Dermatophytic onychia: Effectiveness of rapid immunochromatographic diagnostic testing directly on samples compared to culture.

BACKGROUND: Until now, definite diagnosis of dermatophytic onychia has been made by taking a nail sample and placing it in culture. The result is usually obtained only after 2 to 3weeks. More recently, diagnosis within a few minutes after sampling has become possible thanks to an immunochromatography technique developed in Japan and now available in France: the Diafactory Tinea Unguium® test strip (Biosynex, France). METHODS: Over a 12-month period, 80nail samples from 80patients giving rise to a positive fungal culture were included in the study. For each patient, part of the removed nail was stored at room temperature and an immunochromatographic test was retrospectively performed according to the supplier's instructions. A small fragment of nail (≥ 1mg) was mixed with a few drops of reagent in a tube for 1min and the test strip was then placed in the tube with the result being visible to the naked eye (control strip, positivity strip) after incubation for a few minutes. RESULTS: Compared with the culture method used for 51 isolated dermatophytes (42 Trichophyton rubrum, 9 Trichophyton interdigitale), the sensitivity of the rapid test was 96.07% (49/51). For the 29other fungal cultures (10Fusarium sp., 3Scytalidium sp., 3Scopulariopsis brevicaulis,3Aspergillus sp., 1Alternaria sp., 3Candida albicans, 1Candida parapsilosis, 1Trichosporons sp., 1Rhodotorula sp., and 3Corynebacterium sp.), the specificity was 75.86% (22/29). False positives were mainly due to the genera Fusarium and Scopulariopsis (6 of 7false positives), which were the likely cause of onychomycosis. DISCUSSION: This rapid test could be useful in limiting excessive clinical diagnosis of dermatophyte onychomycosis. The rapid test has several advantages: ease of application, speed of results, and good performance, which, together, could improve diagnostic certainty during the actual consultation, thus limiting prolonged unnecessary prescriptions of antifungal treatments, while waiting for the laboratory culture results (3weeks for a negative result).

Antifungal susceptibility testing practices in mycology laboratories in France, 2018.

A survey of mycology laboratories for antifungal susceptibility testing (AFST) was undertaken in France in 2018, to better understand the difference in practices between the participating centers and to identify the difficulties they may encounter as well as eventual gaps with published standards and guidelines. The survey captured information from 45 mycology laboratories in France on how they perform AFST (number of strains tested, preferred method, technical and quality aspects, interpretation of the MIC values, reading and interpretation difficulties). Results indicated that 86% of respondents used Etest as AFST method, with a combination of one to seven antifungal agents tested. Most of the participating laboratories used similar technical parameters to perform their AFST method and a large majority used, as recommended, internal and external quality assessments. Almost all the participating mycology laboratories (98%) reported difficulties to interpret the MIC values, especially when no clinical breakpoints are available. The survey highlighted that the current AFST practices in France need homogenization, particularly for MIC reading and interpretation.

Pulmonary aspergillosis.

Aspergillosis is a mycotic disease usually caused by Aspergillus fumigatus, a saprophytic and ubiquitous airborne fungus. Aspergillus-related lung diseases are traditionally classified into four different forms, whose occurrence depends on the immunologic status of the host and the existence of an underlying lung disease. Allergic broncho-pulmonary aspergillosis (ABPA) affects patients with asthma or cystic fibrosis. Saprophytic infection (aspergilloma) occurs in patients with abnormal airways (chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis) or chronic lung cavities. Chronic necrotizing aspergillosis (semi-invasive form) is described in patients with chronic lung pathology or mild immunodeficiency. Invasive aspergillosis (angio-invasive or broncho-invasive forms) occurs in severely immuno-compromised patients. Knowledge of the various radiological patterns for each form, as well as the corresponding associated immune disorders and/or underlying lung diseases, helps early recognition and accurate diagnosis.

Late occurrence of Histoplasma duboisii cutaneous and pulmonary infection 18 years after exposure.

We report an imported case of Histoplasma capsulatum var. duboisii (H. duboisii) infection in a white French woman revealed by cutaneous lesions of the scalp, 18 years after her last stay in West and Central Africa. Asymptomatic bilateral pulmonary infiltrates were discovered on thoracic computed tomography. Skin biopsy allowed the positive diagnosis showing the typical yeasts; culture of biopsy specimens was positive for H. capsulatum. In the absence of criteria of severity, the patient was treated for one year with oral itraconazole 400mg/day. The outcome was favourable, skin and pulmonary lesions resolved slowly. The follow up is 5 years without relapse after the end of treatment. This case illustrates the possibility of late occurrence of H. duboisii infection, many years after exposure and the major importance of asking any patient for travelling or residency in tropical countries.

Comparison of real-time PCR with conventional methods to detect dermatophytes in samples from patients with suspected dermatophytosis.

A PCR detecting dermatophytes within a short turnaround time would significantly enhance the management of patients with suspected dermatophytosis. This study aimed at comparing the results of a real-time PCR assay with those of the conventional diagnostic (direct microscopy and culture) performed by a dermatologist working in a medical mycology laboratory for the detection of dermatophytes in nail and skin samples. A total of 112 specimens (54 nail and 58 skin) were collected from 52 patients with one to four suspected dermatophytosis lesions. The PCR diagnostic indices were calculated for either sample- or patient-based dermatophytosis diagnosis. The sample-based diagnostic efficacy yielded 79% sensitivity and 73% specificity. The patient-based diagnostic efficacy was higher with 100% sensitivity and 82% specificity. Interestingly, PCR yielded significantly (p < 0.004) lesser false negative results and performed overall better (diagnostic odds ratio = 24.0 vs. 5.5) in nail than in skin samples. In conclusion, this real-time PCR assay performance was consistent with those of the conventional methods in the hands of a skilled expert and particularly efficacious in diagnosing dermatophyte onychomycosis. This PCR is suited to high throughput batch processing; if used instead of direct microscopy, it could reduce hands-on time in the routine clinical laboratory workflow.

[Emergence of Candida parapsilosis candidemia at Cochin hospital. Characterization of isolates and search for risk factors]. / Émergence de candidémies à Candida parapsilosis à l'hôpital Cochin. Caractérisation des isolats et recherche de facteurs de risque.

Candida parapsilosis is a normal saprophyte of the skin, characterized by their affinity for catheters. This species has, in vitro, a level of sensitivity against the echinocandins, significantly lower than that observed with other Candida species. Recently, new species: Candida orthopsilosis and Candida metapsilosis, phenotypically identical to C. parapsilosis, have been identified by molecular biology. From 2003 to 2007, in the Cochin hospital, the proportion of C. parapsilosis among non-albicans species isolated from blood cultures increased from 17 (3/18) to 38% (5/13). To understand the reasons for this emergence, we retrospectively characterized isolates, conducted a case-control and researched a link between the emergence and introduction of caspofungin in our hospital. We analysed data from 26 patients who had candidemia with C. parapsilosis. Genotypic analysis of isolates has not identified the new species C. orthopsilosis and C. metapsilosis. The case-control study showed a broad-spectrum antibiotics was significantly more frequent for candidemia with C. parapsilosis compared to C. albicans (52 versus 26%, P=0.04) as a previous treatment with caspofungin (11 versus 0%, P=0.04). The introduction of caspofungin is contemporary with the emergence of candidemia with C. parapsilosis with a tendency to be related to its level of consumption in the ICU. Our results should encourage biologists to closely monitor the frequency and level of sensitivity of strains of C. parapsilosis isolated in hospital.

Comparison of antifungal MICs for yeasts obtained using the EUCAST method in a reference laboratory and the Etest in nine different hospital laboratories.

In routine laboratory practice, the determination of MICs of antifungals for yeasts often relies on the Etest, because of a good correlation with reference methods. However, this correlation was established through predesigned studies, rather than prospective testing. The surveillance programme of fungaemia (YEASTS programme), implemented since 2003, facilitated our comparison of the Etest and the EUCAST results, obtained on a routine basis in nine different hospitals and in a reference laboratory, respectively. The analysis included 690 isolates recovered from blood culture (362 Candida albicans, 113 Candida glabrata, 69 Candida parapsilosis, 55 Candida tropicalis, 31 Cryptococcus neoformans, and 60 other yeast species) that were tested for their susceptibility to amphotericin B (n = 655), fluconazole (n = 669), itraconazole (n = 198), voriconazole (n = 588), flucytosine (n = 314), and caspofungin (n = 244). Agreement between the Etest and EUCAST datasets was calculated and categorized on the basis of previously published breakpoints. The level of agreement at ±2 dilutions was 75% for amphotericin B and 90% for flucytosine; for the azoles, it ranged from 71% for itraconazole to 87% for voriconazole. No significant difference was observed among the yeast species, except for Cryptococcus neoformans and flucytosine, with an agreement <40%. Categorical agreement ranged from 60% for itraconazole to 90% for flucytosine. Major and very major discrepancies occurred in <12% and 6%, respectively. The Etest, even when performed on a routine basis, shows a ≥71% agreement with the EUCAST reference method.

[Diagnosis of invasive pulmonary aspergillosis: value of bronchoalveolar lavage galactomannan for immunocompromised patients]. / Diagnostic de l'aspergillose bronchopulmonaire invasive: valeur du dosage du galactomannane dans le lavage bronchoalvéolaire de patients immunodéprimés.

Invasive pulmonary aspergillosis (IPA) is an emerging disease associated with high mortality. The diagnosis is difficult, based on a combination of elements that are clinical, radiological and biological. For early detection of cases of IPA, during 25 months, we have systematically carried out on the LBA (N=355) of immunocompromised patients (N=313) a determination of Aspergillus galactomannan (GM) by ELISA (PlateliaAspergillus, BioRad). We observed 14 cases of probable API. The sensitivity of GM compared to direct examination (DE) and culture is, respectively, 64% versus 29% and 57%. The determination of GM is definitely more sensitive than the ED. Excellent specificity (98%) allows its implementation as a screening test in patients at risk.

Effects of candidaemia on outcome of burns.

AIM: To evaluate the diversity and antifungal susceptibilities of Candida isolates from wounds and blood of burn victims, and the associated mortality rates compared with those of controls without candidaemia. METHODS: We performed a nested case-control study within a database of clinical data for all patients admitted to our burn unit from January 2001 to December 2005. Each candidaemic patient was compared with two matched controls. Bloodstream cultures were performed if the core temperature was >39 degrees C, and three sites were cultured weekly for fungal identification (burn wound, pharynx, urinary tract). RESULTS: At least one episode of candidaemia was diagnosed among 20 of 851 persons admitted during the study period. Isolates in bloodstream infection were Candida albicans (65%), C. parapsilosis (25%) and C. tropicalis (10%). The median time between admission and onset of candidaemia was greater with C. albicans infection (42.6+/-31 days) than with infection by other yeasts (18+/-12 days). Candidaemia was associated with more extensive burn and longer duration of hospital stay but with similar mortality, compared with controls. CONCLUSION: Candidaemia in burn cases is mostly due to fluconazole-susceptible C. albicans and is not associated with increased mortality.

[In vitro susceptibility of isolates of Scytalidium spp. from superficial lesions against posaconazole]. / Etude in vitro de la sensibilité au posaconazole de souches de Scytalidium spp. isolées de lésions superficielles.

Scytalidium spp. is a dematiaceous fungi that has been frequently reported from tropical to semi subtropical regions. We distinguish two pathogenic species: S. dimidiatum and S. hyalinum which is an homologous non-pigmented mutant of S. dimidiatum. This keratinophilic mold may produce superficial disease (skin, nails) indistinguishable from dermatophytes. In Martinique, this pseudodermatophyte could represent more than 50 % of onychomycosis. Contrary to dermatophytes, the clinical response of Scytalidium spp. are typically very poor and topical treatment or systemic agents ineffective. To evaluate the potential efficacy of the new antifungal agent posaconazole, we tested in vitro 12 clinical isolates of Scytalidium spp. (seven S. dimidiatum and five S. hyalinum) against posaconazole by Etest method. For the totality of the isolates, the minimum inhibitory concentrations (MICs) were low: MICs less or equal to 0.25 microg/ml (maximum MICs of 0.25 microg/ml for S. dimidiatum and 0.032 microg/ml for S. hyalinum). These in vitro efficacy suggest that the new agent posaconazole may be a future alternative treatment.

[An update on Candida dubliniensis]. / Actualités sur Candida dubliniensis.

Eleven years ago, Irish authors, using molecular biology, demonstrated the existence of Candida dubliniensis, a new species of Candida close to Candida albicans. Initially isolated from AIDS patients with oral candidiasis, this species was detected, even in immunocompetent patients. Recently, with new, easy to implement identification tests (latex, immunochromatography), numerous epidemiological studies were undertaken. In most studies, C. dubliniensis was most often identified in the oral cavity. In the absence of HIV infection, the proportion C. dubliniensis/C. albicans ranged from 1 to 5% but it increased to 15-20% in case of HIV infection. It should be stressed that, from an experimental point of view, the acquisition of a secondary resistance to fluconazole is more quickly obtained with C. dubliniensis that with C. albicans, this resistance remains exceptionally observed in clinical observations.

Multifocal Scedosporium apiospermum spondylitis in a cystic fibrosis patient.

We report the first case of multifocal Scedosporium apiospermum spondylitis in a cystic fibrosis patient. The infection, which occurred during voriconazole prophylaxis, disseminated contiguously from the base of the left lung and pleura and spread to vertebrae via the epidural space. S. apiospermum osteoarticular infections are rare, and are difficult to diagnose and cure because of their resistance to anti-fungal drugs.

[The latest data on posaconazole]. / Actualités sur le posaconazole.

Posaconazole is a lipophilic triazole antifungal agent that is structurally similar to itraconazole but has an expended spectrum of activity including yeast, molds, and dimorphic fungi. Posaconazole was licensed by the European Commission for the treatment of invasive aspergillosis, fusariosis, mycetoma, chromoblastomycosis, and coccidioidomycosis in adults who are refractory, or intolerant to other antifungal agents. Posaconazole was recently indicated for prophylaxis of invasive fungal infections in the following patients: patients receiving remission-induction chemotherapy for acute myelogenous leukemia (AML) or myelodysplastic syndromes (MDS) expected to result in prolonged neutropenia and hematopoietic stem cell transplant (HSCT) recipients who are undergoing high-dose immunosuppressive therapy for versus host disease. The spectacular activity of posaconazole against refractory infections due to zygomycetes is encouraging and suggests using posaconazole in this case. Posaconazole is only available in oral suspension formulation. Posaconazole was well tolerated in clinical trials and has lower drug interaction profile compared to other available azoles.