| Bacillary dysentery is a kind of acute gut infection disease caused by shigella, it's also confirmed the second serious infection disease by the government of China. According to the whole state monitoring results, the Shigella flexneri 2a and Shigella flexneri 2b are the epidemic serotypes in our main land. But since 2000, the number of shigellosis caused by Shigella flexneri 4c (S. flexneri 4c) has been increasing significantly, absorbing much attention of different classes CDC in China.In order to explore the mechanism and the epidemiology characteristics of the Shigella flexneri 4c in China, 169 S. flexneri 4c isolates were recovered from Shigella monitor sets of Henan province in 2002, 2003, 2005(36 strains in Jiyuan 2002, 12 strains in Xuchang 2002, 29 strains in Shangqiu 2003, 59 strains in Shangqiu,3 strains in Jiyuan, 24 strains in Zhengzhou,6 strains in children hospital of Henan pro.2005.). PCR method is used to examine the positive rates of virulence genes ipaH, shet1, ial, sen .These bacteria are also typed by pulsed-field gel electrophoresis (PFGE) techniques and analyzed with BioNumerics software.The positive rates of ipaH, shet1, ial, and sen are 100%, 99.4%, 97.2% and 98.2% respectively. 3 strains are all negative with ial and sen genes. All the isolates display 46 different NotI-PFGE patterns, 57.4% of them are dendrogram type CNJZXN11.0001, which is the predominant epidemic strain type of Henan province. The similarity coefficient among the type CNJZXN11.0001,CNJZXN11.0025,CNJZXN11.0024,CNJZXN11.0028,CNJZXN11.0033 is more than 95% and they are most likely clonal. The dendrogram type CNJZXN11.0001 proportion is observed to decrease, but the infections of new dendrogram types CNJZXN11.0002, CNJZXN11.0003, CNJZXN11.0012 are rising through the 3 years. Unfortunately, they have low similarity coefficient with CNJZXN11.0001 and are new PFGE pattens.Un-adults infected by CNJZXN11.0001 with high rate indicates children may be more susceptive to these strains.
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