Gene typing of ESBLs-producing third-generation cephalosporins-resistant Shigella in Ningbo, China / 中国人兽共患病学报

We investigated the third-generation cephalosporins-resistant Shigella and its genotype in Ningbo,China,providing a basis for disease prevention and control.Pathogenic bacteria were analyzed by direct isolation combined with enrichment culture isolation.Antimicrobial susceptibility was determined by K-B disk diffusion method and PCR was used for detecting multidrug resistance genes like CTX-M,OXA,TEM and SHV.BLAST analysis was used to determine the genotype.Results showed that 69 strains of third-generation cephalosporins-resistant Shigella were detected by drug sensitivity screening,accounting for 74.19％ of ESBLs Shigella.Drug resistance gene CTX-M(CTM-M-1 and CTM-M-9),OXA and TEM were detected.The detection rate were 79.71％,79.01％ and 26.09％ respectively.With no CTX-M-2 and SHV,DNA sequence alignment showed CTX-M-1 group were mainly of CTX-M-15 type besides seven other types;CTX-M-9 group were mainly of CTX-M-14 type besides six other types;49 strains of OXA and 18 strains of TEM were sequenced to be type 1 (OXA-1 and TEM-1 type).The 21 Shigella strains carrying more than two drug resistance genes accounts for 30.43 ％.Shigella in Ningbo has high third-generation cephalosporins-resistance rate and many kinds of ESBLs enzymes were detected.The mainstream enzyme type was CTX-M,meanwhile they also carried a variety of drug resistance genes,which could bring difficulties to disease prevention and control.The high carrying rate of OXA-1 type suggests that we should pay more attention.The detection rate of group B was higher than that of group D,including not only the phenotype resistance but also the drug-resistance genes;these findings will be useful in the study of the drug resistance prevalence of Shigella.

Gene typing of Legionella pneumophila serogroup 1 in Sichuan Province, China / 中国人兽共患病学报

The aim of the research is to investigate the genetic characteristics of Legionella pneumophila serogroup1 (LP1)in Sichuan Province.The sequence-based typing (SBT) and multiple-locus VNTR analysis (MLVA) were used to describe the genetic polymorphism of 42 strains which were isolated from 1989-2016 in Sichuan Province,China.According to the reference,PCR was used to detect the 8-VNTR loci and 7 housekeeping genes respectively.The VNTR results were determined by using capillary electrophoresis,and the SBT results were sequenced and compared with the database of EWGLI.Results showed that totally 42 stains were divided into 8 MLVA types with the advantage types were M08 (47.6 ％) and M07 (23.8 ％).Twelve ST types were obtained with 3 main clonal complex and 2 singleton,including 2 novel ST types,among those,ST1 was the predominant type,accounting for 52.3 ％,following by ST630 (14.2 ％).In conclusion,our results demonstrated MLVA and SBT were both applied to the research for molecular epidemiological investigation of LP1 and showed the high genetic polymorphism and the regional specificity.The results also suggest that the isolates are a potential threat to the public,effective control and prevention strategies are urgently needed.

Gene typing of Legionella pneumophila serogroup 1 in Sichuan Province, China / 中国人兽共患病学报

The aim of the research is to investigate the genetic characteristics of Legionella pneumophila serogroup1 (LP1)in Sichuan Province.The sequence-based typing (SBT) and multiple-locus VNTR analysis (MLVA) were used to describe the genetic polymorphism of 42 strains which were isolated from 1989-2016 in Sichuan Province,China.According to the reference,PCR was used to detect the 8-VNTR loci and 7 housekeeping genes respectively.The VNTR results were determined by using capillary electrophoresis,and the SBT results were sequenced and compared with the database of EWGLI.Results showed that totally 42 stains were divided into 8 MLVA types with the advantage types were M08 (47.6 ％) and M07 (23.8 ％).Twelve ST types were obtained with 3 main clonal complex and 2 singleton,including 2 novel ST types,among those,ST1 was the predominant type,accounting for 52.3 ％,following by ST630 (14.2 ％).In conclusion,our results demonstrated MLVA and SBT were both applied to the research for molecular epidemiological investigation of LP1 and showed the high genetic polymorphism and the regional specificity.The results also suggest that the isolates are a potential threat to the public,effective control and prevention strategies are urgently needed.

PCR sequencing for detection and gene typing of hantavirus isolated from rodents / 中国实验动物学报

Objective To evaluate the application value of PCR-sequencing in clinical detection of hantavirus in rodents .Methods Based on 7 subtypes and 24 strains of representative hantavirus strains downloaded from Genbank , the virus S gene fragments were used for primer design and neighbor joining method was applied for phylogenetic analysis . Thereafter, we identified hantavirus strains isolated from wild rodents in recent years in Zhejiang Province by this method . Results The 24 analyzed strains were divided into 5 regions in the phylogenetic tree .Four of them with topology structure were more stable .Eleven strains of the virus were amplified by PCR and sequenced , and the results showed that the prim-ers were with high sensitivity and specificity .Three HTN strains and 1 strain of serotype SEO were distinguished from 9 strains of unknown strains isolated in Zhejiang Province .We also found that 5 strains of hantavirus belonging to two un-known serotypes .Discussion Our results suggest that the PCR-sequencing method proposed in this study can be used for clinical detection of hantavirus .

Susceptibility phenotype of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus SCCmec genotyping / 中国基层医药

Objective To explore the characteristics of drug resistance of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus SCCmec genotyping.Methods The disc agar diffusion method was taken to test 500 Staphylococcus aureus susceptibility and methicillin-resistant Staphylococcus aureus by multiplex PCR SCCmec genotyping assay.Results The rate of methicillin-resistant Staphylococcus aureus was 40.0％ (200/500),and had a high resistance rate to clindamycin,sulfamethoxazole and tetracycline,which celebrate neomycin and quinolones resist ance rates,while a completely resistant to clindamycin and β-lactam drug,and other performance of multi-drug resist ance,resistance to vancomycin had not uncovered any prime strains; through SCCmec genotyping of MRSA,which mainly SCCmec Ⅲ and SCCmec Ⅳ well SCCmec Ⅴ type,another seven unclassified.Conclusion The separation of Staphylococcus aureus,methicillin-resistant Staphylococcus aureus performance of multiple drug resistance performance of its SCCmec genotyping is SCCmec Ⅲ type and SCCmec Ⅳ and SCCmec Ⅴ type.

Advance in the studies on key techniques of gene chips / 国际生物医学工程杂志

Gene chip is a recently developed high-throughput gene expression analyzing technique. Key techniques and new development of gene chip are reviewed in this paper, including carrier(or substrate) surface chemical modification, preparations of DNA fragment, preparation of gene chips, tagging of the probes, hybridization, and analysis of gene chips. Comprehensive introduction of advantages and disadvantages of various technical taches and elements are introduced in this article. Particular attention is paid to further improvement needed to promote the popularization and application of this technology.

Establishment of eight human platelet antigen systems and HLA-Ⅰ antigen donor bank in Guangzhou area / 中国输血杂志

Objective To establish eight human platelet antigen systems and HLA-Ⅰ antigen donor bank,and to determine the gene frequencies of human platelet antigen(HPA) and HLA-Ⅰin Guangzhou area.Methods A total of 805 blood samples from Chinese Han voluntary platelet donors were included in this study.PCR-SSP was used to detect single-nucleotide polymorphism in HPA systems.Luminex-SSO was used to detect the HLA-Ⅰantigens.Results The distribution of HPA 1,2,3,4,5,6,9,15 was in Hardy-Weiberg equilibrium among study subjects.Allele frequencies of 0.998 and 0.002 were observed for HPA 1a and 1b,0.952 and 0.048 for HPA 2a and 2b,0.553 and 0.447 for HPA 3a and 3b,0.999 and 0.001 for HPA 4a and 4b,0.976 and 0.024 for HPA 5a and 5b,0.982 and 0.018 for HPA 6a and 6b,1 and 0 for HPA 9a and 9b,0.518 and 0.481 for HPA 15a and 15b.The high frequency HLA-Ⅰ alleles were A*02,0.286;A*24,0.162;A*11,0.323;B*46,0.147;B*75,0.100;C*01,0.177;C*03,0.289;C*07,0.179.Conclusions This study confirmed the ethnic and territorial difference of HPA and HLA-Ⅰ.The establishment of HPA and HLA-Ⅰ matched plateletpheresis donor registry is helpful in the improvement in platelet transfusion.