驴源兽疫链球菌的分离鉴定及多位点序列分型分析

The isolation and identification of Streptococcus equi ssp. zooepidemicus from donkey and its multilocus sequence typing

摘要:

【目的】本研究采集了新疆地区驴腺疫病料，从样品中分离鉴定可疑病原菌并对其进行基因水平的分型与进化分析。【方法】对采集的新疆地区某驴场驴腺疫病驴颌下淋巴结拭子进行细菌分离培养，对2个分离株（HT111、HT321）进行染色、培养、生化试验、药敏试验，对其16S rRNA及SeM基因进行测序和进化分析，并通过PCR扩增7个管家基因，利用多位点序列分型（MLST）方法鉴定其分子分型。【结果】2个分离株均属马链球菌兽疫亚种，其中HT111对测试的13种抗生素中的3种（青霉素、克拉霉素和四环素）耐药，HT321对8种抗生素（阿莫西林、头孢呋辛、头孢噻呋、青霉素、克拉霉素、克林霉素、土霉素和四环素）耐药。序列分型发现了一种新的ST型为ST420（HT321），分离株HT111为ST179型。【结论】本研究在新疆地区首次分离了驴源马链球菌兽疫亚种，并鉴定出一个新的ST型（ST420），为驴腺疫的流行病学提供了参考数据。

Abstract:

[Objective] In this study donkey strangles samples were collected from Xinjiang donkey farm, suspicious pathogenic bacteria were isolated and identified. Then we performed genotyping and evolution analysis of these isolates. [Methods] First, bacteria isolation and culture were conducted using the samples collected from the abscess of submandibular lymph node in donkey farm in Xinjiang and two isolates (HT111, HT321) were identified. Then the morphological observation, physiological and biochemical analysis, drug sensitivity test, 16S rRNA sequencing and phylogenetic tree construction were performed. Besides, the seven housekeeping genes were amplified by PCR and the sequences of genes were analyzed through multiple locus sequence typing (MLST). [Results] Two isolates (HT111, HT321) were identified as S. equi ssp. zooepidemicus (S. zooepidemicus) from the samples. The HT111 isolate was resistant to penicillin, charithromycin, and tetracycline and HT321 was resistant to eight drugs, amoxicillin, cefuroxime, ceftiofuroxime, penicillin, clarithromycin, clindamycin, oxytetracycline and tetracycline. MLST result showed that ST179 (HT111), ST420 (HT321) were found and ST420 (HT321) was the first identified type. [Conclusion] Two donkey S. zooepidemicus strains were isolated and one novel genotype ST420 was identified, which could provide some data for the epidemic investigation and the prevention and control of donkey strangle in the future.