Table of Content

28 February 2022, Volume 17 Issue 1

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Original articles

Protein and RNA analysis of extracellular vesicles of Aspergillus fumigatus

CHEN Chen, HE Bingchan, ZHU Yimin, ZHAO Beilei, CHEN Fei, XU Xiaoyong

2022, 17(1):  8-11,26. 

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Objective To analyze the important components in the extracellular vesicles (EVs) of Aspergillus fumigatus to further clarify the pathogenesis of Aspergillus fumigatus. Methods The vesicles of Aspergillus fumigatus were separated by centrifugal method and the morphology was observed by electron microscopy. The size of EVs in solution was analyzed by Marvin nanoparticle tracking analyzer. The processed peptides in the vesicle were analyzed by mass spectrometer. Secondary mass spectrometry data was retrieved using Maxquant (v1.5.2.8). Results The EVs of Aspergillus fumigatus showed obvious bilayer lipid structure under electron microscope. NTA found that the EVs size of Aspergillus fumigatus analysis was mainly concentrated around 130nm. EVs protein contains 9 unstable proteins (15%), the rest was stable proteins, while PI>7 contains 6 proteins. In EVs cytoplasmic proteins was the most, followed by exocrine proteins. However, 25% of EVs could not be located. As predicted by TMPred and GPI, there were 5 proteins located on the bilayer lipid membrane. In RNA, rRNA and tRNA accounted for 59.7% and 29.4% respectively, while miRNA accounted for 0.25%. EVS-miRNA might mainly affect metabolic pathways. Conclusions Aspergillus fumigatus could secrete EVs with a diameter of 130 nm,which containing a variety of proteins, mainly cytoplasmic proteins. EVS-RNA was dominated by rRNA and tRNA, while miRNAs might involve a variety of signaling pathways.

Efficacy and safety of micafungin in preventing invasive fungal infection in patients with hematological malignancies: a Meta-analysis

KANG Ye, ZHANG Wentao, YAN Lan

2022, 17(1):  12-16. 

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Objective To systematically evaluate the effectiveness and safety of micafungin in preventing invasive fungal infections (IFIs) in patients with hematological malignancies, and to provide evidence-based reference for clinical treatment. Methods Computer searching of PubMed, Embase, Cochrane Library, China Knowledge Network (CNKI), Wanfang data from the establishment of the database to January 2021,randomized controlled trials (RCTs) of micafungin (experimental group) compared with conventional antifungal drugs (amphotericin B and triazole antifungal drugs, control group) were collected.After data extraction and quality evaluation with Cochrane system reviewer's manual 5.0.2, Meta analysis was performed on breakthrough IFIs, fungal infection mortality, all-cause mortality and the incidence of drug withdrawal due to adverse reactions with Rev man 5.3 statistical software. Results Nine RCTs involving 2479 patients were included. Meta analysis showed that the incidence of breakthrough IFIs [OR=0.74, 95% CI (0.50, 1.07), P=0.11], mortality of fungal infection [OR=0.73, 95% CI(0.46, 1.17), P=0.19] and all-cause mortality [OR=0.94, 95% CI(0.69, 1.28), P=0.7] in the experimental group were not significantly different from those in the control group; The incidence of drug withdrawal due to adverse reactions [OR=0.46, 95% CI(0.32, 0.66), P<0.0001] was significantly lower than that in the control group, the difference was statistically significant. Conclusion The effect of micafungin in preventing IFIs in patients with hematological malignancies is equivalent to that of amphotericin B and triazole antifungal drugs, and the safety is higher.

The effect of voriconazole against Fusarium solani in Galleria mellonella larva model

LI Menghan, ZHAO Wang, JIA Gengpei, SUN Yi, ZENG Tongxiang

2022, 17(1):  17-21,31. 

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Objective To construct a F. solani infection model of the G. mellonella larvae and observe the therapeutic effect of voriconazole. Methods One clinical isolate of F. solani was obtained. The concentrations gradient of the spore suspension used in the experiment was 1×10⁵~1×10⁸CFU/mL. The optimal infection concentration was selected according to the mortality rate, and this concentration was used to infect the G. mellonella larvae. The larvae were treated with voriconazole (1.5 mg/kg), an untreated group and a saline control group were set up at the same time. During the experiment, the carcasses of the G. mellonella larvae were collected for pathological examination and the death within 5 days was recorded every 24 hours. The evaluation was carried out through two aspects of post-infection pathological tissue section and analysis of survival rate of the G. mellonella larvae. Results After a concentration of 1×10⁷CFU/mL F. solani infection, the mortality of the G. mellonella larvae reached 100% in 5 days. 1×10⁷CFU/mL was the best infection concentration in this experimental group; the larvae died on the second day after infection. Pathological examination revealed a large number of hypha and spores. After treatment with voriconazole, the hypha decreased in the single larva. The survival curve of the larvae showed that the survival rate of the voriconazole treatment group was significantly improved compared with that of the single infection group (P <0.05). Conclusions The larva of the G. mellonella can be used as an animal model of F. solani infection in vivo, as well as used to observe the effect of antifungal treatment.

Microbiome analysis of nails in patients with onychomycosis

HU Jian, ZHANG Shuyu, ZHANG Wenge, YAN Ziheng, LI Houmin

2022, 17(1):  22-26. 

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Objective To analyze the structure of microbial community of onychomycosis and provide evidence for further elucidating the pathogenesis of onychomycosis. Methods A total of 47 patients with onychomycosis and 7 healthy volunteers were enrolled. Specimens from the nail scraps of the patients were examined by microscopy and culture. DNA was extracted from the diseased nail scraps of patients, healthy nail scraps of patients, and healthy nail scraps of volunteers. ITS sequence analysis of fungal rDNA and V3-V4 sequence analysis of bacterial 16S rDNA were performed by PCR amplification to analyze the microbiome. And α diversity, β diversity, Simper analysis, and Spearman related analysis were also performed. Results The structures of microbial community were different in diseased nails, healthy nails of patients with onychomycosis, and nails of healthy volunteers. The richness of fungal community in diseased nails was higher than that of healthy nails of patients with onychomycosis. The bacterial diversity in healthy nails of patients was the highest. The structure of bacterial community in self-control group was partially overlapped with that in patient group and healthy control group. Conclusions The structure of bacterial community in healthy nails of patients with onychomycosis has a tendency changing from that of a healthy nail to a diseased nail. Some fungi and bacteria may interact with each other.

The distribution and drug resistance of 212 Candida isolates from blood culture

YU Xiaochen, GUO Dawen, SUN Yan, CHEN Shulan, GUAN Xiuru

2022, 17(1):  27-31. 

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Objective To investigate the clinical distribution characteristics and drug resistance of Candida infection in bloodsteam, and provide basis for clinical diagnosis and treatment. Methods A retrospective analysis was carried out to analysis the Candida isolates from clinical blood from January 2017 to December 2020. Pathogen distribution, antibiotic resistance and the results of G test of the Candida infection were analyzed. Results In blood culture, 314 cases of Candida strains were incubated with a positive rate of 2.1% and 212 cases of non-repetitive isolates were isolated. Candida parapsilosis (72 strains,34.0%) had the highest detection rate, followed by Candida albicans (55 strains,25.9%) and Candida glabrata (28 strains, 13.2%). These patients mainly came from the department of ICU(62 strains,29.2%), department of neonatology(39 strains,18.4%) and department of hematology(20 strains,9.4%). Except of a strain of Candida parapsilosis, other Candida strains were wild strains of amphotericin B. The sensitivity rate of Candida albicans to azole drugs was over 90%. However, Candida parapsilosis and Candida tropicalis were less sensitive to azoles. Within 96 hours before or after the isolation of Candida from blood culture, the positive rate of G test was 73.7%. Conclusion The top three isolates in our hospital were Candida parapsilosis, Candida albicans and Candida glabrata. Candida glabrata and Candida tropicalis are less sensitive to azoles, so it was necessary to select antifungal drugs reasonably. G test was of high value in the treatment of candidiasis and the results need to be monitored dynamically.

Epidemiology and analysis of azole drug resistance of yeast isolates causing invasive infections in China in 2013

WANG Tong, YU Shuying, XIAO Meng, ZHANG Ge, ZHANG Jingjia, DUAN Simeng, KANG Wei, ZHANG Yanhai, ZHAO Ying, ZHANG Li, WANG He, XU Yingchun

2022, 17(1):  32-37. 

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Objective By analyze the epidemiological distribution and azole resistance of 1562 strains of yeast collected from 48 general hospitals in China by CHIF-NET in 2013, so as to provide the data basis for the azole drugs use in clinical invasive yeast. Methods A total of 1562 yeast strains and their original information were collected from 48 hospitals of China's invasive fungal surveillance network in 2013. The strains were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometer (MALDI-TO MS, Biomerieux, France) and ribosomal DNA sequencing. The susceptibility of the strains to fluconazole and voriconazole was determined by CLSI M44-A2 disc-diffusion method. Results A total of 1562 yeast strains were isolated in this study. Candida albicans had the highest isolation rate (38.4%), followed by Candida parapsilosis complex (18.4%), Candida tropicalis complex (16.4%), Candida glabrata complex (9.4%) and other rare strains (<6.4%).The separation rate of male (60.7%) was higher than that of female (38.9%).The patients aged over 65 years were the most (34.2%), followed by the patients aged 50-65 years (30.6%), 15-49 years (29.9%) and 0-14 years (<1.9%).Blood samples (46.4%) were the main source of samples, followed by ascites (10.2%), catheter (9.2%), drainage fluid (8.5%) and secretion (5.2%), and other types of samples were less (<4.7%).The separation rate of inpatients (93%) was significantly higher than that of outpatient and emergency patients (7%).Among the types of departments, surgical patients (33.8%) were the main, followed by intensive care unit ICU patients (27.5%), internal medicine patients (20.5%) and other wards (<18.2%).Drug susceptibility results showed that C.albicans and C.parapsilosis complex sensitivity to fluconazole and voriconazole were higher (> 94%). C. tropicalis showed the highest (21.9%) cross-resistance to fluconazole and voriconazole, C.parapsilosis complex took second place of such cross-resistance (15%), Candida guilliermondii (8.1%) and Candida pelliculosa (4.3%) ranked third and fourth. Conclusion The surveillance of invasive yeast in China should be strengthened continuously, and the dosage of antibacterial drugs should be controlled reasonably to prevent the increase of drug resistance.

Case reports

Children under three years old suffered from Talaromyces marneffei: report of two cases

HAN Ying, HU Dandan, SHEN Jun, LIU Guangming, HONG Yan, XIE Yongqiang, SUN Jing

2022, 17(1):  38-41. 

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Case one, male, one and a half years old presented with cough for 15 days and fever for a week. Case two, male, 11-month-old presented with thrush for 3 months and cough for twenty days. Blood cultures of two cases were positive of Talaromyces marneffei. Both of them had immunodeficiency, non HIV infection. Multiple nodules were visible in the lung CT. Treatment with voriconazole was successful in two cases. There was no recurrence in 12 months follow-up.

A case of sporotrichosis secondary to dog bite

SUN Jinpeng, LIU Shirui, GAO Ruijia, LI Fuqiu

2022, 17(1):  42-43. 

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A case of sporotrichosis secondary to dog bite was reported. Patient, female, 5 years old. Several dark red nodules of peanut size appeared on the lateral side of the left lower leg for more than 1 month. The patient was accidentally bitten by a dog on the outside of her left lower leg 2 months ago. According to the patient's history, symptoms and signs, pathological results, fungal culture and molecular identification results, the patient was diagnosed as sporotrichosis. After oral administration of itraconazole capsule for 3 months, the rash became significantly flatter and smaller than before. The drug has been stopped and the case is still being followed up.

Pulmonary tuberculosis combined infection with two strains of Aspergillus fumigatus with different phenotypes

WANG Shuling, LI Yanmin, ZHANG Zhen, WANG Liying, YAN Ling, XU Lanlan, LIAO Pu

2022, 17(1):  44-48. 

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The patient was a 69-year-old male patient. He had recurrent coughing and sputum production for 8 months, with aggravated hemoptysis for 4 days. The patient had pulmonary tuberculosis 7 years ago, he was cured after 1 year of anti-tuberculosis treatment. Mycobacterium tuberculosis was detected by metagenomic second-generation sequencing of bronchoscopy lavage samples. Serum and bronchoscopy lavage fluid Aspergillus antigen galactomannan tests were positive. Two forms of Aspergillus fumigatus (white strain and typical smoke-green strain)were cultured from bronchoscopy lavage fluid .The two strains had the same susceptibility test results and high degree of homology. The patient was diagnosed as tuberculosis combined with invasive Aspergillus fumigatus infection. Anti-tuberculosis and voriconazole were given. Regular follow-up review of chest CT and sputum smear for acid-fast bacilli were recommended after discharged.

A case of tinea incognito

LI Xingye, LV Mingfang, DONG Zhuanping, DU Hua

2022, 17(1):  49-50,63. 

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A 36-year-old female patient had papules, erythema, pustules, and exudate on the right leg with itching for 5 months. The papules and erythema of varying sizes on the right calf were accompanied by erosion and exudate. The patient was diagnosed with tinea incognito by positive fungal fluoroscopy and fungal culture of Trichophyton mentagrophytes. After being given oral itraconazole dispersible tablets 0.1 g twice a day and topical ketoconazole cream twice a day for 2 weeks, the skin lesions improved significantly, and the skin of the right calf basically returned to normal after 1 month of treatment.