Distributions of pathogenic capsular types and in vitro antimicrobial susceptibility of different serotypes of Streptococcus suis isolated from clinically healthy sows from 10 provinces in China / 中华流行病学杂志

Objective To determine the distributions of major pathogenic capsular types and in vitro antimicrobial susceptibility of different serotypes of Streptococcus suis isolated from clinically healthy sows in China. Methods Tonsil specimens of clinically healthy sows from 10 different provinces in China were collected, a total of 421 S.suis were isolated. Capsular types of S.suis were decided using the sera agglutination reaction. Antimicrobial susceptibility testing was performed using a broth microdilution method and the differences between serotypes were decided statistically. Results The prevalent capsular types of S.suis isolated from clinically healthy sows were 9(26.6% ), 3 (23.5%) and 7(15.7% ) types, respectively. 7.4% of isolates were confirmed to be S.suis type 2. Overall, differences in antimicrobial susceptibility among serotypes of S. suis were found. By comparison, lower resistance was observed for S.suis type 2 from clinically healthy sows. Conclusion The prevalence of pathogenic S.suis serotypes from clinically healthy sows again indicates S.suis is a conditional pathogenic bacterium. Differential prevention and treatment regimes should be considered according to antimicrobial susceptibility of different serotypes of S.suis.

SEQUENCE ANALYSIS OF THE PARTICAL CODING SEQUENCE OF E2 GENE OF 22 HOG CHOLERA VIRUS STRAINS / 微生物学通报

s:The partical coding sequence of E2 gene of 13 Hog Cholera Virus(HCV) field isolates, Shimen strain, Chinese vaccine strain(C strain) and Thiverval strain attenuated by low temperature in France,were obtained by reverse trancriptase -polymerse chain reation (RT-PCR) and sequenced.All size were 251bp.The obtained 224bp sequences were analysed by DNA star and compared with the previously published sequences of Alfort strain ,Brescia strain and other references strains.The results showed that those sequencing fragments of 13 HCV field strains were the sequence of E2 gene of HCV.Compared with Shimen strain,the base substitute of all stains were randomly distributed in the entire sequence,and had not base insert and base gap.The variation most occurred at 3' end. The identity of nucleotide sequence and amino acid sequenceof 22 HCV strains were 78.1%～100%?78.4%～100%. The identity of nucleotide sequence and amino acid sequence of 13 HCV field strains were 78.1%～100%?78.4%～100%.The identity of nucleotide sequence and amino acid sequence of 4 HCV field strains isolated in the 1970s～1980s were 79.0%～88.3%?81.1%～87.8%.The identity of nucleotide sequence and amino acid sequence of 9 HCV field strains isolated in the 1990s were 80.8%～100%?83.8%～100% respectively. This paper showed that the genetic variation of HCV was diversity.