ERG11 mutations and upregulation in clinical itraconazole-resistant isolates of Candida krusei

To better understand the association between the ERG11 gene and drug resistance in Candida krusei, C. krusei strains were isolated from patients from January 2010 to May 2013. Susceptibility to 5-fluorocytosine (5-FC), amphotericin B (AMB), voriconazole (VRC), fluconazole (FLC), and itraconazole (ITR) were tested by broth microdilution method. Mutations were detected using PCR amplification and gene sequencing. Expression levels of ERG11 were measured by real-time PCR and compared by a 2-tailed Student’s t test between ITR-susceptible strains and ITR-resistant strains. In total, 15 C. krusei strains were obtained, of which 20.00%, 53.33%, and 40.00% were resistant to 5-FC, FLC, and ITR, respectively, whereas all isolates were susceptible to AMB and VRC. Three synonymous codon substitutions were found in ERG11, including T939C, T642C, and A756T. However, T939C was found in both resistant and susceptible C. krusei strains. The expression level of ERG11 was significantly higher in resistant C. krusei strains (1.34 ± 0.08) than in susceptible C. krusei strains (0.94 ± 0.14) (t = 3.74, p < 0.05). Our study demonstrates that point mutations (T642C and A756T) accompanied with the overexpression of ERG11 might be involved in the molecular mechanisms of drug resistance in C. krusei.

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Tentative epidemiologic cut-off value and resistant characteristic detection of apramycin against Escherichia coli from chickens

FEMS Microbiology Letters ◽

10.1093/femsle/fnz196 ◽

2019 ◽

Vol 366 (16) ◽

Cited By ~ 2

Author(s):

Erjie Tian ◽

Ishfaq Muhammad ◽

Wanjun Hu ◽

Zhiyong Wu ◽

Rui Li ◽

...

Keyword(s):

Escherichia Coli ◽

Drug Resistance ◽

Multiple Drug Resistance ◽

Aminoglycoside Antibiotic ◽

Multiple Drug ◽

Broth Microdilution ◽

E Coli ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Resistant Strains

ABSTRACT Escherichia coli are important foodborne zoonotic pathogens. Apramycin is a key aminoglycoside antibiotic used by veterinarians against E. coli. This study was conducted to establish the epidemiological cut-off value (ECV) and resistant characteristics of apramycin against E. coli. In this study, 1412 clinical isolates of E. coli from chickens in China were characterized. Minimum inhibitory concentrations (MICs) of apramycin were assessed by broth microdilution method. MIC50 and MIC90 for apramycin against E. coli (0.5–256 µg/mL) were 8 and 16 µg/mL, respectively. In this study, the tentative ECV was determined to be 16 µg/mL by the statistical method and 32 µg/mL by ECOFFinder software. Besides, the percentages of aac(3)-IV positive strains ascended with the increase of MIC values of apramycin, and the gene npmA was detected in strains with higher MICs. Sixteen apramycin highly resistant strains displayed multiple drug resistance (100%) to amoxicillin, ampicillin, gentamicin, doxycycline, tetracycline, trimethoprim and florfenicol, while most of them were susceptible to amikacin and spectinomycin. In summary, the tentative ECV of apramycin against E. coli was recommended to be 16 µg/mL.

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Variation in erythromycin and clindamycin susceptibilities of Streptococcus pneumoniae by four test methods.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.41.1.129 ◽

1997 ◽

Vol 41 (1) ◽

pp. 129-134 ◽

Cited By ~ 39

Author(s):

E L Fasola ◽

S Bajaksouzian ◽

P C Appelbaum ◽

M R Jacobs

Keyword(s):

Streptococcus Pneumoniae ◽

Susceptibility Testing ◽

Ambient Air ◽

Test Methods ◽

Disk Diffusion ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Agar Dilution ◽

Resistant Strains

Susceptibilities of 124 strains of Streptococcus pneumoniae to erythromycin and clindamycin were determined by the National Committee for the Clinical Laboratory Standards (NCCLS) broth microdilution method, with incubation for 20 to 24 h in ambient air and with modifications of this method by incubation for up to 48 h in air and CO2. Strains were also tested by agar dilution, E-test, and disk diffusion; good correlation was obtained with these methods, with clear separation into bimodal populations of susceptible and resistant stains. The broth microdilution method, however, using incubation in air for 24 h (NCCLS method), misclassified 4 of 92 erythromycin-resistant strains (1 as susceptible and 3 as intermediate) and 25 of 58 clindamycin-resistant strains (all as susceptible). With the exception of one strain with clindamycin, susceptible and resistant strains were correctly classified by the microdilution method with incubation in CO2 for 24 h or in ambient air for 48 h. Disk diffusion, agar dilution, and E-test methods with incubation in 5% CO2 are therefore reliable methods for susceptibility testing of pneumococci against these agents. However, the NCCLS microdilution method, which specifies incubation for 20 to 24 h in ambient air, produced significant very major errors (43%) clindamycin. Modification of the microdilution method by incubation in 5% CO2 or by extension of incubation time in ambient air to 48 h corrected these errors. Disk diffusion, however, was shown to be a simple, convenient, and reliable method for susceptibility testing of pneumococci to erythromycin and clindamycin and is suggested as the method of choice for these agents.

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Antibiotic Resistance and Virulence Traits in Vancomycin-Resistant Enterococci (VRE) and Extended-Spectrum β-Lactamase/AmpC-producing (ESBL/AmpC) Enterobacteriaceae from Humans and Pets

Antibiotics ◽

10.3390/antibiotics9040152 ◽

2020 ◽

Vol 9 (4) ◽

pp. 152 ◽

Cited By ~ 4

Author(s):

Ramona Iseppi ◽

Alessandro Di Cerbo ◽

Patrizia Messi ◽

Carla Sabia

Keyword(s):

Antibiotic Resistance ◽

Virulence Factors ◽

Pcr Amplification ◽

Surface Protein ◽

Fecal Samples ◽

E Coli ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Resistance Patterns ◽

Amoxicillin Clavulanate

Background: We investigated the virulence factors, genes, antibiotic resistance patterns, and genotypes (VRE and ESBL/AmpC) production in Enterococci and Enterobacteriaceae strains isolated from fecal samples of humans, dogs, and cats. Methods: A total of 100 fecal samples from 50 humans, 25 dogs, and 25 cats were used in the study. MICs of nine antimicrobials were determined using the broth microdilution method. Polymerase chain reaction was used for the detection of genes responsible for antibiotic resistance (VRE and ESBL/AmpC) and virulence genes both in Enterococcus species, such as cytolysin (cylA, cylB, cylM), aggregation substance (agg), gelatinase (gelE), enterococcal surface protein (esp), cell wall adhesins (efaAfs and efaAfm), and in Enterobacteriaceae, such as cytolysin (hemolysin) and gelatinase production (afa, cdt, cnf1, hlyA, iutA, papC, sfa). Results: Enterococcus faecium was the most prevalent species in humans and cats, whereas Enterococcus faecalis was the species isolated in the remaining samples. A total of 200 Enterobacteriaceae strains were also detected, mainly from humans, and Escherichia coli was the most frequently isolated species in all types of samples. In the Enterococcus spp, the highest percentages of resistance for ampicillin, amoxicillin/clavulanate, erythromycin, tetracycline, ciprofloxacin, teicoplanin, and vancomycin were detected in cat isolates (41.6%, 52.8%, 38.9%, 23.6%, 62.5%, 20.8%, and 23.6% respectively), and in E. coli, a higher rate of resistance to cefotaxime and ceftazidime emerged in cat and dog samples, if compared with humans (75.4% and 66.0%, 80.0% and 71.4%, and 32.0% and 27.2%, respectively). Regarding the total number of enterococci, 5% and 3.4% of the strains were vancomycin and teicoplanin resistant, and the vancomycin resistance (van A) gene has been detected in all samples by PCR amplification. All the Enterobacteriaceae strains were confirmed as ESBL producers by PCR and sequencing, and the most frequent ESBL genes in E. coli strains from humans and pet samples were blaCTX-M-1 and blaCTX-M-15. Conclusions: Our results provide evidence that one or more virulence factors were present in both genera, underlining again the ability of pet strains to act as pathogens.

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Antibiotic Resistance among Clinical Ureaplasma Isolates Recovered from Neonates in England and Wales between 2007 and 2013

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00889-15 ◽

2015 ◽

Vol 60 (1) ◽

pp. 52-56 ◽

Cited By ~ 29

Author(s):

Michael L. Beeton ◽

Victoria J. Chalker ◽

Lucy C. Jones ◽

Nicola C. Maxwell ◽

O. Brad Spiller

Keyword(s):

Antibiotic Resistance ◽

Molecular Mechanisms ◽

Treatment Options ◽

Tetracycline Resistance ◽

Health Clinic ◽

Broth Microdilution ◽

England And Wales ◽

Content Type ◽

Microdilution Method ◽

Broth Microdilution Method

ABSTRACTUreaplasmaspp. are associated with numerous clinical sequelae with treatment options being limited due to patient and pathogen factors. This report examines the prevalence and mechanisms of antibiotic resistance among clinical strains isolated from 95 neonates, 32 women attending a sexual health clinic, and 3 patients under investigation for immunological disorders, between 2007 and 2013 in England and Wales. MICs were determined by using broth microdilution assays, and a subset of isolates were compared using the broth microdilution method and the Mycoplasma IST2 assay. The underlying molecular mechanisms for resistance were determined for all resistant isolates. Three isolates carried thetet(M) tetracycline resistance gene (2.3%; confidence interval [CI], 0.49 to 6.86%); two isolates were ciprofloxacin resistant (1.5%; CI, 0.07 to 5.79%) but sensitive to levofloxacin and moxifloxacin, while no resistance was seen to any macrolides tested. The MIC values for chloramphenicol were universally low (2 μg/ml), while inherently high-level MIC values for gentamicin were seen (44 to 66 μg/ml). The Mycoplasma IST2 assay identified a number of false positives for ciprofloxacin resistance, as the method does not conform to international testing guidelines. While antibiotic resistance amongUreaplasmaisolates remains low, continued surveillance is essential to monitor trends and threats from importation of resistant clones.

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Major Bloodstream Infection-Causing Bacterial Pathogens and Their Antimicrobial Resistance in South Korea, 2017–2019: Phase I Report From Kor-GLASS

Frontiers in Microbiology ◽

10.3389/fmicb.2021.799084 ◽

2022 ◽

Vol 12 ◽

Author(s):

Dokyun Kim ◽

Eun-Jeong Yoon ◽

Jun Sung Hong ◽

Min Hyuk Choi ◽

Hyun Soo Kim ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Phase I ◽

Bloodstream Infection ◽

Molecular Mechanisms ◽

Diffusion Method ◽

Disk Diffusion Method ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Glass Target ◽

Blood Specimens

To monitor national antimicrobial resistance (AMR), the Korea Global AMR Surveillance System (Kor-GLASS) was established. This study analyzed bloodstream infection (BSI) cases from Kor-GLASS phase I from January 2017 to December 2019. Nine non-duplicated Kor-GLASS target pathogens, including Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter spp., and Salmonella spp., were isolated from blood specimens from eight sentinel hospitals. Antimicrobial susceptibility testing, AMR genotyping, and strain typing were carried out. Among the 20,041 BSI cases, 15,171 cases were caused by one of the target pathogens, and 12,578 blood isolates were collected for the study. Half (1,059/2,134) of S. aureus isolates were resistant to cefoxitin, and 38.1% (333/873) of E. faecium isolates were resistant to vancomycin. Beta-lactamase-non-producing ampicillin-resistant and penicillin-resistant E. faecalis isolates by disk diffusion method were identified, but the isolates were confirmed as ampicillin-susceptible by broth microdilution method. Among E. coli, an increasing number of isolates carried the blaCTX–M–27 gene, and the ertapenem resistance in 1.4% (30/2,110) of K. pneumoniae isolates was mostly (23/30) conferred by K. pneumoniae carbapenemases. A quarter (108/488) of P. aeruginosa isolates were resistant to meropenem, and 30.5% (33/108) of those carried acquired carbapenemase genes. Over 90% (542/599) of A. baumannii isolates were imipenem-resistant, and all except one harbored the blaOXA–23 gene. Kor-GLASS provided comprehensive AMR surveillance data, and the defined molecular mechanisms of resistance helped us to better understand AMR epidemiology. Comparative analysis with other GLASS-enrolled countries is possible owing to the harmonized system provided by GLASS.

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Screening for antifolate and artemisinin resistance in Plasmodium falciparum clinical isolates from three hospitals of Eritrea

F1000Research ◽

10.12688/f1000research.54195.1 ◽

2021 ◽

Vol 10 ◽

pp. 628

Author(s):

Harriet Natabona Mukhongo ◽

Johnson Kang'ethe Kinyua ◽

Yishak Gebrekidan Weldemichael ◽

Remmy Wekesa Kasili

Keyword(s):

Drug Resistance ◽

Plasmodium Falciparum ◽

Point Mutations ◽

Artemisinin Resistance ◽

Pcr Amplification ◽

Clinical Isolates ◽

Genetic Mechanism ◽

Dried Blood Spot ◽

Nested Polymerase Chain Reaction ◽

Blood Spot

Background: Antimalarial drug resistance is a major challenge hampering malaria control and elimination. Plasmodium falciparum, the leading causative parasite species, has developed resistance to basically all antimalarials. Continued surveillance of drug resistance using genetic markers provides important molecular data for treatment policies. This study sought to verify the genetic mechanism of resistance to sulfadoxine-pyrimethamine and assess the occurrence of point mutations associated with artemisinin resistance in P. falciparum clinical isolates from Eritrea. Methods: Nineteen dried blood spot samples were collected from patients visiting Adi Quala, Keren and Gash Barka Hospitals, Eritrea. The patients were followed up after receiving treatment with first line artesunate-amodiaquine. Nested polymerase chain reaction and Sanger sequencing techniques were employed to genotype point mutations in the P. falciparum bifunctional dihydrofolate reductase-thymidylate synthase (Pfdhfr, PF3D7_0417200), dihydropteorate synthase (Pfdhps, PF3D7_0810800) and kelch 13 (PfK13, PF3D7_1343700) genes. Results: Eight of nineteen (42%) of the dried blood spot samples were successful for PCR-amplification. Data analyses of the PCR-positive isolates revealed the following point mutations: Pfdhfr N51I in four isolates, C59R in one isolate, S108N in four isolates, a rare non-synonymous substitution V45A in four isolates and Pfdhps K540E in four isolates. No PfK13 point mutations were reported. Conclusions: Pfdhfr C59R and Pfdhps K540E point mutations are reliable markers for the sulfadoxine-pyrimethamine quintuple mutant haplotype combination. These findings highlight first reports in Eritrea, which verify the underlying genetic mechanism of antifolate resistance. Continuous monitoring of the PfK13 marker is recommended.

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656. Sulbactam-Durlobactam MIC Determination: Comparative Evaluation of the New ETEST® SUD to the CLSI 2021 Broth Microdilution Method

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.853 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S430-S430

Author(s):

Veronique Sauvonnet ◽

Elodie Escoffier ◽

Christine Franceschi ◽

Diane Halimi ◽

Roland Martelin ◽

...

Keyword(s):

Reference Method ◽

Multidrug Resistant ◽

Error Rates ◽

Broth Microdilution ◽

Microdilution Method ◽

Mueller Hinton ◽

Broth Microdilution Method ◽

Lactam Antibiotic ◽

Visible Growth ◽

Resistant Strains

Abstract Background Species belonging to the Acinetobacter baumannii-calcoaceticus (ABC) complex, such as A. baumannii, A. pittii and A. nosocomialis, are a major cause of hospital acquired infections and outbreaks with increasing occurrence of multidrug-resistance. Sulbactam-durlobactam (SUD), a combination of one active β-lactam antibiotic (sulbactam) with a new β-lactamase inhibitor (durlobactam), is currently being tested in a phase 3 clinical trial by Entasis Therapeutics for the treatment of serious infections caused by ABC, including multidrug-resistant strains. At the same time, an ETEST® SUD (sulbactam-durlobactam - MIC range 0.004/4-64/4 µg/mL) has been developed and calibrated versus the broth microdilution reference method (BMD) as described by the Clinical and Laboratory Standards Institute (CLSI). This test is intended to determine the MIC of sulbactam-durlobactam for species of the ABC complex. The aim of this study was to perform a first comparative study of ETEST SUD with the CLSI BMD method on a panel of 263 isolates. Methods The panel consisted of 204 A. baumannii, 29 A. pittii, 30 A. nosocomialis, including 24 SUD-resistant strains, and one CLSI QC strain. BMD was performed using the 2021 CLSI guidelines. ETEST SUD was evaluated using the standard ETEST procedure for Acinetobacter spp. (inoculum 0.5 McFarland, Mueller Hinton medium, incubation at 35°C for 20-24h). For each method, the MIC was read at complete inhibition of visible growth. To determine category agreement (CA) and error rates, the sulbactam-durlobactam provisional breakpoint of 4 µg/mL was applied. Results The QC strain MICs were in the expected range with reproducible results. The essential MIC agreement [EA, ±1 dilution] was 97.7% without any tendency to over- or underestimate the MIC when compared to BMD. The CA was 98.5%. Two Very Major Errors, both within the EA, and two Major Errors, one within the EA, were observed. Conclusion In this study, the ETEST SUD was found to be equivalent to the CLSI reference method. MIC end points were easy to read. With a 15-dilution range and simplicity of use, ETEST SUD could represent a valuable tool for MIC determination and could be an alternative to BMD. For Research Use Only. The performance characteristics of this product have not been established yet. Disclosures All Authors: No reported disclosures

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Geographical and Ecological Analysis of Resistance, Coresistance, and Coupled Resistance to Antimicrobials in Respiratory Pathogenic Bacteria in Spain

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.49.5.1965-1972.2005 ◽

2005 ◽

Vol 49 (5) ◽

pp. 1965-1972 ◽

Cited By ~ 102

Author(s):

Emilio Pérez-Trallero ◽

Celia García-de-la-Fuente ◽

César García-Rey ◽

Fernando Baquero ◽

Lorenzo Aguilar ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Cefuroxime Axetil ◽

Beta Lactamase ◽

Erythromycin Resistance ◽

Ecological Analysis ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Amoxicillin Clavulanic Acid ◽

Resistant Strains ◽

Tract Infections

ABSTRACT A multicenter susceptibility surveillance (the S.A.U.C.E. project) including 2,721 Streptococcus pneumoniae, 3,174 Streptococcus pyogenes, and 2,645 Haemophilus influenzae consecutive isolates was carried out in 25 hospitals all over Spain from November 2001 to October 2002 to evaluate the current epidemiology of resistance of the main bacteria involved in community-acquired respiratory tract infections. Susceptibility testing was performed in a single centralized laboratory by a broth microdilution method. The prevalence of resistant S. pneumoniae strains was 0.4% for cefotaxime, 4.4% for amoxicillin and amoxicillin-clavulanic acid, 25.6% for cefuroxime-axetil, 34.5% for erythromycin, clarithromycin, and azithromycin, and 36.0% for cefaclor. Phenotypes of resistance to erythromycin were MLSB (macrolide-lincosamide-streptogramin B) in 89.9% (gene ermB) and M (macrolide) in 9.7% of cases (gene mefA). No strain harbored both genes simultaneously. Serotypes 19, 6, 23, 14, and 3 were the most prevalent, accounting for 54.6% of the total isolates. Resistance to macrolides seems to be the most alarming point, since among penicillin-susceptible isolates it reached 15.1% compared to 55.8% among penicillin-resistant strains. Geographically, a number of regions had rates of erythromycin resistance above 40% (even higher in children). Resistance to erythromycin was also high in S. pyogenes isolates: mean regional 33.2%, beta-lactamase-producing H. influenzae were 20%, whereas 4.4% had a beta-lactamase-negative, ampicillin-resistant phenotype. We highlight the importance of different geographical frequencies of coresistance (associations of resistance to different drugs within the same species) and coupled resistance (association of resistance between different species) probably resulting from different local coselective events.

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Resistance phenotype and molecular epidemiology of Carbapenem-resistant Klebsiella pneumoniae isolates in Shanghai

10.21203/rs.3.rs-22213/v1 ◽

2020 ◽

Author(s):

Jue Zhang ◽

Wenxia Zhang ◽

Hongyou Chen ◽

Chen Chen ◽

Junhao Chen ◽

...

Keyword(s):

Drug Resistance ◽

Klebsiella Pneumoniae ◽

Molecular Epidemiology ◽

Genetic Relatedness ◽

Control Strategies ◽

Microdilution Method ◽

Carbapenem Resistant ◽

Broth Microdilution Method ◽

Polymerase Chain ◽

Relationship Of

Abstract Background: The emergence and wide global spread of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates are of great concern, and the aim of this study was to investigate drug resistance, molecular epidemiology, and genetic relationship of CRKP isolates from patients in Shanghai, China. Methods: A retrospective study was conducted from April 2018 to July 2019, and a total of 133 CRKP isolates were collected. Antimicrobial susceptibility was determined by VITEK-2 automated microbiology analyzer platform (bioMérieux, France) and the broth microdilution method. Polymerase chain reaction (PCR) assays were used to investigate the presence of drug resistance genes. A modified carbapenem inactivation method (mCIM) was performed to detect carbapenemases. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were conducted for genetic relatedness of 50 CRKP isolates selected. Results: Among 670 isolates of K. pneumoniae, 133 (19.85%) strains were identified as carbapenem-resistant K. pneumoniae (CRKP), of which, 76.69% (102/133) strains were isolated from ICUs. All the 133 CRKP isolates were found to be carbapenemase-producers and harbor blaKPC-2 gene. No other carbapenemase genes of blaNDM, blaOXA−48, blaVIM, and blaIMP were detected. Furthermore, β-lactamase genes of blaSHV, blaCTX, and blaTEM were the most common resistance-associated genes among these KPC-2 producing isolates. All the 133 CRKP strains displayed more than 95% of resistance to cephalosporins and carbapenems, except for gentamicin, Trimethoprim-sulfamethoxazole, amikacin, tigecycline and colistin. The most common sequence type was ST11, accounting for 90.0% of the 50 CRKP selected, followed by ST15 (10%). PFGE analysis clustered the 50 KPC-2-producing isolates into seven (A-G) distinct clonal clusters at 85% cut off. Of which, cluster A and G were the two major clusters, accounting for the majority of the strains collected in emergency ICU and neurosurgical ICU. And all the strains of cluster D and E were collected in cardiothoracic surgery ICU, expect for one strain collected in one outpatient. Conclusion: The KPC-2-producing K.pneumoniae belonged to ST11 was widely disseminated in ICUs, and active and effective surveillance of infection control strategies was initiated to limit the spread of CRKP strains.

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Hazard of agricultural triazole fungicide: Does cyproconazole induce voriconazole resistance in Aspergillus fumigatus isolates?

Current Medical Mycology ◽

10.18502/cmm.6.4.5329 ◽

2021 ◽

Author(s):

Maryam Moazeni ◽

Elaheh Ghobahi Katomjani ◽

Iman Haghani ◽

Mojtaba Nabili ◽

Hamid Badali ◽

...

Keyword(s):

Aspergillus Fumigatus ◽

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Homology Model ◽

In Vitro Activity ◽

Environmental Isolates ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Resistant Strains

Background and Purpose: The present study aimed to evaluate the effect of cyproconazole, the most used fungicide in Iranian wheat farms, on the induction of voriconazole resistance in Aspergillus fumigatus isolates. Materials and Methods: A collection of 20 clinical and environmental isolates were selected for investigation of the in vitro activity of fungicides. The minimum inhibitory concentrations (MICs) were determined by the documented broth microdilution method M38-A2 (CLSI, 2008). Induction experiments were performed and the possibly induced isolate(s) were subjected to antifungal susceptibility testing, sequencing of the CYP51A promoter, and full coding gene. Furthermore, CYP51-protein homology modeling and docking modes were evaluated using SWISS-MODEL (https://swissmodel.expasy.org/) and SEESAR software (version 9.1). Results: Among 10 susceptible isolates, only one strain showed a high MIC value against voriconazole (MIC=4μg/ml) after 25 passages. Nevertheless, sequencing of the CYP51A promoter and full coding gene did not reveal any mutations. Cyproconazole, which has three nitrogen atoms in the aromatic ring, coordinated to the iron atom of heme through a hydrogen bond contact to residue Lys147 present in the active site of the A. fumigates Cyp51 homology model. Conclusion: Cyproconazole is being applied extensively in wheat farms in Iran. According to the results, cyproconazole may not play a key role in the induction of azole resistance in the isolates through the environmental route. However, the potential ability of the fungicide to induce medically triazole-resistant strains over a long period of application should not be neglected.

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