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Objective:To investigate the distribution of integrons and plasmid-mediated quinolone resistance (PMQR) genes in clinical isolates of Klebsiella aerogenes and to analyze the relationship between integrons and bacterial resistance to antimicrobial agents. Methods:Ninety-one Klebsiella aerogenes strains isolated from clinical samples in the Fengxian District Central Hospital from November 2015 to March 2021 were used in this study. Class 1 and class 2 integron-integrase genes ( intI1 and intI2) and PMQR genes were screened by PCR. The types of promoters and gene cassette arrays of variable regions were determined by sequencing. Besides, the relationship between integrons and antimicrobial resistance was analyzed. Results:The resistance rate of the 91 Klebsiella aerogenes isolates to aztreonam was more than 40.00% and the resistance rates to other commonly used antimicrobial agents were less than 35.00%. Among the 91 isolates, 30 carried the intI1 gene, while none of them carried the intI2 gene. Seven class 1 integron gene cassette arrays of variable regions were detected and the gene cassette array of aac(6′)-11 C- ΔereA2- IS1247- aac3- arr- ΔereA2 was detected in Klebsiella aerogenes. PcH1 with weak activity was the predominant variable region promoter of class 1 integrons. The detection rates of intI1-positive and intI1-negative isolates in ICU, neurosurgery and other clinical departments were statistically different ( P<0.05). The resistance rate of intI1-positive isolates to some commonly used antibiotics was significantly higher than that of intI1-negative isolates ( P<0.05). qnrS gene was the prevalent PMQR gene. The detection rates of integrons and PMQR genes in Klebsiella aerogenes isolates was low except for the strains isolated in 2016. Conclusions:Antimicrobial resistance in Klebsiella aerogenes was closely related to integrons. The distribution of integrons in Klebsiella aerogenes strains isolated from different clinical departments was different, and the monitoring of drug-resistant strains should be strengthened in ICU and neurosurgery. The resistance to quinolones in Klebsiella aerogenes strains in this region was mainly related to qnrS gene.
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Objective:To explore the distribution of integrons in Escherichia coli isolated from community patients with urinary tract infections and their relationship with the phylogenetic groups and antimicrobial resistance. Methods:From November 2015 to December 2018, 152 isolates of E. coli that collected without repetition from the urine samples of outpatients in nephrology of Fengxian District Central Hospital in Shanghai, were studied retrospectively. Bacterial identification and antimicrobial susceptibility analysis was carried out by Phoenix 100 automatic microbiological analyzer. Class 1, 2 integron integrase genes, variable regions of integrons and the phylogenetic groups of isolated E.coli were screened by PCR. The type of promoters and gene cassette arrays of variable regions were determined by sequencing. The relationship of intergon with the phylogenetic groups and antimicrobial resistance was also analyzed. Results:The resistance rate of 152 E. coli to ampicillin was 70.39% (107/152), and the resistance rates to other antibacterial drugs were all less than 40.00%. Among the 152 E. coli isolates, class 1 integron integrase gene intI1 was detected in 65 isolates (42.76%), 8 gene cassette arrays and 14 antimicrobial resistance gene cassettes were detected in 68 class 1 integrons. The most popular gene cassette array was dfrA17-aadA5 (51.47%, 35/68), while the variable regions of class 1 integrons were failed to detected in 12 intI1-positive isolates. Five variable region promoters were detected in 68 class 1 integrons, with the relative weak promoter PcH1 to be the most popular type (77.94%, 53/68). The gene cassette array arr- 2-cmlA5-bla OXA-10-aadA1 was also detected in this study. 65 intI1-positive isolates were mainly belonged to group B2 and D. The class 2 integron integrase gene intI2 was detected in 4 isolates (2.63%,4/152), and their variable region gene cassette arrays were all dfrA1-sat2-aadA1. Conclusions:Class 1 integrons were closely related to antimicrobial resistance in E. coli isolated from community patients with urinary tract infection. Most of the variable region promoters of class 1 integrons were relatively weak promoters. The distribution of each phylogenetic group in the intI1-positive isolates was consistent with the distribution of the overall isolates. The gene cassette array arr-2-cmlA5-bla OXA-10-aadA1 was detected in E. coli.
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Objective To investigate the distribution of integrons in clinical isolates of carbapen-em-resistant Acinetobacter baumannii and their relationships to bacterial resistance to antimicrobial agents.Methods A total of 115 carbapenem-resistant Acinetobacter baumannii strains were isolated from clinical samples of patients from January to October, 2017. Phoenix 100 automatic microbiological analyzer was used for antimicrobial sensitivity analysis. Classes 1 and 2 integrase genes and carbapenemase-encoding genes, bla IMP , blaVIM , blaKPC , blaNDM and blaOXA-23 , were screened by PCR. The variable regions of integrons were amplified by long fragment PCR. The types of promoters and gene cassette arrays of variable regions were de-termined by sequencing and overlap PCR. Relationships between integrons and antimicrobial resistance were analyzed. Results The 115 isolates of carbapenem-resistant Acinetobacter baumannii were resistant to most commonly used antimicrobial agents, but sensitive to polymyxin E. All of the isolates carried blaOXA-23 gene and none of them were positive for blaIMP , blaVIM , blaKPC or blaNDM gene. Class 1 integrase gene intI1 was de-tected in 40 isolates (34. 8％ ), while class 2 integrase gene intI2 was not detected. Two gene cassette ar-rays of variable regions, aacA4-catB8-aadA1 (39 isolates) and aacC1-gacP-gacQ-aadA1a (23 isolates), were detected in intI1-positive isolates. Twenty-two isolates carried both aacA4-catB8-aadA1 and aacC1-gacP-gacQ-aadA1a. The upstream promoters of the variable regions were relatively strong promoters, PcH2 and PcS. The gene cassettes of the variable regions endowed bacteria with resistance to chloramphenicol and aminoglycoside antibiotics. The resistance rate of class 1 integron-positive isolates to compound sulfamethox-azole was higher than that of negative strains. However, their resistance rate to ampicillin/sulbactam was lower than that of negative strains. Conclusions Antimicrobial resistance in carbapenem-resistant Acineto-bacter baumannii was serious. Carbapenem resistance was associated with blaOXA-23 gene. The types of pro-moters of variable regions in class 1 integrons were all relatively strong promoters. Class 1 integrons were closely related to sulfonamides resistance.
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Molecular testing are more and more widely used in clinical practice. The premise of clinical application is the verification or validation of the molecular testing procedure. Establishing a verification and validation model suitable for the testing procedures of clinical molecular testing is helpful for the practitioners of clinical molecular testing to carry out the verification and validation work more conveniently and efficiently. It is also helpful for the standardization of testing and quality control significantly. This article will elaborate on the status of verification and validation of molecular testing projects, the requirements of the ISO15189 accreditation system, the establishment of verification validation models and the prospects in the field.
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Objective To investigate the diagnostic value of hypersensitive troponin I (hs-cTnI) , homocysteine (Hcy) , hypersensitive C-reactive protein (hs-CRP) and calcitonin (PCT) detection in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) .Methods Ninety-six patients with AECOPD were enrolled in this study.50healthy subjects were included in the healthy control group.Hs-cTnI was measured by electrochemiluminescence, Hcy level was measured by circulating enzyme method, hs-CRP level was determined by immunoturbidimetry, and colloidal gold blotting was performed.PCT levels, correlation analysis using Pearson correlation analysis, analysis of the correlation between the indicators and AECOPD, using ROC curve analysis of hs-cTnI, Hcy, hs-CRP, PCT diagnosis COPE acute exacerbation curve area (AUC) .Results The levels of hs-cTnI, hs-CRP and PCT in the AECOPD group were higher than those in the healthy control group (P<0.05) .The Hcy in the AECOPD group was lower than that in the healthy control group.The difference was not statistically significant (P>0.05) .Pearson correlation analysis shows that hs-cTnI, hsCRP and PCT were positively correlated with AECOPD (r=0.346, 0.401, 0.509) , and Hcy had a poor correlation with AECOPD (r=0.078) .In the ROC curve analysis, the area under the curve (AUC) for hs-cTnI, hsCRP, and PCT were 0.825, 0.834, and 0.922, respectively, The best diagnostic cut-off values were:0.082, 18.25, 3.075, and the sensitivities were 0.823, 0.802, and 0.781, respectively.The specificities were:0.92, 0.62, and 0.94.Youden′s index was 0.743, 0.422, and 0.721, respectively.The kappa values are:0.699, 0.423, 0.664.Conclusion The detection value of Hcy in the diagnosis of AECOPD is low.The detection of hs-cTnI, hsCRP and PCT has a certain diagnostic value in AECOPD.It can be used as an auxiliary diagnosis index of AECOPD.
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Objective To investigate the value of real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) in the detection of Streptococcus agalactiae in early screening of Streptococcus agalactiae in pregnant women in the third trimester, and to study the effect of Streptococcus agalactiae infection on them.Methods A retrospective analysis of 5 855pregnant women with vaginal discharge and rectal secretions from January 2017to January 2018in our hospital were performed to detect Streptococcus agalactiae by RT-qPCR.Meanwhile, 100vaginal non-vaginosis women in the third trimester were selected as the negative group and100healthy women as the control group.The vaginal micro-environment-related indexes (Lactobacilli content, flora diversity and cleanliness) of three groups were analyzed.Results The total carrier rate of Streptococcus agalactiae of the third trimester from January 2017to January 2018in our hospital was 9.6％, of which vaginal carriage rate was 2.4％, rectum carriage rate was 7.2％, Streptococcus agalactiae positive group (GradeⅡ-Ⅲ), rates of population diversity (GradeⅡ-Ⅲ) cleanliness (Ⅰdegree) and microenvironment imbalance were 30.1％, 36.4％, 25.9％and 76.2％respectively, while those in the negative group were 58.0％, 55.0％, 61.0％and 63.0％and those in the control group were 87.0％, 91.0％, 83.0％, 24.0％.The positive rate of Streptococcus agalactiae in each group was significantly higher than that in the control group (P＜0.05).The differences of all the indexes between the negative group and the control group were also statistically significant (P＜0.05).Conclusion The carrying rate of Streptococcus agalactiae in third trimester pregnancy in our hospital was within the normal range reported in the literature.The detection of Streptococcus agalactiae by RT-qPCR could be effectively screened and monitored.Carrying Streptococcus agalactiae might increase the risk of vaginal infection in third trimester women.
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Molecular diagnosis plays more and more important role in disease diagnosis, prognosis evaluation and curative effect monitoring.With the support of relevant national policies and the gradual release of accurate medical needs from society, molecular diagnosis relies on its advantages of accuracy, convenience,sensitivity, non-invasiveness and automation to develop rapidly in the direction of precision inspection.The application of molecular diagnostic automation is undoubtedly the catalyst for the development of molecular diagnostics, but its application status is far from satisfactory.It is necessary to analyze the causes,study countermeasures and look forward to the future.
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Objective To analyze the structures of atypical class 1 integrons in clinical Proteus isolates. Methods This study included 26 class 1 integron integrase gene-positive clinical Proteus isolates, from which the variable regions of class 1 integrons could not be amplified. Six isolates were chosen from them to amplify the flanking DNA segments of class 1 integron integrase gene using inverse PCR. The se-quences of PCR products were analyzed with BLAST to identify the target homologous sequences as well as their accession numbers in GenBank. Primers for overlap PCR were designed according to the flanking se-quences. Then the 26 clinical Proteus isolates were analyzed with overlap PCR and sequencing analysis. Re-sults The variable regions of class 1 integrons in 25 out of the 26 clinical Proteus isolates were completely or partly identified by using inverse PCR,overlap PCR and sequencing analysis. A gene cassette array of estX-psp-aadA2-cmlA1-aadA1a-qacI-tnpA-sul3 was detected in 22 isolates. The variable regions of class 1 integrons in the other three isolates were identified to be estX-psp-aadA2-cmlA1,dfrA14 and IS26,respectively. All of the 25 isolates lacked the 3'conserved segements in class 1 integron. Conclusion Inverse PCR can be used to analyze the structures of atypical class 1 integrons. Gene cassette psp and gene cassette arrays of estX-psp-aadA2-cmlA1-aadA1a-qacI-tnpA-sul3 and estX-psp-aadA2-cmlA1 in clinical Proteus isolates are reported for the first time.
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Objective To develop a simple high-resolution melting ( HRM) analysis method for differentiation of Pc and P2 variants in class 1 integron.Methods DNA fragments containing Pc and P2 variants were amplified from plasmids pACW ( PcW ) and pACWP2 ( PcW-P2 ) respectively , then these purified PCR products and P 2 promoters were analyed full-length amplicon by HRM .Eight DNA fragments containing different Pc promoters were amplified and site-specific mutated from plasmids pACS ( PcS ) , pACH2 ( PcH2 ) , pACH1 ( PcH1 ) , pACW ( PcW ) , genomic DNA of Klebsiellar pneumonia HS07-68 (PcWTGN-10)and HS05-1792(PcH2TGN-10)respectively.The purified PCR products and eight Pc variants were characterized by HRM analyses of an unlabeled probe and full-length amplicon.This assay was applied to the differentiate Pc and P2 variants in 109 class 1 integrons from 95 urine clinical Escherichia coli isolates in Huashan Hospital during 2004 -2007.The differentiation results were compared with that determined by direct sequencing .Results P2 promoter with a significant higher melting temperature ( Tm ) can be identified by HRM analysis clearly .P2 promoters were identified in 2 class 1 integrons and consistent with direct sequencing results .Eight Pc variants were classified into three groups: PcS, PcSTGN-10 , PcW, PcWTGN-10, PcH1, PcH1TGN-10.Using direct HRM analysis.PcH2, PcH2TGN-10 were classified into four groups:PcS, PcH1, PcH2, PcW, PcSTGN-10 , PcH1TGN-10 , PcH2TGN-10 , PcWTGN-10 according to the melting curves of the unlabeled probe .Combined the HRM analyses of the whole amplicon and unlabeled probe , the eight Pc variants can be differentiated from each other .Five different Pc variants, PcS, PcW, PcH1, PcH2TGN-10 and PcWTGN-10 , were identified and consistent with direct sequencing results .Conclusions This developed a simple Pc and P 2 variants differentiation method via simultaneous HRM analyses of an unlabeled probe and full-length amplicon .This method is cost-effective and accurate , could be used in differentiation of Pc and P2 variants of class 1 integrons in clinical isolates .
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Objective To understand the infection status and distribution characteristics of human papillomavirus (HPV)in fe-male genital tract in Fengxian district of Shanghai City in order to provide preliminary recommendations for prevention and treat-ment of HPV in this area.Methods The women aged over 1 6 years old receiving HPV testing in the Southern branch Hospital of Shanghai Sixth People′s Hospital From January 2011 to December 2015 were taken as the research subjects and their cervical secre-tions were performed the HPV 21 subtypes detection,among them,1 374 cases underwent colposcopic fixed point biopsy of cervix for determining the pathological grade.Then the data were recorded and analyzed by the SPSS20.0 software.Results Twenty-one HPV subtypes were detected,in which the HPV positive rate was 17.54% (6 313/35 977),and types with high HPV infection rate in these five years were in turn HPV18,HPV52,HPV16,HPVCP8304,HPV58,HPV53,HPV53,HPV53 and HPV58;the HPV positive rate in 1374 cases of cervical lesions was 82.75% (237/1 374),the common types distributions in cervical lesions were HPV16,HPV58,HPV52,HPV18 and HPV31 respectively.Conclusion The HPV infection situation in Fengxian district of Shang-hai City has certain regional characteristics.Then the HPV prevention and treatment strategy suitable for this region may be formu-lated according to the research results.
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Objective To establish a high resolution melting based method for the rapid identifica-tion of functional class 2 integron.Methods Nighty-nine non-repetitive Proteus spp.strains positive for genes encoding class 2 integrase were isolated from August, 2011 to August, 2012.The genomic DNAs were extracted and used as templates to amplify 60 base pair fragments containing the mutated point in class 2 in-tegrase gene by PCR.The high resolution melting analysis was conducted to identify the functional class 2 in-tegrons that were further compared by sequence analysis.Results There were remarkable differences with the high resolution melting curves between the functional class 2 integrons and the ordinary class 2 integrons. The results of high resolution melting analysis were consistent with those by using sequence analysis.Con-clusion High resolution melting analysis could be used for the rapid and accurate identification of functional class 2 integron.
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ObjectiveTo prepare antiserum specific to aminoacy1-3″-adenylyltransferase [ AAD (3″) ],and to explore the application value of the prepared antiserum in detecting the expression levels of aadA2 gene that downstream of 8 different promoters (PcS,PcH2,PcH1,PcW,PcS-P2,PcH2-P2,PcH1P2 and PcW-P2 ) of variable regions in class 1 integron.MethodsaadA2 gene was amplified by polymerase chain reaction(PCR) and cloned into the expression plasmid pET19b.After inducing,the recombined aminoacy1-3″-adenylyltransferase[ AAD(3″)] with His-tag was expressed,purified and immunized rabbits to get anti- AAD(3″) specific serum.The prepared antiserum was used to detect the translation levels of aadA2 gene that downstream of different promoters of variable regions in class 1 integron by Western blotting (WB).Broth microdilution method was used to detect the minimal inhibitory concentrations (MIC) to streptomycin in Escherichia coli JM109 with aadA2 gene downstream of different promoters of variable regions.ResultsRecombined AAD (3″) expression plasmid pET19b-aadA2 was constructed successfully and was verified by sequence analysis.After transformed into E.coli BL21 ( DE3 ),a resoluble recombined AAD(3″) high expression strain was obtained.After fermentation,recombined AAD(3″) was purified and immunized rabbits.The anti- AAD(3″) specific serum was obtained with titer ＞ 1∶100 000.WB was used to detect the expression levels of AAD (3″),the translation product of aadA2 gene,that downstream of 8 different promoters of variable regions.The relative expression level of AAD (3″) that downstream of PcW was assumed to be 1,then the relative expression levels of AAD(3″),which all were detected 3 times independently,that downstream of PcS,PcH2,PcH1,PcS-P2,PcH2-P2,PcH1-P2 and PcW-P2 were 12.9±2.3,9.1±1.0,2.0±0.4,16.0±1.3,14.1 ±1.3,10.5±0.7 and 8.9 ±1.7 respective.Very different expression levels of AAD (3″) that downstream of different promoters of variable regions were obtained( F =32.421,P ＜ 0.01 ).The mean values of MIC,which all were detected 3 times independently,to streptomycin in E.coli JM109 with aadA2 gene downstream of PcS,PcH2,PcH1,PcW,PcS-P2,PcH2P2,PcH1-P2 and PcW-P2 were 256,256,64,128,32,128,4 and 64 mg/L respective.These results indicated the different expression levels of aadA2 gene that downstream of different promoters of variable regions can confer their host bacteria different resistance levels to streptomycin.Conclusions Resoluble recombined AAD(3″) is purified successfully and high titer anti- AAD(3″) specific antiserum is obtained from the immunized rabbits.This laid foundation for further investigation on the correlationship between the expressions of intI1 gene and the gene cassettes within variable regions.The expression levels of antibiotic gene cassettes that downstream of different promoters of variable regions are very different,so are the very different antibiotic resistance levels of the host bacteria.Therefore more attentions should be paid to the researches on the classification of promoters of variable regions when molecular epidemiology studies on the class 1 integrons in clinical isolates were conducted.
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ObjectiveTo determine whether aadA2 gene can be translated from the ATG triplet,which there was no plausible ribosome binding site preceding it,and synthetized a functional protein in class 1 integron.MethodsSite-specific mutagenesis was used to construct aadA2 gene cassette with different start codons,together with their upstreamed promoters of variable regions were cloned into plasmid pACYC184 respective.The constructed plasmids were then transfored into Escherichia coli JM109,Western blot was used to detect the translation products of aadA2 gene with different start codons.Broth microdilution method was used to detect the minimal inhibitory concentrations to streptomycin in Escherichia coli JM109 containing aadA2 gene with different start codons.ResultsaadA2 gene can initiate translation from both ATG and GTG triplets in aminoacyl -3-adenylyltransferase protein synthesis,though there was no plausible ribosome binding site preceding the ATG triplet.Besides GTG and ATG triplets,there was other start codon downstream of the GTG triplet in aadA2 gene.The translated products that initiated from the start codons that described above were all functional AAD(3) proteins that can be detected by anti- aminoacyl -3-adenylyltransferase polyclonal antisera in Western blot and conferred different resistance levels to streptomycin in E.coli.ConclusionWhen inserted as the first gene cassette in class 1 integron,aadA2 gene can initiate translation from ATG triplet and synthetized a functional protein,though there was no plausible ribosome binding site preceding it.This structural characterization of class 1 integron can initiate translation of the open reading frame harbored in gene cassette that integrated into class 1 integron,though there was no plausible RBS preceding the start codon.This make class 1 integron be more convenience to express the genes that capture from environment.
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Objective To understand the epidemic characteristics of an outbreak of panresistance Klebsiella pneumoniae occurred between 2006 and 2009 in a university hospital of Shanghai, China. Methods A total of 57 panresistance K. pneumoniae isolates were collected from August 2006 to December 2009.Antibiotic susceptibility of the isolates were determined by Kirby-Bauer disc diffusion method and microbroth dilution (MBD). ESBLs-producing initial screen test and phenotypic confirmatory test and carbapenemase-producing modified Hodge test ( MHT) were performed to detect the resistance phenotype of the isolates. Be-ta-lactamases were studied by IEF, PCR and the product sequencing. While conjugation assay were conducted to understand the transferability of these genes. The genetic relationship between isolates was established by ERIC-PCR and multilocus sequence typing (MLST). Except for the antibiotics recommended by CLSI guideline in the routine test, the other antibiotics were added to find out the effective drugs to treat the infection. Results All 57 isolates were highly resistant to all examined antibiotics. All isolates produced ESBLs and carbapenemase. IEF revealed that each isolate produced four beta-lactamases. All isolates carried blaKPC-2,blaCTX-M-14,blaSHV12,blaTEM-1,qnrB and aac(6') - I b-cr. Forty-four of the 57 (77.2% ) isolates were successful to transfer their resistance genes to E. coli recipient J53 by conjugation assay. By RAPD, all 57 isolates were grouped into two genotypes that were further identified as members of MUST types 423 and 11.Sequence types 423(ST423) only occurred before May 2008 and ST11 occurred (52 isolates) after May 2008. Most of isolates of the outbreak were ST11 (91. 2% ). A part of isolates were susceptive to added antibiotics. Conclusion The outbreak of panresistance K.pneumoniae was caused by those isolates which carried multiple resistant genes. There is a different ability of dissemination between different ST types K. pneumoniae isolate. It was necessary to add the antibiotics to find out the effective drugs to treat the infection.
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Objective To detect quantitatively AKAP12 methylation and evaluate its clinical significance in peripheral blood in colorectal cancer. Methods MS-HRM technology was used to detect quantitatively AKAP12 methylation in peripheral blood from 80 colorectal cancer patients and 20 healthy volunteers. They also validated the reproducibility and compared with MSP. Results Thirty-eight of the 80 colorectal cancer samples (47. 5% ) were found to be methylated at the AKAP12 promoter region by MS-HRM (the methylation levels of 24 cancer samples ranged between 1 % and 20% , the methylation levels of 12 cancer samples ranged between 20% and 60% , the methylation levels of 2 cancer samples ranged between 60% and 100% ). The methylation levels of 2 health samples were less than 10% . They also compared the results generated by MS-HRM with a traditional MSP assay. The AKAP12 MS-HRM assay was able to reproducibly detect 1% AKAP12 methylated DNA, whereas the MSP method was unable to detect less than 10% methylation. No significant correlation was observed between the AKAP12 methylation levels and patients' age and gender. However, AKAP12 methylation was significantly higher in DNA from colorectal cancer patients with high Dukes stage and differentiation (x2 =5. 93 or 8. 41, P = 0.01). Conclusions The authors demonstrate here for the first time, the utility of quantitative AKAP12 MS-HRM analysis of promoter methylation in peripheral blood samples. AKAP12 MS-HRM quantitative methods have many promising applications in the detection of colorectal cancer.
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Objective To establish a new method, applying high resolution melt, to discriminate the VEB-3 hypotype from the clinical gram negative isolates. Methods From January to December 2003,292 consecutive and non-repetitive gram-negative bacteria producing VEB extended spectrum β-lactamase (ESBL) were collected. Extract the DNA of clinical gram negative isolates with phenol-chloroform. PCR was performed to amplify the VEB gene with the DNA being template. After that, we amplify the fragment of VEB gene containing the position 168. Then we detect the high resolution melt curve and analyze them. At last, we analyze the results of sequence and high resolution melt( HRM ). Results VEB-1 and VEB-3 gene are markedly different through HRM analysis. Conclusion It is accurately and quickly for us to identify the VEB-3 from other hypotype through the technology of HRM.
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Objective To investigate the prevalence of VRE in Huashan hospital of Shanghai from 2007 to 2009, and to examine the molecular characteristics of the VRE isolates.Methods A total of 890 non-repetive clinical isolates of Enterococcus were screened by the agar screening method ( ADSP method).Broth dilution susceptibility test was performed to determine the antimicrobial susceptibility of Enterococcus isolates to vancomycin and teicoplanin.The resistant genes and virulent genes of VRE isolates were investigated by PCR and sequencing methods.VRE isolates were classified by MLST and six isolates of VRE from 2007 to 2008 were analyzed by PFGE.Results Thirteen VRE isolates were identified by ADSP method and broth dilution susceptibility test. Six of them were resistant to vancomycin but sensitive to teicoplanin ( vancomycin MICs were from 64 to 256 μg/ml).The sequencing data of PCR products indicated these isolates might harbor a potential novel vancomycin resistant gene, which was different from the one reported in previous studies. The rest 7 isolates harbored vanA gene. The MICs of these isolates to vancomycin and teicoplanin were 32 - 64 μg/ml and 16 - 32 μg/ml, respectively.MLST results revealed 4 STs were identified in 13 VRE isolates.Eleven isolates belonged to clonal complexes(CC) 17.The positive rates of esp gene and hyl gene were 69.2% and 30.8%, respectively.Conclusions This study suggests that the most common VRE clone in Huashan Hospital was CC17.A potentially novel vancomycin resistance gene was identified, and further work needs to be done to investgate the function and the location of this novel gene.
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Objective To investigate transcriptional expression and promoter CpG methylation status of A-kinase anchoring protein 12 (AKAP12) gene and analyze their correlation with clinical pathological stage in bladder transitional cell carcinoma. Methods AKAP12 mRNA expression level and promoter CpG metbylation status was measured by fluorescent quantitative RT-PCR (FQ-RT-PCR) and methylation specific PCR (MSP) in 30 bladder transitional cell carcinoma and adjacent normal tissues. The products of PCR were cloned and bisulfite sequenced. Results Decreased AKAP12 mRNA expression was demonstrated in 22 carcinomas (73. 3% ) and was significantly associated with turnout grade (P =0. 02).The frequency of promoter methylation of AKAP12 gene was 53. 3 % (16/30) and correlated with the tumor stage(r =0.52,Pn =0.03)and grade(r =0.61,Pn =0.01). Conclusion Aberrant promoter methylation of AKAP12 can result in the loss of gene expression and may association with bladder transitional cell carcinoma.
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Objective To establish a system for detecting integration frequency of antibiotic resist-ante integron.Methods We cloned integron and aadA2 gene cassette into different sites of plasmid pACYC 184,and the plasmid was transformed into E.coli BL21(DE3)containing plasmid overexpressing integrase.The positive clone was cultured overnight and then was spread on LB agar plate with or without streptomycin respectively,and with appropriate amount of bacteria.Clones after cultured overnight were counted to detect the integration frequency.Meanwhile we used positive clones in LB agar plate containing streptomycin as templates to carry out PCR.The purified PCR products were sequenced to identify the integration sites.Re-suits The integration frequency of integron capturing aadA2 gene cassette in BL21(DE3) host was 1.1 x 10-3 mainly at attI site.Conclusion This system can be used to detect integration frequency.