Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto, Japan.
J Antimicrob Chemother. 2012 Nov;67(11):2612-20. doi: 10.1093/jac/dks278. Epub 2012 Jul 26.
The increasing prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has been associated with the emergence of the CTX-M-producing sequence type 131 (ST131) pandemic clonal group, a member of the O25b serogroup and the B2 phylogenetic group. To assess the clonal spread of ESBL-producing E. coli in Japan, a regional surveillance programme was conducted.
A total of 581 ESBL-producing clinical specimen E. coli isolates were collected between 2001 and 2010. Clonal groups, including ST131, D-ST405, D-ST393 and D-ST69, were determined using the PCR O type, phylogenetic grouping by triplex PCR, allele-specific PCR and multilocus sequence typing (MLST). A subset of clonal groups underwent PFGE.
Among clonal strains, 215 isolates (37%) were identified as belonging to the ST131 group, 185 as B2-ST131-O25b (32%), 26 as B2-ST131-O16 (4%), 3 as B1-ST131-O25b (0.5%) and 1 as B2-ST131-O-non-typeable (0.1%). Forty-one isolates (7%) were identified as belonging to the D-ST405 clonal group, seven (1%) as D-ST69 and two (0.3%) as D-ST393. The B2-ST131-O16 clonal group was characterized by CTX-M-14 and a significantly lower ciprofloxacin resistance rate than the B2-ST131-O25b clonal group. The B2-ST131-O16 and B2-ST131-O25b clonal groups each made up a single PFGE cluster, with 65% similarity. The rate of ESBL-producing E. coli increased over the years (0.2% in 2001 to 9.7% in 2010) and corresponded to increases in the numbers of the B2-ST131-O25b, B2-ST131-O16 and D-ST405 clonal groups.
The B2-ST131-O25b, B2-ST131-O16 and D-ST405 clonal groups have contributed to the spread of ESBL-producing E. coli in Japan.
产Extended-spectrum β-lactamase (ESBL)的大肠杆菌的流行率不断增加，这与CTX-M 型产生的序列型 131（ST131）流行克隆群的出现有关，该克隆群是 O25b 血清群和 B2 进化群的成员。为了评估产 ESBL 的大肠杆菌在日本的克隆传播，进行了一项区域监测计划。
2001 年至 2010 年间共收集了 581 株产 ESBL 的临床标本大肠杆菌分离株。通过 PCR O 型、三重 PCR 进行的系统发育分组、等位基因特异性 PCR 和多位点序列分型 (MLST) 确定克隆群，包括 ST131、D-ST405、D-ST393 和 D-ST69。对部分克隆群进行 PFGE。
在克隆株中，215 株（37%）被鉴定为 ST131 组，185 株（32%）为 B2-ST131-O25b，26 株（4%）为 B2-ST131-O16，3 株（0.5%）为 B1-ST131-O25b，1 株（0.1%）为 B2-ST131-O-非定型。41 株（7%）被鉴定为 D-ST405 克隆群，7 株（1%）为 D-ST69，2 株（0.3%）为 D-ST393。B2-ST131-O16 克隆群的特点是 CTX-M-14 和明显低于 B2-ST131-O25b 克隆群的环丙沙星耐药率。B2-ST131-O16 和 B2-ST131-O25b 克隆群各形成一个 PFGE 聚类，相似度为 65%。产 ESBL 的大肠杆菌的比例逐年增加（2001 年为 0.2%，2010 年为 9.7%），与 B2-ST131-O25b、B2-ST131-O16 和 D-ST405 克隆群的数量增加相对应。
B2-ST131-O25b、B2-ST131-O16 和 D-ST405 克隆群促成了产 ESBL 的大肠杆菌在日本的传播。
