摘要
OBJECTIVE:To understand the change of the dominant serogroup of Shigella spp.causing dysentery,their antimicrobial resistance over more than two decades in Tianjin,their phylogenetic similarity and to determine their evolutionary biology by using REP-PCR and MLST in order to study their epidemiological character.METHODS:96 strains of Shigella spp were isolated and their serogroups identified.16 different kinds of antimicrobial agents were used to study their characters of drug resistance.Multi-locus Sequence Typing was performed to determine their lineage and phylogenetic similarity.Repetitive Extragenic Palindromic Polymerase Chain Reaction(REP-PCR) typing was used to study the homology of their genomic DNA.RESULTS:The isolated rate of group D Shigella in 2009 and 2010 had obviously increased.Antimicrobial susceptibility test results showed that the resistant rates of the 1981-1983 Shigella flexneri to tetracycline,streptomycin and chloramphenicol varied from 76.47 to 100%,but,they were all sensitive to gentamicin,amikacin,the third and fourth Generation Cephalosporins,quinolones and Imipenem.However,between 2009-2010,the resistance rates of the isolated Shigella flexneri to gentamicin,amikacin,third and fourth Generation Cephalosporins and quinolones had increased.Multi-locus Sequence typing results produced five sequence types(ST) and two sequence type complexes.REP-PCR showed DNA band similarities between the 1981-1983 and 2009-2010 strains.CONCLUSIONS:The dominant serogroup of Shigella in Tianjin has changed from Shigella flexneri to Shigella sonnei.Increased drug resistance of Shigella flexneri is higher than Shigella sonnei because a great variety of antibiotics has been used.Shigella sonnei were 100%susceptible to the fourth Generation Cephalosporins and quinolones.The MLST results showed that the 1981-1983 strains had the same sequence type(ST)with some of the 2009-2010 strains.REP-PCR was a valid and rapid genotyping method for homological analysis and tracking the source of infection during epidemic outbreak.Combination of MLST and REP-PCR produced better discriminatory power than using either method alone.
OBJECTIVE:To understand the change of the dominant serogroup of Shigella spp.causing dysentery,their antimicrobial resistance over more than two decades in Tianjin,their phylogenetic similarity and to determine their evolutionary biology by using REP-PCR and MLST in order to study their epidemiological character.METHODS:96 strains of Shigella spp were isolated and their serogroups identified.16 different kinds of antimicrobial agents were used to study their characters of drug resistance.Multi-locus Sequence Typing was performed to determine their lineage and phylogenetic similarity.Repetitive Extragenic Palindromic Polymerase Chain Reaction(REP-PCR) typing was used to study the homology of their genomic DNA.RESULTS:The isolated rate of group D Shigella in 2009 and 2010 had obviously increased.Antimicrobial susceptibility test results showed that the resistant rates of the 1981-1983 Shigella flexneri to tetracycline,streptomycin and chloramphenicol varied from 76.47 to 100%,but,they were all sensitive to gentamicin,amikacin,the third and fourth Generation Cephalosporins,quinolones and Imipenem.However,between 2009-2010,the resistance rates of the isolated Shigella flexneri to gentamicin,amikacin,third and fourth Generation Cephalosporins and quinolones had increased.Multi-locus Sequence typing results produced five sequence types(ST) and two sequence type complexes.REP-PCR showed DNA band similarities between the 1981-1983 and 2009-2010 strains.CONCLUSIONS:The dominant serogroup of Shigella in Tianjin has changed from Shigella flexneri to Shigella sonnei.Increased drug resistance of Shigella flexneri is higher than Shigella sonnei because a great variety of antibiotics has been used.Shigella sonnei were 100%susceptible to the fourth Generation Cephalosporins and quinolones.The MLST results showed that the 1981-1983 strains had the same sequence type(ST)with some of the 2009-2010 strains.REP-PCR was a valid and rapid genotyping method for homological analysis and tracking the source of infection during epidemic outbreak.Combination of MLST and REP-PCR produced better discriminatory power than using either method alone.
引文