[Application of multilocus enzyme electrophoresis in studies of taxonomy and population genetics of S. typhi in Xinjiang].
Multilocus enzyme electrophoresis (MEE) was employed to study the genotype taxon and population genetics of 154 isolates of S. typhi from Xinjiang in recent 11 years. Seven kinds of enzymes were examined and determined. One hundred and fifty-four strains of S. typhi were classified into 69 electroretic types (ETs) and 10 clones (CLa-CLj). Among those 154 strains 80 epidemic isolates belonged to 21 ETs and 3 clones (CLe, f, j). ET17, 20, 21, 24, 26, 27 were the main ETs (61.30%), and CLf was the dominant clone (95.00%). Seventy-four non-epidemic isolates belonged to 48 ETs and 9 clones (CLa, b, c, d, f, g, h, i, j), no obvious dominant ET was found in them, and the main clone CLh accounted for 43.30%. It demonstrated that both outbreak and sporadic epidemics could be caused by many strains of ETs and clones, but the distribution of the former ETs was more concentrated and the preponderance of clones was more obvious. The analyses on structure of population genetics indicated that all of 7 enzymes were polymorphic. Genetic diversity among the enzyme loci was quite high, with an average of 0.35 per locus (H). The average number of alleles per locus (h) was 6.14. There was no significant difference in h or H between the isolates of different sources (P > 0.05). It was clear that S. typhi of different sources in Xinjiang were originated from the same population. The results also showed that there was a dominant allele in every enzyme locus. Natural selection was the main role in the evolution of S. typhi.
Yang
S
S
Xinjiang Uighur Autonomous Regional Hygiene and Epidemic Prevention Station, Urumchi.
Xu
W
W
Liu
M
M
D000483:Alleles; D000818:Animals; D001219:Aspartate Aminotransferases / Q000235:genetics*; D004586:Electrophoresis / Q000379:methods; D005952:Glucose-6-Phosphatase / Q000235:genetics*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000235:genetics*; D011110:Polymorphism, Genetic; D012485:Salmonella typhi / Q000145:classification / Q000201:enzymology / Q000235:genetics*
D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D005952:Glucose-6-Phosphatase