Debaryomyces is enriched in Crohn's disease intestinal tissue and impairs healing in mice.

Alterations of the mycobiota composition associated with Crohn's disease (CD) are challenging to link to defining elements of pathophysiology, such as poor injury repair. Using culture-dependent and -independent methods, we discovered that Debaryomyces hansenii preferentially localized to and was abundant within incompletely healed intestinal wounds of mice and inflamed mucosal tissues of CD human subjects. D. hansenii cultures from injured mice and inflamed CD tissues impaired colonic healing when introduced into injured conventionally raised or gnotobiotic mice. We reisolated D. hansenii from injured areas of these mice, fulfilling Koch's postulates. Mechanistically, D. hansenii impaired mucosal healing through the myeloid cell-specific type 1 interferon-CCL5 axis. Taken together, we have identified a fungus that inhabits inflamed CD tissue and can lead to dysregulated mucosal healing.

In vitro susceptibility of dermatophytes to oral antifungal drugs and amphotericin B in Uttar Pradesh, India.

BACKGROUND: Dermatophytosis is a major public health problem in our country. Although resistance to conventional oral and topical antifungal agents is being increasingly encountered, the sensitivity pattern of dermatophytes has not been systematically analysed. AIMS: We aimed to determine the sensitivity pattern of dermatophyte isolates to amphotericin B and six oral antifungal drugs. MATERIALS AND METHODS: Patients with dermatophytosis attending the outpatient department of dermatology were enrolled in the study. Samples were collected for mycological examination and in vitro antifungal sensitivity testing was done by broth microdilution as per the Clinical and Laboratory Standard Institute M38-A standards. RESULTS: A total of 804 patients were enrolled. Specimens from 185 patients (23%) were both KOH and culture positive, and 44 of these isolates (41 Trichophyton mentagrophytes and 3 Trichophyton rubrum) were subjected to sensitivity testing. Minimum inhibitory concentrations (MIC) of itraconazole, ketoconazole, voriconazole and amphotericin B were comparable. The median MIC to fluconazole was higher than the other tested drugs. Dermatophytes were most susceptible to ketoconazole and voriconazole, followed by itraconazole, amphotericin B, fluconazole and griseofulvin. A high incidence of resistance was found to terbinafine and the difference was statistically significant in comparison to fluconazole, itraconazole, voriconazole, ketoconazole (P = 0.001) and griseofulvin (P = 0.003). The strains were more sensitive to amphotericin B as compared to griseofulvin (P = 0.02) and terbinafine (P < 0.001). LIMITATIONS: This was a hospital-based study and may not reflect the true pattern in the community. Only a few of the isolates were selected for study. The clinical response of patients, whose isolates were studied for in vitro sensitivity of the antifungals, was not studied. CONCLUSIONS: The sensitivity pattern of dermatophytes to various antifungals including amphotericin B, ketoconazole, voriconazole and itraconazole were determined. The studied isolates were least susceptible to terbinafine.

Diversity, in-vitro virulence traits and antifungal susceptibility pattern of gastrointestinal yeast flora of healthy poultry, Gallus gallus domesticus.

BACKGROUND: Poultry farming and consumption of poultry (Gallus gallus domesticus) meat and eggs are common gastronomical practices worldwide. Till now, a detailed understanding about the gut colonisation of Gallus gallus domesticus by yeasts and their virulence properties and drug resistance patterns in available literature remain sparse. This study was undertaken to explore this prevalent issue. RESULTS: A total of 103 specimens of fresh droppings of broiler chickens (commercial G domesticus) and domesticated chickens (domesticated G domesticus) were collected from the breeding sites. The isolates comprised of 29 (33%) Debaryozyma hansenii (Candida famata), 12 (13.6%) Sporothrix catenata (C. ciferrii), 10 (11.4%) C. albicans, 8 (9.1%) Diutnia catenulata (C. catenulate), 6 (6.8%) C. tropicalis, 3 (3.4%) Candida acidothermophilum (C. krusei), 2 (2.3%) C. pintolopesii, 1 (1.1%) C. parapsilosis, 9 (10.2%) Trichosporon spp. (T. moniliiforme, T. asahii), 4 (4.5%) Geotrichum candidum, 3 (3.4%) Cryptococcus macerans and 1 (1%) Cystobasidium minuta (Rhodotorula minuta). Virulence factors, measured among different yeast species, showed wide variability. Biofilm cells exhibited higher Minimum Inhibitory Concentration (MIC) values (µg/ml) than planktonic cells against all antifungal compounds tested: (fluconazole, 8-512 vs 0.031-16; amphotericin B, 0.5-64 vs 0.031-16; voriconazole 0.062-16 vs 0.062-8; caspofungin, 0.062-4 vs 0.031-1). CONCLUSIONS: The present work extends the current understanding of in vitro virulence factors and antifungal susceptibility pattern of gastrointestinal yeast flora of G domesticus. More studies with advanced techniques are needed to quantify the risk of spread of these potential pathogens to environment and human.

In vitro susceptibility studies of Cryptococcus neoformans isolated from patients with no clinical response to amphotericin B therapy.

The in vitro activities of three antifungal drugs alone and in combination were evaluated against five isolates of Cryptococcus neoformans using time-kill curves (TKC). The isolates were from AIDS patients who had either died or had failed to show a clinical response during amphotericin B (AMB) treatment. AMB, fluconazole (FCZ) and flucytosine (5FC), and combinations of the drugs (AMB plus 5FC, AMB plus rifampicin (RIF) and FCZ plus 5FC), were evaluated. With all five isolates AMB did not show fungicidal activity; instead, a persistent or tolerant effect was observed. Combinations of AMB plus 5FC and AMB plus RIF showed a clear synergic effect, except for one isolate tested with AMB plus RIF. In contrast, the FCZ plus 5FC combination did not inhibit growth of any isolate.

Amphotericin B and 5-fluorocytosine: effects on cell-mediated immunity

Although single-dose amphotericin B therapy appears to be immunostimulatory in mice, no data are available regarding the effects of chronic anti-fungal drug therapy on the immune system. We studied the effects on the guinea-pig cellular immune system of 4 weeks of treatment with amphotericin B, 5-fluorocytosine, or the combination of both drugs. The in vitro lymphocyte response to phytohaemagglutinin and the specific antigen, picryl human serum albumin (picHSA), were not affected by anti-fungal drug treatment. At 1.5 weeks of therapy with amphotericin B, skin test reactivity to picHSA was significantly reduced but returned toward normal by the end of 3.5 weeks of drug therapy. Macrophage migration inhibitory factor production by guinea-pig peripheral blood lymphocytes was significantly reduced after 4 weeks of amphotericin B therapy. No immunostimulatory properties could be ascribed to amphotericin B. 5-fluorocytosine had no effect on cellular immunity.