Antifungal Susceptibility Testing Of Dermatophytes Research Articles

A Road Less Traveled: E-test Method for Antifungal Susceptibility Testing in Trichophyton mentagrophyte Isolates Among Patients Presenting With Dermatophytosis at a Tertiary Healthcare Center in North India.

Introduction Dermatophytosis is a common infection of the skin, hair, and nails caused by dermatophytes, a group of filamentous fungi capable of digesting and obtaining nutrients from keratin. Dermatophytes comprise three important genera: Epidermophyton, Microsporum,and Trichophyton. This study aimed to analyze the antifungal susceptibility patterns of Trichophyton mentagrophytes isolates using the epsilometer test (E-test) method. Material and methods This prospective observational study was conducted on clinically suspected cases of dermatophytosis. All samples, including skin scrapings, hair, and nails, were subjected to potassium hydroxide (KOH) examination followed by fungal culture. The Trichophyton mentagrophytes isolates were then subjected to antifungal susceptibility testing using the E-test method for the two most prescribed antifungals: itraconazole and fluconazole. Results In this study, one-third of the patients who tested positive for dermatophytosis belonged to the same family, with spouses being the most commonly affected. Tinea corporis was the most common clinical presentation, with Trichophyton mentagrophytes identified as the most common etiological agent. Itraconazole was more effective than fluconazole. Conclusion The current study demonstrated that antifungal susceptibility testing of dermatophytes using the E-test is easier and can be applied in routine laboratories as a screening method, serving as an alternative to broth microdilution.

Evaluation of Gradient Concentration Strips for Detection of Terbinafine Resistance in Trichophyton spp.

The number of dermatophytosis cases resistant to terbinafine is increasing all over the world. Therefore, there is a need for antifungal susceptibility testing of dermatophytes for better management of the patients. In the present study, we have evaluated a gradient test (GT) method for testing the susceptibility of dermatophytes to terbinafine. MIC values to terbinafine determined by the EUCAST reference technique and by gradient test were compared for 79 Trichophyton spp. isolates. Overall, MICs were lower with gradient test (MIC50 of 0.002 μg/mL) than with EUCAST (MIC50 of 0.016 μg/mL). Good categorical agreement (>90%) between the 2 techniques was obtained but the essential agreement was variable depending on the batch of gradient test.

A study of dermatophytosis in patients attending dermatology outdoor patient department at a tertiary care center

BACKGROUND AND PURPOSE: Dermatophytosis is a superficial fungal infection of keratinized tissue caused by dermatophytes. The dermatophytes are included in three fungal genera: Epidermophyton, Microsporum, and Trichophyton. The infections caused by dermatophytes are known as ringworm or tinea infections. Although there are increasing numbers of antifungals available for the treatment of dermatophytes, some cases and relapses have been unresponsive to treatment. The aim and objectives of the present study are to identify the dermatophyte species causing superficial fungal infections and study their susceptibility to antifungals.MATERIALS AND METHODS: A total of 60 clinically diagnosed cases of dermatophytosis of patients attending the dermatology outdoor patient department were studied. The samples of these patients were collected and processed for microscopic examination and fungal culture. The causative dermatophytes were isolated and identified. Antifungal susceptibility testing of dermatophytes was done by Epsilometer strip minimum inhibitory concentration method against antifungal agents – fluconazole, itraconazole, and terbinafine.RESULTS: The most common clinical presentation in patients found was tinea corporis. Maximum dermatophyte isolates obtained on culture were Trichophyton rubrum. On antifungal susceptibility testing, terbinafine showed good results compared to azoles.CONCLUSION: Antifungal susceptibility testing of dermatophytes could be performed to study response and assist clinicians in choosing an effective therapy for patients.

P107 Spectrum of Dermatophyte infections and drug susceptibility pattern of Dermatophytes in patients visiting to tertiary care hospital in Chhattisgarh state of India

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMObjectives1. To isolate and identify various species of Dermatophytes from clinical specimens 2. To perform and analyze the antifungal susceptibility testing of isolated Dermatophytes for commonly used antifungal agents; terbinafine and itraconazole.MethodsA prospective study was conducted from December 2019 to October 2021. Clinical specimens (skin, hair, and nail) from suspected cases of dermatophytosis were received and processed in the department of microbiology. All the samples were subjected to microscopic examination and culture by standard techniques. Their clinico-demographic profile was obtained. Specimen were processed for KOH and fungal culture. Dermatophytes were identified by studying macroscopic and microscopic characteristics of the isolates. The conidium-forming dermatophyte isolates were processed for antifungal susceptibility testing for terbinafine and itraconazole by Microbroth dilution testing following the CLSI M-38A2 guidelines.ResultsTotal 248 patients with male predominance (68%) were noted in the above-mentioned study period. Predominance of study population belonged to rural area. Maximum numbers of cases were from the age group 21-30 years. Majority of patients belong to poor socioeconomic status. Out of 248 samples, 178 (72%) had a positive KOH mount amongst which 72% had positive culture results. Amongst 2 4881% were skin scraping, 17% were nail, and 1.6% hair samples were processed. Out of culture-positive samples 52% were Dermatophytes. The most clinical form of dermatophytosis was combination of both Tinea cruris and T. carporis (31%) followed by T. cruris (22%), and T. corporis (17%) for which skin scraping was processed. The most common isolate was Trichophyton tonsurans (73%) followed by T. mentagrophytes (10%), and T. verrucosum. Onychomycosis was diagnosed in 17% patients of which 59% were positive by KOH 49% were culture positive.11.5% isolates from nails were dermatophytes.Antifungal susceptibility testing was done by Microbroth dilution method and analyzed the range. The MIC range of major isolates, i.e., T. tonsurans showed MIC ranges against terbinafine <0.03-4 μg/ml and itraconazole 0.03-2 μg/ml. Trichophyton mentagrophyte for terbinafine <0.12-4 μg/ml and for itraconazole 0.12-2 μg/ml. Four isolates of T. tonsurans had higher MIC values for terbinafine and two isolates had higher MIC for itraconazole. One isolate of T. mentagrophytes had higher MIC values of itraconazole, and one another isolate had higher MIC for terbinafine.ConclusionThis study highlights the change in pattern of causative agents of dermatophytosis. The present study showed the predominance of T. tonsurans. More extensive studies are needed to evaluate the cut-off range of antifungal susceptibility testing of dermatophytes with clinical follow-up to see the response of respective antifungals and to guide the therapy.

Isolation, Identification and Antifungal Susceptibility Testing Of Dermatophytes in Kimshrc, Bangalore

Isolation, Identification and Antifungal Susceptibility Testing Of Dermatophytes in Kimshrc, Bangalore

Identification and antifungal susceptibility testing of dermatophytes

Identification and antifungal susceptibility testing of dermatophytes

Antifungal Susceptibility Testing of Dermatophytes by ABDD and E-Test, a Comparative Study

Aim: The objective of this study was to isolate, identify, and explore the in-vitro antifungal susceptibility pattern of dermatophytes isolated from clinically suspected cases of dermatophytosis (tinea infections) attending the Dermatology Department at J.S.S Hospital. Methods: This study was conducted at JSS Medical College and Hospital from December 2016 to December 2017. Clinical samples (e.g., skin scrapings and hair stumps) were collected under aseptic precautions. The identification of dermatophytes was performed through microscopic examination using 10%, 20% & 40% potassium hydroxide (KOH) and culture on Sabouraud dextrose agar (SDA), SDAac, PDA and Dermatophyte test medium (DTM). All dermatophytes isolates were subjected to antifungal susceptibility testing using the agar-based disk diffusion (ABDD) and E-test method against Terbinafine, Itraconazole, Fluconazole, and Griseofulvin. Data were analyzed by using Chi square test. Results: A 100 samples were studied, 46% tinea corporis, 2%tinea cruris, 9% tinea pedis, 5% tinea faciei. The dermatophytes isolated were Trichophyton rubrum 11 (35%), Trichophyton mentagrophyte 8 (25%), Trichophyton tonsurans 5 (16%), Microsporum gypseum 3 (10%), Trichophyton verrucosum 2 (6%), Trichophyton violaceum 1 (3%) and Microsporum audouinii 1 (3%). Out of 31 dermatophytes 17 were sensitive to all four antifungal agents within the range of FLC (2 - 6 mcg/ml), ITR (0.125 - 2), TER (0.125 - 2), and GRI (0.125 - 2), 5 isolates were resistant in which 2 were resistant to FLC (64.256 mcg/ml), 2 isolates were resistant to TER 2 (32.38 mcg/ml), 1 isolate was resistant to both GRI and TER (16.32 mcg/ml) and 9 isolates were within the intermediate range. Conclusion: Every patient with a tinea infection should be properly studied for a mycological examination and should be treated accordingly. Dermatophyte test medium is more useful as an identification medium in the isolation of dermatophytes. The ABDD method appears to be a simple, cost-effective, and promising method for the evaluation of antifungal susceptibility of dermatophytes. E-test method is the most sensitive method due to the fact that quantitative MICs can be obtained directly from the E-strip. However, the E-test method is expensive and difficult in defining the precise borders of the inhibition zones in dermatophytes.

Antifungal drug susceptibility profile of clinically important dermatophytes and determination of point mutations in terbinafine-resistant isolates.

With regard to increasing number of antifungal-resistant dermatophytes, antifungal susceptibility testing of dermatophytes serves as a useful tool in managing clinical dermatophytosis. This study aimed to determine antifungal susceptibility profile of clinically important dermatophytes and determination of point mutations in terbinafine-resistant isolates. Based on our results, dermatophytosis was confirmed in 97 cases by direct microscopic examination, culture, and sequencing of ITS region. Antifungal susceptibility of 97 dermatophyte isolates distributed in four species including Trichophyton interdigitale (26 isolates), T. rubrum (19 isolates), T. tonsurans (29 isolates), and Epidermophyton floccosum (21 isolates) was assessed to nine antifungal agents using CLSI M38-A2 guidelines. Minimum inhibitory concentration range (MIC range) for luliconazole and terbinafine was 0.001-0.008 μg/ml and 0.003-> 32 μg/ml, compared to 0.03-64 μg/ml for griseofulvin, 0.01-16 μg/ml for itraconazole and voriconazole, 0.03-8 μg/ml for ketoconazole, 0.03-32 μg/ml for econazole, 0.03-1 μg/ml for lanoconazole, and 0.01-4 μg/ml for butenafine. Trichophyton tonsurans was the most susceptible (MIC = 0.006 μg/ml) and E. floccosum was the most resistant (MIC = 0.02 μg/ml) species to terbinafine. Terbinafine resistance was reported for two species, i.e., T. rubrum and T. tonsurans at the total rate of 2% which was due to Leu393Phe substitution in both species. Taken together, our results assist clinicians and prompt the current knowledge about the necessity of antifungal susceptibility testing to select effective strategies for management of clinical cases of dermatophytosis.

Specific Identification and Antifungal Susceptibility Pattern of Clinically Important Dermatophyte Species Isolated from Patients with Dermatophytosis in Tehran, Iran

Background: With regard to the increasing number of antifungal-resistant dermatophytes, the requirement for precise identification of causative agents of infections and antifungal susceptibility test is vital. Antifungal susceptibility testing of dermatophytes plays a pivotal role in managing dermatophytosis. The current study aimed at determining antifungal susceptibility profile of 161 important dermatophyte species isolated from Iranian patients. Methods: The current descriptive, cross sectional study was conducted on 508 clinically suspected samples of dermatophytosis collected and identified by conventional methods. All dermatophyte isolates were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The susceptibility of dermatophyte strains to two routine antider-matophyte agents (terbinafine and griseofulvin) was evaluated using micro-dilution method according to CLSI (the clinical and laboratory standards institute) M38-A2 guidelines. Trichophyton rubrum PTCC 5143 and Candida krusei ATCC 6258 were used as quality controls. Results: Among 161 dermatophyte isolates, T. interdigitale was reported as the most frequent species isolated from patients using PCR-RFLP and Microsporum ferruginum was the least isolated species. The minimum inhibitory concentration (MIC) values of griseofulvin and terbinafine were ranged 0.0312-8 and 0.008-4 µg/mL, respectively. The most susceptible and resistant species to griseofulvin were T. interdigitale (MIC = 0.0312 µg/mL) and T. interdigitale/T. rubrum (MIC = 8 µg/mL), respectively. The results indicated that T. verrucosum (MIC = 0.008 µg/mL) was the most susceptible species to terbinafine, whereas T. interdigitale and T. rubrum were the most resistant species to it (MIC = 4 µg/mL). Conclusions: The obtained results assist clinicians to monitor the trend and be able to choose effective medications to treat patients with dermatophytosis, especially in countries such as Iran, where dermatophytosis is still a public health problem. © 2018, Archives of Clinical Infectious Diseases.

Is Antifungal Resistance a Cause for Treatment Failure in Dermatophytosis: A Study Focused on Tinea Corporis and Cruris from a Tertiary Centre?

Background:Dermatophytoses are one of the most common skin diseases that have been largely simple to treat. However, in recent years, these infections have become recalcitrant to treatment which can possibly be due to antifungal resistance.Aim:To analyze the resistance pattern of patients with recalcitrant dermatophytoses.Materials and Methods:A cross-sectional evaluation was undertaken of 40 consecutive patients with recalcitrant tinea corporis/cruris/both who had taken systemic antifungal treatment and did not respond completely to therapy or had recurrent lesion within 1 month of stopping the therapy. Terbinafine, fluconazole, itraconazole, ketoconazole, amphotericin B, and voriconazole were the antifungals tested using broth microdilution assay for antifungal susceptibility testing of dermatophytes, and MIC50, 90 values were recorded.Results:KOH mount was positive in 18 (45%) patients, culture was positive in 28 (70%) patients. Trichophyton mentagrophytes (35%) and T. rubrum (27.5%) were the predominant isolates. Overall, activity of terbinafine and itraconazole were significantly higher than the other drugs tested. For terbinafine, both T. mentagrophytes and T. rubrum were inhibited at MIC90 of 0.125 μg/ml. Itraconazole-inhibited T. mentagrophytes and T. rubrum at MIC90 of 0.0625 and 0.25 μg/ml, respectively. All isolates had reduced susceptibility to fluconazole.Conclusion:While MIC seen were higher than western data, in-vitro resistance (>1 μg/ml) to antifungals was not seen and probably may not be a cause of treatment failure. Possibly, treatment failure lies in the intricate host fungal interaction and virulence of species which help it to evade host immune response.

Antifungal Susceptibility Testing of Dermatophytes by Agar Based Disk Diffusion Assay in Tertiary Care Hospital, Nepal

Antifungal Susceptibility Testing of Dermatophytes by Agar Based Disk Diffusion Assay in Tertiary Care Hospital, Nepal

Multilaboratory Evaluation of In Vitro Antifungal Susceptibility Testing of Dermatophytes for ME1111.

ME1111 is a novel small molecule antifungal agent under development for the topical treatment of onychomycosis. Standardization of the susceptibility testing method for this candidate antifungal is needed. Toward this end, 8 independent laboratories determined the interlaboratory reproducibility of ME1111 susceptibility testing. In addition, we subsequently identified 2 strains as quality control (QC) isolates for the method. In the reproducibility study, 5 blinded clinical strains each of Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum were tested, while the QC study tested 6 blinded T. rubrum or T. mentagrophytes ATCC strains. Testing was performed in frozen microtiter panels according to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 methodology. In the reproducibility study, 9 of 15 clinical strains showed interlaboratory agreement of >90% at the 80% inhibition endpoint, with a range of agreement of 76.2% to 100%. In the QC study, 4 of the 6 ATCC strains showed interlaboratory agreement of >90%. ME1111 demonstrated excellent interlaboratory agreement when tested against dermatophytes. Based on this data, the CLSI Subcommittee on Antifungal Susceptibility Tests approved the susceptibility testing of ME1111 against dermatophytes according to M38-A2 methodology, which stipulates RPMI 1640 as the test medium, an inoculum size of 1 to 3 × 10(3) CFU/ml, and an incubation time and temperature of 96 h at 35°C. The MIC endpoint should be 80% inhibition compared with the growth control. T. rubrum ATCC MYA-4438 and T. mentagrophytes ATCC 28185 were selected as QC isolates, with an acceptable range of 0.12 to 1 μg/ml for the two strains.

Investigation of In Vitro Activity of Five Antifungal Drugs against Dermatophytes Species Isolated from Clinical Samples Using the E-Test Method.

Dermatomycosis is an infection with fungi related to the skin: glabrous skin, hair and/or nails. Oral treatment of fungal infections in dermatology has become a preferred modality for the management of these very common conditions. Although there are increasing numbers of antifungals available for treatment of dermatophytes, some cases and relapses have been unresponsive to treatment. The determination of fungus in-vitro antifungal susceptibility has been reported to be important for the ability to eradicate dermatophytes. It is necessary to perform antifungal susceptibility testing of dermatophytes. E-test (AB Biodisk, Sweden) is a rapid, easy-to-perform in-vitro antifungal susceptibility test. The aim of this study was to investigate the susceptibility of the different species of dermatophyte strains isolated clinical specimens to five antifungal agents using the E-test method. A total of 66 specimens were collected from the nails, feet, inguinal region, trunk and hands. These strains tested MIC endpoints of E-test for amphotericin B, fluconazole, itraconazole, caspofungin, and ketoconazole were read after 72, and 96 hours incubation for each strain on RPMI 1640 agar. The dermatophytes tested included Trichophyton rubrum 43 (65.1%), Trichophyton mentagrophytes 7 (10.7%), Microsporum canis 5 (7.6%), Trichophyton tonsurans 5 (7.6%), Epidermophyton floccosum 4 (6.0%) and Trichophyton violaceum 2 (3.0%). The most active agent against all dermatophytes species was caspofungin with a minimal inhibitory concentration (MIC) range (μg/mL(-1)) (0.02-3, 0.032-4, 0.125-0.50, 0.032-2, 0.25-0.50, 0.125-0.50) and it raconazole with an MIC range (μg/mL(-1)) (0.038-1.5, 0.094-1.5, 1-32, 0.016-0.50, 0.25-0.50, 0.125-0.50). The least active agent was fluconazole with an MIC range (μg/mL(-1)) (0, 19-48, 2-256, 2-8, 256, 256, 8-24). E-test seems to be an alternative method to MIC-determination of antifungal drugs for dermatophytes species, since it is a less-laborious methodology and results could be obtained faster.

In vitro activities of antifungal drugs against dermatophytes isolated in Tokat, Turkey

In this study, we aimed to establish the in vitro antifungal susceptibilities of terbinafine, miconazole, itraconazole, ketoconazole, griseofulvin, and amphotericin B against dermatophyte isolates. One hundred and seventy-seven clinical isolates were tested: Trichophyton rubrum (n = 78), Trichophyton mentagrophytes (n = 49), Epidermophyton floccosum (n = 30), Trichophyton verrucosum (n = 16), and Trichophyton tonsurans (n = 4). The broth microdilution assay for antifungal susceptibility testing of dermatophytes was performed according to Clinical and Laboratory Standards Institute guidelines in the M38-A2 document. Our minimum inhibitory concentration (MIC) results showed that the values for terbinafine for all dermatophyte isolates were significantly lower than the values for amphotericin B, miconazole, itraconazole, ketoconazole, and griseofulvin. For T. rubrum isolates, amphotericin B was more active than miconazole, itraconazole, and ketoconazole. Among the antifungal drugs tested, griseofulvin had the highest minimum inhibitory concentration values for T. mentagrophytes isolates. Terbinafine was found to be the most effective antifungal drug against all tested dermatophyte isolates. Griseofulvin was the less active antifungal drug against T. mentagrophytes isolates. Performing antifungal susceptibility testing is especially important for screening the development of antifungal resistance.

Antimycotics susceptibility testing of dermatophytes

Dermatophytes are moulds that produce infections of the skin, hair and nails of humans and animals. The most common forms among these infections are onychomycosis and tinea pedis affecting 20% of world population. These infections are usually chronic. The treatment of dermatophytoses tends to be prolonged partly because available treatments are not very effective. Antifungal drug consumption and public health expenditure are high worldwide, as well as in Serbia. For adequate therapy, it is necessary to prove infection by isolation of dermatophytes and to test the antifungal susceptibility of isolates. Susceptibility testing is important for the resistance monitoring, epidemiological research and to compare in vitro activities of new antifungal agents. The diffusion and dilution methods of susceptibility tests are used, and technical issues of importance for the proper performance and interpretation of test results are published in the document E.DEF 9.1 (EUCAST) and M38-A2 (CLSI). The aim of our paper is to promptly inform the public about technical achievements in this area, as well as the new organization of laboratory for medical mycology in our country. The formation of laboratory networks coordinated by the National Reference Laboratory for the cause of mycosis need to enable interlaboratory studies and further standardization of methods for antifungal susceptibility testing of dermatophytes, reproducibility of tests and clinical correlation monitoring (MIK values and clinical outcome of dermatophytosis). The importance of the new organization is expected efficient improvement in the dermatophytosis therapy at home, better quality of patient's life and the reduction of the cost of treatment.

Comparison between the Standardized Clinical and Laboratory Standards Institute M38-A2 Method and a 2,3-Bis(2-Methoxy-4-Nitro-5-[(Sulphenylamino)Carbonyl]-2 H -Tetrazolium Hydroxide- Based Method for Testing Antifungal Susceptibility of Dermatophytes

In this study, we determined the utility of a 2,3-bis(2-methoxy-4-nitro-5-[(sulfenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT)-based assay for determining antifungal susceptibilities of dermatophytes to terbinafine, ciclopirox, and voriconazole in comparison to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 method. Forty-eight dermatophyte isolates, including Trichophyton rubrum (n = 15), Trichophyton mentagrophytes (n = 7), Trichophyton tonsurans (n = 11), and Epidermophyton floccosum (n = 13), and two quality control strains, were tested. In the XTT-based method, MICs were determined spectrophotometrically at 490 nm after addition of XTT and menadione. For the CLSI method, the MICs were determined visually. With T. rubrum, the XTT assay revealed MIC ranges of 0.004 to >64 mug/ml, 0.125 to 0.25 mug/ml, and 0.008 to 0.025 mug/ml for terbinafine, ciclopirox, and voriconazole, respectively. Similar MIC ranges were obtained against T. rubrum by using the CLSI method. Additionally, when tested with T. mentagrophytes, T. tonsurans, and E. floccosum isolates, the XTT and CLSI methods resulted in comparable MIC ranges. Both methods revealed similar lowest drug concentrations that inhibited 90% of the isolates for the majority of tested drug-dermatophyte combinations. The levels of agreement within 1 dilution between both methods were as follows: 100% with terbinafine, 97.8% with ciclopirox, and 89.1% with voriconazole. However, the agreement within 2 dilutions between these two methods was 100% for all tested drugs. Our results revealed that the XTT assay can be a useful tool for antifungal susceptibility testing of dermatophytes.

Comparison of the Sensititre YeastOne® Colorimetric Antifungal Panel with the Modified Clinical and Laboratory Standards Institute Broth Microdilution (M38-A) Method for Antifungal Susceptibility Testing of Dermatophytes

Background: To compare the susceptibility of different dermatophyte species to itraconazole (I), fluconazole (F) and voriconazole (V) by the modified reference (microdilution, CLSI M38-A) and the colorimetric method Sensititre YeastOne® . The microdilution method is not very practical for use in routine susceptibility testing in the clinical laboratory, thus necessitating the use of other methods. Methods: We studied a total of 46 dermatophyte strains isolated from clinical specimens. The microdilution reference susceptibility testing was performed following the CLSI M38-A document, using I, F and V drugs. The MIC were defined as the lowest drug concentration that produced 100% (I and V) and 50% inhibition (F) after 72 h incubation at 35°C. The Sensititre MIC were detected by a change in color from pink to blue or purple. Results: Agreement levels between the 2 methods (±2 dilutions) for I, F and V were 30, 53.3 and 83.3%, 0, 12.5 and 66.6% and 37.5, 44.4 and 75% for Trichophyton mentagrophytes, Trichophyton rubrum and Microsporumgypseum, respectively. The MIC_50/90 (mg/l) of I, F and V for T. mentagrophytes were 0.25/0.5, 16/64 and 0.12/0.25 by the microdilution method and 0.016/0.06, 8/16 and 0.03/0.06 by the Sensititre method. The MIC for I, F and V for T. rubrum were 0.25/1, 8/64 and 0.25/0.5 by the microdilution and 0.008/0.03, 2/8, 0.016/0.03 by the Sensititre method. For M. gypseum, MIC were 0.5/1 (I), /256 (F) and 0.25/1 (V) as well as 0.016/0.25 (I), 16/256 (F) and 0.06/0.25 (V) by the microdilution and Sensititre methods, respectively. Conclusions: The MICs obtained were lower by the Sensititre than the microdilution method. The best correlation between both methods was obtained for V in T. mentagrophytes (>80%), but was low for T. rubrum. Although the Sensititre method is easy to use in a clinical laboratory, it shows poor agreement with the reference method for dermatophytes.

Global gene expression of Trichophyton rubrum in response to PH11B, a novel fatty acid synthase inhibitor

To determine the transcriptional responses of Trichophyton rubrum to the artificial substance, PH11B. The broth microdilution assay for antifungal susceptibility testing of dermatophytes was used to measure the minimum inhibitory concentration (MIC) of PH11B. cDNA microarray technology and real-time RT-PCR were used to study the transcriptional responses of T. rubrum to PH11B. The MIC determined was 16 microg ml(-1). The analysis of microarray data revealed that 787 genes were affected. Transcript levels from 476 genes increased at least two times, while 311 gene transcript levels decreased at least two times. PH11B has strong antifungal activity and the transcriptional response of T. rubrum to PH11B was determined. This microarray data set provides an analysis of gene expression of T. rubrum under PH11B treatment. The data provide an insight into the various metabolic processes altered or activated by PH11B. This study provided an insight into the action mode of the PH11B on T. rubrum.

Comparison of disk diffusion method and broth microdilution method for antifungal susceptibility testing of dermatophytes

The use of the agar diffusion Neo-Sensitabs method to determine antifungal susceptibility of 59 isolates of dermatophytes, namely Epidermophyton floccosum, Microsporum canis, M. gypseum, Trichophyton mentagrophytes, T. rubrum and T. tonsurans to Clotrimazole (CLZ), Itraconazole (ITZ) and Terbinafine (TBF) is described. Results obtained are compared to the minimum inhibitory concentrations (MIC) determined by an adaptation of the NCCLS-M38-A procedure. Using the diffusion method, all strains showed a broad zone of inhibition at the first available reading time (3 or 7 days). Using the broth microdilution method, the geometric mean MIC (microg/ml) with regard to all isolates was < or = 0.03 for TBF, < or = 0.069 for CLZ and < or = 0.919 for ITZ. In both methods, TBF was the most active antifungal agent against all isolates tested. The two methods evaluated were able to detect the resistance of the quality control strains of Aspergillus fumigatus to ITZ. Even though a reference method for testing dermatophytes still has not been developed, our data suggest that the Neo-Sensitabs diffusion method could provide a simple procedure for the antifungal susceptibility testing of dermatophytes in the routine clinical laboratory.

Interlaboratory evaluation of the Etest® for antifungal susceptibility testing of dermatophytes

Interlaboratory evaluation of the Etest® for antifungal susceptibility testing of dermatophytes