Detecting On The Virulence Genes And Molecular Typing Of Shigella Boydii Isolated From Clinical

Objective: According to the ways of biochemical identification and susceptibility of antimicrobial and the technology of PCR and PFGE,making a detailed research on Shigella boydii isolated form stool samples of patients with diarrhea from the Enteric Disease Clinic of the Second Hospital of Tianjin Medical University in June-October 2015 by the 2015,further understanding the virulence genetic distribution,drug resistance,molecular typing and the epidemiological relativeness between strains of the Shigella boydii.Methods: 1.Drug susceptibility analysis: Adoptintg method of Kirby-Bauer disk diffusion : including thirteen drugs: Ampicillin(AMP)? Ceftazidime(CTZ)? streptomycin(STR)?gentamycin(GM)?Compound sulfamethoxazole(SMZco)? Cefotaxime(CTX)? Ceftriaxone(CTR)? tetracycline(TE)? Novo levofloxacin(NOR)?Left-ofloxacin(LVP)?Amikacin(AMK)?Cefoperazone-sulbactam and Imipenem(IMP)2.Using the technology of polymerase chain reaction to amplificate the.virulence genes:ipa H,ial,set1 A,set1B,sen,vir A,ics A,sat,pic,sep A,Sig A.3.Adopting the technology of MLST and PFGE to analysis relationship between Shigella.Results: 1.Serotyping and biochemical identification: nine strains of Shigella boydii are divided into 3 subgroups: subgroups I(C2),subgroups II(C10,C12),subgroups IV(C4,C8,C14,C15,C16).2.All of the 9 isolates were multidrug resistant.The resistant rate of these strains for ampicillin was 100%(9/9),and then the resistant rates of these strains for 3.ceftazidime,streptomycin,gentamicin,trimethoprim/sulfamethoxazole,cefotaxime,ceftriaxone,norfloxacin and levofloxacin were 11.1%(1/9),44.4%(4/9),44.4%(4/9),44.4%(4/9),55.6%(5/9),55.6%(5/9),66.7%(6/9),66.7%(6/9)and 66.7%(6/9),respectively.All of these strains were sensitive to amikacin,cefperazone-sulbactam and imipenem.4.The ipa H was carried by all the testing strains,and none of the strains carried the sen,set1 A,set1B,ial,vir A,ics A and Sig A.The detective rates of pic,sep A and sat were 4/9,5/9 and 7/9 strains,respectively.The genes of pic?sat?sep A were detected in three isolates simultaneously.one isolate was detected two genes of pic and sep A simultaneously,.one isolate was detected two genes of sat and sep A simultaneously.5.Nine shigella boydii strains were divided into 8 PFGE types.The similarity between the spectrums of PFGE was 63.21% ~ 100%.>90% to similarity judgment for the same clone group:C10 and C13 belong to same gene type which similarity is 100%.The other isolates keep each one gene type.According to analysis of nine strains in MLST:strains of C10 and C13 belong to ST131: adk(53)?fum C(40)?gyr B(47)?icd(13)?mdh(36)?pur A(28)?rec A(29);,strains of C4?C8?C12?C14?C15?C16 belong to ST648: adk(92)?fum C(4)?gyr B(87)?icd(96)?mdh(70)?pur A(58)?rec A(2);just one isolate of C2 belong to ST10: adk(10)?fum C(11)?gyr B(4)?icd(8)?mdh(8)?pur A(8)?rec A(2)Conclude: 1.The result of biochemical reaction of nine Shigella boydii according with Escherichia coli 2.All strains of Shigella boydii tested in this study are multidrug-resistant,resistance rate of LVP is very high 3.The invasion plasmid Antigen ipa H exist in all strains,getting a same conclusion compared with other serogroup 4.Through the analysis of PFGE and MLST showed that the epidemiological correlation of Shigella boydii is low,with the treatment time of patients,clinical symptoms,diagnosis of infection may be sporadic.Although the separation number has increased,the reasons for increasing separation rate also needs further research in the circumstance of lacking epidemiologic date.