贾琴妹, 杨传莲, 黄艳梅. 普通变形杆菌KM-19的培养鉴定及相关机制研究[J]. 疾病监测, 2020, 35(1): 52-56. DOI: 10.3784/j.issn.1003-9961.2020.01.012
引用本文: 贾琴妹, 杨传莲, 黄艳梅. 普通变形杆菌KM-19的培养鉴定及相关机制研究[J]. 疾病监测, 2020, 35(1): 52-56. DOI: 10.3784/j.issn.1003-9961.2020.01.012
Qinmei Jia, Chuanlian Yang, Yanmei Huang. Culture, identification and related mechanism research of Proteus vulgaris KM-19[J]. Disease Surveillance, 2020, 35(1): 52-56. DOI: 10.3784/j.issn.1003-9961.2020.01.012
Citation: Qinmei Jia, Chuanlian Yang, Yanmei Huang. Culture, identification and related mechanism research of Proteus vulgaris KM-19[J]. Disease Surveillance, 2020, 35(1): 52-56. DOI: 10.3784/j.issn.1003-9961.2020.01.012

普通变形杆菌KM-19的培养鉴定及相关机制研究

Culture, identification and related mechanism research of Proteus vulgaris KM-19

  • 摘要:
    目的分析研究自中段尿培养中分离鉴定出的无迁徙性生长β溶血普通变形杆菌KM-19的生物学特性、耐药机制及基因组特点,为临床合理用药提供指导。
    方法常规方法分离培养菌株;采用VITEK-2 Compact全自动微生物分析仪进行菌种鉴定和体外药物敏感性试验;利用鞭毛染色和半固体动力试验观察鞭毛缺失情况;采用高通量测序技术对该菌全基因组测序,采用生物信息学方法进行序列组装、基因预测与功能注释,并深入挖掘菌株的表型机制及耐药机制相关基因簇信息。
    结果VITEK-2 Compact鉴定结果为普通变形杆菌。 全基因组测序结果显示基因组组装共得48个重叠群,基因总长度3 319 152 bp,平均长度904.89 bp,占基因组全长的85.50%,无重复序列,鸟嘌呤(G)和胞嘧啶(C)(G+C)含量为38%。 该菌比对到普通变形杆菌可信度最高,也验证了VITEK-2 Compact鉴定结果准确。 该菌对一二代头孢菌素、氨苄西林、呋喃妥因、复方新诺明、替加环素耐药,其余均敏感。 鞭毛染色油镜下未见鞭毛结构,半固体动力试验阴性;基因组测序序列与VFDB数据库比对结果显示细菌鞭毛基因及相关基因未缺失,但鞭毛基因序列中发现可接受甲基化的趋化性蛋白基因Ⅲ/Ⅰ位点和甲基转移酶基因,还有溶血素基因(hlyB)。基因组序列与CARD数据库比对结果显示存在OXY型和CTX-M型基因及主动外排泵基因。
    结论该株菌无迁徙性生长现象,其主要机制可能是鞭毛基因或相关基因被甲基化,使细菌不能有效表达菌体外鞭毛蛋白,丧失迁徙生长能力;β溶血表型可能由外源性溶血素基因(hlyB)插入细菌基因组中并有效表达。 该菌体外耐药情况与OXY型和CTX-M型基因及主动外排泵基因密切相关。

     

    Abstract:
    ObjectiveTo analyze the biological characteristics, drug resistance mechanism and genomic characteristics of a beta hemolytic Proteus vulgaris KM-19 strain isolated and identified from middle urinary culture deficient in migratory growth, and provide evidence for clinical rational use of antibiotics.
    MethodsThe strain was cultured and isolated by using conventional methods. Then, VITEK-2 Compact automatic microbiological analyzer was used for the strain identification and drug sensitivity test in vitro. The absence of flagella was observed by staining and semisolid dynamic test. The whole genome of the strain was sequenced by high-throughput sequencing. The sequence assembly, gene prediction and functional annotation were carried out with bioinformatics method, and gene clusters related to phenotypic mechanism and drug resistance mechanism of the strain were further explored.
    ResultsVITEK-2 Compact identified the strain as Proteus vulgaris. The whole genome sequencing results showed that 48 Contigs were obtained from genome assembly; the total length of the gene was 3 319 152 bp, and the average length was 904.89 bp, accounting for 85.50% of the total length of the genome; the genome had no repeat sequence and had 38% C+G content. This strain was most likely to be Proteus vulgaris, which also verified the accurate identification result of the VITEK-2 Compact. This Proteus vulgaris strain was resistant to the first and second generation of cephalosporin, ampicillin, furantoin, compound neostigmine and tigecycline, but is was sensitive to the other drugs. No flagellum structure was observed under oil microscope and semisolid dynamic test was negative. The comparison between the genome sequencing sequence and the VFDB database showed that the bacterial flagellar gene and related genes were not missing, but, in flagellar gene sequences, the Methyl-accepting chemotaxis protein Ⅲ/Ⅰ genes was found. Methyltransferase genes and hlyB genes were also found in the genome. In addition, the comparison between the genome sequence and the CARD database showed that there were OXY and CTX-M genes and active efflux pump genes.
    ConclusionThe main mechanism of no migrating growth of this strain might be the methylation of flagellar genes or related genes, which indicated that the bacteria wasunable to effectively express flagellin in vitro and lost the ability of migrating growth. The beta hemolytic phenotype might be due to the insertion of exogenous hemolysin gene (hlyB), which was expressed effectively the bacterial genome. The drug resistance in vitro was closely related to OXY and CTX-M genes and active efflux pump genes.

     

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