Li Jun-Jie, Spychala Caressa N, Hu Fupin, Sheng Ji-Fang, Doi Yohei
Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA State Key Laboratory for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China.
Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Antimicrob Agents Chemother. 2015;59(6):3002-7. doi: 10.1128/AAC.04772-14. Epub 2015 Mar 9.
Community-associated infections due to Escherichia coli producing CTX-M-type extended-spectrum β-lactamases are increasingly recognized in the United States. The bla(CTX-M) genes are frequently carried on IncF group plasmids. In this study, bla(CTX-M-15)-harboring plasmids pCA14 (sequence type 131 [ST131]) and pCA28 (ST44) and bla(CTX-M-14)-harboring plasmid pCA08 (ST131) were sequenced and characterized. The three plasmids were closely related to other IncFII plasmids from continents outside the United States in the conserved backbone region and multiresistance regions (MRRs). Each of the bla(CTX-M-15)-carrying plasmids pCA14 and pCA28 belonged to F31:A4:B1 (FAB [FII, FIA, FIB] formula) and showed a high level of similarity (92% coverage of pCA14 and 99% to 100% nucleotide identity), suggesting a possible common origin. The blaC(TX-M-14)-carrying plasmid pCA08 belonged to F2:A2:B20 and was highly similar to pKF3-140 from China (88% coverage of pCA08 and 99% to 100% nucleotide identity). All three plasmids carried multiple antimicrobial resistance genes and modules associated with virulence and biochemical pathways, which likely confer selective advantages for their host strains. The bla(CTX-M)-carrying IncFII-IA-IB plasmids implicated in community-associated infections in the United States shared key structural features with those identified from other continents, underscoring the global nature of this plasmid epidemic.
在美国，由产CTX-M型超广谱β-内酰胺酶的大肠埃希菌引起的社区获得性感染日益受到关注。bla(CTX-M)基因通常携带在IncF群质粒上。在本研究中，对携带bla(CTX-M-15)的质粒pCA14（序列型131 [ST131]）和pCA28（ST44）以及携带bla(CTX-M-14)的质粒pCA08（ST131）进行了测序和特征分析。这三个质粒在保守主干区域和多重耐药区域（MRRs）与来自美国以外各大洲的其他IncFII质粒密切相关。携带bla(CTX-M-15)的质粒pCA14和pCA28均属于F31:A4:B1（FAB [FII、FIA、FIB] 公式），并显示出高度相似性（pCA14的覆盖率为92%，核苷酸同一性为99%至100%），表明可能有共同起源。携带blaC(TX-M-14)的质粒pCA08属于F2:A2:B20，与来自中国的pKF3-140高度相似（pCA08的覆盖率为88%，核苷酸同一性为99%至100%）。所有三个质粒都携带多个抗菌耐药基因以及与毒力和生化途径相关的模块，这可能为其宿主菌株赋予了选择优势。在美国涉及社区获得性感染的携带bla(CTX-M)的IncFII-IA-IB质粒与从其他各大洲鉴定出的质粒具有共同的关键结构特征，凸显了这种质粒流行的全球性。
