Olesen Bente, Scheutz Flemming, Menard Megan, Skov Marianne N, Kolmos Hans Jørn, Kuskowski Michael A, Johnson James R
Department of Clinical Microbiology, Hillerød Sygehus, Helsevej 2, DK-3400 Hillerød, Denmark.
J Clin Microbiol. 2009 Jun;47(6):1857-62. doi: 10.1128/JCM.00230-09. Epub 2009 Apr 1.
The successful Escherichia coli O15:K52:H1 clonal group provides a case study for the emergence of multiresistant clonal groups of Enterobacteriaceae generally. Accordingly, we tested the hypotheses that, over time, the O15:K52:H1 clonal group has become increasingly (i) virulent and (ii) resistant to antibiotics. One hundred archived international E. coli O15:K52:[H1] clinical isolates from 100 unique patients (1975 to 2006) were characterized for diverse phenotypic and molecular traits. All 100 isolates derived from phylogenetic group D and, presumptively, sequence type ST393. They uniformly carried the F16 papA allele and papG allele II (P fimbria structural subunit and adhesin variants), iha (adhesin-siderophore), fimH (type 1 fimbriae), fyuA (yersiniabactin receptor), iutA (aerobactin receptor), and kpsM II (group 2 capsule); 85% to 89% of them contained a complete copy of the pap operon and ompT (outer membrane protease). Slight additional virulence profile variation was evident, particularly within a minor diarrhea-associated subset (biotype C). However, in contrast to the clonal group's fairly stable virulence profiles over the past 30+ years, during the same interval the clonal group members' antimicrobial resistance profiles increased by a mean of 2.8 units per decade (P < 0.001). Moreover, the numbers of virulence genes and resistance markers were positively associated (P = 0.046), providing evidence against antimicrobial resistance and virulence being mutually exclusive in these strains. Thus, the O15:K52:H1 clonal group has become increasingly resistant to antimicrobials while maintaining (or expanding) its virulence potential, a particularly concerning trend if other emerging multiresistant enterobacterial clonal groups follow a similar pattern.
成功的大肠杆菌O15:K52:H1克隆群总体上为肠杆菌科多重耐药克隆群的出现提供了一个案例研究。因此，我们检验了以下假设：随着时间的推移，O15:K52:H1克隆群已变得越来越（i）具有毒力且（ii）对抗生素耐药。对来自100名不同患者（1975年至2006年）的100株已存档的国际大肠杆菌O15:K52:[H1]临床分离株进行了多种表型和分子特征的鉴定。所有100株分离株均来自系统发育组D，推测为序列类型ST393。它们均携带F16 papA等位基因和papG等位基因II（P菌毛结构亚基和粘附素变体）、iha（粘附素-铁载体）、fimH（1型菌毛）、fyuA（yersiniabactin受体）、iutA（气杆菌素受体）和kpsM II（2组荚膜）；其中85%至89%含有完整的pap操纵子和ompT（外膜蛋白酶）拷贝。明显存在轻微的额外毒力谱变异，特别是在一个与腹泻相关的较小亚组（生物型C）内。然而，与该克隆群在过去30多年里相当稳定的毒力谱形成对比的是，在同一时期，该克隆群成员的抗菌药物耐药谱每十年平均增加2.8个单位（P<0.001）。此外，毒力基因数量和耐药标记呈正相关（P = 0.046），这为这些菌株中抗菌药物耐药性和毒力并非相互排斥提供了证据。因此，O15:K52:H1克隆群在保持（或扩大）其毒力潜能的同时，对抗菌药物的耐药性越来越强，如果其他新兴的多重耐药肠杆菌克隆群遵循类似模式，这将是一个特别令人担忧的趋势。
