Table of Content

28 October 2015, Volume 10 Issue 5

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论文

Genetic regulation of conidiation in Aspergillus fumigatus:an update

SANG Hong, ZHANG Cai-yun

2015, 10(5):  257-260. 

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Aspergillus fumigatus is one of the most important human pathogen, causing invasive aspergillosis by releasing numerous asexual spores(conidia).Conidia can grow on almost every microbiological culture medium under various environmental conditions.In this paper, the recent research progress in the genetic regulatory system which dictates conidiation in Aspergillus fumigatus was discussed.

Establishment of a rat model of acute invasive fungal rhinosinusitis

YAN Yu-yan, ZHAO Zuo-tao, Liu Honggang

2015, 10(5):  261-265,278. 

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Objective To develop a rat model of acute invasive fungal rhinosinusitis(AIFR) which is stable and easy to operate in order to promote the basic and clinical researches of AIFR.Methods Sprague-Dawley(SD) rats were divided randomly into four groups.Immunosuppression, right nasal packing Merocel sponge and nasal inoculation with Aspergillus fumigatus spores were all involved in group A.Only right nasal packing Merocel sponge and nasal inoculation with A.fumigatus spores were involved in group B.Only immunosuppression and nasal inoculation with A.fumigatus spores were involved in group C.No treatment was involved in group D.A.fumigatus was dropped into rat nasal for three consecutive days in group A, B and C.All rats were killed four days after the first fungi intranasal instillation.Hematology, fungal culture and histopathology investigations were performed.Results The neutrophil quantities reduced after immunosupression, and less than 0.1×10⁹/L on the first administration day of A.fumigatus spores.An AIFR rat model was established successfully only in group A with an incidence rate of 90%(9/10).A.fumigatus invasion was also observed in 10%(1/10) of the lungs in group A and 20%(2/10) in group C.Positive rates of fungal culture of nasal tissue was about 71%(5/7) in group A, while the remaining groups was zero.Conclusion Immunosupression, nasal obstruction, and fungal inoculation were the three essential conditions for successfully developping a stable AIFR rat model.This model is stable, easy to operate, and closely mimics the pathophysiology of anthropic AIFR.It can be used in a further study in immunity, pathology, drug of AIFR.

The effects of T.asahii on monocyte-derived DCs phenotypic and function

Wang Ruili, AO Jun-hong, LIAO Yong, YANG Rong-ya, YANG Dong-qian, LV Xue-lian, Chen Shanshan

2015, 10(5):  266-271. 

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Objective To investigate the effects of Trichosporon asahii on the phenotypic and functional maturation of human peripheral blood monocyte-derived dendritic cells(DCs).Methods The monocyte-derived DCs of health donors were obtained by culture in vitro.In the experimental groups, DCs stimulated by different doses of heat-inactived T.asahii conidia(DCs:T.asahii=1:1, 1:5, 1:10), RPMI-1640 and lipopolysaccharide(LPS) stimulation groups were as the blank control and positive control, respectively.Shapes of the cells were observed under the inverted microscope, the rate of phagocytosis was calculated by Wright Giemsa staining.DCs maturation was analysed by using flow cytometry.Results The morphology of DCs was significantly changed during incubation.At 24 h, more than one T.asahii conidias were efficiently bound and internalized by DCs and the phagocytic rates were significantly different between the experimental groups(P<0.05).The expressions of CD80, CD86, CD83 in the experimental groups were much higher than the blank control group(P<0.05), but significantly lower than LPS group(P<0.05).Conclusion T.asahii can change the morphology of DCs and promote the expression of surface molecules, which enhance the maturation of the dendritic cells.

In vitro activities of flutrimazole against fungal pathogens isolated from tinea pedis

LI Ya-li, WAN Zhe, CHEN Wei, WANG Ai-ping, LI Ruo-yu

2015, 10(5):  272-275. 

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Objective To evaluate the in vitro activities of flutrimazole against fungal pathogens isolated from tinea pedis.Methods In vitro drug sensitivities were determined using the broth microdilution methods according to the CLSI M38-A2(for dermatophytes) and M27-A3(for yeasts) documents.Results When against Trichophyton rubrum, the range of minimum inhibitory concentration(MIC), MIC₅₀, MIC₉₀, and geometric mean(GM) MIC for flutrimazole were 0.031~2μg/mL, 0.5μg/mL, 1μg/mL and 0.637μg/mL;for bifonazole were 0.031~16μg/mL, 0.25μg/mL, 2μg/mL and 0.634μg/mL;no significant(P=0.974) difference was found for the GM MIC between the two drugs.When against Trichophyton interdigitale, the range of MIC, MIC₅₀, MIC₉₀, and GM MIC for flutrimazole were 0.031~1μg/mL, 0.031μg/mL, 0.5μg/mL and 0.17μg/mL;for bifonazole were 0.125~16μg/mL, 1μg/mL, 2μg/mL and 1.886μg/mL;significant(P=0.001) difference was found for the GM MIC between the two drugs.Even though there are a few number of yeast strains, this study showed that the two drugs had significant difference for the GM MIC against Candida spp.(P=0.000) and Trichosporon spp.(P=0.031).Conclusion In vitro activity of flutrimazole was similar to bifonazole when against T.rubrum, but better than bifonazole when against T.interdigitale, Candida spp.and Trichosporon spp..

The effects of tetrandrine on Candida albicans biofilm and germ tube formation

GUO Lan-fang, LIU Da-biao, ZHOU Meng-jie, HUA Teng-jiang

2015, 10(5):  276-278. 

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Objective To study the effects of tetrandrine(Tet) on Candida albicans biofilm and germ tube formation.Methods Using the XTT method to observe the effect of Tet on C.albicans biofilm.0.01, 0.1, 1μmol/L of Tet and C.albicans suspensions were incubated together, then the rates of bud tube were counted.The experiment was repeated 5 times.Results Tet had obvious inhibitory effects on C.albicans biofilm and the germ tube(P<0.05).The biofilm and germ tube formation inhibition rate was the highest in 1μmol/L of Tet, compared with the negative control group(P<0.05) and the 0.01, 0.1μmol/L groups(P<0.05).Conclusions Tet had inhibitory effect on C.albicans biofilm and germ tube formation.

Species identification of Sporothrix clinical isolates in Northern and Southern of China

HE Yu, Huang Mengya, HU Qing-bi, ZHOU Xun

2015, 10(5):  279-282. 

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Objective To identify 50Sporothrix clinical isolates in Northern and Southern of China.Methods All isolates from patients were subcultured at 25℃ and morphological characteristic was analysed by microscope and visual inspection.The total genomic DNA was extracted to amplify the partial β-tubulin gene and the internal transcribed(ITS) region by polymerase chain reaction(PCR).The phylogenetic tree was constructed by DNA sequences analyses based on datasets of ITS and a combined ITS and partial β-tubulin region using maxium likehood(ML) and neighbor-joining(NJ) methods with MEGA5 software.The Reference sequences used for phylogenetic analyses were retrieved from GenBank.Result The macroscopic morphologies and microscopic features of all isolates were comformed to Sporothrix spp.The phylogenetic tree showed that all of the isolates were clustered in a distinct clade with a type of Sporothrix globosa.Conclusion S.globosa may be the major Sporothrix existing in northern and southern of China, which can provide basis for the epidemiological investigation of Sporothrix.

The application of nucleic acid sequence-based amplification,real-time PCR and GM test in invasive aspergillosis diagnosis

WANG Li-peng, BAO Cui-xia, YU Li-mei, ZHANG Xiao-lu, YU Wei-juan, ZHANG Xia, LI Wei, HUANG Bao-hua, LI Jie, Sun Chengming

2015, 10(5):  283-287. 

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Objective To study the diagnostic performance of nucleic acid sequence-based amplification(NASBA) assay, real-time PCR and GM test in detecting invasive aspergillosis for clinical diagnosis.Methods Blood samples from 80 patients at a high risk for IA were collected during from November 2013 to June 2014.These patients were categorized as 8 proven IA, 26 probable IA, and 46 non-IA according to the 2008 revised definitions of EORTC/MSG.Blood samples were tested by NASBA, real-time PCR and GM test and their diagnostic parameters were calculated, respectively.Result The sensitivity of NASBA, real-time PCR and GM test was 76.47%, 67.65% and 52.94%, while their specificity was 80.43%, 89.13%, 80.43%, respectively.The efficiency of various combinations of tests was also evaluated.Perfect specificity(100%) and positive predictive value(100%) were achieved by combining NASBA and real-time PCR as a serial testing.A combination of NASBA and real-time PCR as a parallel testing was the most sensitive(94.12%).Conclusion The sensitivity and specificity of NASBA and real-time PCR were superior to GM test.Combination of these assays could be particularly useful in specific clinical situations.

A case of subcutaneous phaeohyphomycosis manifested as cystic acne caused by Cladosporium cladosporioides

ZHOU Ya-bin, GE Jie, CHEN Ping, SUN Ting-ting, LI Dong-ming

2015, 10(5):  291-293. 

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To report a case of subcutaneous phaeohyphomycosis manifested as cystic acne caused by Cladosporium cladosporioides.A male patient, 21 years old, was suffered from cysts and nodules on the face and neck for fiver years.He was diagnosed phaeohyphomycosis according to the findings of fungal elements in histopathological examination and direct microscopic examination of cyst pus, with the positive fungal culture result of the cyst pus.After a 4-month treatment with oral itraconazole 400 mg/d, he almost completely resolved the inflammatory lesions with some residual scarring.

A case of adult black-dot ringworm due to Trichophyton tonsurans

YANG Yang, LIU Han, JIN Dong-yun, PENG Lin-lin, WANG Ling, XIA Yu-kun, YANG Rong-ya, LV Xuelian

2015, 10(5):  294-296. 

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A 68-year old female farmer presented with hair loss for 3 months.Physical examination showed irregularly dark red patch with a little amount of scales.The hairs in the red lesion broke off from the scalp presented with black dotted like, while the hair follicles showed swollen with mild fluctuation.Direct fungal microscopic examination presented a large amount of chain-like spores distribution along the inside of hair shaft.Fungal culture isolated yellow-white woolly colony presented with short rod-like or pear-shaped microconidiain by slide culture and positive urease test.Molecular identification by BLAST based on rDNA ITS sequencing confirmed as Trichophyton tonsurans.The diagnosis was confirmed as black-dot ringworm caused by Trichophyton tonsurans.Therapeutic drugs included oral itraconazole, 0.2-0.4 per day, external ketoconazole lotion, triamcinolone acetonide and econazole nitrate cream, and ketoconazole cream.After 2 months treatment, skin lesions completely faded and broken hair grew back without scarring alopecia.No recurrence after treatment was observed in 6-month follow-up.

Adult tinea capitis and tinea corporis due to Trichophyton violaceum:a case report

GAO Yun-lu, GAO Zhi-qing, JU Qiang, Li Min

2015, 10(5):  297-298. 

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A 23-year-old female patient had widespread erythema and pustules with pruitus for half years.Erythematous patch was annular in shape distributed on her trunk and limbs diffusely;scales and pustules were found in the marginal zone;and hairs were broken off a few millimetres from the follicular opening with black dots.The patient was diagnosed as tinea capitis and tinea corporis by histopathological examination(PAS staining) findings from scalp and positive fungal culture from scalp and skin.

A case of kerion caused by Trichophyton rubrum

SHI Qing, ZHANG Li, SUN Yi, CHEN Qi-hong, Zeng Tongxiang

2015, 10(5):  299-301. 

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Objectives We reported a girl with kerion due to Trichophyton rubrum.By molecular diagnosis of affected hairs, the pathogenic isolate was identifiedso that direct treatment could be executed.Methods As well as direct microscopic examination and fungal culture of affected hairs, fungal DNA of them was extracted, and amplification of ITS and sequencing.Results The molecular identification of affected hairs revealed T.rubrum, which was in accordance with fungal culture from the affected hairs.The patient was diagnosed as kerion due to T.rubrum and treated with oral terbinafine 125 mg per day.The lesions subsided after 1 month.Conclusion PCR-based molecular diagnosis of DNA from hair could help to identify pathogenic fungus promptly and indicate proper antifungal treatment.

MLPA application in clinical diagnosis of pathogen

FANG Wen-jie, LIU Jia, PAN Wei-hua, Liao Wanqing

2015, 10(5):  307-311. 

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As for patients diagnosed with Infectious diseases, favorable prognosis is determined by correct diagnosis and proper treatment.So it is important to diagnose clinical pathogens rapidly.Compared with other clinical test methods, MLPA is a simple, valid, and fast one which can detect several gene sequences in quantity at the same time.The steps include:the degeneration of DNA sample, hybridization, ligation, and PCR amplification.Although being at its first stage, there are already certain applications of MLPA in diagnosing and researching of clinic microorganism, and the peculiarity of easy operation, fast reaction, high pass rate and high sensitivity have reveal bright prospect of MLPA.

Research on molecular mechanisms of Candida albicans infection

KANG Ye, ZHOU Mi, Yan Lan

2015, 10(5):  312-316. 

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Candida albicans is the most common human opportunistic fungal pathogen which have to cope with mechanical(e.g., epithelial) barriers, biochemical, chemical, and physical antagonists(e.g., bile, mucus, pH), and the innate and adaptive immune system of thehost during its invading.Candida albicans's biochemistry, morphology flexibility and the ability to escape the host innate immunity plays crucial pathogenic roles.In this review we present an update on current understanding of the molecular mechanisms of infection of this pathogen in order to provide the reference to further explore new drugs.