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ObjectiveTo dynamically observe the paradoxical effect (inhibitory at low concentratin but promotive at high concentration) of caspofungin and micafungin across Candida species in vitro.MethodsA broth microdilution testing was performed following the Clinical and Laboratory Standards Institute(CLSI) M27-A2 document to observe the paradoxical effect of caspofungin and micafungin across 85 Candida strains.The growth of Candida was observed on a daily basis for 7 days.ResultsAt 48 hours,the prevalence of paradoxical growth in C.albicans,C.glabrata,C.parapsilosis,C.tropicalis,C.dubliniensis and other species of Candida was 90%,20%,41.7%,37.5%,33.3% and 28.6% respectively after caspofungin treatment,and 5%,0,0,25%,33.3%and 0 respectively after micafungin treatment.The concentration range of caspofungin required for the paradoxical growth of C.albicans,C.glabrata,C.parapsilosis,C.tropicalis,C.dubliniensis and other species of Candida was 4-16,8-32,8-32,2-8,2-8,8-32 μg/ml respectively,and that of micafungin for the paradoxical growth of C.albicans,C.tropicalis and C.dubliniensis was 4-16,4-32 and 1-8 μg/ml,respectively.After 48 hours,the prevalence of paradoxical growth still increased in C.parapsilosis,C.glabrata,and other species of Candida following caspofungin treatment,and in C.albicans and C.glabrata following micafungin treatment.ConclusionsThe occurrence,and time of occurrence,of paradoxical effect of echinocandins is Candida speciesand drug-specific.The prevalence of paradoxical effect is higher for caspofungin than for micafungin,which seems unrelated to their MICs against Candida species.
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ObjectiveTo investigate the predisposing factors and pathogenic fungal species of Malassezia folliculitis in different geographical areas and body sites.MethodsTotally,241 patients diagnosed with Malassezia folliculitis were asked to complete a questionnaire.The content of hair follicles was obtained and subjected to fungal smear and culture examination.Fungal species were identified according to morphological,physiological and biochemical features.Results Of the 241 patients with Malassezia folliculitis,204 (84.65%) were positive for smear examination.A total of 259 specimens were collected from these patients,and fungal culture grew 213(82.24%) strains,of which,209 belonged to Malassezia species,4(1.54%) to Candida species.Among the 209 Malassezia strains,186 were activated and subjected to species identification which resulted in 6 species,including M.furfur (111 strains,59.68% ),M.sloofiae (43 strains,23.12% ),M.sympodialis (17 strains,9.14%),M.globosa (9 strains,4.84%),M.pachydermatis (4 strains,2.15%),and M.obtuse(2 strains,1.08% ).Of the pathogenic fungi of Malassezia folliculitis,M.furfur predominated in the chest,back,abdomen,face and neck,M.sloofiae in the upper limbs,shoulders and vertex,M.globosa in the lower limbs.There were obvious differences in the distribution of pathogenic fungal species at different body sites in a same host,and M.furfur with M.sloofiae or M.sympodialis appeared to be the most common pathogens.ConclusionsIn this study,6 Malassezia species are identified in patients with Malassezia folliculitis in Nantong and Nanjing area,M.furfur and M.sloofiae appear to be the dominant pathogens.
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Objective To evaluate the in vitro activity of seven imidazole antifungals against clinical isolates of common Candida species.Methods According to the Clinical and Laboratory Standards Institute (CLSI) microdilution method M27-A3,the in vitro activity of luliconazole,ketoconazole,miconazole,econazole,clotrimazole,sertaconazole and bifonazole was determined among 183 clinical isolates belonging to 5 species of Candida.Results The minimal inhibitory concentration range was 0.03-8 (geometric mean:0.067) mg/L for ketoconazole,0.03-16 (geometric mean:0.071 ) mg/L for miconazole,0.03-8 (geometric mean:0.207) mg/L for econazole,0.03-8 (geometric mean:0.061 ) mg/L for clotrimazole,0.03-16 (geometric mean:0.187) mg/L for sertaconazole and 0.03 ->16 (geometric mean:1.050) mg/L for bifonazole. Luliconazole exhibited a superior activity against the 5 species of Candida in vitro,with the MIC range being 0.03-8 mg/L,geometric mean MIC 0.087 mg/L,MIC50 0.06 mg/L and MIC90 0.5 mg/L,respectively.However,some Candida isolates were identified to be relatively insensitive to these tested antifungals,including luliconazole.Conclusion All the tested imidazole antifungals,except for bifonazole,show an excellent activity against Candida species in vitro,but there exist a few Candida strains with relative insensitivity.
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Objective To compare broth microdilution and agar dilution methods for in vitro testing of activities of fluconazole,ketoconazole and itraconazole against clinical Malassezia isolates.Methods Broth microdilution and agar dilution methods were used to determine the minimal inhibitory concentration(MIC)of fluconazole,ketoconazole and itraconazole for 27 clinical strains(5 species)of Malassezia.Results The minimal inhibitory concentration(MIC)ranges of fluconazole,ketoconazole and itraconazole were 0.25-≥64 mg/L,≤0.03-0.5 mg/L and ≤0.03-0.125 mg/L respectively as shown by broth microdilution method,2-≥64 mg/L,≤0.03-0.5 mg/L and ≤0.03-0.25 mg/L respectively as revealed by agar dilution method.Both methods demonstrated that itraconazole possessed the strongest activity against Malassezia species,followed by ketoconazole and fluconazole.The agreement rate in MICs between the two methods was 78.8%,85.2% and 88.9%,respectively for fluconazole,ketoconazole and itraconazole,with the intraclass correlation coefficients (ICCs)being 0.88,0.80 and 0.76 respectively.Conclusions Fluconazole,ketoconazole and itraconazole are highly active against Malassezia species in vitro,and itraconazole is the most active.Broth microdilution and agar dilution method coincide well in,and are applicable for,the antifungal susceptibility testing of Malassezia species in vitro.
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Objective To determine the extracellular enzymatic activity of common pathogens for onychomycosis, in the hope of finding virulence factors associated with the pathogenesis of onychomycosis. Methods Strains tested in this study included standard strains of common dermatophyte and non-dermatophyte fungi as well as clinical isolates of Trichophyton rubrum from patients with onychomycosis. All the tested strains were cultured in medium containing nail fragments at 25 ℃ for 10 to 21 days followed by the determination of the nail fragment-containing medium, a significant increase was observed in the activities of esterase, esterase lipase, N-acetyl-β-glucosaminidase and α-mannosidase in dermatophytes compared with non-dermatophytes (all P < 0.05 ), as well as in the activity of N-acetyl-β-glucosaminidase in Trichophyton rubrum compared with the other tested species of fungi (all P < 0.05). No significant difference was noted in the activity of extracellular enzymes, except for that of naphthol-AS-BI-phosphohydrolase, between the isolates of Trichophyton rubrum from patients with different ranges of scoring clinical index for onychomycosis (SCIO). Conclusions In specific conditions, the extracellular enzymatic activity of fungi isolated from patients with onychomycosis is associated with fungal species, and may have a certain influence on the manifestations of anychomycosis.
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Objective To estimate the application value of colony PCR in the detection of pathogenic filamentous fungi. Methods Colony PCR was established and performed to amplify the internal transcribed spacer (ITS) region of 19 species (strains) of filamentous fungus followed by sequencing analysis. At the same time, DNA extracts from 8 of the 19 species of filamentous fungus were subjected to conventional PCR. Hha I and Hinf I endonucleases were used for restriction fragment length polymorphism (RFLP) analysis of the conventional and colony PCR products. Comparison analysis was carried out between the colony and conventional PCR. Results Of the 19 strains, 16(84.2%) yielded positive results by colony PCR; sequence analysis of the PCR products of ITS region revealed a 96% - 100% similarity with the reference sequence (NCBI database)of corresponding fungi. The amplification product length and RFLP profile of these products from the 8 species of filamentous fungus, except for those from Aspergillus nidulans, were consistent between the colony and conventional PCR. Conclusions Compared with conventional PCR, colony PCR-based detection of filamentous fungi is easy to operate, time and labor-saving, with high accuracy and reliability, and can be applied to the rapid identification of filamentous fungi.
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A 19-year-old man was admitted to the hospital for erythema and nodules on the face and postauricular region for 6 years. Microscopic examination of lesion scrapings revealed brown septate hyphae. A restricted, velvety and black colony grew on Sabouraud's dextrose agar. Slide culture on potato dextrose agar plate showed flask-shaped phialides at the apex of or around the hyphae with clear collarettes and flaring apex,mucilage-encapsuled, round to oval, semi-endogenous phialosporae accumulating at the apex of the phialides,giving a flower-like appearance. Anti-fungal susceptibility test showed that the fungus was sensitive to itraconazole, terbinafine and amphotericin B, but resistant to fluconazole. Sequence analysis of the ITS1-ITS4 region revealed a 98% consistency with the reference sequence of ITS1-ITS4 of Phialophora verrucosa. On the basis of above findings, the patient was diagnosed with cutaneous phaeohyphomycosis. Clinical improvement was seen after treatment with oral itraconazole (400 mg/d).
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Objective To evaluate the cell-mediated immune tissue reactions of mice model of chromoblastomycosis. Methods First we developed a murine model of chromoblastomycosis subcutaneous infection with F. pedrosoi inoculated into the footpads using immunocompetent and immunocompromised mice immuned by CTX, and then by immunohistochemistry methods analyzed the expression of cytokines IL-4, IL-10, TNF-α and IFN-γ at the seventh and thirtieth day, the expression of these cytokines at the same time in the healthy mice footpads were used as control. Results In the immunocompetent mice, The expression of IL-4, IL-10 and TNF-α was significantly higher when compared with healthy control at the seventh day,showing an up-regulation pattern of Th2 and Th1 type cellular immune functions with a predominance of the Th2 response. At the 30th day, the expression of IL-10 was significantly lower when compared with the 7th day and no difference with healthy controls, while IFN-γand TNF-α were gradually increased, the T cellmediated immune drives to Th1 response from Th2. In the immunocompromised mice, the expression of IL4 and IL-10 were significantly higher, meanwhile IFN-γwas lower than those in immunocompetent or healty mice, the levels of TNF-α was not significantly different fiom healty control at the 7th day, it showed that Th2 response was more increased with the Th1 responses was significantly inhibited in the early immune reactions. At the 30th day, the Th1 type cytokines IFN-γ and TNF-α were highly significantly higher than early stage but still lower than immunocompetent levels, the level of Th2 type cytokine IL-10 rradually decreased although it was still above the other two rroups. Conclusion In different immune state, there was an immune defence translation from the predominance of Th2 type cellular immunity to Th1 type in the process of murine model of chromoblastomycosis. Thl type cytokines which favors resistance to fungal disease, played a major role at controlling the development of chromoblastomycosis.
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Objective To develop a PCR-RFLP method to rapidly identify filamentous fungi causing deep infection. Methods Universal fungal primers were used to amplify the internal transcribed spacer (ITS) region of Aspergillus fumigatus, Aspergillus Bavus, Aspergillus terreus, Aspergillus niger, Aspergillus versicolor, Aspergillus nidulans, Scedosporium apiospermum and Fusarium moniliforme followed by restriction fragment length polymorphism (RFLP) analysis with restrictive endonucleases Hha I, Hae III, Hinf I, Taq I and Msp I. Then, 22 clinical and 2 environmental fungal isolates were identified with the developed PCR-RFLP method. Results The RFLP analysis of PCR products with restrictive endonucleases Hha I and Hinf I allowed discrimination of 8 filamentous fungi causing invasive infection, and it took only 1 day to carry out the whole procedure from DNA extraction to PCR and restriction digestion. The identification results of 22 clinical strains and 2 environmental isolates with this PCR-RFLP method were completely consistent with those with conventional morphological method. Conclusion PCR-RFLP analysis is an efficient method for rapid identification of cultured filamentous fungi.
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A 16-year-old woman presented plaques on the left auricle and face over a period of 3 years. Fungal culture grew black-grey or dust velvety colony on Sabouraud's dextrose agar plate. A slide culture on potato dextrose agar plate showed conidiophores which were unbranched or occasionally loosely branched. The conidia were sympodial, zero- to two- septate, with rounded apices and truncated bases. The optimum growth temperature was 26℃ - 30℃. The fungus had the ability to liquefy glutin and hydrolyze starch. Anti-fungal susceptibility test showed the fungus was susceptible to itraconazole, terbinafine and amphoterecin B, but resistant to fluconazole. Cutaneous biopsy specimens revealed brown hyphae and budding yeast cells. The sequence of internal transcribed spacer (ITS) 1-ITS4 region of the isolate rDNA was assessed and compared against the Genebank databases. A 99% consistence was observed in the ITS sequence between clinical isolate and reference strain of Veronaea botryose Ciferri et Momtemartini. Based on the above findings, the mold was identified as Veronaea botryose Ciferri et Momtemartini. The lesions gradually subsided after 8-month treatment with oral itraconazole of 100 mg twice daily.
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Objective To develop a murine model for infection by Cladosporium carrioni. Methods A total of 72 ICR mice were equally divided into 4 groups, group A (healthy mice inoculated by C. Carrioni suspension of 1 × 108 cfu conidia mL-1, group B (immune-suppressed mice inoculated by C. Carrioni sus pension of 1 × 108 cfu conidia mL-1), group C (immune-suppressed mice inoculated by C. Carrioni suspen-sion of 1 × 106 cfu conidia mL-1), group D (healthy mice inoculated by sodium chloride solution). C. Car-rioni suspension or sodium chloride solution was subcutaneously inoculated into foot pads of mice. On day 7, 30 and 60 after inoculation, 6 mice were killed in each group followed by the measurement of thickness of foot pads, pathology and mycology of skin samples taken from foot pads. Results In group A, B and C, there were swelling, blackening, ulceration and crusts at the inoculation site of all mice, with a morbidity of 100%. The thickness of foot pads in group A on day 30 was significantly higher than that on day 7 (2.40 ± 0.45 mm vs 2.85 ± 0.47 mm, P < 0.05), but lower than that on day 60 (1.64 ± 0.13 ram, P < 0.05). In group B, increased thickness of foot pads was observed on day 30 compared with that on day 7 and day 60 (2.19 ± 0.27 mm vs 1.80 ± 0.21 mm and 1.86 + 0.22 mm, respectively, both P < 0.05), which was the case with group C (1.98 ± 0.06 nun vs 1.51 ± 0.11 mm and 1.82 ± 0.09 mm, respectively, both P < 0.05). No significant changes occurred to the thickness of foot pads in group D from day 7 to day 60 (P > 0.05). Pathological changes in group A, B and C included necrosis, abscess and chronic granuloma formation; dark brown sclerotic bodies were observed on HE and PAS staining as well as on direct microscopy; cultures of tissue samples grew Cladosporium carrionii. The mice in group D remained uninfected. Conclusion Mouse model for chromoblastomycosis may be established by subcutaneous inoculation of Cladosporium carrionii suspension into foot pads of healthy or immuno-suppressed mice.
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Objective To investigate the effect of electron transfer system on the hyphal formation of Candida albicans. Methods Candida albicans was cultured in RPMI 1640 supplemented with 10% new-born calf serum in 5% CO2 at 37 ℃ with or without the presence of inhibitors or activators of electron transfer system. Growth curve, morphology and percent of filamentation were observed for Candida albicans. MTT assay was used to assess the viability of Candida albicans. Results The solvents (chloroform and dimethyl sulfoxide) had no significant effect on the growth of and filamentation in Candida albicans. After incubation with thenoyltrifluoroacetone (TTFA) or benzhydroxamic acid for 24 hours, yeast cells of Candida albicans predominated in the culture. The growth of Candida albicans was significantly inhibited in log phase by the incubation with classic respiratory chain inhibitors such as rotenone, antimycin A, oligomycin, sodium azide, TTFA and sodium malonate, compared with the controls (all P < 0.01). Benzhydroxamic acid, an inhibitor of alternative oxidative pathway, also significantly inhibited the growth of Candida albicans in log phase (t = 10.92, P < 0.01). After incubation with rotenone, antimycin A, oligomycin, sodium azide, TTFA, sodium malonate, benzhydroxamic acid and disodium gnanylate, the percentage of filamentation in Candida albicans at 12 hours was 87.49 ± 0.52, 48.75 ± 4.44, 50.33 ± 8.50, 99.00 ± 1.00, 1.60 ± 0.53, 94.01 ± 0.99, 0.00 ± 0.00 and 92.33 ± 2.08, respectively, and the growth of Candida albicans at 7 hours was inhibited by (1.34 ± 0.15)%, (70.61 ± 1.02)%, (50.63 ± 5.38)%, (17.80 ± 7.89)%, (45.17 ± 1.27)%, (10.75 ± 3.62)%, (72.46 ± 1.14)% and -(5.96 ± 4.07)%, respectively. Conclusions Hyphal formation of Candida albicans could be suppressed by inhibitors of classic respiratory chain or alternative oxidative pathway, and is mainly regulated by alternative oxidative pathway.
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Objective To study the difference in pathogenicity and genotype between two isolates of Veronaeae botryosa with different temperature tolerance. Methods Two strains of Veronaeae botryose were isolated from two patients with phaeohyphomycosis in Jiangsu and Henan province respectively. Of them, the Jiangsu strain could grow well at 37 ℃, but Henan strain could not grow at 36 ℃. Eighty mice were equally classified into immunocompetent and immune-suppressed (induced by cyclophosphamide) groups to be inoculated with the two strains of Veronaeae botryosa respectively. Ten mice remained uninoculated and served as the control. The general condition, growth and organic involvement of mice were observed for 4 weeks followed by the killing of surviving mice. Homogenated tissue samples were obtained from liver, spleen, lung, kidney and brain; then, tissue culture, direct microscopy and pathological examination were performed. Genomie DNA was extracted from tissue samples and subjected to random amplified polymor-phic DNA (RAPD) analysis. PCR was performed to amplify the intemal transcribed spacer (ITS) of rDNA followed by sequencing Results Systemic phaeohyphomycosis was induced in both immunocompetent and immune-suppressed mice by the Jiangsu strain of Veronaeae botryose; the mortality was 30% in immune-competent mice and 65% in immune-suppressed mice with statistical significance between the two groups. In immune-suppressed mice inoculated with the Jiangsu strain, the infection rate was 100% in the lung,signifi-cantly higher than in other organs; on direct microscopy the infection rate reached 64.7% in the liver, and 70.5% on tissue culture. There was no significant difference in the infection rate among these organs in immunocompetent mice inoculated with the Jiangsu strain, with the infection rate being 57.8% in the lung and 42.1% in the liver. Increased infection rate was observed in the lung of immune-suppressed mice com-pared with immunocompetent mice (P < 0.05). No definite infection was seen in immunoeompetent or immune-suppressed mice innoculated with the Henan strain. RAPD analysis and sequencing revealed that there was a base variation (A/G) at position 236 of ITS gene between the two strains. Conclusions The two strains of Veronaeae botryosa have different genotypes. Systemic phaeohyphomycosis can be caused in immunocompetent and immuno-suppressed mice by the Veronaeae botryosa isolate from Jiangsu Province; the mortality was higher in immuno-suppressed mice than in immunocompetent mice. The pathogenicity of Veronaeae botryose is associated with the immune status of hosts. In immuno-suppressed mice, lung is the organ most susceptible to infection by Veronaeae botryosa.
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Objective To report a case of vaginal colonization due to Trichosporon inkin. Methods A 34-year-old female presented with increased vaginal discharge accompanied by abnormal odor for 2 months. Clinical laboratory examination was carried out. Cultures of vaginal discharge yielded yeast-like colony. Subsequently, the isolate underwent the following mycological examinations: purification, slide micro-culture, temperature test, urea enzyme test, biochemistry identification, antifungal susceptibility test, and gene sequencing. Results Gynecological examination revealed white homogeneous secretions attached to mucous membrane of the vagina. Nugent scores of vaginal discharge amounted to 5-6. Two rounds of culture of vaginal discharge resulted in stramineous, reductus and yeast-like colony. The isolate could grow in 42 ℃. Appressorium on the top of hypha and typical sarcinae formed in slide microculture of corn agar, and yeast malt agar was the optimal growth medium for it. Urea enzyme test was positive. API 20C AUX biochemical test and gene sequencing revealed that the isolate was consistent with Trichosporon inkin. The isolate was sensitive to amphotericin B and azoles such as clotrimazole and fluconazole, but resistant to flucytosine and caspofungin. Conclusions It is the first report of vaginal colonization due to T. Inkin in China. The accu-rate identification of T. Inkin relies on synthetic analysis of phenotype characteristics, biochemistry test and molecular sequencing.
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Objective To investigate the genotype of Trichophyton rubrum isolated from children and adults with dermatophytosis,and to explore the relationship between the genotype and location of lesions as well as drug susceptability of T.rubrum.Methods Dermatophytes were isolated from 67 children and 88 adults who had been diagnosed with dermatophytosis by microscopy and fongal culture.DNA was extracted from the clinical isolates of T. mbrum and random amplification of polymorphic DNA(RAPD)assay was performed with two random primers.i.e.,OPA11 5'ACCCGACCTC3'and OPD18 5'GAGAGCC AAC3',respectively.PCR products were subjected to electrophoresis to identify the genotypes of clinical isolates.Broth microdilution method was applied to assess the in vitro susceptibility of T. rubrum isolates to eight antifungal agents:fluconazole,itraconazole,terbinafine,ketoconazole,liranaflate,butenafine,econazole and bifonazole.Results T. rubrum was isolated from 47 children and 62 adults with dermatophytosis.RAPD assay yielded clear and stable DNA band profile.With primer OPA 11,these T.rubrum isolates were classified into 4 genotypes,i.e.,Ⅰ a,Ⅱ a,Ⅲa and Ⅳa.Both type Ⅰ a and Ⅲa represented 41.94%of the T. rubrmn isolates from adults,while type Ⅰa 65.96%of those from children;there was a significant difference in the genotype distribution between the two groups(P<0.05).Also,the genotype distilbution was statistically different for tinea corporis and tinea pedis(P<0.01,<0.05 respectively)between adults and children,however,no significant difierence was observed for onychomycosis and tinea cruris(both P>0.05).In vitro susceptibility test showed that all antifungal agents were effective against these T. rubrum isolates.Among these antifungals,terbinafine had the highest efficacy,and fluconazole exhibited the lowest effect against these isolates.Moreover,a higher efficacy was observed for ketoconazole and fluconazole against T. rubrum of type Ⅰ a than against other types of T. rubrum,and for bifonazole against T. rubrum isolates of type Ⅱ a than against other types.while the efficacy of itraconazole was lower against T. rubmm isolates of type Ⅲ a than against other types.Conclusions T. rubrum is the main pathogenic microorganism in adults and children with dermatophytosis.In adults,Ⅰ a and Ⅲ a are the predominate types of T. rubrum associated with dermatophytosis,while Ⅰ a is the common type in children.All the 8 antifungals tested have a good efficacy for various genotypes of T. rubrum,whereas the efficacy of fluconazole,itraconazole,kctoconazole,terbinafine and bifonazole varies with the genotypes of T. rubrum.
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Objective To investigate the relationship between the clinical manifestations,prognosis and histopathological findings of mucormycosis.Methods The clinical data on and pathological findings from 7 cases of mucormycosis confirmed by fungal culture in the institute from 1989 to 2006 were analyzed retrospectively.Results There was 1 case of hinocerebral mucormycosis and 6 cases of cutaneous mucormycosis,among them,2 were mucormycotic necrotizing fasciitis (MNF).The condition of patients with rhinocerebral mucormycosis or MNF aggravated rapidly and all the 3 patients died from mucormycosis. Histopathological examination showed mixed infiltrates of inflammatory cells as well as necrosis and angioin vasion.On the contrary,the condition of the remaining 4 patients with cutanesus mucormycosis,who presented mainly with indurated erythematous patch,progressed slowly,and 2 patients were cured.Histologically,the lesions were characterized by granulbmatous infiltration with a few hyphae;no typical angioinva sion phenomenon was noted.There was no evidence of perineural invasion with hyphae in any of the 7 cases.ConclusionIn patients with mucormycosis,histopathological findings characterized by mixed infiltrates of inflammatory cells,numerous hyphae and typical angioinvasion phenomenon may herald a poor prognosis.
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Objective To investigate the growth inhibition of Aspergillns fumigatus by Candida albicans in vitro and to develop the selective medium for clinical isolation of Aspergillus fumigatus.Methods Aspergillus fumigatus and Candida albicans were single or co-cultured in sabouraud dextrose agar(SDA) medium and SDA broth in dark at 25 ℃,and fungal growth,pigmentation,as well as colony diameter weredocumented.Results ①The sensitivity of culture of Aspergillus fumigatus and Candida albicans on SDAplate was 100CFU/ml.②The growth of 106CFU/ml and 103CFU/ml Aspergills fumigatus was completely inhibited by 106CFU/ml Candida albicans.③Growth inhibition of Aspergillus fumigatus was correlated with the concentration of Candida albicans.④SDA containing 1 mg/L fluconazole inhibited growth of Candida albicans,and no Candida albicans was detected on SDA containing 5 mg/L and 25 mg/L fluconazole.Growth of Aspergillus fumigatus was partially inhibited on SDA containing 25 mg/L fluconazole.Conclusions Candida albicans can inhibit the growth of Aspergillus fumigatus in vitro.SDA containing 5 mg/L fluconazole can be used as the selective medium for the isolation of Aspergillus fumigatus.
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Objective To rapidly detect and identify pathogenic fungi of some deep fungal infections by PCR.Methods The suspensions of22pathogenic fungi(23strains)were amplified by PCR with fungal universal primers ITS86and ITS4which were labeled by FAM.The precise length of amplified fragments was determined by ABI PRISM TM 377Sequencer and Genescan analysis software,then compared with that of am-plicons of corresponding fungal DNA which were previously extracted.Results(1)Amplification of17pathogenic fungi with ITS4,ITS86resulted in a unique fragment length(except for A.nidulans and A.niger,C.albicans and C.stellatoidea,F.pedrosoi and E.dermatitidis).(2)No significant difference of the length of am-plicons was found between the fungal suspension and control organisms,based on the results of Genescan analysis.(3)The whole process took only6h to complete the detection.Conclusion The combination of fun-gal suspension PCR with ITS fungal universal primers and Genescan analysis might provide an accurate,spe-cific,sensitive,and rapid approach to detect and identify22pathogenic fungi causing deep fungal infections,and hold promise to be applied for the diagnosis of deep fungal infection.
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Objective To develop a murine model of chromomycosis by using Cladosporium carrioni and explore the pathogenicity of Cladosporium carrio nii in mice. Methods The suspension of Cladosporium carrioni was inoculated to two groups of mice, the immunocompetent mice and the immunosuppressed mice, b y intraperitoneal route using 1 ml inoculum containing 108 conidia/mL. All mice were sacrificed 30 days after inoculation, and then macroscopic examination, his topathology and fungal culture were performed. Results The morbidity in both g roups was 100% according to the dark brown hyphae and sclerotic bodies found in histopathologic examination and fungal culture. Macroscopic examination found th at the adhesion among the internal organs in immunocompetent mice was more sever e than that in immunosuppressed mice. Histopathologic sections showed that necro sis and inflammatory infiltration in immunocompetent mice were more obvious than those in immunosuppressed mice. Conclusions The virulence of Cladosporium car rionii strains is strong enough to construct experimental murine model of chromo mycosis, and animal passage of the strains is unnecessary. This murine model cou ld be used to study the pathogenesis of chromomycosis.
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Objectives To develop a rapid genotyping method of clinical isolates of Malassezia from patients with tinea versicolor by PCR-RFLP,and to evaluate reliability of the approach as compared with biochemical classification.Methods Tween assimilation test and catalase reaction were carried out to identify 74 isolates of Malassezia species from patients with tinea versicolor and 7 Malassezia reference strains.The sequence of 28S rDNA of Malassezia species was amplified by PCR,and then the product was analyzed by RFLP with Eco88I,Bsp143Ⅱ and BshNⅠ,respectively.Results M.restricta,M.obtusa and M.pachydermatis were successfully identified by three restriction endonucleases.M.restricta was found to be more diverse from the other 6 species in genetic homology.By comparison with PCR-RFLP technique,a possible mistake was discovered with biochemical method.Conclusion PCR-RFLP is a promising molecular biological technique,which could rapidly and correctly classify Malassezia species.