Universal in vitro antifungal resistance of genetic clades of the Fusarium solani species complex

Activities of E1210 and comparator agents tested by CLSI and EUCAST broth microdilution methods against Fusarium and Scedosporium species identified using molecular methods

Fusarium (n = 67) and Scedosporium (n = 63) clinical isolates were tested by two reference broth microdilution (BMD) methods against a novel broad-spectrum (active against both yeasts and molds) antifungal, E1210, and comparator agents. E1210 inhibits the inositol acylation step in glycophosphatidylinositol (GPI) biosynthesis, resulting in defects in fungal cell wall biosynthesis. Five species complex organisms/species of Fusarium (4 isolates unspeciated) and 28 Scedosporium apiospermum, 7 Scedosporium aurantiacum, and 28 Scedosporium prolificans species were identified by molecular techniques. Comparator antifungal agents included anidulafungin, caspofungin, itraconazole, posaconazole, voriconazole, and amphotericin B. E1210 was highly active against all of the tested isolates, with minimum effective concentration (MEC)/MIC(90) values (μg/ml) for E1210, anidulafungin, caspofungin, itraconazole, posaconazole, voriconazole, and amphotericin B, respectively, for Fusarium of 0.12, >16, >16, >8, >8, 8, and 4 μg/ml. E1210 was very potent against the Scedosporium spp. tested. The E1210 MEC(90) was 0.12 μg/ml for S. apiospermum, but 1 to >8 μg/ml for other tested agents. Against S. aurantiacum, the MEC(50) for E1210 was 0.06 μg/ml versus 0.5 to >8 μg/ml for the comparators. Against S. prolificans, the MEC(90) for E1210 was only 0.12 μg/ml, compared to >4 μg/ml for amphotericin B and >8 μg/ml for itraconazole, posaconazole, and voriconazole. Both CLSI and EUCAST methods were highly concordant for E1210 and all comparator agents. The essential agreement (EA; ±2 doubling dilutions) was >93% for all comparisons, with the exception of posaconazole and F. oxysporum species complex (SC) (60%), posaconazole and S. aurantiacum (85.7%), and voriconazole and S. aurantiacum (85.7%). In conclusion, E1210 exhibited very potent and broad-spectrum antifungal activity against azole- and amphotericin B-resistant strains of Fusarium spp. and Scedosporium spp. Furthermore, in vitro susceptibility testing of E1210 against isolates of Fusarium and Scedosporium may be accomplished using either of the CLSI or EUCAST BMD methods, each producing very similar results.

[Taxonomy and biology of fungi causing human infection]

The advent of molecular techniques, mainly DNA sequencing, has led to important changes in the taxonomy of pathogenic fungi and a better understanding of the phylogenetic relationships among them. The number of fungal species potentially pathogenic for humans has increased dramatically. Most of them are cryptic species belonging to complex species that have replaced traditional single morphospecies. This has occurred in several genera of mucorales and particularly in different ascomycetous genera, such as Aspergillus, Fusarium, Sporothrix and Scedosporium, among others. The correct identification of these species is crucial for a better management of patients, since on many occasions those species show different virulence and different antifungal responses. This review summarises some of the most striking recent taxonomic changes produced in pathogenic fungi.

Lessons from animal studies for the treatment of invasive human infections due to uncommon fungi

Clinical experience in the management of opportunistic infections, especially those caused by less common fungi, is, due to their rarity, very scarce; therefore, the most effective treatments remain unknown. The ever-increasing numbers of fungal infections due to opportunistic fungi have repeatedly proven the limitations of the antifungal armamentarium. Moreover, some of these fungi, such as Fusarium spp. or Scedosporium spp., are innately resistant to almost all the available antifungal drugs, which makes the development of new and effective therapies a high priority. Since it is difficult to conduct randomized clinical trials in these uncommon mycoses, the use of animal models is a good alternative for evaluating new therapies. This is an extensive review of the numerous studies that have used animal models for this purpose against a significant number of less common fungi. A table describing the different studies performed on the efficacy of the different drugs tested is included for each fungal species. In addition, there is a summary table showing the conclusions that can be derived from the analysis of the studies and listing the drugs that showed the best results. Considering the wide variability in the response to the antifungals that the different strains of a given species can show, the table highlights the drugs that showed positive results using at least two parameters for evaluating efficacy against at least two different strains without showing any negative results. These data can be very useful for guiding the treatment of rare infections when there is very little experience or when controversial results exist, or when treatment fails.

Accurate and practical identification of 20 Fusarium species by seven-locus sequence analysis and reverse line blot hybridization, and an in vitro antifungal susceptibility study

Eleven reference and 25 clinical isolates of Fusarium were subject to multilocus DNA sequence analysis to determine the species and haplotypes of the fusarial isolates from Beijing and Shandong, China. Seven loci were analyzed: the translation elongation factor 1 alpha gene (EF-1α); the nuclear rRNA internal transcribed spacer (ITS), large subunit (LSU), and intergenic spacer (IGS) regions; the second largest subunit of the RNA polymerase gene (RPB2); the calmodulin gene (CAM); and the mitochondrial small subunit (mtSSU) rRNA gene. We also evaluated an IGS-targeted PCR/reverse line blot (RLB) assay for species/haplotype identification of Fusarium. Twenty Fusarium species and seven species complexes were identified. Of 25 clinical isolates (10 species), the Gibberella (Fusarium) fujikuroi species complex was the commonest (40%) and was followed by the Fusarium solani species complex (FSSC) (36%) and the F. incarnatum-F. equiseti species complex (12%). Six FSSC isolates were identified to the species level as FSSC-3+4, and three as FSSC-5. Twenty-nine IGS, 27 EF-1α, 26 RPB2, 24 CAM, 18 ITS, 19 LSU, and 18 mtSSU haplotypes were identified; 29 were unique, and haplotypes for 24 clinical strains were novel. By parsimony informative character analysis, the IGS locus was the most phylogenetically informative, and the rRNA gene regions were the least. Results by RLB were concordant with multilocus sequence analysis for all isolates. Amphotericin B was the most active drug against all species. Voriconazole MICs were high (>8 μg/ml) for 15 (42%) isolates, including FSSC. Analysis of larger numbers of isolates is required to determine the clinical utility of the seven-locus sequence analysis and RLB assay in species classification of fusaria.

Internet-accessible DNA sequence database for identifying fusaria from human and animal infections

Because less than one-third of clinically relevant fusaria can be accurately identified to species level using phenotypic data (i.e., morphological species recognition), we constructed a three-locus DNA sequence database to facilitate molecular identification of the 69 Fusarium species associated with human or animal mycoses encountered in clinical microbiology laboratories. The database comprises partial sequences from three nuclear genes: translation elongation factor 1α (EF-1α), the largest subunit of RNA polymerase (RPB1), and the second largest subunit of RNA polymerase (RPB2). These three gene fragments can be amplified by PCR and sequenced using primers that are conserved across the phylogenetic breadth of Fusarium. Phylogenetic analyses of the combined data set reveal that, with the exception of two monotypic lineages, all clinically relevant fusaria are nested in one of eight variously sized and strongly supported species complexes. The monophyletic lineages have been named informally to facilitate communication of an isolate's clade membership and genetic diversity. To identify isolates to the species included within the database, partial DNA sequence data from one or more of the three genes can be used as a BLAST query against the database which is Web accessible at FUSARIUM-ID (http://isolate.fusariumdb.org) and the Centraalbureau voor Schimmelcultures (CBS-KNAW) Fungal Biodiversity Center (http://www.cbs.knaw.nl/fusarium). Alternatively, isolates can be identified via phylogenetic analysis by adding sequences of unknowns to the DNA sequence alignment, which can be downloaded from the two aforementioned websites. The utility of this database should increase significantly as members of the clinical microbiology community deposit in internationally accessible culture collections (e.g., CBS-KNAW or the Fusarium Research Center) cultures of novel mycosis-associated fusaria, along with associated, corrected sequence chromatograms and data, so that the sequence results can be verified and isolates are made available for future study.

International retrospective analysis of 73 cases of invasive fusariosis treated with voriconazole

The outcomes for 73 invasive fusariosis patients treated with voriconazole were investigated. Patients with proven (n = 67) or probable (n = 6) infections were identified from the voriconazole clinical database (n = 39) and the French National Reference Center for Mycoses and Antifungals database (n = 34). Investigator-determined success was a complete or partial response. Survival was determined from day 1 of voriconazole therapy to the last day known alive. Patients were 2 to 79 years old (median, 43 years), and 66% were male. Identified Fusarium species (62%) were F. solani, F. moniliforme, F. proliferatum, and F. oxysporum. Underlying conditions analyzed included hematopoietic stem cell transplant (HSCT; 18%), hematologic malignancy (HM; 60%), chronic immunosuppression (CI; 12%), or other condition (OC; 10%). Infection sites were brain (5%), disseminated excluding brain (67%), lungs/sinus (15%), and other (12%). Most patients (64%) were or had recently been neutropenic (<500 cells/mm(3)). Therapy duration was 1 to 480 days (median, 57 days), with a 47% success rate. Baseline neutropenia impacted success adversely (P ≤ 0.03). Success varied by underlying condition (HSCT, 38%; HM, 45%; CI, 44%; OC, 71%) and infection site (brain, 0%; disseminated, 45%; other, 56%; lung/sinus, 64%) (P > 0.05). Combination therapy (13 patients) was no better than treatment with voriconazole alone. Overall, 59% of the patients died (49% died of fusariosis), and 90-day survival was 42%. Site of infection influenced survival (P = 0.02). Median survival (in days) by species was as follows: F. solani, 213; F. oxysporum, 112; Fusarium spp., 101; F. proliferatum, 84; F. moniliforme, 76. We conclude that voriconazole is a therapeutic option for invasive fusariosis.

Characterization of cultivated fungi isolated from grape marc wastes through the use of amplified rDNA restriction analysis and sequencing

Microbial assessment of grape marc wastes, the residual solid by-product of the wine-industry, was performed by identifying phylogenetically the fungal culturable diversity in order to evaluate environmental and disposal safety issues and to discuss ecological considerations of applications on agricultural land. Fungal spores in grape marc were estimated to 4.7 x 10(6) per g dry weight. Fifty six fungal isolates were classified into eight operational taxonomic units (OTUs) following amplified ribosomal DNA restriction analysis (ARDRA) and colony morphology. Based on 18S rRNA gene and 5.8S rRNA gene-ITS sequencing, the isolates representing OTUs #1, #2, #3, and #4, which comprised 44.6%, 26.8%, 12.5%, and 5.3%, respectively, of the number of the total isolates, were identified as Aspergillus fumigatus, Bionectria ochroleuca, Haematonectria haematococca, and Trichosporon mycotoxinivorans. The isolates of OTU#5 demonstrated high phylogenetic affinity with Penicillium spp., while members of OTUs #6 and #7 were closer linked with Geotrichum candidum var. citri-aurantii and Mycocladus corymbifer, respectively (95.4 and 97.9% similarities in respect to their 5.8S rRNA gene-ITS sequences). The OTU#8 with a single isolate was related with Aspergillus strains. It appears that most of the fungal isolates are associated with the initial raw material. Despite the fact that some of the species identified may potentially act as pathogens, measures such as the avoidance of maintaining large and unprocessed quantities of grape marc wastes in premises without adequate aeration, together with its suitable biological treatment (e.g., composting) prior to any agriculture-related application, could eliminate any pertinent health risks.

In vitro response of cutaneous mycosis fungal agents to the most widely used systemic antifungals in dermatology

BACKGROUND

The high frequency of cutaneous mycosis justify the need to evaluate the possible contribution of in vitro profile of susceptibility to antifungal agents.

OBJECTIVE

To evaluate whether there is variability in in vitro susceptibility by filamentous fungi, previously isolated from cutaneous mycosis, to fluconazole, ketoconazole, itraconazole and terbinafine.

METHODS

Fungi were isolated and identified by classical methods and the antifungal susceptibility test was performed using the method of broth microdilution, according to a protocol recommended by the Clinical Laboratory Standards Institute (CLSI), through M38-A document.

RESULTS

Amongst the 80 filamentous fungi identified, Trichophyton genus represented 81%. The four examined drugs showed great variation for Trichophyton spp and Microsporum spp. Fusarium spp was resistant to all tested drugs. Terbinafine was the most effective drug against the majority of the isolated fungi.

CONCLUSION

There was great variability in response profiles to the tested antifungals. The definition of a reference test method will offer higher objectivity for physicians to choose the appropriate therapy.

Molecular phylogenetic diversity of dermatologic and other human pathogenic fusarial isolates from hospitals in northern and central Italy

Fifty-eight fusaria isolated from 50 Italian patients between 2004 and 2007 were subject to multilocus DNA sequence typing to characterize the spectrum of species and circulating sequence types (STs) associated with dermatological infections, especially onychomycoses and paronychia, and other fusarioses in northern and central Italy. Sequence typing revealed that the isolates were nearly evenly divided among the Fusarium solani species complex (FSSC; n = 18), the F. oxysporum species complex (FOSC; n = 20), and the Gibberella (Fusarium) fujikuroi species complex (GFSC; n = 20). The three-locus typing scheme used for members of the FSSC identified 18 novel STs distributed among six phylogenetically distinct species, yielding an index of discrimination of 1.0. Phylogenetic analysis of the FOSC two-locus data set identified nine STs, including four which were novel, and nine isolates of ST 33, the previously described widespread clonal lineage. With the inclusion of eight epidemiologically unrelated ST 33 isolates, the FOSC typing scheme scored a discrimination index of 0.787. The two-locus GFSC typing scheme, which was primarily designed to identify species, received the lowest discrimination index, with a score of 0.492. The GFSC scheme, however, was used to successfully identify 17 isolates as F. verticillioides, 2 as F. sacchari, and 1 as F. guttiforme. This is the first report that F. guttiforme causes a human mycotic infection, which was supported by detailed morphological analysis. In addition, the results of a pathogenicity experiment revealed that the human isolate of F. guttiforme was able to induce fusariosis of pineapple, heretofore its only known host.

Novel multilocus sequence typing scheme reveals high genetic diversity of human pathogenic members of the Fusarium incarnatum-F. equiseti and F. chlamydosporum species complexes within the United States

Species limits within the clinically important Fusarium incarnatum-F. equiseti and F. chlamydosporum species complexes (FIESC and FCSC, respectively) were investigated using multilocus DNA sequence data. Maximum-parsimony and maximum-likelihood analyses of aligned DNA sequences from four loci resolved 28 species within the FIESC, within which the species were evenly divided among two clades designated Incarnatum and Equiseti, and four species within the FCSC. Sequence data from a fifth locus, beta-tubulin, was excluded from the study due to the presence of highly divergent paralogs or xenologs. The multilocus haplotype nomenclature adopted in a previous study (K. O'Donnell, D. A. Sutton, A. Fothergill, D. McCarthy, M. G. Rinaldi, M. E. Brandt, N. Zhang, and D. M. Geiser, J. Clin. Microbiol. 46:2477-2490, 2008) was expanded to all of the species within the FIESC and FCSC to provide the first DNA sequence-based typing schemes for these fusaria, thereby facilitating future epidemiological investigations. Multilocus DNA typing identified sixty-two sequence types (STs) among 88 FIESC isolates and 20 STs among 26 FCSC isolates. This result corresponds to indices of discrimination of 0.985 and 0.966, respectively, for the FIESC and FCSC four-locus typing scheme using Simpson's index of discrimination. Lastly, four human and two veterinary isolates, received as members of the FIESC or FCSC, were resolved as five phylogenetically distinct species nested outside these species complexes. To our knowledge, these five species heretofore have not been reported to cause mycotic infections (i.e., F. armeniacum, F. brachygibbosum, F. flocciferum, and two unnamed Fusarium species within the F. tricinctum species complex).

Use of mass spectrometry to identify clinical Fusarium isolates

Fusarium spp. have recently emerged as significant human pathogens. Identification of these species is important, both for epidemiological purposes and for patient management, but conventional identification based on morphological traits is hindered by major phenotypic polymorphism. In this study, 62 strains, or isolates, belonging to nine Fusarium species were subjected to both molecular identification TEF1 gene sequencing and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) analysis. Following stringent standardization, the proteomic-based method appeared to be both reproducible and robust. Mass spectral analysis by comparison with a database, built in this study, of the most frequently isolated species, including Fusarium solani, Fusarium oxysporum, Fusarium verticilloides, Fusarium proliferatum and Fusarium dimerum, correctly identified 57 strains. As expected, the four species (i.e. Fusarium chlamydosporum, Fusarium equiseti, Fusarium polyphialidicum, Fusarium sacchari) not represented in the database were not identified. Results from mass spectrometry and molecular identification agreed in five of the six cases in which results from morphological and molecular identification were not in agreement. MALDI-TOF yielded results within 1 h, making it a valuable tool for identifying clinical Fusarium isolates at the species level. Uncommon species must now be added to the database. MALDI-TOF may also prove useful for identifying other clinically important moulds.

Less-frequent Fusarium species of clinical interest: correlation between morphological and molecular identification and antifungal susceptibility

Forty-eight Fusarium isolates morphologically identified as belonging to seven species of clinical interest (i.e., Fusarium chlamydosporum, Fusarium dimerum, Fusarium incarnatum, Fusarium napiforme, Fusarium nygamai, Fusarium proliferatum, and Fusarium sacchari) were characterized molecularly by the analysis of the sequences of the TUB region of the beta-tubulin gene. F. chlamydosporum and F. dimerum were the most genetically heterogeneous species. A high degree of correlation between the morphological and molecular identification was shown among the isolates studied. A table with the key morphological features for the identification of these Fusarium species is provided. The antifungal susceptibilities of the Fusarium isolates to 11 antifungal drugs were tested; terbinafine was the most active drug against all the species tested with the exception of F. incarnatum, for which amphotericin B was the most active.

High genetic diversity and poor in vitro response to antifungals of clinical strains of Fusarium oxysporum

OBJECTIVES

The aim of this study was to determine the genetic variability of clinical isolates morphologically identified as Fusarium oxysporum and to assess if there are differences in antifungal susceptibility among the possible genetic clades obtained.

METHODS

Twenty-eight isolates were molecularly characterized by sequence analysis of the elongation factor 1alpha gene. The antifungal susceptibilities of these isolates to 11 antifungal drugs were tested using a microdilution method.

RESULTS

and conclusions We obtained four different phylogenetic clades in the molecular study. Although all the antifungals tested showed poor activity against all the genetic clades, terbinafine showed the best results.

Interactions between triazoles and amphotericin B in treatment of disseminated murine infection by Fusarium oxysporum

We have evaluated and compared the efficacies of high doses of amphotericin B (AMB; 3 mg/kg of body weight/day), voriconazole (60 mg/kg), and posaconazole (PSC; 100 mg/kg) alone and combined in a murine model of disseminated infection by Fusarium oxysporum. The combination of AMB with PSC showed the best results, prolonging the survival of mice and reducing their organ fungal loads. This combination might constitute a therapeutic option for those infections where monotherapies fail.

Determination of in vitro susceptibility of ocular Fusarium spp. isolates from keratitis cases and comparison of Clinical and Laboratory Standards Institute M38-A2 and E test methods

We evaluated the susceptibility of 85 Fusarium spp. isolates from cases of fungal keratitis with 8 antifungal drugs using the standard Clinical and Laboratory Standards Institute broth microdilution and E test methods. Members of the Fusarium solani species complex showed consistently higher MICs to the triazole drugs itraconazole, voriconazole, and posaconazole than did members of other species complexes (Fusarium oxysporum and other minor species). High MICs to amphotericin B, natamycin, and echinocandins were consistently obtained with no discrimination based on species or method. Further work is required to determine any potential correlation between MIC and clinical outcome in keratitis.

Molecular phylogenetic diversity, multilocus haplotype nomenclature, and in vitro antifungal resistance within the Fusarium solani species complex

Members of the species-rich Fusarium solani species complex (FSSC) are responsible for approximately two-thirds all fusarioses of humans and other animals. In addition, many economically important phytopathogenic species are nested within this complex. Due to their increasing clinical relevance and because most of the human pathogenic and plant pathogenic FSSC lack Latin binomials, we have extended the multilocus haplotype nomenclatural system introduced in a previous study (D. C. Chang, G. B. Grant, K. O'Donnell, K. A. Wannemuehler, J. Noble-Wang, C. Y. Rao, L. M. Jacobson, C. S. Crowell, R. S. Sneed, F. M. T. Lewis, J. K. Schaffzin, M. A. Kainer, C. A. Genese, E. C. Alfonso, D. B. Jones, A. Srinivasan, S. K. Fridkin, and B. J. Park, JAMA 296:953-963, 2006) to all 34 species within the medically important FSSC clade 3 to facilitate global epidemiological studies. The typing scheme is based on polymorphisms in portions of the following three genes: the internal transcribed spacer region and domains D1 plus D2 of the nuclear large-subunit rRNA, the translation elongation factor 1 alpha gene (EF-1alpha), and the second largest subunit of RNA polymerase II gene (RPB2). Of the 251 isolates subjected to multilocus DNA sequence typing, 191 sequence types were differentiated, and these were distributed among three strongly supported clades designated 1, 2, and 3. All of the mycosis-associated isolates were restricted to FSSC clade 3, as previously reported (N. Zhang, K. O'Donnell, D. A. Sutton, F. A Nalim, R. C. Summerbell, A. A. Padhye, and D. M. Geiser, J. Clin. Microbiol. 44:2186-2190, 2006), and these represent at least 20 phylogenetically distinct species. Analyses of the combined DNA sequence data by use of two separate phylogenetic methods yielded the most robust hypothesis of evolutionary relationships and genetic diversity within the FSSC to date. The in vitro activities of 10 antifungals tested against 19 isolates representing 18 species that span the breadth of the FSSC phylogeny show that members of this complex are broadly resistant to these drugs.

Species distribution and in vitro antifungal susceptibility patterns of 75 clinical isolates of Fusarium spp. from northern Italy

Fusarium isolates from 75 Italian patients were identified by molecular methods, and their susceptibilities to antifungals were tested in vitro. Fusarium verticillioides was the species most frequently isolated from deep-seated infections, and F. solani was the species most frequently isolated from superficial infections. F. solani isolates showed high azole MICs, while F. verticillioides isolates showed low posaconazole MICs.

In vitro antifungal susceptibility and molecular characterization of clinical isolates of Fusarium verticillioides (F. moniliforme) and Fusarium thapsinum

A microdilution method was used to test 11 antifungal drugs against clinical isolates of Fusarium thapsinum and three different phylogenetic clades of Fusarium verticillioides that were characterized by sequencing a region of the beta-tubulin gene. Terbinafine was the most-active drug against both species, followed by posaconazole against F. verticillioides.

Fusarium keratitis and contact lens wear: facts and speculations

Over the past several decades mycotic keratitis has been considered a rare sequel to hydrogel contact lens wear. In 2005--2006 an upswing in the incidence of Fusarium keratitis was associated with a disproportionate use of one multipurpose contact lens solution (MPS, ReNu with MoistureLoc, Bausch & Lomb, Rochester, NY). The MPS, as manufactured and marketed, was sterile and met regulatory guidelines for antimicrobial activity. A multivariant interaction of poor hygienic practices and the contact lens paraphernalia were associated with a mostly selective contamination in or on the lens storage case by members of the F. solani/F. oxysporum species complexes from the environment of the user. A decline of the anti-fusaria properties of the MPS in the lens case appeared related to its dissociation from drying, or dilution and the potential for sorption of antimicrobial solution components (e.g., alexidine) to various hydrogel lenses. These factors and capacities of the fusaria for rapid amplification by microcycle conidiation, production of dormant resistant cells, and potential for attachment and penetration of hydrogel lenses, were linked to the occasional selective fungal survival and growth during storage of the lens in MPS. Lack of a manual rubbing-cleaning step in the MPS disinfection process was considered a risk factor for keratitis.

Genotypic identification of Fusarium species from ocular sources: comparison to morphologic classification and antifungal sensitivity testing (an AOS thesis)

PURPOSE

Ocular infections caused by fungal organisms can cause significant ocular morbidity, particularly when diagnosis and treatment are delayed. Rapid and accurate identification of Fusarium species at the subgenus level using current diagnostic standards is timely and insensitive. The purpose of this study is to examine the usefulness of polymerase chain reaction (PCR) analysis of the internal transcribed spacer (ITS) regions (ITS1, 5.8S, and ITS2) in detecting and differentiating Fusarium species from isolates of ocular infections, and to assess the correlation between the genotypic and morphologic classification.

METHODS

Fifty-eight isolates from 52 patients diagnosed with Fusarium ocular infections were retrieved from storage at the Bascom Palmer Eye Institute's ocular microbiology laboratory. Morphologic classification was determined at both a general and a reference microbiology laboratory. DNA was extracted and purified, and the ITS region was amplified and sequenced. Following DNA sequences, alignment and phylogenetic analysis were done. Susceptibility to antifungal drugs was measured according to the Clinical and Laboratory Standards Institute reference method.

RESULTS

Sequence analysis demonstrated 15 unique sequences among the 58 isolates. The grouping showed that the 58 isolates were distributed among 4 main species complexes. At the species level, morphologic classification correlated with genotypic classification in 25% and 97% of the isolates in a general microbiology and a reference mycology laboratory, respectively.

CONCLUSIONS

The sequence variation within the ITS provides a sufficient quantitative basis for the development of a molecular diagnostic approach to the Fusarium pathogens isolated from ocular infections. Morphology based on microscopic and macroscopic observations yields inconsistent results, particularly at nonreference laboratories, emphasizing the need for a more reproducible test with less user-dependent variability. Fusarium solani tends to be more resistant to certain antifungals (azoles).