Background: ESBL-producing strains of Klebsiella pneumoniae, one of the main causes of nosocomial and hospital-acquired infections, are commonly associated with therapeutic impasses. Surveillance of these multidrug-re...Background: ESBL-producing strains of Klebsiella pneumoniae, one of the main causes of nosocomial and hospital-acquired infections, are commonly associated with therapeutic impasses. Surveillance of these multidrug-resistant pathogens is a crucial tool for controlling and preventing infections. This surveillance involves the use of appropriate molecular and phenotypic typing techniques. The choice of techniques is based on criteria such as discriminatory power, intra- and inter-laboratory reproducibility, epidemiological concordance, ease of use and cost. The aim of our study was to identify clusters of Extended-Spectrum Beta-Lactamase-producing Klebsiella pneumoniae (ESBL-K. pneumoniae) strains circulating in neonatology using quantitative antibiogram (QA) and Pulsed Field Gel Electrophoresis (PFGE). Materials and Methods: This cross-sectional study included 55 K. pneumoniae strains isolated from a total of 513 samples. These various samples are taken from newborns, healthcare personnel, and the environment. K. pneumoniae identification followed standard bacteriological procedures and was confirmed using the Vitek® 2 (bioMérieux). The detection of the ESBL phenotype was performed using the synergy test. QA and PFGE were used to identify clonal relationships between the various strains isolated. Concordance between these two methods was assessed by calculating Cohen’s KAPPA coefficient and Simpson’s diversity index. Results: Among the 55 K. pneumoniae strains included in this study, 58.2% (32/55) were found to be Extended-Spectrum Beta-Lactamase (ESBL) producers. Most of these strains were isolated from neonatal samples (blood samples and rectal swabs). The quantitative antibiogram method applied to 28 out of the 32 ESBL-producing strains revealed that the isolates were grouped into 5 clusters. Pulsed Field Gel Electrophoresis performed on a total of 16 ESBL-producing strains showed the existence of four profiles. A perfect concordance was observed between the two methods. Conclusion: The results of this study highlighted the existence of clonal strains of various origins within neonatology units.展开更多
Objective To establish and compare the pulsed-field gel electrophoresis （PFGE）, multiple-locus variable number tandem repeat analysis （MLVA） and automated ribotyping for subtyping of Citrobacter strains. Methods P...Objective To establish and compare the pulsed-field gel electrophoresis （PFGE）, multiple-locus variable number tandem repeat analysis （MLVA） and automated ribotyping for subtyping of Citrobacter strains. Methods PFGE protocol was optimized in terms of plug preparation procedure, restriction enzymes and configuration of electrophoretic parameters. MLVA method was evaluated by finding variable number tandem repeats in two genomes of Citrobacter strains. The ribotyping was performed by using the automated RiboPrinter system. Results We optimized the plug preparation procedure, focused on the cell suspension concentration （turbidity of 2.5 to 3.5）, SDS addition （no SDS needed） and lysis time （1 h）, and selected the appropriate restriction enzyme （Xbal） and the electrophoretic parameters （1.0 s-20.0 s for 19 h） of PFGE. There was nearly no discriminatory power of MLVA between Citrobacter strains. For 51 Citrobacter strains, automated ribotyping gave a D-value of 0.9945, while PFGE gave a D-value of 0.9969. Both PFGE and automated ribotyping clustered strains from the same sources （with the same species from the same place at the same time identified as the same source） and divided strains from different sources （from different years, places and hosts） into different subtypes. Conclusion PFGE protocol established in this paper and automated ribotyping are suitable for application in Citrobacter subtyping.展开更多
Pulsed field gel electrophoresis(PFGE) has been firstly introduced in characterization of the pathogenic fungi Penicillium marne f fei and Exophiala dermatitidis genomes.The numbers and sizes of their chromosomes have...Pulsed field gel electrophoresis(PFGE) has been firstly introduced in characterization of the pathogenic fungi Penicillium marne f fei and Exophiala dermatitidis genomes.The numbers and sizes of their chromosomes have been detected.Polymorphism was identified on the smallest chromosome of E.dermatitidis.The result shows that PFGE for characterization of large molecular DNA pathogenic fungi is very suitable,it is more simple and more efficacy.The result also shows the diversity of pathogenic fungi is relative common even in rare occurred pathogenic fungi such as E.dermatitidis.展开更多
Objective To optimize the performance of Pulsed-Field Gel Electrophoresis （PFGE） for the comparison of inter-laboratory results and information exchange of Borrelia burgdorferi subtypingo Methods A panel of 34 strai...Objective To optimize the performance of Pulsed-Field Gel Electrophoresis （PFGE） for the comparison of inter-laboratory results and information exchange of Borrelia burgdorferi subtypingo Methods A panel of 34 strains of B. burgdorferi were used to optimize PFGE for subtyping. In order to optimize the electrophoretic parameters （EPs）, all 34 strains of B. burgdorferi were analyzed using four EPs, yielding different Simpson diversity index （D） values and the epidemiological concordance was also evaluated. Results The EP of a switch time of l s to 25 s for13 h and l s to10 s for 6 h produced the highest D value and was declared to be optimal for Mlul and 5mal PFGE of B. burgdorferi. Mlul and Smal were selected as the first and second restriction enzymes for PFGE subtyping of B. burgdorferi according to discrimination and consistency with epidemiological data. Conclusion PFGE can be used as a valuable test for routine genospecies identification of B burgdorferi.展开更多
Background The rise of the production of CTX-M class extended spectrum β-lactamases （ESBLs） has been well documented in traveling countries but no data are found for Macao, an international travel city. The objecti...Background The rise of the production of CTX-M class extended spectrum β-lactamases （ESBLs） has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China. Methods Antimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis （PFGE）. Results Imipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracylcline, ciprofloxacin, sulfamethoxazole trimethoprin and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs （76.2%）. Two strains showed indistinguishable patterns by PFGE. Conclusions The prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.展开更多
目的了解2013-2014年贵阳市腹泻监测病例中沙门菌的血清型别分布及脉冲场凝胶电泳(Pulse-Field Gel Electrophoresis,PFGE)分型特征,为贵阳市沙门菌病的防控提供科学依据。方法收集2013-2014年贵阳市4家哨点医院感染性腹泻病例的432份...目的了解2013-2014年贵阳市腹泻监测病例中沙门菌的血清型别分布及脉冲场凝胶电泳(Pulse-Field Gel Electrophoresis,PFGE)分型特征,为贵阳市沙门菌病的防控提供科学依据。方法收集2013-2014年贵阳市4家哨点医院感染性腹泻病例的432份粪便标本,对其进行沙门菌的分离培养、生化鉴定、血清分型及PFGE分型。结果 432例感染性腹泻患者的粪便标本共检出沙门菌35株,检出率为8.10%(35/432),男女检出之比为1.5:1,发病年龄主要集中在0~5岁;各季度间沙门菌检出率经Fisher确切概率法比较无统计学差异(P=0.052)。35株沙门菌分成9种血清型,其中优势血清型为肠炎沙门菌11株(占31.43%)和鼠伤寒沙门菌9株(占25.71%),其次克勒肯威尔沙门菌6株(占17.14%),斯坦利沙门菌3株,德尔卑沙门菌2株,阿贡纳沙门菌、婴儿沙门菌和病牛沙门菌血清型各1株,1株未分型。经XbaⅠ酶切后11株肠炎沙门菌分成8种PFGE型,优势型为JEGX01.CN0007;9株鼠伤寒沙门菌分成9种PFGE型,总体型别呈多样性分布。结论贵阳市引起感染性腹泻的沙门菌以肠炎沙门菌和鼠伤寒沙门菌为主,PFGE型别呈多样性。展开更多
文摘Background: ESBL-producing strains of Klebsiella pneumoniae, one of the main causes of nosocomial and hospital-acquired infections, are commonly associated with therapeutic impasses. Surveillance of these multidrug-resistant pathogens is a crucial tool for controlling and preventing infections. This surveillance involves the use of appropriate molecular and phenotypic typing techniques. The choice of techniques is based on criteria such as discriminatory power, intra- and inter-laboratory reproducibility, epidemiological concordance, ease of use and cost. The aim of our study was to identify clusters of Extended-Spectrum Beta-Lactamase-producing Klebsiella pneumoniae (ESBL-K. pneumoniae) strains circulating in neonatology using quantitative antibiogram (QA) and Pulsed Field Gel Electrophoresis (PFGE). Materials and Methods: This cross-sectional study included 55 K. pneumoniae strains isolated from a total of 513 samples. These various samples are taken from newborns, healthcare personnel, and the environment. K. pneumoniae identification followed standard bacteriological procedures and was confirmed using the Vitek® 2 (bioMérieux). The detection of the ESBL phenotype was performed using the synergy test. QA and PFGE were used to identify clonal relationships between the various strains isolated. Concordance between these two methods was assessed by calculating Cohen’s KAPPA coefficient and Simpson’s diversity index. Results: Among the 55 K. pneumoniae strains included in this study, 58.2% (32/55) were found to be Extended-Spectrum Beta-Lactamase (ESBL) producers. Most of these strains were isolated from neonatal samples (blood samples and rectal swabs). The quantitative antibiogram method applied to 28 out of the 32 ESBL-producing strains revealed that the isolates were grouped into 5 clusters. Pulsed Field Gel Electrophoresis performed on a total of 16 ESBL-producing strains showed the existence of four profiles. A perfect concordance was observed between the two methods. Conclusion: The results of this study highlighted the existence of clonal strains of various origins within neonatology units.
基金supported by the project (grant 2005CB522904 and 2005CB522905) from the Ministry of Scientific Technologythe project (grant 2008ZX10004-001, 2008ZX10004-008, and 2009ZX10004-101) from the Ministry of Scientific Technology and the Ministry of Health of the People’s Republic of China
文摘Objective To establish and compare the pulsed-field gel electrophoresis （PFGE）, multiple-locus variable number tandem repeat analysis （MLVA） and automated ribotyping for subtyping of Citrobacter strains. Methods PFGE protocol was optimized in terms of plug preparation procedure, restriction enzymes and configuration of electrophoretic parameters. MLVA method was evaluated by finding variable number tandem repeats in two genomes of Citrobacter strains. The ribotyping was performed by using the automated RiboPrinter system. Results We optimized the plug preparation procedure, focused on the cell suspension concentration （turbidity of 2.5 to 3.5）, SDS addition （no SDS needed） and lysis time （1 h）, and selected the appropriate restriction enzyme （Xbal） and the electrophoretic parameters （1.0 s-20.0 s for 19 h） of PFGE. There was nearly no discriminatory power of MLVA between Citrobacter strains. For 51 Citrobacter strains, automated ribotyping gave a D-value of 0.9945, while PFGE gave a D-value of 0.9969. Both PFGE and automated ribotyping clustered strains from the same sources （with the same species from the same place at the same time identified as the same source） and divided strains from different sources （from different years, places and hosts） into different subtypes. Conclusion PFGE protocol established in this paper and automated ribotyping are suitable for application in Citrobacter subtyping.
文摘Pulsed field gel electrophoresis(PFGE) has been firstly introduced in characterization of the pathogenic fungi Penicillium marne f fei and Exophiala dermatitidis genomes.The numbers and sizes of their chromosomes have been detected.Polymorphism was identified on the smallest chromosome of E.dermatitidis.The result shows that PFGE for characterization of large molecular DNA pathogenic fungi is very suitable,it is more simple and more efficacy.The result also shows the diversity of pathogenic fungi is relative common even in rare occurred pathogenic fungi such as E.dermatitidis.
基金supported by the National Natural Science Foundation of China (NSFC)(31100105)the 12th Five-Year Major National Science and Technology Projects of China(No.2012ZX10004219-007)
文摘Objective To optimize the performance of Pulsed-Field Gel Electrophoresis （PFGE） for the comparison of inter-laboratory results and information exchange of Borrelia burgdorferi subtypingo Methods A panel of 34 strains of B. burgdorferi were used to optimize PFGE for subtyping. In order to optimize the electrophoretic parameters （EPs）, all 34 strains of B. burgdorferi were analyzed using four EPs, yielding different Simpson diversity index （D） values and the epidemiological concordance was also evaluated. Results The EP of a switch time of l s to 25 s for13 h and l s to10 s for 6 h produced the highest D value and was declared to be optimal for Mlul and 5mal PFGE of B. burgdorferi. Mlul and Smal were selected as the first and second restriction enzymes for PFGE subtyping of B. burgdorferi according to discrimination and consistency with epidemiological data. Conclusion PFGE can be used as a valuable test for routine genospecies identification of B burgdorferi.
文摘Background The rise of the production of CTX-M class extended spectrum β-lactamases （ESBLs） has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China. Methods Antimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis （PFGE）. Results Imipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracylcline, ciprofloxacin, sulfamethoxazole trimethoprin and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs （76.2%）. Two strains showed indistinguishable patterns by PFGE. Conclusions The prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.
文摘目的了解2013-2014年贵阳市腹泻监测病例中沙门菌的血清型别分布及脉冲场凝胶电泳(Pulse-Field Gel Electrophoresis,PFGE)分型特征,为贵阳市沙门菌病的防控提供科学依据。方法收集2013-2014年贵阳市4家哨点医院感染性腹泻病例的432份粪便标本,对其进行沙门菌的分离培养、生化鉴定、血清分型及PFGE分型。结果 432例感染性腹泻患者的粪便标本共检出沙门菌35株,检出率为8.10%(35/432),男女检出之比为1.5:1,发病年龄主要集中在0~5岁;各季度间沙门菌检出率经Fisher确切概率法比较无统计学差异(P=0.052)。35株沙门菌分成9种血清型,其中优势血清型为肠炎沙门菌11株(占31.43%)和鼠伤寒沙门菌9株(占25.71%),其次克勒肯威尔沙门菌6株(占17.14%),斯坦利沙门菌3株,德尔卑沙门菌2株,阿贡纳沙门菌、婴儿沙门菌和病牛沙门菌血清型各1株,1株未分型。经XbaⅠ酶切后11株肠炎沙门菌分成8种PFGE型,优势型为JEGX01.CN0007;9株鼠伤寒沙门菌分成9种PFGE型,总体型别呈多样性分布。结论贵阳市引起感染性腹泻的沙门菌以肠炎沙门菌和鼠伤寒沙门菌为主,PFGE型别呈多样性。
