Virulence characteristics and phylogenetic background of multidrug-resistant and antimicrobial-susceptible clinical isolates of Escherichia coli from across the United States, 2000-2001
Virulence characteristics and phylogenetic background of multidrug-resistant and antimicrobial-susceptible clinical isolates of Escherichia coli from across the United States, 2000-2001
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DOI：
10.1086/425018
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发表时间：
2004-11-15
影响因子：
6.4
通讯作者：
Karlowsky, JA
中科院分区：
文献类型：
--
作者：
Johnson, JR;Kuskowski, MA;Karlowsky, JA
背景。大肠杆菌抗菌素耐药性的增加与大肠杆菌脓毒症发病率的增加是平行的，这表明耐药性和毒力之间可能存在联系。本文研究了2000-2001年《今日美国》追踪耐药性研究中报告的所有76株多重耐药（MDR）大肠杆菌分离株（即对大于或等于3种抗菌药物，包括氨苄西林、头孢他啶、甲氧苄啶-磺胺甲恶唑、庆大霉素和环丙沙星）和76株密切匹配的全敏感对照分离株。扩展的毒力谱和大肠杆菌系统发育组（A、B1、B2或D）在组间进行比较。与主要来自b2组的对照分离株（58%）相比，主要代表非b2系统发育群的MDR分离株（91%）表现出显著降低的分子毒力。与61%的对照菌株（P < 0.001）相比，只有30%的MDR菌株符合肠外致病性大肠杆菌（ExPEC）的标准（P < 0.001），即使这些菌株的毒力评分也明显低于易感的ExPEC （7.25 vs. 9.0; P = 0.001）。系统发育差异解释了耐多药菌株和对照菌株之间明显的毒力差异。这些发现反驳了大肠杆菌毒力特征与抗菌素耐药性之间的直接联系。相反，他们提出了一个问题，为什么非b2菌株更常见的耐多药耐药，不同的选择压力暴露（包括农业）是一个可能的解释。
Background. Increases in antimicrobial resistance in Escherichia coli have been paralleled by an increasing incidence of E. coli sepsis, suggesting a possible link between resistance and virulence.Methods. All 76 multidrug-resistant (MDR) E. coli isolates (i.e., those resistant to greater than or equal to3 antimicrobial agents, including ampicillin, ceftazidime, trimethoprim-sulfamethoxazole, gentamicin, and ciprofloxacin) reported to the Tracking Resistance in the United States Today studies during 2000-2001 and 76 closely matched pansusceptible control isolates were studied. Extended virulence profiles and E. coli phylogenetic group ( A, B1, B2, or D) were compared between groups.Results. The MDR isolates, which represented predominantly non-B2 phylogenetic groups (91%), exhibited significantly reduced molecular virulence, compared with the predominantly group B2-derived control isolates (58%). Only 30% of MDR isolates, compared with 61% of control isolates (P < .001), qualified as extraintestinal pathogenic E. coli (ExPEC), and even these isolates exhibited significantly lower virulence scores than did susceptible ExPEC (7.25 vs. 9.0; P = .001). Phylogenetic differences accounted for the apparent virulence differences between MDR and control isolates.Conclusions. These findings argue against a direct link between virulence traits and antimicrobial resistance in E. coli. Instead, they call into question why non-B2 strains are more commonly MDR, with differential exposure to selection pressure ( including in agriculture) as one possible explanation.