ABSTRACT The pathogenic yeast Candida albicans displays at its cell surface β-1,2 oligomannosides (β-1,2-Mans). In contrast to the ubiquitous α-Mans, β-1,2-Mans bind to galectin-3, a major endogenous lectin expressed on epithelial cells. The specific role of β-1,2-Mans in colonization of the gut by C. albicans was assessed in a mouse model. A selected virulent strain of C. albicans (expressing more β-1,2-Man epitopes) induced more intense and sustained colonization than an avirulent strain (expressing less β-1,2-Man epitopes). Synthetic (Σ) β-and α-linked tetramannosides with antigenicities that mimicked the antigenicities of C. albicans -derived oligomannosides were then constructed. Oral administration of Σβ-1,2-Man (30 mg/kg of body weight) prior to inoculation with the virulent strain resulted in almost complete eradication of yeasts from stool samples, whereas administration of Σα-Man at the same dose did not. As most cases of human systemic candidiasis are endogenous in origin, this first demonstration that a synthetic analogue of a yeast adhesin can prevent yeast colonization in the gut opens the possibility of new prophylactic strategies.

OBJECTIVE:To study the influence of gender and age on the course of infection and the cytokine response in a murine model of disseminated cryptococcosis.METHODS:The course of the infection (survival and fungal load in blood and tissues) as well as pro-inflammatory and anti-inflammatory cytokine responses in plasma and organs were compared according to gender and age in outbred mice previously infected with Cryptococcus neoformans NIH52D.RESULTS:Although survival and fungal load were similar in male and female mice, the expression of all cytokines in plasma and of tumour necrosis factor-alpha and interferon-gamma in spleen was significantly increased in female mice compared to male mice in two independent experiments. Young male mice had a significantly shortened survival, were significantly more infected and had predominant tumour necrosis factor-alpha and interferon-gamma responses in comparison with older male mice.CONCLUSION:Host factors should be taken into account when studying the immune response to experimental C. neoformans infection. Our data support epidemiological and clinical data showing differences in susceptibility to cryptococcosis according to gender and age.

SCH 56592 (SCH Posaconazole) is a new antifungal agent with potent activity against filamentous fungi. Material and methods. The minimum inhibitory concentration (MIC) of SCH, itraconazole (ITZ) and amphotericin B (AmB) were determined for 15 clinical isolates of A. fumigatus by using a broth microdilution method. Results. Under the best conditions (dissolution of both ITZ and SCH in polyethylene glycol), SCH exhibited in vitro activity (MIC50/90 = 0.06/0.12 mug/ml) equivalent to ITZ (MIC50/90 = 0.12/0.25 mug/ml) and better than AmB (I mug/ml). However, the fungicidal activity of SCH (MFC50/90 = 0.06/0.25 mug/ml) was better than ITZ (MFC50/90 = 0.50/6.40). The efficacy of the 3 drugs was also compared in a marine model of disseminated aspergillosis. Mice were infected i.v. with approximate to 2 x 10(6) conidia of A.fumigatus isolate F1 (ITZ MFC = 0.12 mug/ml) or F2 (ITZ MFC = 8 mug/ml). Mice were divided into groups of 10 animals and gavage treated daily for 7 days starting 24 hrs after infection. Groups included untreated controls (F I-C F2-C), and gavage with SCH at 5 mg/kg/d (F1-SCH5, F2 SCH5), or 20 mg/kg/d (FI-SCH20, F2-SCH20), ITZ at 20 mg/kg/d (F1-ITZ 20, F2-ITZ 20) or 50 mg/kg/d (F1-ITZ 50, F2-ITZ 50), or i,p. injection of AmB at 3 mg/kg, 3/week (F1-A. F2-A). CFUs in the kidneys were significantly reduced by all treatments in mice infected with F1, but only by SCH and AmB in mice infected with F2. Against both strains. SCH20 was the most efficient regimen (> 2 log reduction). Conclusion. Under these experimental conditions, SCH was the most effective drug against A. fumigatus, This study shows the potential correlation between in vivo and in vitro MFC results for ITZ susceptibility testing.

The capsule is certainly the most obvious virulence factor for Cryptococcus neoformans. The main capsule constituents are glucuronoxylomannans (GXM). Several studies have focused on the structure and chemistry of the GXM component of the capsule, yet little is known about the genetic basis of the capsule construction. Using a monoclonal antibody specific to a sugar epitope, we isolated a capsule‐structure mutant strain and cloned by complementation a gene named CAS1 that codes for a putative membrane protein. Although no sequence homology was found with any known protein in the different databases, protein analysis using the Propsearch software classified Cas1p as a putative glycosyltransferase. Cas1p is a well‐conserved evolutionary protein, as we identified one orthologue in the human genome, one in the drosophila genome and four in the plant Arabidopsis thaliana genome. Analysis of the capsule structure after CAS1 deletion showed that it is required for GXM O‐acetylation.

Pro- and anti-inflammatory mediators (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6, IL-8, IL-10, and soluble TNF receptor II [sTNFR] II) were measured in cerebrospinal fluid (CSF) before treatment (day 0), and after 2 weeks and 3 months of antifungal therapy in 51 human immunodeficiency virus (HIV)-positive and 7 HIV-negative patients with culture-confirmed cryptococcosis. On day 0, all mediator concentrations, except IL-10 in HIV-positive patients, were higher in patients with meningeal, rather than extrameningeal cryptococcosis or in control subjects (P<.05). For meningitis patients, all mediator levels, except sTNFR II, were higher in HIV-negative than HIV-positive patients (P<.05). Day 0 CSF IL-8 levels were higher in HIV-positive patients receiving antiretroviral therapy than in untreated persons (P<.02). Day 0 sTNFR II levels were higher in HIV-positive survivors at 3 months, and elevated levels were sustained in HIV-positive patients with meningitis. Overall, these data support the idea that inflammatory responses are crucial to the eradication of cryptococcal infections in the central nervous system.

The time of initiation of fluconazole treatment with or without dexamethasone, and the impact on mycological outcome and drug pharmacokinetics were assessed in a murine model of disseminated cryptococcosis. Non-infected mice and mice with disseminated cryptococcosis were given saline, dexamethasone, or fluconazole +/- dexamethasone, 1 or 8 days after infection. Cfus were counted in tissues, and fluconazole concentrations were determined in plasma and tissues by HPLC and a bioassay. Despite fluconazole tissue and plasma concentrations which were above the minimal inhibitory concentration, the numbers of cfus in brain and lung tissues were reduced after early (P = 0.002 and 0.04, respectively), but not after late fluconazole treatment. The administration of dexamethasone did not have a deleterious effect on the number of cfus, fluconazole pharmacokinetics or antifungal activity. In conclusion, the size of the fungal burden influences the effective level of fluconazole activity in lung and brain. These results strongly suggest that potential antifungal agents should be studied following both early and late administration in experimental cryptococcosis.

ABSTRACTCryptococcosis is an hematogenously disseminated meningoencephalitis during which the relationship between the disease severity and the immune response remains unclear. We thus analyzed, by enzyme-linked immunosorbent assay, proinflammatory (tumor necrosis factor alpha [TNF-α] and interleukin-6 [IL-6]) and anti-inflammatory (IL-10) cytokine levels in plasma at the time of diagnosis in 51 AIDS patients with culture-proven cryptococcosis. We used a murine model to determine the correlation between cytokine levels and fungal burden in blood and tissues and the kinetics of the immune response and of the formation of cerebral lesions. In AIDS patients, plasma TNF-α and IL-10, but not IL-6, levels were significantly higher in the case of fungemia or disseminated infection than in their absence, whereas the presence of meningitis had no influence on these levels. In mice, none of these cytokines were detected within the first day after inoculation. Later on, TNF-α and IL-10, but not IL-6, levels in plasma correlated significantly with the fungal burden in the blood and spleen but not the brain. In the brain, cytokine levels were low compared to those in other compartments, and tissue lesions and a degree of infection similar to those observed in humans were seen, further suggesting the relevance of this experimental model. Thus, AIDS patients with cryptococcosis produce an immune response that reflects the dissemination but not the meningeal involvement. This murine model of disseminated cryptococcosis can be used to investigate the pathophysiology of cryptococcosis and new therapeutic approaches.

We studied fungemia over time in outbred mice infected with Cryptococcus neoformans and looked at its relationship with the intravenous (i.v.) inoculum size, tissue burden and survival. Fungemia was evaluated by culture of 10 microl of peripheral blood from living mice or by culture of buffy coats from sacrificed animals. For all inoculum sizes studied, fungemia could last several weeks after the i.v. inoculation. Individual susceptibility of outbred mice to cryptococcal infection was evidenced by variations in the course, duration and magnitude of fungemia and tissue localizations. These results suggest that the fungus can recirculate after the initial i.v. inoculation. Fungemia, assessed by culture of buffy coats, correlated with the extent of infection in the spleen, lung or brain (P<<0.001) on day 1 after inoculation but only with yeast burden in lung or spleen on day 8, thus demonstrating that brain reacts differently to C. neoformans infection than other organs. Comparison of blood culture techniques and examination of smears suggest that cryptococci might circulate within leucocytes. Finally, quantitative blood cultures may accurately assess the fungal load during experimental cryptococcosis.

BACKGROUND:Fluconazole resistance has emerged among Candida albicans isolates and has been associated with the prolonged or repeated use of the drug. This study was designed to discover whether transmission of oral isolates could occur between sexual partners and thereby explain fluconazole resistance in patients never treated with the drug.MATERIALS AND METHODS:The oral flora of 10 HIV-infected couples (five heterosexual and five homosexual) were studied. In vitro susceptibility testing and genotyping (restriction fragment length polymorphism with EcoRI and HinfI) were used to delineate strain relatedness for 230 clones (five clones per sample, one to four samples per patient).RESULTS:The genetic diversity of the clones with one DNA subtype was specific to a given patient or a given couple, except in one case in which unrelated patients shared clones of the same genotype. The persistence of clones between partners was stable over time in six out of 10 couples and only transient in one couple. Fluconazole resistance in isolates from patients who had never been treated with azoles was associated in three patients with the first episode of oropharyngeal candidiasis and treatment failure.CONCLUSION:The observation that couples tended to share genetically indistinguishable clones was highly suggestive of transmission between partners. This phenomenon may, in part, explain the pathogenesis of oropharyngeal candidiasis and the increased frequency of fluconazole resistance both in vitro and in vivo.

Introduction: Entomophthoromycosis is an infection caused by fungi of the order Entomophthorales belonging to the class Zygomycetes. They occur in tropical and subtropical climates. These fungi are ubiquitous and saprophyte of plant detritus. Observation: We report the case of a 13-year-old boy with rhinofacial Conidiobolus coronatus infection, unusual by local invasion with osteolysis and failure of treatment with itraconazole, ketoconazole, fluconazole and potassium iodide. Discussion: Three species of Entomophthorales are responsible for human infections. C, coronatus causes rhinofacial entomophthoromycosis or rhinophycomycosis. The infection begins in the submucosa of the nose extending slowly to the skin and pharynx, leading to monstrous distorsion of the face. Conidiobolus incongruus causes visceral entomophthoromycosis, an uncommon and life-threatening;infection. Basidiobolus ranarum causes subcutaneous entomophlhoromycosis, presenting as chronic inflammatory subcutaneous infiltration of the trunk, shoulders and thighs. C. coronatus or B, ranarum infections are usually successfully treated with azole derivatives. Conclusion: We report a new case of C. coronatus rhinophycomycosis, unusual by clinical features (local invasion, osteolysis) and therapeutic problems (failure of azole antifungal agents).

This is the first case report of an exceptional maxillary infection due to Scedosporium prolificans. This recently discovered fungus was identified in the sinus. In the literature, it has been observed at different locations. Identification requires careful sample taking for mycology and pathology studies emphasizing the importance in maxillary surgery. This pathogenic fungus is very invasive, particularly in immunodepressed or immunocompromised patients. Therapeutic modalities vary with the patient's immune status.

Introduction: Les entomophthoromycoses regroupent des infections causees par des champignons appartenant a la famille des zygomycetes, de l'ordre des entomophthorales, que l'on observe le plus souvent dans les regions tropicales et sub-tropicales. Ces champignons sont cosmopolites, saprophytes du sol et des debris vegetaux. Observation: Nous rapportons le cas d'un adolescent de 13 ans atteint de rhinophycomycose a Conidiobolus coronatus, atypique par l'importance de l'envahissement loco-regional avec lyse osseuse et polyadenopathie, et par les difficultes therapeutiques. Apres un echec des traitements par itraconazole, fluconazole, ketoconazole et iodure de potassium, seul un nouvel antifongique triazole a permis une resolution durable des symptomes. Mais une recidive est survenue, 10 jours apres l'arret de celui-ci, malgre un traitement de 4 mois. Discussion: Parmi les entomophthorales, trois especes sont pathogenes chez l'homme. C. coronatus est responsable de l'entomophthoromycose rhino-faciale ou rhinophycomycose. Il infecte les voies aeriennes superieures. Les lesions s'etendent localement au pharynx et aux tissus sous-cutanes de la face, donnant des deformations monstrueuses du visage. Conidiobolus incongruus est l'agent de l'entomophthoromycose viscerale, pathologie beaucoup plus rare et incurable jusqu'a present. Enfin, Basidiobolus ranarum est responsable de l'entomophthoromycose sous-cutanee, placard inflammatoire touchant le plus souvent le tronc ou la racine des membres, d'evolution chronique. Les infections a C. coronatus et B. ranarum posent habituellement peu de probleme therapeutique. En effet si l'amphotericine B est peu efficace, les derives azoles permettent en general une guerison rapide. Conclusion: Nous rapportons un nouveau cas de rhinophycomycose a C. coronatus, remarquable par son evolution clinique (envahissement loco-regional, lyse osseuse) et therapeutique (echec des derives azoles).

Fluconazole (FCZ) has been extensively used as a primary therapy for oropharyngeal candidosis in AIDS patients. Clinical resistance to FCZ is now encountered, often related to decreased susceptibility of the isolate in vitro, We wondered if low levels in saliva play a role in the therapeutic failure, especially in patients complaining of dry mouth, Sixteen AIDS patients treated for oropharyngeal candidosis with FCZ were studied, MICs for the isolates were determined, Serum and saliva samples were collected to measure FCZ levels with a bioassay using paper disks loaded with the clinical specimens, We showed that (i) paper disks were convenient for collecting saliva in patients with dry mouth; (ii) levels in saliva depended on the FCZ dosage regimen but did not correlate with the response to therapy; (iii) correlation between concentrations in saliva and serum was poor and independent of clinical response to treatment, other therapies, or decreased salivation; and (iv) levels in saliva were always lower than MICs in patients who failed to respond to treatment, In conclusion, therapeutic failures are more likely to be related to in vitro resistance of the isolate to FCZ or insufficient dosage regimen than to decreased salivary secretion.

Objective: To study the fungal flora and the antifungal susceptibility of yeasts isolated from buccal lesions from AIDS patients with oral candidiasis and to see if our antifungal susceptibility testing method could predict the emergence of resistant isolates.Patients and methods: The buccal lesions from ten AIDS patients with oral candidosis were sampled. Twenty colonies were identified to the species level and studied for their susceptibility to three azole antifungal agents. The minimal inhibitory concentrations of fluconazole, itraconazole and ketoconazole were determined at 24 hours and 48 hours using a microbroth dilution method. Four of the patients were also sampled during the following episode and five colonies were then studied in the same conditions.Results: Patients with AIDS were found to be colonized/infected by various genus (Candida and Geotrichum) and species (C. albicans, C. glabrata, C. krusei) during the same episode. The species changed overtime. Susceptibility to fluconazole could vary among colonies of C. albicans isolated from the same patient and also, for some colonies according to the duration of the in vitro incubation. This pattern defined as unstable susceptibility might be predictive of resistance.Conclusions: The diversity among fungal buccal flora of AIDS patients and the emergence of Candida isolates resistant to fluconazole suggest that clinical practice as well as routine laboratory techniques may have to change. Finally, preliminary results suggest that our antifungal susceptibility testing method may offer a means to predict resistance to fluconazole.

Journal Article Mechanisms and clinical impact of antifungal drug resistance Get access H. Vanden Bossche, H. Vanden Bossche Search for other works by this author on: Oxford Academic PubMed Google Scholar D.W. Warnock, D.W. Warnock Search for other works by this author on: Oxford Academic PubMed Google Scholar B. Dupont, B. Dupont Search for other works by this author on: Oxford Academic PubMed Google Scholar D. Kerridge, D. Kerridge Search for other works by this author on: Oxford Academic PubMed Google Scholar S. Sen Gupta, S. Sen Gupta Search for other works by this author on: Oxford Academic PubMed Google Scholar L. Improvisi, L. Improvisi Search for other works by this author on: Oxford Academic PubMed Google Scholar P. Marichal, P. Marichal Search for other works by this author on: Oxford Academic PubMed Google Scholar F.C. Odds, F.C. Odds Search for other works by this author on: Oxford Academic PubMed Google Scholar F. Provost, F. Provost Search for other works by this author on: Oxford Academic PubMed Google Scholar O. Ronin O. Ronin Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Medical and Veterinary Mycology, Volume 32, Issue Supplement_1, December 1994, Pages 189–202, https://doi.org/10.1080/02681219480000821 Published: 01 December 1994

Six human pathogenic Trichosporon species are described with respect to criteria for routine identification, epidemiology and clinical origin: T. ovoides, T. inkin, T. asahii, T. asteroides (Fissuricella filamenta), T. cutaneum, and T. mucoides. These species are causative agents of white piedra and cutaneous infections and are involved in systemic, localized or disseminated mycoses, particularly in patients with underlying haematological malignancy. Data on in vitro sensitivity to antifungal drugs are provided.

The genusCryptococcus was found to be heterogeneous on the basis of partial rRNA sequences. The human-pathogenic speciesC. neoformans, comprising 4 serotypes and havingFilobasidiella neoformans andF. bacillispora as teleomorphs, was found at a relatively large distance fromFilobasidium. Serotypes B and C had identical sequences, while in A and D they were different, with D closer to B and C than to A.Filobasidiella depauperata, which lacks a yeast-like anamorph, clustered withF. neoformans.