Laboratorio de Referencia de E. coli (LREC), Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), Lugo, Spain.
J Antimicrob Chemother. 2011 Sep;66(9):2011-21. doi: 10.1093/jac/dkr235. Epub 2011 Jun 13.
To evaluate the current prevalence of the three clonal groups O25b:H4-B2-ST131, O15:H1-D-ST393 and CGA-D-ST69 (where ST stands for sequence type) among Escherichia coli isolates causing extraintestinal infections in Spain and to characterize their virulence background, 500 consecutive non-duplicate E. coli isolates causing extraintestinal infections were analysed.
The 500 isolates were collected during February 2009 from five hospitals in different Spanish regions. Phylogenetic groups, STs, serotypes, virulence genes, PFGE profiles, antimicrobial resistance and extended-spectrum β-lactamase (ESBL) enzymes were determined.
The three clonal groups accounted for 19% of the 500 isolates. Furthermore, they accounted for 37% of the isolates exhibiting trimethoprim/sulfamethoxazole plus ciprofloxacin resistance, 34% of aminoglycoside-resistant isolates and 30% of multidrug-resistant isolates. Clonal group ST131 was the most prevalent, and accounted for 12% of isolates overall and for 23% of multidrug-resistant isolates. The ST131 isolates exhibited a significantly higher virulence score (mean of virulence genes 8.1) compared with the ST393 (6.0) and ST69 (5.4) isolates. The prevalence of ESBL-producing isolates was 7%. Six (10%) of the 59 ST131 isolates were positive for CTX-M-15 and one (6%) of the 16 ST393 isolates was positive for CTX-M-14, whereas none of the 22 ST69 isolates produced ESBL enzymes.
The three clonal groups investigated accounted for 30% of the multidrug-resistant isolates, which gives evidence of an important clonal component in the emergence of resistances among extraintestinal pathogenic E. coli. Notably, a single high virulence clonal group (O25b:H4-B2-ST131) causes approximately 1 in every 10 extraintestinal infections in Spain, representing an important public health threat. A new variant of the ST131 clonal group, which is non-ESBL-producing but trimethoprim/sulfamethoxazole resistant and with high virulence content, is reported.
评估西班牙肠外感染大肠埃希菌分离株中 O25b:H4-B2-ST131、O15:H1-D-ST393 和 CGA-D-ST69（其中 ST 代表序列类型）这三个克隆群的当前流行率，并分析其毒力背景。方法：2009 年 2 月，从西班牙五个不同地区的五家医院收集了 500 例连续非重复大肠埃希菌肠外感染分离株。确定了它们的进化群、ST、血清型、毒力基因、PFGE 图谱、抗微生物药物耐药性和扩展谱β-内酰胺酶（ESBL）酶。结果：这三个克隆群占 500 株分离株的 19%。此外，它们占表现出甲氧苄啶/磺胺甲噁唑加环丙沙星耐药性的 37%的分离株、氨基糖苷类耐药性分离株的 34%和多药耐药性分离株的 30%。克隆群 ST131 最为普遍，占所有分离株的 12%，占多药耐药性分离株的 23%。ST131 分离株的毒力评分（平均毒力基因 8.1）明显高于 ST393（6.0）和 ST69（5.4）分离株。产 ESBL 分离株的流行率为 7%。59 株 ST131 分离株中有 6 株（10%）为 CTX-M-15 阳性，16 株 ST393 分离株中有 1 株（6%）为 CTX-M-14 阳性，而 22 株 ST69 分离株均未产生 ESBL 酶。结论：所研究的三个克隆群占多药耐药性分离株的 30%，这表明肠外致病性大肠埃希菌耐药性的出现存在重要的克隆因素。值得注意的是，西班牙每 10 例肠外感染中就有 1 例是由单一高毒力克隆群（O25b:H4-B2-ST131）引起的，这对公共卫生构成了重大威胁。报道了一种新的 ST131 克隆群变体，该变体不产生 ESBL，但对甲氧苄啶/磺胺甲噁唑耐药，且具有高毒力。
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