Virulence factors in Escherichia coli with CTX-M-15 and other extended-spectrum β-lactamases in the UK
Virulence factors in Escherichia coli with CTX-M-15 and other extended-spectrum β-lactamases in the UK
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DOI：
10.1093/jac/dkm401
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发表时间：
2008-01-01
影响因子：
5.2
通讯作者：
Woodford, N.
中科院分区：
文献类型：
--
作者：
Karisik, E.;Ellington, M. J.;Woodford, N.
目的：具有CTX-M-15广谱β -内酰胺酶（ESBL）的多重耐药大肠杆菌在英国广泛存在。我们检查了它们的系统发育类群和毒力因子。方法：对2003 ~ 2006年收集的114株临床分离大肠杆菌进行系统发育分组，采用PCR方法对33个毒力因子基因进行筛选。他们包括具有CTX-M-15酶的英国五种主要流行大肠杆菌菌株的代表，以及具有CTX-M或其他类型ESBLs的非克隆分离株。结果：所有具有代表性的流行大肠杆菌菌株均属于毒力强的肠外系统发育群B2, 60%（34/56）具有ctx - m -15样酶的非克隆分离株和75%（15/20）具有非ctx - m ESBLs的非克隆分离株均属于毒力强的肠外系统发育群B2。具有CTX-M-9样酶的菌株中有一半属于毒力组d。在系统发育组B2中，具有CTX-M酶的克隆和非克隆分离株以及具有非CTX-M ESBLs的克隆和非克隆分离株中大多数毒力因子的流行率具有可比性。最常见的毒力基因为PAI、fyuA、fyuA、kpsMTII、K5、traT、uidA和usp。在5个流行克隆中，afa/draBC特异于菌株A，而P菌毛仅在菌株D中检测到，只有B-C-E群的代表特异性携带sfaS、kpsMTII和K5。然而，在30%的CTX-M ESBLs非克隆分离株中也发现了afa/draBC，并且没有流行菌株特有的毒力基因。结论：携带CTX-M型ESBLs的大肠杆菌多属于强毒系统发育类群，以B2为主。成功流行株的毒力并没有增强，但iutA和fyuA在这些菌株中的流行率明显高于同样属于系统发育类群B2的非克隆分离株。最成功的CTX-M-15酶(A)克隆在携带afa/draBC方面与其他流行克隆不同，但在具有CTX-M-15酶的非克隆分离株中也发现了这一点。
Objectives: Multiresistant Escherichia coli with CTX-M-15 extended-spectrum beta-lactamase (ESBL) are widespread in the UK. We examined their phylogenetic groups and virulence factors.Methods: Clinical E. coli isolates ( n = 114), collected between 2003 and 2006, were phylogenetically grouped and screened by PCR for 33 virulence factor genes. They included representatives of the five major UK epidemic E. coli strains with CTX-M-15 enzyme, as well as non-clonal isolates with CTX-M or other types of ESBLs.Results: All representatives of the epidemic E. coli strains belonged to the virulent extra-intestinal phylogenetic group B2, as did 60% (34/56) of the non-clonal isolates with CTX-M-15-like enzymes and 75% (15/20) of those with non-CTX-M ESBLs. Half of those with CTX-M-9-like enzymes belonged to virulence group D. Within phylogenetic group B2, the prevalence of most virulence factors was comparable among clonal and non-clonal isolates with CTX-M enzymes, and among those with non-CTX-M ESBLs. The most frequent virulence genes were PAI, fimH , fyuA , iutA , kpsMTII , K5 , traT , uidA and usp . Among the five epidemic clones, afa/draBC was specific to strain A, whereas P fimbriae were only detected in strain D, and only representatives of the B-C-E group specifically harboured sfaS , kpsMTII and K5 . However, afa/draBC was also found in 30% of non-clonal isolates with CTX-M ESBLs, and no virulence gene was unique to the epidemic strains.Conclusions: Most E. coli with CTX-M ESBLs belonged to virulent phylogenetic groups, mainly B2. The successful epidemic strains did not appear more virulent, but iutA and fyuA were significantly more prevalent among these than in non-clonal isolates also belonging to phylogenetic group B2. The most successful clone with CTX-M-15 enzyme (A) differed from other epidemic clones in harbouring afa/draBC , but this was also found in non-clonal isolates with CTX-M-15 enzyme.