ithree Institute, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia.
ithree Institute, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia; Department of Primary Industries, Elizabeth Macarthur Agriculture Institute, PMB 4008, Camden, NSW 2567, Australia.
Int J Antimicrob Agents. 2018 Sep;52(3):430-435. doi: 10.1016/j.ijantimicag.2018.06.017. Epub 2018 Jun 30.
Sequence type 58 (ST58) phylogroup B1 Escherichia coli have been isolated from a wide variety of mammalian and avian hosts but are not noted for their ability to cause serious disease in humans or animals. Here we determined the genome sequences of two multidrug-resistant E. coli ST58 strains from urine and blood of one patient using a combination of Illumina and Single Molecule, Real-Time (SMRT) sequencing. Both ST58 strains were clonal and were characterised as serotype O8:H25, phylogroup B1 and carried a complex resistance locus/loci (CRL) that featured an atypical class 1 integron with a dfrA5 (trimethoprim resistance) gene cassette followed by only 24 bp of the 3'-CS. CRL that carry this particular integron have been described previously in E. coli from cattle, pigs and humans in Australia. The integron abuts a copy of Tn6029, an IS26-flanked composite transposon encoding bla, sul2 and strAB genes that confer resistance to ampicillin, sulfathiazole and streptomycin, respectively. The CRL resides within a novel Tn2610-like hybrid Tn1721/Tn21 transposon on an IncF, ColV plasmid (pSDJ2009-52F) of 138 553 bp that encodes virulence associated genes implicated in life-threatening extraintestinal pathogenic E. coli (ExPEC) infections. Notably, pSDJ2009-52F shares high sequence identity with pSF-088-1, a plasmid reported in an E. coli ST95 strain from a patient with blood sepsis from a hospital in San Francisco. These data suggest that extraintestinal infections caused by E. coli carrying ColV-like plasmids, irrespective of their phylogroup or ST, may pose a potential threat to human health, particularly to the elderly and immunocompromised.
序列类型 58（ST58）B1 型肠杆菌科细菌已从多种哺乳动物和禽类宿主中分离出来，但它们并非以能够引起人类或动物严重疾病而闻名。在这里，我们使用 Illumina 和单分子实时（SMRT）测序相结合的方法，对来自一名患者尿液和血液中的两株多药耐药性大肠杆菌 ST58 菌株的基因组序列进行了测定。这两株 ST58 菌株均为克隆株，血清型为 O8:H25， phylogroup B1，携带复杂的耐药基因座/基因座（CRL），该基因座/基因座具有一个非典型的 I 类整合子，带有一个 dfrA5（甲氧苄啶耐药）基因盒，其后仅带有 3'-CS 的 24 个碱基。以前在澳大利亚的牛、猪和人类的大肠杆菌中已经描述过携带这种特殊整合子的 CRL。该整合子与 Tn6029 的一个拷贝相邻，Tn6029 是一个由 IS26 侧翼的复合转座子编码的 bla、sul2 和 strAB 基因，分别赋予对氨苄西林、磺胺嘧啶和链霉素的耐药性。CRL 位于一个新型的 Tn2610 样混合 Tn1721/Tn21 转座子内，该转座子位于一个 IncF、ColV 质粒（pSDJ2009-52F）上，大小为 138553bp，该质粒编码与危及生命的肠外致病性大肠杆菌（ExPEC）感染相关的毒力相关基因。值得注意的是，pSDJ2009-52F 与 pSF-088-1 具有高度的序列同一性，pSF-088-1 是一种质粒，曾在旧金山一家医院血源性败血症患者的大肠杆菌 ST95 菌株中报道过。这些数据表明，携带 ColV 样质粒的大肠杆菌引起的肠外感染，无论其 phylogroup 或 ST 如何，都可能对人类健康构成潜在威胁，尤其是对老年人和免疫功能低下者。
