Autophagy benefits the in vitro and in vivo clearance of Talaromyces marneffei.

Talaromycosis, namely Talaromyces marneffei infection, is increasing gradually and has a high mortality rate even under antifungal therapy. Although autophagy acts differently on different pathogens, it is a promising therapeutic strategy. However, information on autophagy in macrophages and animals upon infection by T. marneffei is still limited. Therefore, several models were employed here to investigate the role of autophagy in host defense against T. marneffei, including RAW264.7 macrophages as in vitro models, different types of Caenorhabditis elegans and BALB/c mice as in vivo models. We applied the clinical T. marneffei isolate SUMS0152 in this study. T. marneffei-infected macrophages exhibit increased formation of autophagosomes. Further, macrophage autophagy promoted by rapamycin or Earle's balanced salt solution (EBSS) inhibited the viability of intracellular T. marneffei. In vivo, compared with uninfected Caenorhabditis elegans, the wild-type nematodes upregulated the expression of the autophagy-related gene lgg-1 and atg-18, and nematodes carrying GFP reporter were induced to form autophagosomes (GFP::LGG-1) after T. marneffei infection. Furthermore, the knockdown of lgg-1 significantly reduced the survival rate of T. marneffei-infected nematodes. Likewise, the autophagy activator rapamycin reduced the fungal burden and suppressed lung inflammation in a mouse model of infection. In conclusion, autophagy is essential for host defense against T. marneffei in vitro and in vivo. Therefore, autophagy may be an attractive target for developing new therapeutics to treat talaromycosis.

Rapid identification and characterization of Penicillium marneffei using multiplex ligation-dependent probe amplification (MLPA) in paraffin-embedded tissue samples.

Penicillium marneffei infection is a deadly disease and early diagnosis leads to prompt and appropriate antifungal therapy. To develop a sensitive method to diagnose P. marneffei infection, a multiplex ligation-dependent probe amplification (MLPA) assay was adapted. This method can rapidly and specifically detect P. marneffei DNA in cultured cells and paraffin-embedded tissue samples. Three pairs of probes were designed for amplifying the internally (intergenic) transcribed spacer (ITS) region of P. marneffei rRNA using a systematic phylogenetic analysis. These three probe sets produced three amplicons of 198, 166, and 152 bp, respectively, specific for P. marneffei. In contrast, there was only one 198 bp amplicon produced for Talaromyces stipitatus, and one 152 bp amplicon for P. funiculosum, T. intermedius and T. derxii. The probes did not amplify any other reference strains. An array of 40 P. marneffei strains isolated from human patients, bamboo rat, and the local environment was tested by using MLPA, and all were positively identified. Most importantly, P. marneffei in paraffin-embedded tissue specimens from infected human patients was positively amplified by MLPA. The sensitivity and specificity of the MLPA assay could be a useful tool for prompt diagnosis, pathogen characterization, and epidemiological studies of fungal infections.

In vitro susceptibility testing of Aspergillus spp. against voriconazole, itraconazole, posaconazole, amphotericin B and caspofungin.

BACKGROUND: During recent years, the incidence of serious infections caused by opportunistic fungi has increased dramatically due to alterations of the immune status of patients with hematological diseases, malignant tumors, transplantations and so forth. Unfortunately, the wide use of triazole antifungal agents to treat these infections has lead to the emergence of Aspergillus spp. resistant to triazoles. The present study was to assess the in vitro activities of five antifungal agents (voriconazole, itraconazole, posaconazole, amphotericin B and caspofungin) against different kinds of Aspergillus spp. that are commonly encountered in the clinical setting. METHODS: The agar-based Etest MIC method was employed. One hundred and seven strains of Aspergillus spp. (5 species) were collected and prepared according to Etest Technique Manuel. Etest MICs were determined with RPMI agar containing 2% glucose and were read after incubation for 48 hours at 35°C. MIC(50), MIC(90) and MIC range were acquired by Whonet 5.4 software. RESULTS: The MIC(90) of caspofungin against A. fumigatus, A. flavus and A. nidulans was 0.094 µg/ml whereas the MIC(90) against A. niger was 0.19 µg/ml. For these four species, the MIC(90) of caspofungin was the lowest among the five antifungal agents. For A. terrus, the MIC(90) of posaconazole was the lowest. For A. fumigatus and A. flavus, the MIC(90) in order of increasing was caspofungin, posaconazole, voriconazole, itraconazole, and amphotericin B. The MIC of amphotericin B against A. terrus was higher than 32 µg/ml in all 7 strains tested. CONCLUSIONS: The in vitro antifungal susceptibility test shows the new drug caspofungin, which is a kind of echinocandins, has good activity against the five species of Aspergillus spp. and all the triazoles tested have better in vitro activity than traditional amphotericin B.

Comparison of a glucose consumption based method with the CLSI M38-A method for testing antifungal susceptibility of Trichophyton rubrum and Trichophyton mentagrophytes.

BACKGROUND: The prevalence of dermatophytoses and the development of new antifungal agents has focused interest on susceptibility tests of dermatophytes. The method used universally for susceptibility tests of dermatophytes was published as document (M38-A) in 2002 by the Clinical and Laboratory Standards Institute (CLSI), dealing with the standardization of susceptibility tests in filamentous fungi, though not including dermatophytes especially. However, it is not a very practical method for the clinical laboratory in routine susceptibility testing. In this test, we developed a novel rapid susceptibility assay-glucose consumption method (GCM) for dermatophytes. METHODS: In this study, we investigated the antifungal susceptibilities of dermatophytes to itraconazole (ITC), voriconazole (VOC), econazole nitrate (ECN) and terbinafine (TBF) by glucose consumption method (GCM), in comparison to the Clinical and Laboratory Standards Institute (CLSI) M38-A method. Twenty-eight dermatophyte isolates, including Trichophyton rubrum (T. rubrum) (n = 14) and Trichophyton mentagrophytes (T. mentagrophytes) (n = 14), were tested. In the GCM, the minimum inhibitory concentrations (MICs) were determined spectrophotometrically at 490 nm after addition of enzyme substrate color mix. For the CLSI method, the MICs were determined visually. RESULTS: Comparison revealed best agreement for TBF against T. mentagrophytes and T. rubrum, since MIC range, MIC50, and MIC90 were identical from two methods. However, for ITC and VOC, GCM showed wider MIC ranges and higher MICs than CLSI methods in most isolates. For ECN against T. rubrum, high MICs were tested by GCM (0.125-16 microg/ml) but not M38-A method (0.5-1 microg/ml). The overall agreements for all isolates between the two methods within one dilution and two dilutions for ITC, VOC, ECN and TBF was 53.6% and 75.0%, 57.1% and 75.0%, 82.1% and 89.3%, and 85.7 and 85.7%, respectively. CONCLUSION: Measurement of glucose uptake can predict the susceptibility of T. rubrum and T. mentagrophytes to ECN and TBF.

[Inhibitory effect of dexamethasone on myeloid differentiation factor 88 and tumor necrosis factor-alpha expressions in mouse peritoneal macrophages].

OBJECTIVE: To study the inhibitory effect of dexamethasone (DEX) on myeloid differentiation factor 88 (MyD88) and tumor necrosis factor-alpha (TNF-alpha) expression in mouse peritoneal macrophages in innate immune response to Penicillium marneffei (PM). METHODS: Mouse peritoneal macrophages were cultured in the presence of heat-inactivated yeast-phase PM with or without DEX, and the protein and mRNA expressions of MyD88 in the macrophages were detected using Western blotting and real-time PCR, respectively. TNF-alpha in the cell culture supernatant was measured with enzyme-linked immunosorbent assay. RESULTS: DEX suppressed TNF-alpha production by the macrophages co-cultured with PM. The expressions of MyD88 were up-regulated by PM stimulation, whose effect was inhibited by the application of DEX. CONCLUSION: The inhibitory effect of DEX on PM-induced proinflammatory responses of the macrophage is directly associated with the inhibition of MyD88 expression.

Synergistic effects of terbinafine and itraconazole on clinical isolates of Fonsecaea monophora.

Our objective was to develop new approaches to the chemotherapy of invasive infections caused by Fonsecaea monophora. The in vitro effects of a combination of terbinafine with itraconazole on 18 clinical isolates were evaluated using a checkerboard microdilution method. The mode of interaction between the two drugs on the 18 isolates was analyzed using fractional inhibitory concentration index (FICI) analysis. FICI analysis demonstrated that 12 (67%) were synergistic, 4 (22%) were additive, and 2 (11%) were indifferent, with no antagonism being observed. The minimal inhibitory concentrations (MICs) obtained with the terbinafine-itraconazole combination were within levels that can be achieved in plasma at clinically relevant doses. Our results indicate the terbinafine-itraconazole combination may be an effective therapy for Fonsecaea monophora infection, which should be tested in clinical setting with patients with this disease.

Pseudomembranous-like tinea of the scrotum: report of six cases.

Six cases of tinea of the scrotum with atypical clinical features were observed in the dermatology department of our hospital between 2001 and 2007. The age of onset ranged from 14 to 26 years. Unusual clinical presentations of pseudomembranous-like disease were observed in every patient. Causative agents were Microsporum gypseum in five patients and Trichophyton rubrum in one patient. Three of the M. gypseum isolates had atypical morphologies. All six isolates were identified by cultural morphologies and DNA sequence analysis of the internal transcribed spacer region of the ribosomal DNA.

[Effect of Penicillium marneffei on TLR-2, TLR-4, and Dectin-1 expression and TNF-alpha production in macrophage].

OBJECTIVE: To study the effects of heat-killed Penicillium marneffei (PM) on the expressions of toll-like receptor-4 (TLR-4), toll-like receptor-2 (TLR-2) and dendritic cell associated C-type lectin-1 (Dectin-1)and the production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). in mouse peritoneal macrophages. METHODS: Mouse peritoneal macrophages were cultured in the presence of heat-killed yeast-phase PM for 24 h, and the average fluorescence intensity of TLR-2, TLR-4, and Dectin-1 in the macrophages was detected using flow cytometry. Fluorescent staining of the macrophages was performed to observe the fluorescence of TLR-2, TLR-4, and Dectin-1 with confocal microscopy. TNF-alpha mRNA in the cell culture supernatant was measured with real-time PCR, and TNF-alpha protein detected using enzyme-linked immunosorbent assay (ELISA). RESULTS: The average fluorescence intensity of TLR-2, TLR-4 and Dectin-1 in the macrophages was increased in response to a 24-h PM stimulation, and the stimulated macrophages produced large amounts of TNF-alpha. CONCLUSION: PM up-regulates the expression of TLR-2, TLR-4 and Dectin-1 in mouse peritoneal macrophages, and their expressions are directly associated with macrophage activation.

[Differential expression of isocitrate lyase in P. marneffei phagocytized by nonstimulated and stimulated murine macrophages].

OBJECTIVE: To investigate the differential expression of isocitrate lyase in Penicillium marneffei phagocytized by nonstimulated and stimulated murine macrophages, and explore the role of glyoxylate pathway in pathogenesis of Penicilliosis marneffei. METHODS: Penicillium marneffei conidia and Raw264.7 cells were incubated in 16 cultures, which were divided to 4 groups for treatment with N-monomethyl-L-arginine (LNMMA, CI group), murine interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS) (T group), IFN-gamma plus LPS and LNMMA (TI group), or the same volume of culture medium (C group). The transcriptional levels of isocitrate lyase were detected using real-time RT-PCR, and its expression levels detected biochemically. RESULTS: The transcriptional levels of isocitrate lyase in C, CI, T, TI groups were 1.00, 1.42, 33.09, and 74.88 (P<0.05), while the expression levels were 0.06, 0.07, 0.18, and 0.93, respectively (P<0.05). The content of nitric oxide in T group was significantly higher than that in the other groups (P<0.01), but the CFU of T group was the lowest (P<0.01). CONCLUSION: Reactive nitrogen intermediates induced by stimulated murine macrophages restrain the expression of isocitrate lyase of Penicillium marneffei and development of Penicillium marneffei, in which process the glyoxylate pathway may play an important role.