肉牛源细极链格孢菌的分离鉴定

Isolation,identification and antimicrobia sensitivity test of Alternaria tenuissima of beef cattle origin

为鉴定肉牛皮肤病病原及其致病性并筛选其敏感药物,本研究取患皮肤病肉牛病变部位皮屑、毛发和痂皮进行病原菌的分离,并对分离菌株进行了形态学鉴定、ITS序列分析、小鼠致病性试验和药敏试验。结果显示分离到1株形态特征与细极链格孢菌极其相似的菌株(PY2-1-2);经PCR扩增、测序和BLAST序列比对,结果显示分离株(PY2-1-2)的ITS基因序列与细极链格孢菌(MG975630.1)的ITS基因序列的相似性为99%,分离株PY2-1-2的ITS基因序列长度为543 bp,该片段包括ITS1、5.8S rDNA和ITS2的全部基因序列以及18S rDNA和28S rDNA的部分基因序列,提交GenBank(MH656780.1)。根据形态学结合ITS基因序列分析结果确定该分离株为细极链格孢菌。小鼠致病性试验结果显示该菌对小鼠有致病性。药敏试验结果显示:该菌对灰黄霉素、氟康唑、伊曲康唑、酮康唑的最小抑菌浓度(MIC)值分别为0.5μg/mL、4μg/mL、1μg/mL、1μg/mL。本研究为今后进一步探究细极链格孢菌引起的皮肤病诊治提供科学有效的参考。

To investigate the pathogens,antimicrobial susceptibility test,pathogenicity of beef cattle dermatoses and select the effective antibiotics.Strain was isolated from dander,hair and crustafrom the lesions of the dermatoses beef cattle,and then morphological identification,ITS gene sequence analysis,pathogenicity of mouse and drug sensitivity test were also performed.As a result,one strain of fungus(PY2-1-2)was identified as Alternaria tenuissima.The ITS gene was 543 bp,which was submitted to GenBank under accession number MH656780.1,which included the entire gene sequence of ITS1,5.8S rDNA and ITS2 and a partial gene sequence of 18S rDNA and 28S rDNA.The analysis of NCBI Blast searching showed that it had 99%similarity to Alternaria tenuissima(ID,MG975630.1).It was identified as Alternaria tenuissima according to morphological and molecular biological methods.The result of pathogenicity showed it was pathogenic to mice.The results of drug sensitivity test showed that the minimum inhibitory concentration(MIC)values(μg/mL)of griseofulvin,fluconazole,itraconazole and ketoconazole were 0.5μg/mL,4μg/mL,0.0313μg/mL,1μg/mL,respectively.This study enriched the understanding of beef dermatomycoses caused by Alternaria tenuissima,and provided a scientific and effective reference for further research.