Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157
Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157
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DOI：
10.1128/aem.06646-11
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发表时间：
2012-05-01
影响因子：
4.4
通讯作者：
Kumagai, Susumu
中科院分区：
文献类型：
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作者：
Lee, Ken-ichi;French, Nigel P.;Kumagai, Susumu
为了评价细菌基因型与抗逆性之间的关系，我们将57株产志贺毒素的大肠杆菌(STEC)O157暴露在酸、冻融、热、渗透、氧化和饥饿胁迫下。计算每次检测的失活率，并进行单变量和多变量分析，包括主成分分析(PCA)和聚类分析。对每个菌株进行STX基因分型和谱系特异性多态分析(LSPA6)分型。在单变量分析中，STX(1)STX(2)型菌株表现出比STX(1)STX(2c)型菌株更强的抗热性，而且STX(1)STX(2)型菌株比STX(2)或STX(2c)型菌株表现出更强的抗饥饿性。LSPA6系I(LI)品系表现出比LSPA6系II(LII)品系更强的抗热和耐饥性。主成分分析揭示了一个总体趋势，即对一种类型的压力具有更大抗性的菌株往往对其他类型的压力具有更大的抵抗能力。在聚类分析中，STEC O157菌株被划分为耐应激、应激敏感和中间群。在STX基因分型中，STX(1)STX(2c)型菌株中，STX(1)STX(2c)型菌株中有72.7%(8/11)的菌株属于应力敏感型，而STX(1)STX(2c)型菌株全部归为耐应激基因簇。在LI株中，77.8%(14/18)的菌株属于耐应激簇，64.7%(11/17)的LII株属于应力敏感簇。这些结果表明，与人类疾病频繁相关的STEC O157基因型，即LI或STX(1)STX(2)基因型，比其他基因型的菌株具有更强的多重应激抗性。
To evaluate the relationship between bacterial genotypes and stress resistance patterns, we exposed 57 strains of Shiga toxin-producing Escherichia coli (STEC) O157 to acid, freeze-thaw, heat, osmotic, oxidative, and starvation stresses. Inactivation rates were calculated in each assay and subjected to univariate and multivariate analyses, including principal component analysis (PCA) and cluster analysis. The stx genotype was determined for each strain as was the lineage-specific polymorphism assay (LSPA6) genotype. In univariate analyses, strains of the stx(1) stx(2) genotype showed greater resistance to heat than strains of the stx(1) stx(2c) genotype; moreover, strains of the stx(1) stx(2) genotype showed greater resistance to starvation than strains of the stx(2) or stx(2c) genotypes. LSPA6 lineage I (LI) strains showed greater resistance to heat and starvation than LSPA6 lineage II (LII) strains. PCA revealed a general trend that a strain with greater resistance to one type of stress tended to have greater resistance to other types of stresses. In cluster analysis, STEC O157 strains were grouped into stress-resistant, stress-sensitive, and intermediate clusters. In stx genotypes, all strains of the stx1 stx2 genotype were grouped with the stress-resistant cluster, whereas 72.7% (8/11) of strains of the stx(1) stx(2c) genotype grouped with the stress-sensitive cluster. In LI strains, 77.8% (14/18) of the strains were grouped with the stress-resistant cluster, whereas 64.7% (11/17) of LII strains were grouped with the stress-sensitive cluster. These results indicate that the genotypes of STEC O157 that are frequently associated with human illness, i.e., LI or the stx(1) stx(2) genotype, have greater multiple stress resistance than do strains of other genotypes.