Minimum Inhibitory Concentration Of Itraconazole Research Articles

Resazurin to determine the minimum inhibitory concentration on antifungal susceptibility assays for Fonsecaea sp. using a modified EUCAST protocol.

Chromoblastomycosis is a fungal chronic disease, which affects humans, especially in cutaneous and subcutaneous tissues. There is no standard treatment for Chromoblastomycosis, and it is a therapeutic challenge, due natural resistance of their causative agents, inadequate response of patients and common cases of relapse. Protocols for determination of antifungal drugs susceptibility are not standardized for chromoblastomycosis agents and endpoint definition is usually based on visual inspection, which depends on the analyst, making it sometimes inaccurate. We presented a colorimetric and quantitative methodology based on resazurin reduction to resofurin to determine the metabolic status of viable cells of Fonsecaea sp. Performing antifungal susceptibility assay by a modified EUCAST protocol allied to resazurin, we validated the method to identify the minimum inhibitory concentrations of itraconazole, fluconazole, amphotericin B, and terbinafine for eight Fonsecaea clinical isolates. According to our data, resazurin is a good indicator of metabolic status of viable cells, including those exposed to antifungal drugs. This work aimed to test resazurin as an indicator of the metabolic activity of Fonsecaea species in susceptibility assays to antifungal drugs. Species of this genus are the main causative agents of Chromoblastomycosis, which affects humans.

Analysis of the relationship between drug susceptibility of Cryptococcus neoformans isolates and mortality in HIV-negative cryptococcal meningitis

ObjectivesThe relationship between antifungal susceptibility and mortality of cryptococcal meningitis (CM) in HIV-negative patients is poorly understood. MethodsWe conducted a retrospective analysis of 1-year follow-up of 200 HIV-negative CM patients with an initial cerebrospinal fluid (CSF) culture for Cryptococcus neoformans. According to the cut-off values of minimum inhibitory concentration (MIC), two groups of five antifungal agents were classified: amphotericin B (AmB), ≤0.5 µg/mL, >0.5 µg/mL; 5-flucytosine (5-FC), ≤4 µg/mL, >4 µg/mL; fluconazole (FLU), ≤4 µg/mL, >4 µg/mL; itraconazole (ITR), ≤0.125 µg/mL, >0.125 µg/mL; and voriconazole (VOR), <0.25 µg/mL, ≥0.25 µg/mL. Comparisons were performed to analyse clinical features, laboratory, modified Rankin Scale (mRS) scores, and CSF findings under different prognosis outcomes in 1-year. ResultsAll of Cryptococcus neoformans isolates were sensitive to AmB and VOR, most of them were sensitive to 5-FC and FLU (95.5% and 90.5%, respectively) while only 55.0% of them were susceptible to ITR. Minimum inhibitory concentrations of ITR and VOR were significantly related to baseline mRS scores. All-cause mortality was not significantly related to MICs in Cryptococcus neoformans strains. The combination of actual antifungal agents and two groups of the MICs values for antifungal agents had no significant effects on all-cause mortality. ConclusionMost Cryptococcus neoformans isolates were sensitive to AmB, VOR, 5-FC, and FLU. Because of the small number of deaths, we are not able to comment on whether MIC is associated with mortality of CM in HIV-negative patients.

Effect of the 1064 nm Nd: YAG Laser on the MICs of Antifungals Used in Clinical Practice for the Treatment of Fungal Nail Infections.

Introduction: The fungal nail infection (onychomycosis) involves 18%-40% of all nail disorders, which, although not fatal, can cause mechanical, aesthetic, occupational, and economic problems. Drug treatments due to prolonged treatment periods, drug interactions, adverse effects, and slow progression may associate with numerous negative outcomes. This study aimed to evaluate the long-pulsed 1064-nm Nd: YAG laser effect on fungal colonies and subsequently possible change in the minimum inhibitory concentrations (MICs) of common antifungals compared with the same non-lasered colonies as a novel way to investigate laser and antifungal interaction. Methods: Sixty onychomycosis samples consisting of saprophyte (n=20), dermatophyte (n=20), and yeast (n=20) duplicate colonies were isolated. A series was treated by a long-pulsed 1064-nm Nd: YAG laser. Afterward, the MIC (CLSI-M38-A2 and CLSI-M27-A3) of two series against common antifungals were compared. Results: After 1064-nm Nd: YAG laser irradiation in all 20 tested saprophytes, the MICs of terbinafine (P value<0.035) were changed, and in all 20 tested dermatophytes, the MICs of voriconazole (P value<0.021) were changed. Also, in all 20 tested yeasts, the MICs of caspofungin (P value<0.037) were changed. Moreover, in saprophytes, dermatophytes, and yeasts, significant changes in the MICs of itraconazole (P value<0.032), terbinafine (P value<0.025), and caspofungin (P value<0.037) were detected. Our result showed the GM MICs of the 1064-nm Nd: YAG laser in all saprophyte, dermatophyte, and yeast groups were lower than in the control group. Conclusion: The present study indicated that the long-pulsed 1064-nm Nd: YAG laser significantly changes the MICs of antifungals in onychomycosis clinical samples.

Spectrum and functional properties of &lt;i&gt;ERG11&lt;/i&gt; gene mutations in fluconazole-resistant &lt;i&gt;Candida albicans&lt;/i&gt; strains isolated from HIV-infected patients

Rationale. The low efficacy of azole antimycotics in treatment of Candida infections, especially in HIV-infected patients, is often associated with overexpression of the ERG11 gene in Candida spp., which results in increased production of ergosterol the target of the above antimycotic drugs. Researchers have found ERG11 gene mutations that can modify its overexpression effects by increasing or decreasing it. However, the findings reported by different laboratories and countries are highly contradictory.&#x0D; The purpose of the study is to explore the spectrum and functional properties of ERG11 gene mutations in fluconazole-resistant Candida albicans strains isolated from HIV-infected patients.&#x0D; Materials and methods. The study was performed using 10 C. albicans strains inherently resistant to fluconazole and voriconazole and isolated from the oropharynx of HIV-infected patients; the strains were provided from the collection of the Gabrichevsky Moscow Research Institute of Epidemiology and Microbiology. The strains were assessed by their sensitivity to antimycotic agents: anidulafungin, micafungin, caspofungin, posaconazole, voriconazole, itraconazole, fluconazole, amphotericin B, 5-flucytosine. Expression levels of the ERG11 gene were measured by quantitative PCR. ERG11 gene mutations were identified by Sanger sequencing.&#x0D; Results. Five mutations (E266D, G464S, I471L, D116E, and V488I) were detected in the ERG11 gene in seven C. albicans strains; six strains carried non-associated co-occurring mutations. Increased expression of the ERG11 gene was found in six C. albicans strains. The V488I mutation demonstrated a strong negative association with the increased expression of the ERG11 gene (r = 0.845; p 0.05). The minimum inhibitory concentration (MIC) in strains carrying mutations was a hundred times as low (p 0.05) as MIC in strains without mutations. In mutation carriers, posaconazole and itraconazole MICs were on average 16.5 times as low as MICs of voriconazole and fluconazole (p 0.001). The presence of mutations in the ERG11 gene had almost no effect on MICs of the tested antimycotics of the echinocandin, polyene, and pyrimidine groups.&#x0D; Conclusion. Multiple mutations were detected in the ERG11 gene in most of the C. albicans strains isolated from HIV-infected patients and resistant to fluconazole and voriconazole. Except for the V488I mutation, the detected mutations were not associated with the overexpression of the ERG11 gene and decreased the effects of overexpression of the ERG11 gene by up to 100 times, though they did not eliminate the inherent resistance to triazole antimycotics.

Antifungal Resistance, Susceptibility Testing and Treatment of Recalcitrant Dermatophytosis Caused by Trichophyton indotineae: A North American Perspective on Management.

There is an ongoing epidemic of chronic, relapsing dermatophytoses caused by Trichophyton indotineaethat are unresponsive to one or multiple antifungal agents. Although this new species may have originated from the Indian subcontinent, there has been a notable increase of its reporting in other countries. Based on current literature, antifungal susceptibility testing (AFST) showed a large variation of terbinafine minimum inhibitory concentrations (MICs) (0.04 to ≥ 32 µg/ml). Elevated terbinafine MICs can be attributed to mutations in the squalene epoxidase gene (single mutations: Leu393Phe, Leu393Ser, Phe397Leu, and double mutations: Leu393Phe/Ala448Thr, Phe397Leu/Ala448Thr). Itraconazole MICs had a lower range when compared with that of terbinafine (0.008-16 µg/ml, with most MICs falling between 0.008 µg/ml and < 1 µg/ml). The interpretation of AFST results remains challenging due to protocol variations and alack of established breakpoints. Adoption of molecular methods for resistance detection, coupled with AFST, may provide a better evaluation of the in vitro resistance status of T. indotineae. There is limited information on treatment options for patients with confirmed T. indotineae infections by molecular diagnosis; preliminary evidence generated from case reports and case series points to itraconazole as an effective treatment modality, while terbinafine and griseofulvin are generally not effective. For physicians working outside of endemic regions, there is currently an unmet need for standardized clinical trials to establish treatment guidelines; in particular, combination therapy of oral and topical agents (e.g., itraconazole and ciclopirox), as well as with other azoles (i.e., fluconazole, voriconazole, ketoconazole), warrants further investigation as multidrug resistance is a possibility for T. indotineae.

A Whole Genome Sequencing-Based Approach to Track down Genomic Variants in Itraconazole-Resistant Species of Aspergillus from Iran.

The antifungal resistance in non-fumigatus Aspergillus spp., as well as Aspergillus fumigatus, poses a major therapeutic challenge which affects the entire healthcare community. Mutation occurrence of cyp51 gene paralogs is the major cause of azole resistance in Aspergillus spp. To obtain a full map of genomic changes, an accurate scan of the entire length of the Aspergillus genome is necessary. In this study, using whole genome sequencing (WGS) technique, we evaluated the mutation in cyp51A, cyp51B, Cdr1B, AtrR, Hmg1, HapE and FfmA genes in different clinical isolates of Aspergillus fumigatus, Aspergillus niger, Aspergillus tubingensis, Aspergillus welwitschiae and Aspergillus terreus which responded to minimum inhibitory concentrations of itraconazole above 16 µg mL−1. We found different nonsynonymous mutations in the cyp51A, cyp51B, Cdr1B, AtrR, Hmg1, HapE and FfmA gene loci. According to our findings, Aspergillus species isolated from different parts of the world may represent different pattern of resistance mechanisms which may be revealed by WGS.

P240 Candida nivariensis infection in South East Asia: series of case reports from Selayang Hospital, Malaysia and South East Asia Region

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM Introduction Candida nivariensis, first described from Spain in 2005 is an emerging fungal pathogen. Malaysia has captured a total of 11 cases since its first reported here in 2014. Indonesia, Thailand, and Vietnam are among South East Asia countries that reported its occurrence too.ObjectivesThe occurrence and characteristics of Candida nivariensis in South East Asia are studied. We would like to highlight two cases from Selayang Hospital, Malaysia that occurred during pandemic COVID-19 in 2020 and 2022.Case DescriptionIn July 2020, a 60-year-old lady underlying poorly controlled diabetes mellitus, CKD stage V approaching ESRD, congestive cardiac failure, hypertension, and dyslipidemia was diagnosed as complicated MSSA bacteremia secondary to right gluteal carbuncle. Appropriate antibiotics were commenced. Aggressive source control including incision and drainage, cauterization of right gluteal carbuncle, and multiple wound debridement for the infected gluteal wound was performed. She underwent a trephine sigmoid loop colostomy. Tracheostomy was done following prolong ventilation. Anidulafungin as empirical fungal coverage was commenced in ICU as she further deteriorated. Candida nivariensis was isolated later from her blood culture.In February 2022, a 74-year-old man underlying Diabetes mellitus, chronic kidney disease, hypertension, ischemic heart disease with two vessels disease stented, post-Whipple's procedure due to necrotizing pancreatitis in 2014 complicated with chronic abdominal pain with hyperalgesia admitted to the ward for acute right lacunar infarct with failed swallowing test and neurogenic bladder. His general condition deteriorated with worsening of biochemical and septic parameters. His blood culture grew C. nivariensis following which anidulafungin was started. No distant seeding and no signs of endophthalmitis. He then required mechanical ventilatory support complicated with multiorgan failure, leading to ICU admission.MethodsFor both cases, yeast isolates were subcultured on Sabouraud dextrose agar and CHROMagar. Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) with molecular testing was performed for confirmation of isolates. Phylogenetic tree among isolates from Malaysia was analyzed. Antifungal susceptibility test (AFST) to study the minimum inhibitory concentration (MIC) among treatment options was performed using the e-test method.ResultsWide use of MALDI-TOF MS with molecular testing increased the detection rate of the species. Isolation sites in Malaysia and South East Asia region include blood culture, peritoneal fluid, high vaginal swab, and oropharyngeal swab. Risk factors namely immunocompromised status, indwelling vascular catheter, abdominal surgeries, renal failure or on dialysis support, polymicrobial usage, and prolonged stay in ICU. AFST established susceptibility towards fluconazole, high MIC to itraconazole and low MIC against amphotericin B, anidulafungin and voriconazole for both patients who unfortunately succumbed to their illness.ConclusionDiagnosing C. nivariensis is challenging due to its closely related phylogenetic with C. glabrata, and C. bracarensis, thus molecular testing is vital. Inadequate antifungal coverage or delay of treatment could be detrimental to patient's outcome. Continuous epidemiological surveillance is crucial to address this potential invasive fungal pathogen and to observe emerging of drug resistance.

Green synthesis of selenium nanoparticles and evaluate their effect on the expression of ERG3, ERG11 and FKS1 antifungal resistance genes in Candida albicans and Candida glabrata.

Drug resistance in Candida species has been considerably increased in the last decades. Given the opposition to antifungal agents, toxicity and interactions of the antimicrobial drugs, identifying new antifungal agents seems essential. This study assessed the antifungal effects of nanoparticles (NPs) on the standard strains of Candida albicans and Candida glabrata and determined the expression genes, including ERG3, ERG11 and FKS1. Selenium nanoparticles (Se-NPs) were biosynthesized with a standard strain of C. albicans and approved by several methods including, ultraviolet-visible spectrophotometer, X-ray diffraction technique, Fourier-transform infrared analysis, field-emission scanning electron microscopy and EDX diagram. The antifungal susceptibility testing performed the minimum inhibitory concentrations (MICs) using the CLSI M27-A3 and M27-S4 broth microdilution method. The expression of the desired genes was examined by the real-time PCR assay between untreated and treated by antifungal drugs and Se-NPs. The MICs of itraconazole, amphotericin B and anidulafungin against C. albicans and C. glabrata were 64, 16 and 4 µg ml-1 . In comparison, reduced the MIC values for samples treated with Se-NPs to 1 and 0·5 µg ml-1 . The results obtained from real-time PCR and analysis of the ∆∆Cq values showed that the expression of ERG3, ERG11 and FKS1 genes was significantly down-regulated in Se-NPs concentrations (P < 0·05). This study's evidence implies biosafety Se-NPs have favourable effects on the reducing expression of ERG3, ERG11 and FKS1 antifungal resistance genes in C. albicans and C. glabrata.

Utility of itraconazole and terbinafine in mucormycosis: a proof-of-concept analysis

An epidemic of mucormycosis followed the second wave of COVID 19 in the state of Uttar Pradesh, India in May 2021. This epidemic, however, had additional challenges to offer in...

Predicting a therapeutic cut-off serum level of itraconazole in recalcitrant tinea corporis and cruris-A prospective trial.

With rising resistance to terbinafine, and consistently high MICs to fluconazole and griseofulvin, itraconazole is being increasingly used as a first line drug for tinea corporis/cruris. However, inadequate clinical responses are often seen with it in spite of in vitro susceptibility. This is possibly related to a variable pharmacokinetic profile of itraconazole. The drug serum levels associated with the therapeutic outcome have not been defined in dermatophytic infections. Forty treatment naïve patients with tinea corporis/cruris were randomised to one of the three dose groups (100, 200 and 400mg/day) of itraconazole. The drug serum levels of 21 of these patients were obtained after 2weeks of treatment and correlated with the final clinical outcome and in vitro antifungal susceptibility data. Trichophyton indotineae was identified by sequencing of ITS region of rDNA and TEF1α. All isolates were sensitive to itraconazole (Minimum Inhibitory Concentration (MICs) range: 0.06-0.5µg/ml), while MICs to terbinafine were uniformly high (range 8-32µg/ml). Thirty-seven patients (92.5%) achieved complete cure, while three failed treatment. Serum levels achieved with 400mg/day were significantly higher than levels with 100 or 200mg dose. All patients with itraconazole serum levels of >0.2µg/ml were cured, while two out of the 10 patients with serum levels <0.2µg/ml failed treatment. Therapeutic failures are uncommon with itraconazole, and the prevalent strain in India has low itraconazole MICs. Treatment failure is likely with itraconazole serum levels of <0.2µg/ml, while levels >0.2µg/ml are consistently associated with a positive therapeutic outcome.

The effect of biosynthesized selenium nanoparticles on the expression of CYP51A and HSP90 antifungal resistance genes in Aspergillus fumigatus and Aspergillus flavus.

The application of biological nanoparticles (NPs) can be considered as a way to overcome the problem of antifungal resistance in pathogenic fungi. This study takes a new approach to biosynthesized NPs influence on the expression of CYP51A and HSP90 antifungal resistance genes in Aspergillus fumigatus and A. flavus, and comparison with antifungal agents. Selenium NPs (Se-NPs) were biosynthesized using Aspergillus strains and their production was proved by several methods including, UV-Vis, XRD, FTIR, FESEM, and EDX techniques. The minimum inhibitory concentrations (MICs) of Aspergillus strains were determined using the CLSI M38-A2 broth microdilution method. The differences in expression levels of CYP51A and HSP90 genes were examined between untreated and treated of A. fumigatus and A. flavus using itraconazole and amphotericin B and biosynthesized Se-NPs through real-time PCR. After confirming the results of NPs synthesis, the MIC of itraconazole and amphotericin B against A. fumigatus and A. flavus was 4μg/ml. Based on the real-time PCR results, the obtained ∆∆CTs for these strains were -0.18, -1.46, and -1.14. Whereas the MIC values for treated samples with Se-NPs have decreased to 0.5μg/ml, and the ∆∆CTs for these were -0.25, -1.76, and -1.68. The expression of CYP51A and HSP90 genes was significantly down-regulated through the use of Se-NPs against A. fumigatus and A. flavus.

Effects of Itraconazole and Micafungin on Aspergillus fumigatus Biofilms.

Aspergillus fumigatus (A. fumigatus) is the most common airborne opportunistic fungal pathogen. Biofilm formation is one of the main pathogenic mechanisms of A. fumigatus. During the past decades, A. fumigatus azole resistance has become prevalent due to the medical and agricultural use of antifungal drugs and fungicides. Until now, the role of fungal biofilms in azole resistance of A. fumigatus remains unclear. In the present study, we compared biofilm drug susceptibility and biofilm formation under itraconazole of azole-resistant strains, sensitive strains, and standard strains, separately. The biofilm viability and matrix thickness at the early and the late stage were measured by XTT assay and Calcofluor white. Our results showed that the sessile minimum inhibitory concentration of itraconazole, which describing the inhibition of drugs on fungi sessile with biofilm, was much higher than the traditional minimal inhibitory concentration of itraconazole. Additionally, low concentrations of itraconazole inhibited biofilm formation of A. fumigatus strains. Notably, biofilm formation by azole-resistant strains could not be inhibited by high concentrations of itraconazole but could be effectively restrained by low concentrations of micafungin, revealing the efficacy of a cell-wall inhibitor to disrupt A. fumigatus biofilm formation. However, late-stage biofilms of both azole-resistant strains and standard strains were hard to disrupt using itraconazole. We found that itraconazole was effective to prevent A. fumigatus biofilm formation at the early stage. For the treatment of A. fumigatus biofilm, our findings suggest that an early-stage preventive strategy is preferred and micafungin is effective to control the azole-resistant strain infection.

Prediction of itraconazole minimum inhibitory concentration for Fonsecaea pedrosoi using Fourier Transform Infrared Spectroscopy (FTIR) and chemometrics.

Fonsecaea pedrosoi is one of the main agents of chromoblastomycosis, a chronic subcutaneous mycosis. Itraconazole (ITC) is the most used antifungal in its treatment, however, in vitro antifungal susceptibility tests are important to define the best therapy. These tests are standardized by the Clinical and Laboratory Standards Institute (CLSI), but these protocols have limitations such as the high complexity, cost and time to conduct. An alternative to in vitro susceptibility test, which overcomes these limitations, is FTIR. This study determined the minimum inhibitory concentration (MIC) of itraconazole for F. pedrosoi, using FTIR and chemometrics. The susceptibility to ITC of 36 strains of F. pedrosoi was determined according to CLSI and with the addition of tricyclazole (TCZ), to inhibit 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis. Strains were grown in Sabouraud agar and prepared for Attenuated Total Reflection (ATR)/FTIR. Partial least squares (PLS) regression was performed using leave-one-out cross-validation (by steps of quintuplicates), then tested on an external validation set. A coefficient of determination (R²) higher than 0.99 was obtained for both the MIC-ITC and MIC-ITC+TCZ ATR/PLS models, confirming a high correlation of the reference values with the ones predicted using the FTIR spectra. This is the first study to propose the use of FTIR and chemometric analyses according to the M38-A2 CLSI protocol to predict ITC MICs of F. pedrosoi. Considering the limitations of the conventional methods to test in vitro susceptibility, this is a promising methodology to be used for other microorganisms and drugs.

The H741D mutation in Tac1p contributes to the upregulation of CDR1 and CDR2 expression in Candida albicans.

The wide use of antifungal agents has led to the development of resistance in the pathogenic yeast strain Candida albicans. Gain-of-function mutations in transcription factors such as Tac1p demonstrated their ability to control expression of the ABC transporter genes CDR1 and CDR2, and mediation of azole resistance. Previously, we obtained a series of azole-resistant isolates with high-level expression of CDR1 or/and CDR2, and identified the novel H741D mutation in Tac1p. In the present study, the TAC1 alleles from isolate C13 were introduced into tac1Δ/Δ mutant. The H741D change was seen in TAC1C13 in addition to several other amino acid differences. Hyperactive alleles TAC1C13 exhibited higher minimum inhibitory concentrations (MICs) of fluconazole and itraconazole than that observed in SN152 containing the wild-type TAC1 allele. And alleles TAC1C13 conferred constitutively high levels of Cdr1p and Cdr2p. Moreover, the importance of H741D in conferring hyperactivity to TAC1 was also confirmed by site-directed mutagenesis. Compared with SN152, the presence of H741D resulted in > 2-fold increase in CDR1 and CDR2 gene and protein expression, > 4-fold increase in fluconazole and itraconazole MICs and higher rates of Rhodamine 6G efflux by 43.24%.

Synergistic Effects of Efflux Pump Modulators on the Azole Antifungal Susceptibility of Microsporum canis.

The microbiologic and clinical resistance of dermatophytes is seldom reported, and the mechanisms associated with resistance are not well known. This study investigated the effect of efflux pump modulators (EPMs) (i.e., haloperidol HAL andpromethazine PTZ) and their inhibiting activity on the minimum inhibitory concentrations of itraconazole (ITZ) and fluconazole (FLZ) against selected M. canis strains. M. canis strains with low (≤ 1μg/ml itraconazole and < 64μg/ml fluconazole) and high (> 1μg/ml itraconazole and ≥ 64μg/ml fluconazole) azole MIC values were tested using Checkerboard microdilution assay. The disk diffusion assay, the minimum fungicidal concentration and the time-kill assay were also performed in order to confirm the results of checkerboard microdilution assay. The MIC values of ITZ and FLZ ofM. canisdecreased in the presence of subinhibitory concentrations of HAL and PTZ, the latter being more effective with a greater increased susceptibility. Synergism was observed in all strains with high azole MICs (FICI < 0.5) and no synergism in the strains with low azole MICs. A fungicidal activity was observed after 48h of incubation when ITZ and FLZ were tested in combination with HAL or PTZ. These results suggest that the drug efflux pumps are involved in the defense mechanisms to azole drugs in M. canis strains. The synergism might be related to an increased expression of efflux pump genes, eventually resulting in azole resistance phenomena. Complementary studies on M. canis resistance are advocated in order to investigate the molecular mechanisms of this phenomenon.

Low in vitro activity of sertaconazole against clinical isolates of dermatophyte

Background and Purpose:Dermatophytes are a group of fungi specialized in invading humans and other vertebrate keratinized tissues. These fungi cause a variety of skin, nail, and hair disorders, called dermatophytosis (tinea). In some cases, drug resistance to antifungals necessitates special treatment. Among the antifungal agents, sertaconazole (i.e., a third-generation imidazole) has a broad-spectrum against dermatophyte species. Regarding this, the present study was conducted to investigate the antifungal susceptibility of dermatophytes obtained from patients with dermatophytosis in Mashhad located in northeastern Iran.Materials and Methods:A total of 75 clinical dermatophyte isolates, including Trichophyton mentagrophytes (n=21), T. interdigital (n=18), T. tonsurans (n=16), Epidermophyton floccosum (n=11), Microsporum canis (n=5), Nannizzia fulvum (n=2), T. benhamiae (n=1), and T. verrucosum (n=1), were evaluated against five antifungal agents of sertaconazole, itraconazole, clotrimazole, terbinafine, and griseofulvin based on the CLSI M38-A2 guideline.Results: According to the results, the minimum inhibitory concentration (MIC) ranges of sertaconazole, terbinafine, griseofulvin, itraconazole, and clotrimazole were estimated at 0.125-16, 0.002-1, 0.5-4, 0.031-4, and 0.016-4 µg/ml, respectively, for dermatophyte species. In addition, the geometric mean (GM) values of the MIC of sertaconazole, terbinafine, griseofulvin, itraconazole, and clotrimazole were obtained as 3.39, 1, 1.44, 1.52, and 1.93, respectively.Conclusion:Among the tested antifungals, terbinafine and griseofulvin were the most effective agents against dermatophyte isolates. However, sertaconazole, a third-generation imidazole, did not show any significant effect. Furthermore, M. canis and E. floccosum showed the best response to the antifungal agents.

Susceptibility of Malassezia pachydermatis Clinical Isolates to Allopathic Antifungals and Brazilian Red, Green, and Brown Propolis Extracts.

Clinical mycoses treatment is associated with issues such as negative side effects, high cost, prolonged treatment, and resistant strain selection. Malassezia pachydermatis is the most frequently isolated yeast in cases of canine otitis and dermatitis. The number of fungal strains exhibiting primary resistance to several drugs in vitro is increasing. Propolis has a diverse chemical composition and well-known therapeutic properties against mycoses. An alternative method for producing propolis extracts using supercritical fluid has higher selectivity, yielding extracts with fewer pollutant residues. This study therefore aimed to evaluate the in vitro susceptibility profile of M. pachydermatis clinical isolates to precharacterized supercritical and ethanolic extracts. Three types of Brazilian propolis extracts (green, red, and brown) and commercial allopathic antifungals were used in this investigation. We used the microdilution broth technique to evaluate the susceptibility profile of the yeasts. The minimum inhibitory concentration (MIC) of the brown propolis ethanolic extract was ≥16 μg/mL for all isolates. The MICs of fluconazole, ketoconazole, itraconazole, and amphotericin B ranged from 8 to >64 μg/mL, 0.032–4 μg/mL, 0.0313–16 μg/mL, and 1–2 μg/mL, respectively. The MICs of ethanolic red propolis extracts were lower than those of supercritical red propolis extracts. However, the green propolis ethanolic extract had more pronounced fungicidal activity. Isolates with lower susceptibility to commercial fungicides were inhibited by red and green propolis extracts. These results indicate that propolis can potentially be used in in vivo experiments as a promising therapeutic agent against M. pachydermatis infections.

Susceptibility profiles and clinical efficacy of antifungals against candida bloodstream isolates from critically ill patients: Focus on intravenous itraconazole

In vitro and clinical data were analysed to evaluate the susceptibility profile of itraconazole in light of the new cut-off points. The in vitro activity of itraconazole was compared with that of eight comparators against 119 Candida bloodstream isolates from 2015 to 2018. Minimum inhibitory concentrations (MICs) were measured by the colorimetric MICRONAUT-S assay. The content of wells without any color change was sub-cultured to measure killing efficacy. No major differences were found against Candida albicans. Itraconazole, posaconazole and amphotericin B were the most active agents against Candida parapsilosis. Of the 32 isolates of C. parapsilosis that were resistant to fluconazole, 96.9%, 78.1% and 93.8% were susceptible to itraconazole, voriconazole and posaconazole, respectively. The ratio of the minimum fungicidal concentration (MFC) to the MIC of itraconazole was lower than for the other azoles against C. parapsilosis and C. glabrata. Itraconazole achieved greater inhibition over-time of the growth of C. parapsilosis than fluconazole. Seventy-three critically ill patients who were unresponsive to antibiotics received intravenous empirical treatment with itraconazole (n = 28) or comparators (n = 45). Case-control matching was conducted for severity, comorbidities, risk factors for candidemia, administered antibiotics and days of antifungal treatment. Breakthrough candidemia was found in 3.6% of patients treated with itraconazole and in 32.1% of patients treated with comparators (P: 0.020); breakthrough candidemia by C. parapsilosis was found in 3.6% and 28.6% of patients, respectively. Results indicate that itraconazole retains a valuable susceptibility profile against Candida isolates, particularly C. parapsilosis. This superior profile may explain the clinical efficacy in the occurrence of breakthrough candidemia and warrants further clinical investigation.

Novel Point Mutations in cyp51A and cyp51B Genes Associated with Itraconazole and Posaconazole Resistance in Aspergillus clavatus Isolates.

Aspergillus clavatus is a common environmental species known to cause occupational allergic disease in grain handlers. We have recently observed azole-resistant isolates of this fungus as a cause of onychomycosis. To further characterize the cause of resistance, the genes encoding 14 α-sterol demethylase enzyme (cyp51A and cyp51B) were characterized and analyzed in 9 ITC-susceptible isolates and 6 isolates with high minimum inhibitory concentrations (MICs) of clinical (nail and sputum) and environmental A. clavatus strains. We found that six isolates with itraconazole MIC >16 mg/L demonstrated nonsynonymous mutations, including V51I, L378P, E483K, and E506G, and synonymous mutations, including F53F, A186A, Q276Q, and H359H. Moreover, P486S was detected in five strains with ITR MIC >16 mg/L. One mutation, F324S, was detected in an isolate with posaconazole MIC >16 mg/L. The effect of E483K and P486S mutations of CYP51A on azole resistance was further investigated using homology modeling and molecular dynamics. We found that E483K and P486S mutations were located near the ligand access channel of CYP51A that could partly lead to narrowing the entry of the ligand access channels. Therefore, we concluded that E483K and P486S mutations may potentially contribute to the limited access of inhibitors to the binding pocket and therefore confer resistance to azole agents.

The Inhibitory Effect of Probiotic Bacteria against Drug - Resistant Candida Species Isolated from the Oral Cavity of the Elderly

Background: Candidiasis includes a range of opportunistic fungal diseases that appear in various forms such as oral thrush and stomatitis in the elderly. Recently, the resistance of Candida species to antibiotics selected to treat oral infections has increased significantly. Objectives: This study aimed to determine the antagonistic effects of probiotics on oral candidiasis in the elderly. Patients and Methods: Swab samples from the saliva and mouth of 72 elders residing in the elderly care centers in Gorgan were cultured in Sabouraud dextrose agar (SDA). The Candida spp. and Candida albicans were identified by culturing in CHROMagar Candida medium and using a PCR identification kit and API 20CAUX system. The broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of nystatin and itraconazole based on the CLSI document. The well - diffusion method and the modified agar method were applied to separate dairy - isolated probiotics from cultures in MRS and M17 media and to study their antimicrobial effect. Results: Overall, 47 Candia isolates in seven different species were diagnosed. The MICs of itraconazole and nystatin were within the range of 0.03 - 16 and 0.03 - 8 µg/mL and the rates of resistance were 87.23% and 74.46%, respectively. The study on dairies showed that most isolated strains belonged to Lactobacilli. It was also revealed that the probiotic bacteria were able to prevent the growth of Candida species. The highest inhibitory effect was seen in Lactobacillus plantarum. Moreover, desirable antifungal effects were observed in preventing the growth of C. albicans as well as non - albicans species, particularly C. glabrata. Conclusions: Concerning the high resistance of Candida isolates to antifungal agents and the inhibitory effects of lactic bacteria, especially Lactobacillus plantarum, it is recommended to use its metabolites directly in the diet of the elderly or to use them in the form of supplements in order to control oral candidiasis.