Molecular Typing of Shigella flexneri 4c and 2a Isolates from Diarrhea Surveillance by Pulse Field Gel Electrophoresis

Objective:To find the molecular characteristic of Shigella flexneri 4c(F4c) and 2a isolates(F2a) from diarrhea surveillance in some area of Beijing, China.Methods:S.flexneri isolates(10 stains as F4c, 20 strains as F2a) from patients in diarrhea patients in Beijing during 2005 and 2006 were serotyped.Antibiotic resistances of these isolates were mea-sured by the Kirby-Bauer method.Invasive plasmid antigen gene ipaH was examined by PCR.Pulse field gel electrophoresis(PFGE) was performed for molecular typing.Results:10 isolates of S.flexneri were confirmed as F4c, of them 7 isolates tested were quite different in PFGE patterns with Dice coefficient from 0.77 to 0.92.However the PFGE patterns of S.flexneri 4c and 2a isolates were demonstrated with adistinct PFGE pattern(Dice coefficient0.8).The antibiotic resistance patterns with 14 kinds of antibiotics had a little difference among the F4c and F2a isolates.Conclusion:PFGE might distinguish the isolates F4c and F2a.Some differences in PFGE patterns, serotypes and antibiotic resistance patterns might occur among S.flexneri 4c isolates during epidemic.