文献类型：期刊文献

英文题名：Multilocus Sequence Typing of an Emerging Cryptosporidium hominis Subtype in the United States

作者：Feng, Yaoyu[1];Tiao, Narry[2];Li, Na[1];Hlavsa, Michele[2];Xiao, Lihua[2]

机构：[1]E China Univ Sci & Technol, Sch Resources & Environm Engn, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[2]Ctr Dis Control & Prevent, Div Foodborne Waterborne & Environm Dis, Natl Ctr Emerging & Zoonot Infect Dis, Atlanta, GA USA

年份：2014

卷号：52

期号：2

起止页码：524

外文期刊名：JOURNAL OF CLINICAL MICROBIOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000330444200020)】；

基金：This work was supported by the Centers for Disease Control and Prevention and the National Natural Science Foundation of China (grants 31229005 and 31110103901). N.T. was the recipient of an APHL/CDC Emerging Infectious Disease Fellowship.

语种：英文

摘要：The United States has experienced a substantial increase in the reported incidence of cryptosporidiosis since 2005. Accompanying this is the emergence of a new subtype of Cryptosporidium hominis based on variation at the 60-kDa glycoprotein (gp60) locus, IaA28R4, which has become a frequently identified subtype in both sporadic and outbreak-related cases. In this study, using multilocus sequence typing (MLST) at eight genetic loci, we characterized 62 specimens of IaA28R4 and 33 specimens of three other gp60 subtypes of C. hominis from four U. S. states with increased cryptosporidiosis incidences during the summer of 2008. Extensive genetic heterogeneity was seen within the gp60 subtype IaA28R4, but specimens from Ohio and southwestern states formed two distinct subpopulations, suggesting that there were at least two origins of IaA28R4 within the United States. Discordance in typing results was observed between gp60 and other genetic markers, especially DZ-HRGP, and this discordance was largely the result of genetic recombination within the gp60 subtype IaA28R4. The results of population genetic analyses supported the presence of two subpopulations of IaA28R4 and the occurrence of genetic recombination within this gp60 subtype. Thus, the IaA28R4 subtype at gp60 is likely a fitness marker for C. hominis, and genetic recombination is potentially a driving force in the emergence of the virulent IaA28R4 subtype in the United States. A rapid evolution of IaA28R4 was indicated by the observation of multiple MLST subtypes of IaA28R4 within two large outbreaks that lasted for extended periods and involved multiple swimming pools.