):  
Aspergillus Fumigatus ◽  
Resistance Mechanism ◽  
Fungal Growth ◽  
Resistance Mechanisms ◽  
Azole Resistance ◽  
Wild Type ◽  
Content Type ◽  
Synergistic Interactions ◽  
Drug Concentrations

ABSTRACTThe majority of azole resistance mechanisms inAspergillus fumigatuscorrespond to mutations in thecyp51Agene. As azoles are less effective against infections caused by multiply azole-resistantA. fumigatusisolates, new therapeutic options are warranted for treating these infections. We therefore investigated thein vitrocombination of posaconazole (POSA) and caspofungin (CAS) against 20 wild-type and resistantA. fumigatusisolates with 10 different resistance mechanisms. Fungal growth was assessed with the XTT [2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt] method. Pharmacodynamic interactions were assessed with the fractional inhibitory concentration (FIC) index (FICi) on the basis of 10% (FICi-0), 25% (FICi-1), or 53 0% (FICi-2) growth, and FICs were correlated with POSA and CAS concentrations. Synergy and antagonism were concluded when the FICi values were statistically significantly (ttest,P< 0.05) lower than 1 and higher than 1.25, respectively. Significant synergy was found for all isolates with mean FICi-0 values ranging from 0.28 to 0.75 (median, 0.46). Stronger synergistic interactions were found with FICi-1 (median, 0.18; range, 0.07 to 0.47) and FICi-2 (0.31; 0.07 to 0.6). The FICi-2 values of isolates with tandem-repeat-containing mutations or codon M220 were lower than those seen with the other isolates (P< 0.01). FIC-2 values were inversely correlated with POSA MICs (rs= −0.52,P= 0.0006) and linearly with the ratio of drug concentrations in combination over the MIC of POSA (rs= 0.76,P< 0.0001) and CAS (rs= 0.52,P= 0.0004). The synergistic effect of the combination of POSA and CAS (POSA/CAS) againstA. fumigatusisolates depended on the underlying azole resistance mechanism. Moreover, the drug combination synergy was found to be increased against isolates with elevated POSA MICs compared to wild-type isolates.

scholarly journals Nonrandom Distribution of Azole Resistance across the Global Population of Aspergillus fumigatus

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Thomas R. Sewell ◽  
Jianing Zhu ◽  
Johanna Rhodes ◽  
Ferry Hagen ◽  
Jacques F. Meis ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Drug Resistance ◽  
Aspergillus Fumigatus ◽  
Pathogenic Fungus ◽  
Crop Protection ◽  
Resistance Mechanisms ◽  
Health Concern ◽  
Azole Resistance ◽  
Content Type ◽  
Global Population

ABSTRACT The emergence of azole resistance in the pathogenic fungus Aspergillus fumigatus has continued to increase, with the dominant resistance mechanisms, consisting of a 34-nucleotide tandem repeat (TR34)/L98H and TR46/Y121F/T289A, now showing a structured global distribution. Using hierarchical clustering and multivariate analysis of 4,049 A. fumigatus isolates collected worldwide and genotyped at nine microsatellite loci using analysis of short tandem repeats of A. fumigatus (STRAf), we show that A. fumigatus can be subdivided into two broad clades and that cyp51A alleles TR34/L98H and TR46/Y121F/T289A are unevenly distributed across these two populations. Diversity indices show that azole-resistant isolates are genetically depauperate compared to their wild-type counterparts, compatible with selective sweeps accompanying the selection of beneficial mutations. Strikingly, we found that azole-resistant clones with identical microsatellite profiles were globally distributed and sourced from both clinical and environmental locations, confirming that azole resistance is an international public health concern. Our work provides a framework for the analysis of A. fumigatus isolates based on their microsatellite profile, which we have incorporated into a freely available, user-friendly R Shiny application (AfumID) that provides clinicians and researchers with a method for the fast, automated characterization of A. fumigatus genetic relatedness. Our study highlights the effect that azole drug resistance is having on the genetic diversity of A. fumigatus and emphasizes its global importance upon this medically important pathogenic fungus. IMPORTANCE Azole drug resistance in the human-pathogenic fungus Aspergillus fumigatus continues to emerge, potentially leading to untreatable aspergillosis in immunosuppressed hosts. Two dominant, environmentally associated resistance mechanisms, which are thought to have evolved through selection by the agricultural application of azole fungicides, are now distributed globally. Understanding the effect that azole resistance is having on the genetic diversity and global population of A. fumigatus will help mitigate drug-resistant aspergillosis and maintain the azole class of fungicides for future use in both medicine and crop protection.

scholarly journals Characterization of Aspergillus fumigatus cross-resistance between clinical and DMI azole drugs

2020 ◽  
pp. AEM.02539-20 ◽  
Author(s):  
Rocio Garcia-Rubio ◽  
Irene Gonzalez-Jimenez ◽  
Jose Lucio ◽  
Emilia Mellado
Keyword(s):  
Aspergillus Fumigatus ◽  
Clinical Setting ◽  
Opportunistic Infections ◽  
Treatment Options ◽  
Critical Role ◽  
Crop Protection ◽  
Public Health Problem ◽  
Resistance Mechanisms ◽  
Cross Resistance ◽  
Azole Resistance

Drug resistance poses a serious threat to human health and agricultural production. Azole drugs are the largest group of 14-α sterol demethylation inhibitor fungicides that are used both in agriculture and in clinical practice. As plant pathogenic molds share their natural environment with fungi that cause opportunistic infections in humans, both are exposed to a strong and persistent pressure of demethylase inhibitor (DMI) fungicides, including imidazole and triazole drugs. As a result, a loss of efficacy has occurred for this drug class in several species. In the clinical setting, Aspergillus fumigatus azole resistance is a growing public health problem and finding the source of this resistance has gained much attention. It is urgent to determine if there is a direct link between the agricultural use of azole compounds and the different A. fumigatus resistance mechanisms described for clinical triazoles. In this work we have performed A. fumigatus susceptibility testing to clinical triazoles and crop protection DMIs using a collection of azole susceptible and resistant strains which harbor most of the described azole resistance mechanisms. Various DMI susceptibility profiles have been found in the different A. fumigatus populations groups based on their azole resistance mechanism and previous WGS analysis, which suggests that the different resistance mechanisms have different origins and are specifically associated to the local use of a particular DMI.Importance Due to the worldwide emergence of A. fumigatus azole resistance, this opportunistic pathogen poses a serious health threat and, therefore, it has been included in the Watch List of the CDC 2019 Antimicrobial Resistance Threats Report. Azoles play a critical role in the control and management of fungal diseases, not only in the clinical setting but also in agriculture. Thus, azole resistance leads to a limited therapeutic arsenal which reduces the treatment options for aspergillosis patients, increasing their mortality risk. Evidence is needed to understand whether A. fumigatus azole resistance is emerging from an agricultural source due to the extended use of demethylase inhibitors as fungicides, or whether it is coming from somewhere else such as the clinical setting. If the environmental route is demonstrated, the current use and management of azole antifungal compounds might be forced to change in the forthcoming years.

Sign in / Sign up

Export Citation Format

Share Document