外耳道真菌病致病曲霉菌菌种鉴定及药物敏感性检测

Identification of Pathogenic Aspergillus Strains for Otomycosis and Detection of Drug Sensitivity

目的鉴定外耳道真菌病的致病曲霉菌种,并检测它们对常用抗真菌药物的敏感性。方法收集2020年10月至2021年5月诊断为外耳道真菌病的94例患者,外耳道分离真菌检测均为曲霉菌,采集患者外耳道排出物,行真菌涂片荧光染色镜检,同时行真菌培养,对培养后的菌落提取真菌DNA行ITS区扩增并测序分析。选取4种常用的抗真菌药联苯咔唑(PCB)、克霉唑(CLO)、特比萘芬(TRB)和伊曲康唑(ITR)行抗真菌药物敏感性检测。结果94例患者外耳道真菌病患者中共分离获得5种曲霉菌,其中土曲霉菌48株(51.1%),黄曲霉菌25株(26.6%),黑曲霉菌13株(13.8%),烟曲霉菌7株(7.4%),花斑菌霉菌1株(1.1%)。药敏结果显示,22株黄曲霉菌对PCB耐药(MIC>16μg/ml),耐药率88.0%;7株对CLO耐药(MIC>16μg/ml),耐药率28.0%。黑曲霉菌4株对PCB耐药(MIC>16μg/ml),耐药率30.8%;5株对CLO耐药(MIC>16μg/ml),耐药率38.5%。烟曲霉菌2株对PCB耐药(MIC>16μg/ml),耐药率28.6%;2株对CLO耐药(MIC>16μg/ml),耐药率28.6%。土曲霉菌4株对PCB耐药(MIC>16μg/ml),耐药率8.3%;17株对CLO耐药(MIC>16μg/ml),耐药率35.4%。所有曲霉菌仅有1株黑曲霉菌对ITR耐药(MIC>8μg/ml),1株土霉菌对TRB耐药(MIC>8μg/ml)。结论土曲霉菌是本组外耳道真菌病患者分离出的最常见的曲霉菌菌种。曲霉菌对PCB和CLO耐药率相对偏高,而对TRB和ITR耐药率极低,故治疗外耳道真菌病时应首选TRB或ITR。

Objective To identify pathogenic aspergillus species which cause otomycosis and to test their sensitivity to commonly used antifungal agents.Methods A total of 94 patients with otomycosis clinically diagnosed from October 2020 to May 2021 were collected,and the fungi isolated from the external auditory canal were detected as aspergillus.The external auditory canal effluents of the patients were collected,and fungal smear fluorescence staining was performed for microscopic examination,and fungal culture was performed simultaneously.The fungal DNA extracted from the culture colony was amplified by ITS region and sequenced.Four commonly used antifungal drugs,biphenylcarbazole(PCB),clotrimazole(CLO),terbinafine(TRB)and itraconazole(ITR),were selected to detect the antifungal drug sensitivity.Results A total of 5 species of aspergillus were isolated from 94 patients with otomycosis,including 48 strains of aspergillus earth,25 strains of aspergillus flavus,13 strains of aspergillus niger,7 strains of aspergillus fumigatus,and 1 strain of mycosis variegata.The results of drug sensitivity showed that 22 strains of aspergillus flavus were resistant to PCB(MIC>16μg/ml),and the drug resistance rate was 88.0%.Seven strains were resistant to CLO(MIC>16μg/ml),and the drug resistance rate was 28.0%.Four strains of aspergillus niger were resistant to PCB(MIC>16μg/ml),and the drug resistance rate was 30.8%.Five strains were resistant to CLO(MIC>16μg/ml),and the drug resistance rate was 38.5%.Two strains of aspergillus fumigatus were resistant to PCB(MIC>16μg/ml),and the drug resistance rate was 28.6%.Two strains were resistant to CLO(MIC>16μg/ml),and the drug resistance rate was 28.6%.Four strains were resistant to PCB(MIC>16μg/ml),and the drug resistance rate was 8.3%.17 strains were resistant to CLO(MIC>16μg/ml),and the drug resistance rate was 35.4%.Among all the aspergillus strains,only one aspergillus niger was resistant to ITR(MIC>8μg/ml),and one aspergillus soil strain was resistant to TRB(MIC>8μg/ml).Conclusion Aspergillus terreus is the most common aspergillus strain isolated from patients with otomycosis.Aspergillus has relatively high resistance rate to PCB and CLO,but very low resistance rate to TRB and ITR,thus,TRB or ITR should be preferred for the treatment of otomycosis.