Fursova N K, Pryamchuk S D, Abaev I V, Kovalev Yu N, Shishkova N A, Pecherskikh E I, Korobova O V, Astashkin E I, Pachkunov D M, Svetoch E A, Sidorenko S V
Antibiot Khimioter. 2010;55(11-12):3-10.
The study showed that bla(CTX-M) genes were present in the genomes of 71% of cephalosporin resistant Enterobacteriaceae nosocomial isolates (n=833) collected in Russian hospitals within 2003-2007, including 91% of E.coli, 90% of Klebsiella spp., 38% of Enterobacter spp., 31% of Citrobacter spp. (n=9), and 36% of the other Enterobacteriaceae species. The genes belonging to the following subtypes (clusters) were identified: bla(CTX-M-1) (529 bla(CTX-M-15) genes; 25 bla(CTX-M-3) genes; 1 bla(CTX-M-22) gene, 1 bla(CTX-M-23) gene, and 1 bla(CTX-M-34) gene); bla(CTX-M-2) (1 bla(CTX-M-2) gene, and 4 bla(CTX-M-5) genes), and bla(CTX-M-9) (2 bla(CTX-M-9) genes, and 28 bla(CTX-M-14) genes). It was shown that bla(CTX-M) genes were located on high-molecular weight (60-160 bp) conjugative plasmids belonging mainly to the incompatibility groups IncF, IncL/M and IncA/C (bla(CTX-M-15) gene); IncL/M(bla(CTX-M-3) gene); and IncF, IncL/Mand IncI1-ly (CTX-M-14 gene). The gene environments of bla(CTX-M) genes were shown specific for the subtype of the genes. A mobile genetic element ISEcp1 (in some cases deleted or inserted by IS26, IS1, IS10, resTn2, or resTn3 sequences, in direct or reverse position) were detected upstream of bla(CTX-M-3), bla(CTX-M-14), and bla(CTX-M-15) genes. A special characteristic was the sequence between ISEcp1 and bla(CTX-M) gene: 48 bp for bla(CTX-M-15) (except 1 E.coli isolate having such a sequence deleted by 3 bp); 127 bp for bla(CTX-M-3); 42 bp for bla(CTX-M-14). Downstream of bla(CTX-M) and bla(CTX-M-15) genes in the major bacterial isolates orf477 mucA and Delta orf477-Delta mucA sequences were detected respectively. Two isolates had additional Delta orf3 insertion inside of Delta orf477-Delta mucA sequence. Insertion sequence IS903 (intact or deleted) was detected downstream of bla(CTX-M-14) gene. Unlike the others, bla(CTX-M-2) and bla(CTX-M-9) genes were located inside of ISCR1 mobile element, downstream of class 1 integron and orf513 sequence.
该研究表明，在2003年至2007年期间俄罗斯医院收集的833株耐头孢菌素的肠杆菌科医院分离株中，71%的分离株基因组中存在bla(CTX-M)基因，其中包括91%的大肠杆菌、90%的克雷伯菌属、38%的肠杆菌属、31%的柠檬酸杆菌属（n = 9）以及36%的其他肠杆菌科菌种。已鉴定出属于以下亚型（簇）的基因：bla(CTX-M-1)（529个bla(CTX-M-15)基因；25个bla(CTX-M-3)基因；1个bla(CTX-M-22)基因、1个bla(CTX-M-23)基因和1个bla(CTX-M-34)基因）；bla(CTX-M-2)（1个bla(CTX-M-2)基因和4个bla(CTX-M-5)基因）以及bla(CTX-M-9)（2个bla(CTX-M-9)基因和28个bla(CTX-M-14)基因）。结果表明，bla(CTX-M)基因位于主要属于不相容群IncF、IncL/M和IncA/C（bla(CTX-M-15)基因）的高分子量（60 - 160 bp）接合质粒上；IncL/M（bla(CTX-M-3)基因）；以及IncF、IncL/M和IncI1-ly（CTX-M-14基因）。bla(CTX-M)基因的基因环境因基因亚型而异。在bla(CTX-M-3)、bla(CTX-M-14)和bla(CTX-M-15)基因上游检测到一个移动遗传元件ISEcp1（在某些情况下被IS26、IS1、IS10、resTn2或resTn3序列直接或反向位置删除或插入）。一个特殊特征是ISEcp1与bla(CTX-M)基因之间的序列：bla(CTX-M-15)为48 bp（1株大肠杆菌分离株除外，其该序列缺失3 bp）；bla(CTX-M-3)为127 bp；bla(CTX-M-14)为42 bp。在主要细菌分离株中，bla(CTX-M)和bla(CTX-M-15)基因下游分别检测到orf477 mucA和Delta orf477 - Delta mucA序列。两株分离株在Delta orf477 - Delta mucA序列内部有额外的Delta orf3插入。在bla(CTX-M-14)基因下游检测到插入序列IS903（完整或缺失）。与其他基因不同，bla(CTX-M-2)和bla(CTX-M-9)基因位于ISCR1移动元件内部，在1类整合子和orf513序列下游。
