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Background: Cryptococcus neoformans is an encapsulated fungal pathogen that causes severe complications primarily in immunocompromised populations. Monocytes and macrophages serve as first line of innate immune defence in tackling Cryptococcus neoformans infection.Nevertheless, the interplay between Cryptococcus neoformans with macrophages remain elusive. In this study, we investigated the interaction between C. neoformans and THP-1 monocyte derived macrophages, emphasising on the role of cryptococci capsule and the host cytoskeleton remodelling upon interactions.Methods and materials: Cryptococcus neoformans encapsulated H99 (ATCC 208821), Cap64 (ATCC 52816, acapsular mutant of B-3501) and B-3501 (ATCC 34873) strains were used in this study. THP-1 (TIB-202, human acute monocytic leukemia cell line) was induced into adherent, macrophage-like cells in the presence of phorbol myristate acetate. The association of Cryptococcus neoformans Cap64, B-3501 and H99 with THP-1 monocyte derived macrophage, particularly adherence and internalisation events, host actin and microtubule changes were examined using differential fluoresence assay. The images were acquisited using inverted epifluorescence microscope. Association indexes (adherence or internalised yeasts/100 host cells) from three independent experiments were calculated. Additionally, the role of actin and complement receptor type-3 (CR3) in the interaction between C.neoformans Cap64 and THP-1 monocyte derived macrophage were studied upon treatment of infected THP-1 monocyte derived macrophage with cytochalasin D and with a combination of anti-CD18 and anti-CD11b, respectively.Results: Acapsular C. neoformans cells were able to efficiently adhere to and become internalised into THP-1 cells without opsonisation and macrophage activation; while presence of capsule reduced the host-pathogen association. Infection by C. neoformans generally led to localised actin but not microtubule remodelling at the host-pathogen interface. Treatment with Cytochalasin D, an actin polymerisation inhibitor, confirmed that the integrity of actin microfilament is required for both adherence and internalisation of cryptococci into macrophage cells. We further demonstrated that antibody inhibition of complement receptor type 3 (CR3) in THP-1 reduced the association of acapsular cryptococci to the host cells. Conclusion:The results presented new insights on how C. neoformans co-opts professional phagocytic cells during primary infection.

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Introduction:Dermatophytosis is a common superficial mycosis causing significant cutaneous morbidity. In recent times, the prevalence of dermatophytosis is increasing. The dermatophyte infections spread easily and rapidly especially in low socioeconomic classes and thus warrant early therapy.Dermatophyte infections are commonly treated by topical antifungal drugs like clotrimazole, terbinafine, ketoconazole. But severe and chronic form of dermatophytosis requires treatment with systemic antifungal drugs like itraconazole, griseofulvin and terbinafine.There is emergence of antifungal resistant strains due to incongruous use of antifungals and poor antifungal policy. There are limited studies related to antifungal susceptibility testing (AFST). So present study was undertaken to determine mycological, clinical profile and antifungal Susceptibility testing ofdermatophytosis. Material & Methods: A prospective study was conducted on patients with superficial fungal infections over a period of 11 months (October 2018 to August 2019). Various samples like skin scrapings, scales, hair and nail clippings were processed by standard fungal culture methods. AFST was performed by using E-test strips (HiMedia) of fluconazole, itraconazole and terbinafine on Sabourauds dextrose agar plates and interpreted according to CLSI (M38A). Results: A total of 25 (23.8%) dermatophytes were isolated from 105 (skin 57, Nail 41, scales 11, Hair 6) samples. Out of 25 culture positive patients, 18 presented as tineacorporis, 3 as tineacruris, 3 onchomycosis, 1 each as tineacapitis&tinea incognito. T. tonsurans was most common dermatophyte 40% (N10), followed by T. rubrum 36% (N9), T. mentagrophytes 12% (N3) and M. canis 8% (N2) and T. megninii 4% (N1). AFST of all 25 isolates revealed that 21 isolates were sensitive to itraconazole (0.023 to 0.75 mcg/ml) wheras a single isolate of T. rubrum and T. tonsurans each were resistant. Two isolates of T.tonsurans showed lower MICs for itraconazole (0.023mcg/ml). For terbinafine (0.002-0.008mcg/ml), 14 isolates (56%) showed resistance with MICs >32 mcg/ml. For fluconazole (range 0.5-4 mcg/ml) only 3 isolates showed MIC in range while22 were resistant MICs >256mcg/ml. The results were communicated with dermatologists and appropriate changes were made in patient therapy. Conclusion: The emergence of resistant dermatophytesemphasises the need of antifungal drug susceptibility tests, antifungal stewardship and strong antifungal policy to enable the clinician to start suitable antifungals to avoid antifungal resistance and treatment failure.