Correlation between Etest, disk diffusion, and microdilution methods for antifungal susceptibility testing of Candida species from infection and colonization

CHARACTERIZATION OF THE FUNGAL MICROBIOTA IN THE NOSTRILS AND RECTUM OF AMAZONIAN MANATEES (TRICHECHUS INUNGUIS) FROM A REHABILITATION PROGRAM IN BRAZIL

The present study characterized the filamentous and yeast-like fungal microbiota of the nasal cavity and rectum of Amazonian manatees (Trichechus inunguis) undergoing rehabilitation at the Laboratory of Aquatic Mammals, National Institute of Amazonian Research, Manaus, Amazonas, and determined the antifungal susceptibility of these organisms. Nasal and rectal swabs were collected from 22 calves and three juveniles. The samples were seeded in Sabouraud agar supplemented with chloramphenicol 10%, incubated at 26°C, and observed daily for up to 7 d. The growth of different filamentous and yeast-like fungi was observed among the two anatomical sites. Filamentous fungi were categorized by macro- and microscopic characteristics of the colonies. Representatives of each group were selected for molecular identification based on the internal transcribed spacer region. Yeast identification was performed using MALDI-TOF MS and molecular analyses. Thirteen genera of filamentous fungi and six genera of yeasts were isolated and identified. The dominant filamentous species were Fusarium spp., Aspergillus spp., and Cochliobolus lunatus in the nostril samples and Aspergillus melleus in the rectal samples. Candida was the dominant genus among the identified yeasts at both anatomical sites. In the antifungal susceptibility test, 28 isolates showed resistance to fluconazole (78%), itraconazole (39%), and nystatin (42%). The knowledge of fungal microbiota composition of Amazonian manatees provides information that assists in monitoring the health status of individuals maintained in captivity, as these organisms can behave either as opportunists or as primary pathogens. Moreover, the composition and resistance of these organisms may vary among different rehabilitation institutions or different time frames of search, reinforcing the importance of constant in loco surveillance of these microorganisms. This study provides new perspectives on the fungal diversity in the microbiota of manatees and supports future studies concerning the clinical and epidemiological aspects and the impacts of these agents on the health of Amazonian manatees undergoing rehabilitation.

Mixed oral candidiasis in type 2 diabetic patients: Identification and spectrum of sensitivity

Introduction

Patients with type 2 diabetes mellitus are susceptible to acquire Candida spp. infections, sometimes involving more than one species. The resistance of some species to antimycotic agents can cause treatment failure.

Objectives

To determine the frequency and clinical varieties of mixed oral candidiasis in patients with type 2 diabetes mellitus, the involved species, and its sensitivity spectra when exposed to antifungals used as candidiasis treatment.

Material and methods

We developed an analytical cross-sectional study with 72 patients with type 2 diabetes mellitus with hyperglycemia (HbA1C ≥ 7%) and an oral candidiasis diagnosis. The causal species of oral candidiasis were identified through microbiological techniques, and sensitivity tests were carried out using the diffusion method in a plate with strips (E-test ®).

Results

We included 72 patients in the study, 32 (44%) males and 40 (56%) females. Patients were divided into three age groups: young adults (17%), adults (74%), and older adults (9%). The mean age of the patients was 51 years. No significant differences were found between mixed oral candidiasis and groups (sex and age), or between mixed oral candidiasis and gender, glycosylated hemoglobin level (HbA1C), antihyperglycemic treatment, or type 2 diabetes mellitus time of diagnosis. We found a correlation between the adult group and development of mixed or simple oral candidiasis. The results showed eight (13%) cases of mixed oral candidiasis: seven with a coinfection of two species and one with a coinfection of three species. The identified species were Candida albicans, C. glabrata, C. dubliniensis, C. kefyr, C. tropicalis, and C. krusei. Most of these species presented sensitivity against ketoconazole and fluconazole, and higher resistance to itraconazole.

Conclusions

Mixed oral candidiasis occurs in approximately 10% of the patients with type 2 diabetes mellitus and its treatment can be ineffective when the etiological agent is not identified.

Raman Spectroscopy of Oral Candida Species: Molecular-Scale Analyses, Chemometrics, and Barcode Identification

Oral candidiasis, a common opportunistic infection of the oral cavity, is mainly caused by the following four Candida species (in decreasing incidence rate): Candida albicans, Candida glabrata, Candida tropicalis, and Candida krusei. This study offers in-depth Raman spectroscopy analyses of these species and proposes procedures for an accurate and rapid identification of oral yeast species. We first obtained average spectra for different Candida species and systematically analyzed them in order to decode structural differences among species at the molecular scale. Then, we searched for a statistical validation through a chemometric method based on principal component analysis (PCA). This method was found only partially capable to mechanistically distinguish among Candida species. We thus proposed a new Raman barcoding approach based on an algorithm that converts spectrally deconvoluted Raman sub-bands into barcodes. Barcode-assisted Raman analyses could enable on-site identification in nearly real-time, thus implementing preventive oral control, enabling prompt selection of the most effective drug, and increasing the probability to interrupt disease transmission.

Antifungal profile of vulvovaginal candidiasis in sexually active females from a tertiary care hospital of Western Rajasthan

Introduction:

Vulvovaginal candidiasis (VVC) is the commonest form of sexually transmitted infection especially in sexually active females. Various species of Candida i.e., Candida albicans and non-albicans Candida are associated with VVC. More than 75% of women experiences vulvovaginal candidiasis at least once in their lifetime and 10% of it can lead to recurrent VVC. So, this study was planned to evaluate the clinico-mycological profile and antifungal profile of VVC in sexually active female attending tertiary care hospital.

Materials and Methods:

The present two months study was conducted in sexually active females attending Obstetrics –gynecology OPD with VVC in tertiary care hospital. Two high vaginal swabs were taken and fungal culture was done on SDA agar by standard methods. Identification and antifungal susceptibility testing of candidial isolates were done by standard mycological methods.

Results:

Most of the patients belonged to younger age group between 18 and 29 years (55%). Lower abdominal pain was the most common symptom after vaginal discharge followed by burning sensation and pruritis. Candida glabrata (15) with 58% of all the isolates was the most common Candida species associated with VVC in this study, followed by Candida albicans (5, 19%). Highest antifungal resistance was observed to itraconazole (81%) followed by amphotericin B (35%) and fluconazole (31%). 81% resistance to itraconazole among Candida glabrata and Candida albicans. Voriconazole was maximum susceptible to all Candida species.

Conclusion:

This study highlights the incidence of VVC among sexually active females of reproductive age group as its recurrence may result into obstetric complications and even infertility and also enlightens the common Candida species and their antifungal profile, which would help the treating clinicians to formulate local antifungal treatment policy for VVC.

Uncommon Non-Candida Yeasts in Healthy Turkeys-Antimicrobial Susceptibility and Biochemical Characteristic of Trichosporon Isolates

The microbiota of the gastrointestinal tract of humans and animals is inhabited by a diverse community of bacteria, fungi, protozoa, and viruses. In cases where there is an imbalance in the normal microflora or an immunosuppression on the part of the host, these opportunistic microorganisms can cause severe infections. The study presented here evaluates the biochemical and antifungal susceptibility features of Trichosporon spp., uncommon non-Candida strains isolated from the gastrointestinal tract of healthy turkeys. The Trichosporon coremiiforme and Trichosporon (Apiotrichum) montevideense accounted for 7.7% of all fungi isolates. The biochemical tests showed that Trichosporon coremiiforme had active esterase (C4), esterase-lipase (C8) valine arylamidase, naphthol-AS-BI phosphohydrolase, α-galactosidase, and β-glucosidase. Likewise, Trichosporon montevideense demonstrated esterase-lipase (C8), lipase (C14), valine arylamidase, naphthol-AS-BI phosphohydrolase, α-galactosidase, and β-glucosidase activity. T.coremiiforme and T. monteviidense isolated from turkeys were itraconazole resistant and amphotericin B, fluconazole, and voriconazole susceptible. Compared with human isolates, the MIC range and MIC values of turkey isolates to itraconazole were in a higher range limit in both species, while MIC values to amphotericin B, fluconazole, and voriconazole were in a lower range limit. Furthermore, the obtained ITS1—5.8rRNA—ITS2 fragment sequences were identical with T. coremiiforme and T. montevideense sequences isolated from humans indicating that these isolates are shared pathogens.

E-test Determination of Antifungal Susceptibility of Candida Species Isolated from Turkeys

INTRODUCTION

Candida species are a natural component of the intestinal tract microflora, but in favourable conditions they can cause superficial, mucosal, or even systemic candidiasis. Poultry production might be a source of human drug-resistant yeast infections, including Candida spp. The limited data concerning the antifungal susceptibility of poultry Candida isolates prompted us to carry out research to determine the susceptibility of isolates from turkey intestinal tracts.

METHOD AND MATERIALS

The beak cavity, crop and cloaca were swabbed of 580 turkeys from 58 flocks in western Poland. The susceptibility tests were conducted using the E-test method with amphotericin B, fluconazole, itraconazole, and voriconazole on 52 isolates of C. albicans, C. catenulata, C. glabrata, C. palmioleophila, C. rugosa, C. krusei and C. lusitaniae.

RESULTS

All isolates were susceptible to voriconazole. According to the MIC values obtained for amphotericin B and fluconazole, all Candida spp. isolates were classified as susceptible according to the described breakpoints except for C. krusei, which was the only isolate that was amphotericin B-, fluconazole- and itraconazole-resistant. The susceptibility to itraconazole varied: 11 of the Candida isolates were susceptible (21.1%), 29 were dose-dependently susceptible (55.8%), and 12 isolates were resistant (23.1%).

CONCLUSION

There are few resistant strains of Candida in turkeys, and the drug resistance varies. When Candida passes from turkeys to humans, there is a wide range of antifungal treatment options.

Application of 2'-OMethylRNA' Antisense Oligomer to Control Candida albicans EFG1 Virulence Determinant

Antisense oligomers and their analogs have been successfully utilized to silence gene expression for the treatment of many human diseases; however, the control of yeast’s virulence determinants has never been exploited before. In this sense, this work is based on the key hypothesis that if a pathogen’s genetic sequence is a determinant of virulence, it will be possible to synthesize a nucleic acid mimic based on antisense therapy (AST) that will bind to the mRNA produced, blocking its translation into protein and, consequently, reducing the pathogen virulence phenotype. EFG1 is an important determinant of virulence that is involved in the regulation of the Candida albicans switch from yeast to filamentous form. Thus, our main goal was to design and synthesize an antisense oligonucleotide (ASO) targeting the EFG1 mRNA and to validate its in vitro applicability. The results show that the anti-EFG1 2′-OMethylRNA (2′OMe) oligomer was able to significantly reduce the levels of EFG1 gene expression and of Efg1p protein translation (both approximately 60%), as well as effectively prevent filamentation of C. albicans cells (by 80%). Moreover, it was verified that anti-EFG1 2′OMe keeps the efficacy in different simulated human body fluids. Undeniably, this work provides potentially valuable information for future research into the management of Candida infections, regarding the development of a credible and alternative method to control C. albicans infections, based on AST methodology.

Antifungal Drug Susceptibility of Candida Species Isolated from HIV-Positive Patients Recruited at a Public Hospital in São Luís, Maranhão, Brazil

Oropharyngeal candidiasis is the most common fungal infection in hospitalized patients with acquired immune deficiency syndrome (AIDS). Its progression results in invasive infections, which are a significant cause of morbidity and mortality. This study aimed to quickly and accurately identify Candida spp. from oral mucosa of AIDS patients recruited at Presidente Vargas Hospital, in São Luís city, Brazil and to evaluate the sensitivity profile of these fungi to antifungals by using an automated system. Isolates were collected from oropharyngeal mucosa of 52 hospitalized AIDS patients, under anti-viral and antifungal therapies. Patients were included in research if they were HIV-positive, above 18 years of age and after obtaining their written consent. CHROMagar^®Candida and the automated ViteK-2^®system were used to isolate and identify Candida spp., respectively. Antifungal susceptibility testing was performed using the ViteK-2^®system, complemented with the Etest^®, using the drugs amphotericin B, fluconazole, flucytosine, and voriconazole. Oropharyngeal candidiasis had a high prevalence in these hospitalized AIDS patients (83%), and the most prevalent species was Candida albicans (56%). Antifungal susceptibility test showed that 64.7% of the Candida spp. were susceptible, 11.8% were dose-dependent sensitive, and 23.5% were resistant. All the Candida krusei and Candida famata isolates and two of Candida glabrata were resistant to fluconazole. Most of AIDS patients presented oropharyngeal candidiasis and C. albicans was the most frequently isolated species. The results showed high variability in resistance among isolated species and indicates the need to identify the Candida spp. involved in the infection and the need to test antifungal susceptibility as a guide in drug therapy in patients hospitalized with AIDS. This is the first relate about AIDS patients monitoring in a public hospital in São Luís concerning the precise identification and establishing of antifungal profile of Candida spp..

Antifungal Susceptibility Testing with Etest for Candida Species Isolated from Patients with Oral Candidiasis

Background

The necessity of performing antifungal susceptibility tests is recently increasing because of frequent cases of oral candidiasis caused by antifungal-resistant Candida species. The Etest (BioMerieux, Marcy l'Etoile, France) is a rapid and easy-to-perform in vitro antifungal susceptibility test.

Objective

The purpose of this study was to determine the minimal inhibitory concentrations (MICs) of antifungal agents by using the Etest for Candida species isolated from patients with oral candidiasis.

Methods

Forty-seven clinical isolates of Candida species (39 isolates of Candida albicans, 5 isolates of C. glabrata, and 3 isolates of C. tropicalis) were tested along with a reference strain (C. albicans ATCC 90028). The MIC end points of the Etest for fluconazole, itraconazole, voriconazole, and amphotericin B susceptibility were read after the 24-hour incubation of each isolate on RPMI 1640 agar.

Results

All Candida isolates were found susceptible to voriconazole and amphotericin B. However, all five isolates of C. glabrata were resistant to itraconazole, among which two isolates were also resistant to fluconazole.

Conclusion

This study revealed that the Etest represented a simple and efficacious method for antifungal susceptibility testing of Candida species isolated from oral candidiasis patients. Therefore, voriconazole and amphotericin B should be recommended as effective alternatives for the treatment of oral candidiasis.

In vitro activity of calcium sulfate and hydroxyapatite antifungal disks loaded with amphotericin B or voriconazole in consideration for adjunctive osteomyelitis management

BACKGROUND

Regarding antibiotic-loaded cements, there is an abundant amount of literature regarding the antibacterial in vitro inhibitory and clinical applications for the treatment of osteomyelitis. The opposite can be said about literature regarding in vitro antifungal-loaded cement drug delivery for the treatment of fungal osteomyelitis.

METHODS

Aspergillus fumigatus and Candida (ATCC 1023ATCC, Manassas, Virginia) were plated on antibiotic/antifungal-free plates. Voriconazole- and amphotericin B-impregnated calcium sulfate and hydroxyapatite (HA) disks, calcium sulfate + HA control disks, and control polymethylmethacrylate disks were laid separately onto plates separately inoculated with Aspergillus and Candida spp. The zones of inhibition obtained were measured in millimeters at 24, 36, and 96 hours.

RESULTS

Etest (bioMérieux, Marcy l'Etoile, France) results demonstrated susceptibility of Aspergillus and Candida to amphotericin B and voriconazole. The zone of inhibition data demonstrated that voriconazole and amphotericin B retained their antifungal activity when mixed into the calcium sulfate + HA bone void filler and eluted at biologically effective antifungal concentrations over 96 hours.

CONCLUSIONS

The calcium sulfate + HA bone void filler is a biocompatible ceramic carrier vehicle that can successfully deliver the antifungal drugs voriconazole and amphotericin B in the adjunctive treatment of fungal osteomyelitis. It is a reliable strategy in the local delivery of antifungal drugs to an area of osteomyelitis.

Molecular identification and antifungal susceptibility of 186 Candida isolates from vulvovaginal candidiasis in southern China

There is limited information regarding the molecular epidemiology and antifungal susceptibilities of Candida isolates using the Neo-Sensitabs method in patients with vulvovaginal candidiasis (VVC). From August 2012 to March 2013, 301 non-pregnant patients aged 18-50 years with suspected VVC were prospectively screened at a teaching hospital in southern China. The vaginal isolates were identified by DNA sequencing of internal transcribed spacer and the D1/D2 domain. Antifungal susceptibility testing of seven antifungal agents was performed using the Neo-Sensitabs tablet diffusion method. Candida species were isolated from 186 cases (61.79 %). The most common pathogen was Candida albicans (91.4 %), followed by Candida glabrata (4.3 %), Candida tropicalis (3.2 %) and Candida parapsilosis (1.1 %). The susceptibility rates to C. albicans were higher for caspofungin, voriconazole and fluconazole than those for itraconazole, miconazole, ketoconazole and terbinafine (P<0.01). The resistance rates to C. albicans were 4.7, 6.5, 7.1, 7.6, 12.3, 27.7 and 74.7 % for caspofungin, miconazole, itraconazole, voriconazole, fluconazole, ketoconazole and terbinafine, respectively. No drugs tested apart from fluconazole exhibited differences in resistance between C. albicans and non-albicans Candida isolates. The results demonstrate that, using DNA sequencing, C. albicans is the most common isolate from Chinese patients with VVC. Caspofungin, voriconazole and fluconazole may be preferable to other azoles and terbinafine in the treatment of VVC.

Antifungal activity of phenolic compounds identified in flowers from North Eastern Portugal against Candida species

ABSTRACT: 

Aim: To evaluate the antifungal effect of gallic acid, catechin, luteolin and quercetin, phenolic compounds identified from flowers of North Eastern Portugal, against Candida planktonic and biofilm cells. Materials & methods: The MICs were determined in Candida planktonic cells and the effect of phenolic compounds on Candida biofilms was assessed through quantification of colony-forming units. Results: MIC values demonstrated that gallic acid presented the highest effect against all Candida species. Catechin showed a similar effect against Candida albicans American Type Culture Collection (ATCC) 90028 cells. In addition, gallic acid and quercetin had demonstrated only a minimal effect against Candida species biofilms. Conclusion: Gallic acid affected the growth of the different planktonic Candida species in all concentrations used; still, catechin showed a similar effect against C. albicans ATCC 90028 and Candida glabrata ATCC 2001 cells. In addition, only gallic acid and quercetin demonstrated a slight effect against all Candida species biofilms.

Correlation between microdilution, Etest, and disk diffusion methods for antifungal susceptibility testing of fluconazole against Candida sp. blood isolates

INTRODUCTION

Antifungal susceptibility testing assists in finding the appropriate treatment for fungal infections, which are increasingly common. However, such testing is not very widespread. There are several existing methods, and the correlation between such methods was evaluated in this study.

METHODS

The susceptibility to fluconazole of 35 strains of Candida sp. isolated from blood cultures was evaluated by the following methods: microdilution, Etest, and disk diffusion.

RESULTS

The correlation between the methods was around 90%.

CONCLUSIONS

The disk diffusion test exhibited a good correlation and can be used in laboratory routines to detect strains of Candida sp. that are resistant to fluconazole.

Susceptibility profile of a Brazilian yeast stock collection of Candida species isolated from subjects with Candida-associated denture stomatitis with or without diabetes

OBJECTIVE

This study investigated the susceptibility of 198 clinical isolates of Candida species against caspofungin, amphotericin B, itraconazole, and fluconazole.

STUDY DESIGN

Suspensions of the microorganisms were spread on Roswell Park Memorial Institute (RPMI) agar plates. Etest strips were placed on the plates, and the minimal inhibitory concentration (MIC) was read after incubation (48 h at 37 °C). Data were analyzed by a factorial analysis of variance and a 2 × 2 post hoc test (α = .05).

RESULTS

C glabrata showed the highest MIC values (P < .001) against caspofungin, itraconazole, and fluconazole. For amphotericin B, the MIC values of C tropicalis and C glabrata (P = .0521) were higher than those of C albicans (P < .001). Itraconazole was the least effective antifungal; 93.3% of the C glabrata isolates, 3.3% of the C albicans, and 1.3% of the C tropicalis were resistant. All microorganisms were susceptible to caspofungin and amphotericin B.

CONCLUSIONS

Caspofungin and amphotericin B should be recommended as an effective alternative for the management of oral Candida infections when treatment with topical or other systemic drugs has definitely failed.

Heparin-benzyl alcohol enhancement of biofilms formation and antifungal susceptibility of vaginal Candida species isolated from pregnant and nonpregnant Saudi women

Biofilm formation by Candida species is a major contribute to their pathogenic potential.The aim of this study was to determine in vitro effects of EDTA, cycloheximide, and heparin-benzyl alcohol preservative on C. albicans (126) and non-albicans (31)vaginal yeast isolates biofilm formations and their susceptibility against three antifungal Etest strips. Results of the crystal violet-assay, indicated that biofilms formation were most commonly observed [100%] for C. kefyr, C. utilis, C. famata, and Rhodotorula mucilaginosa, followed by C. glabrata [70%], C. tropicalis [50%], C. albicans [29%], Saccharomyces cerevisiae [0.0%]. EDTA (0.3mg/ml) significantly inhibited biofilm formation in both C. albicans and non-albicans isolates (P=0.0001) presumably due to chelation of necessary metal cations for the process-completion. In contrast, heparin (-benzyl alcohol preservative) stimulated biofilm formation in all tested isolates, but not at significant level (P=0.567). Conversely, cycloheximide significantly (P=0.0001) inhibited biofilm formation in all C. albicans strains(126) and its effect was even 3 fold more pronounced than EDTA inhibition, probably due to its attenuation of proteins (enzymes) and/or complex molecules necessary for biofilm formation. Results also showed that all nonalbicans yeasts isolates were susceptible to 5-flucytosine (MIC50, 0.016 µg/ml; MIC90, 0.064 µg/ml), but 14% of C. albicans isolates were resistant (MIC50, 0.064 µg/ml; MIC90 >32 µg/ml). The MIC50 value of amphotricin B for all C. albicans and non-albicans isolates was at a narrow range of 0.023 µg /ml, and the MIC90 values were 0.047 µg/ml and 0.064 µg/ml respectively, thereby confirming its efficacy as a first line empiric- treatment of Candida spp infections.

Susceptibility tests of oropharyngeal Candida albicans from egyptian patients to fluconazole determined by three methods

Candida albicans frequently cause oropharyngeal candidiasis in immunocompromised patients. As some of these isolates show resistance against azoles, the clinician is wary of initiating therapy with fluconazole (FZ) until a final susceptibility report is generated. We aimed to evaluate the efficacy of rapid flow cytometry (FCM) and disc diffusion (DD) methods in comparison to reference microdilution (MD) of Clinical and Laboratory Standards Institute (CLSI) method for FZ. Thirty seven Candida albicans isolates were tested by the three methods. By both MD and FCM, 26/37 (70.3%) were sensitive with minimal inhibitory concentration (MIC) ≤ 8μg/ml, 5/37 (13.5%) were susceptible dose dependant (S-DD) with MIC 16-32 μg/ml and 6/37 (16.2%) were resistant with MIC ≥64μg/ml. More than 92% of isolates susceptible to FZ by the MD were susceptible by the DD methods with good agreement (81.08%, P = 0.000). However, 4/5 isolates diagnosed as S-DD by MD were resistant by DD. Interestingly, the MIC by FCM at 4 h showed excellent agreement (95.59%, P = 0.000) to that obtained by MD method at 24 h. Overall, FCM antifungal susceptibility testing provided rapid, reproducible results that are valuable alternative to MD. The DD test is recommended as a simple and reliable screening test for the detection of susceptible Candida albicans isolates to FZ.

Insights into Candida tropicalis nosocomial infections and virulence factors

Candida tropicalis is considered the first or the second non-Candida albicans Candida (NCAC) species most frequently isolated from candidosis, mainly in patients admitted in intensive care units (ICUs), especially with cancer, requiring prolonged catheterization, or receiving broad-spectrum antibiotics. The proportion of candiduria and candidemia caused by C. tropicalis varies widely with geographical area and patient group. Actually, in certain countries, C. tropicalis is more prevalent, even compared with C. albicans or other NCAC species. Although prophylactic treatments with fluconazole cause a decrease in the frequency of candidosis caused by C. tropicalis, it is increasingly showing a moderate level of fluconazole resistance. The propensity of C. tropicalis for dissemination and the high mortality associated with its infections might be strongly related to the potential of virulence factors exhibited by this species, such as adhesion to different host surfaces, biofilm formation, infection and dissemination, and enzymes secretion. Therefore, the aim of this review is to outline the present knowledge on all the above-mentioned C. tropicalis virulence traits.

A Critical Appraisal of the Role of the Clinical Microbiology Laboratory in Diagnosis of Invasive Fungal Infections

The incidence of invasive fungal infections (IFIs) continues to rise in industrialized countries, primarily due to both increasingly potent iatrogenic immunosuppression and immunocompromising therapies aimed at treating hematologic malignancies. As this situation continues to evolve, the clinical microbiology laboratory has few new, innovative methodologies to diagnose these serious infections and existing methods lack sensitivity. This represents a difficult clinical situation for health care providers, as they are left to rely on clinical instincts for the management of patients with potential IFIs, as mycology test results are not consistently reliable. The goals of this session of Camp Clin Micro (CCM) were to critically assess currently available methods and practices for diagnosing IFIs, to discuss the potential of current investigational methods, to evaluate the role of antifungal susceptibility testing, and finally to identify action items that can help move the field of diagnostic mycology in a direction that will improve our ability to identify IFIs in a timely manner. This is meant to be not a comprehensive overview of the diagnosis of IFIs but rather a detailed account of the discussion at CCM among clinical microbiologists with experience in diagnostic mycology and knowledge of the literature.

In Vitro Susceptibility Testing in Fungi: What is its Role in Clinical Practice?

An increasing number of patients are undergoing transplantation procedures or receiving aggressive immunosuppression and chemotherapy. The growing population of immunocompromised hosts has led to a rise in the prevalence of invasive fungal infections due to yeasts and molds. The introduction of new antifungal agents and recent reports of resistance emerging during treatment of fungal infections have highlighted the need for in vitro susceptibility testing. Various testing procedures have been proposed, including macrodilution and microdilution, agar diffusion, disk diffusion, and Etest (AB Biodisk, Solna, Sweden). Establishing clinical correlation with antifungal susceptibility testing, however, is a huge challenge because susceptibility techniques do not take into account the dynamic and complex biology of fungi exposed to an antifungal in vivo. This paper reviews the available methods for antifungal susceptibility testing of yeasts and filamentous fungi and the data regarding the clinical implications of in vitro testing.