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目的分析2001-2003年某省儿童医院分离的268株大肠埃希菌tccP2基因的携带情况及该基因的分子特征。方法 PCR方法筛查临床分离的268株大肠埃希菌中EHEC、EPEC菌株;再筛查tccP2基因的携带情况,克隆阳性菌株tccP2基因,并进行核苷酸测序,同时与GenBank数据库进行比对。结果 2001-2003年临床分离的菌株共检测到7株EPEC菌株,其中有2株菌tccP2基因阳性,长度分别为1458 bp,核苷酸和氨基酸的一致性为100%,与国际上公布的str.11128(O111∶H-)菌株的tccP2基因比对发现核苷酸一致性为61.3%;氨基酸序列比对,发现其N-端与str.11128(O111∶H-)菌株具有完全相同的特异的87个核苷酸序列,脯氨酸富集重复片段序列几乎一致,较str.11128(O111∶H-)菌株多4个重复片段。结论在中国临床分离的菌株中也存在具有tccP2基因的EPEC菌株,应进一步加大临床标本中该类菌株的分离与监测。
Objective To analyze the carrying status of 268 strains of Escherichia coli isolated from children’s hospital in a province from 2001 to 2003 and the molecular characteristics of this gene. Methods EHEC and EPEC strains of 268 Escherichia coli strains were screened by PCR method. The tccP2 gene was further screened by PCR. The positive cloned tccP2 gene was cloned and sequenced. The nucleotide sequence was also compared with that of GenBank database. Results A total of 7 strains of EPEC were detected in clinical isolates from 2001 to 2003, of which 2 strains were positive for tccP2, with a length of 1458 bp and a nucleotide and amino acid identity of 100%, respectively. Compared with the published international str The tccP2 gene of strain 11118 (O111: H-1) showed a nucleotide identity of 61.3%. Amino acid sequence alignment revealed that the N-terminus of the gene was identical to the str.11128 (O111: H- Of the 87 nucleotide sequences, proline-rich repeats almost identical sequence, str.11128 (O111: H) strains more than 4 repeats. Conclusion EPEC strains with tccP2 gene are also present in clinically isolated strains in China. Isolation and monitoring of these strains in clinical specimens should be further intensified.