ABSTRACT
Spotted fever caused by spotted fever group rickettsiae (SFGR) is found throughout China. During 2007—2008, 28 human SFGR isolates and 34 rat SFGR isolates including 15 isolates from <i>Rattus fulvescens</i>, 5 isolates from <i>R.edwardsi</i>, 7 isolates from <i>Callosciurus erythraeus roberti</i> and 7 isolates from <i>Dremomys rufigenis</i>) were obtained from L929 cell culture. Previous research indicated that the 62 strains of SFGR mentioned above shared not only the same serophenotype but also 100% of identity sequences of 16S rRNA, <i>gltA</i>, <i>ompA</i>, <i>groEL</i> and 17KD, which enabled us to apply multispacer typing (MST) to the 62 SFGR isolates in the study. Six primer pairs, which were used for typing of <i>Rickettsia rickettsii</i> and <i>Rickettsia conorii</i>, were chosen, and the results exhibited greater nucleotide polymorphisms among the 62 isolates tested. A total of 48 distinct genotypes were identified. The dominant genotype, represented by h3 isolates, accounted for 21.7% (13/60) of the isolates tested, and the remaining 47 genotypes were all unique. Phylogenetic analysis showed that all the 48 genotypes could be classified in the same clade, while the genetically related strain, <i>R.heilongjiangensis</i>, was close but not the same as the cluster. We concluded that the genetically diverse of spotted fever group rickettsiae strains are endemic in Chengmai County, Hainan Province, China.
ABSTRACT
Spotted fever caused by spotted fever group rickettsiae (SFGR) is found throughout China. During 2007–2008, 28 human SFGR isolates and 34 rat SFGR isolates including 15 isolates from <i>Rattus fulvescens</i>, 5 isolates from <i>R. edwardsi</i>, 7 isolates from <i>Callosciurus erythraeus roberti</i> and 7 isolates from <i>Dremomys rufigenis</i>) were obtained from L929 cell culture. Previous research indicated that the 62 strains of SFGR mentioned above shared not only the same serophenotype but also 100% of identity sequences of 16S rRNA, <i>gltA</i>, <i>ompA</i>, <i>groEL</i> and 17KD, which enabled us to apply multispacer typing (MST) to the 62 SFGR isolates in the study. Six primer pairs, which were used for typing of <i>Rickettsia rickettsii</i> and <i>Rickettsia conorii</i>, were chosen, and the results exhibited greater nucleotide polymorphisms among the 62 isolates tested. A total of 48 distinct genotypes were identified. The dominant genotype, represented by h3 isolates, accounted for 21.7% (13/60) of the isolates tested, and the remaining 47 genotypes were all unique. Phylogenetic analysis showed that all the 48 genotypes could be classified in the same clade, while the genetically related strain, <i>R. heilongjiangensis</i>, was close but not the same as the cluster. We concluded that the genetically diverse of spotted fever group rickettsiae strains are endemic in Chengmai County, Hainan Province, China.
ABSTRACT
Objective To identify and classify six isolates of swine-originated Trichinella from China. Methods Five specific pairs of primers were synthesized based on DNA sequence of expansion segment V region and internal tran-scribed spacers (ITS1 and ITS2) of ribosomal DNA repeat from Trichinella. International reference strains of five Trich-inella species [Trichinella spiralis (T1), T. nativa (T2), T. britovi (T3), T. pseudospiralis (T4) and T. nelsoni(T7)] were used as control. Six swine Trichienlla isolates from Henan, Yunnan, Harbin, Tongjiang of Heilongjiang, Hubei and Tianjin were identified by multiplex PCR and its effecting factors of PCR amplification were observed. Results Electrophoresis results of multiplex PCR products of Trichinella larvae showed that the band (173 bp) of the six isolates was the same as T. spiralis(T1). The specific band (173 bp) was detected by multiplex PCR through amplification from issues of single T. spiralis larva, the larvae conserved in 80% ethanol for 6 months, the larvae stored in 10% formaldehyde, in 0.05% formaldehyde, 0.2% sodium azide or 0.05% merthiotate for 2 weeks,or fresh mouse muscle with larvae. Conclusion All the six swine Trichinella isolates are identified as T. spiralis (T1) by multiplex PCR.