标题:
Prevalence of ST1193 clone and IncI1/ST16 plasmid in E-coli isolates carrying blaCTX-M-55 gene from urinary tract infections patients in China
讲者:
Xialiang
单位:
重庆医科大学附属第一医院
播放:
1707
论文摘要:
To study molecular epidemiology of CTX-M-55-carrying Escherichia coli isolates from urinary tract infections (UTIs) in
China. 111 blaCTX-M-55-positive E.coli isolates from UTIs patients in China were studied.
Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST)
were used to analyze the homologies among the strains. Conjugation
experiments,
S1nuclease PFGE and
PCR analysis were
performed to characterize plasmids harboring blaCTX-M-55
and their genetic environment. 111 isolates were clustered into 86 individual pulsotypes and three clusters by PFGE. Fifty-five(49.5%) of the isolates belonged to 8 STs. Most of the ST1193
isolates belonged to one PFGE cluster. Transconjugants(n=45) derived from randomly selected blaCTX-M-55 donors(n=58), were
found to contain a single 90-kb conjugative plasmid, which mainly belonged to
the IncI1 groups (34, 76%). Among the IncI1 plasmids, the blaCTX-M-55/IncI1/ST16 predominated(23/34, 68%). The blaTEM-1 and aac (3 ')-II genes were frequently detected on the IncI1 plasmids,
and the insertion of ISEcp1
or IS26 was observed at the 48bp or
45bp upstream of the start codon of blaCTX-M-55
gene. The dissemination of blaCTX-M-55 gene among E.
coli UTI isolates, appeared to be due to both the major clonal lineage of
ST1193 and the horizontal transfer of epidemic plasmid IncI1/ST16.