Objective:To survey the prevalence severe diarrhea arising from these bacteria in children under 5 years old in Marvdasht.Methods:In this study faecal sample from 615 children aged <5years old who were hospitalized...Objective:To survey the prevalence severe diarrhea arising from these bacteria in children under 5 years old in Marvdasht.Methods:In this study faecal sample from 615 children aged <5years old who were hospitalized lor gastroenteritis in Fars hospitals in Iran were collected and then enriched in Escherichia coli(E.coli) broth and modified tryplone soy broth with novobiocin media,fermentation of sorbitol,lactose and β— glucoronidase activity of isolated strains was examined by CT—SMAC,VRBA and chromogenic media respectively.Then isolation of E.coli O157:H7 have been confirmed with the use of specific antisera and with multiplex PCR method presence of virulence genes including:xtx_1.stx_2,eae.A.hly has been analyzed.Results:E.coli O157:H7 was detected in 7(1.14%) stool specimens.A significanl difference was seen between detection rale of isolated bacteria from age groups 18-23 months and other age groups(P=0.004).Out of considered virulence genes.only 1 of the isolated strains(0.16%)he stx,and eaeA genes were seen and also all isolated hacleria had resistance to penicillin,ampicillin and erythromycin antibiotics.Conclusions:We found thai children < 2 years of age were at highest risk of infection with E.coli O157:H7.Regarding severity of E.coli O157:H7 pathogenesis,low infectious dose and lack of routine assay for detection ol these bacleria in clinical laboratory,further and completed studies on diagnosis and genolyping of this E.coli O157:H7 strain has been recommended.展开更多
AIM： To establish the rapid, specific, and sensitive method for detecting O157：H7 with DNA microchips. METHODS： Specific oligonucleotide probes （26-28 nt） of bacterial antigenic and virulent genes of E. coliO157...AIM： To establish the rapid, specific, and sensitive method for detecting O157：H7 with DNA microchips. METHODS： Specific oligonucleotide probes （26-28 nt） of bacterial antigenic and virulent genes of E. coliO157：H7 and other related pathogen genes were pre-synthesized and immobilized on a solid support to make microchips. The four genes encoding O157 somatic antigen （rfbE）, H7 flagellar antigen （fliC） and toxins （SLT1, SLT2） were monitored by multiplex PCR with four pairs of specific primers. Fluorescence-Cy3 labeled samples for hybridization were generated by PCR with Cy3-1abeled single prime. Hybridization was performed for 60 min at 45 ℃. Microchip images were taken using a confocal fluorescent scanner. RESULTS： Twelve different bacterial strains were detected with various combinations of four virulent genes. All the O157：H7 strains yielded positive results by multiplex PCR. The size of the PCR products generated with these primers varied from 210 to 678 bp. All the rfbE/fliC/SLT1/SLT2 probes specifically recognized Cy3-1abeled fluorescent samples from O157：H7 strains, or strains containing O157 and H7 genes. No cross hybridization of O157：H7 fluorescent samples occurred in other probes. Non-O157：H7 pathogens failed to yield any signal under comparable conditions. If the Cy3-1abeled fluorescent product of O157 single PCR was diluted 50-fold, no signal was found in agarose gel electrophoresis, but a positive signal was found in microarray hybridization. CONCLUSION： Microarray analysis of O157：H7 is a rapid, specific, and efficient method for identification and detection of bacterial pathogens.展开更多
基金the Islamic Azad University, Jahrom branch,for their executive support of this project
文摘Objective:To survey the prevalence severe diarrhea arising from these bacteria in children under 5 years old in Marvdasht.Methods:In this study faecal sample from 615 children aged <5years old who were hospitalized lor gastroenteritis in Fars hospitals in Iran were collected and then enriched in Escherichia coli(E.coli) broth and modified tryplone soy broth with novobiocin media,fermentation of sorbitol,lactose and β— glucoronidase activity of isolated strains was examined by CT—SMAC,VRBA and chromogenic media respectively.Then isolation of E.coli O157:H7 have been confirmed with the use of specific antisera and with multiplex PCR method presence of virulence genes including:xtx_1.stx_2,eae.A.hly has been analyzed.Results:E.coli O157:H7 was detected in 7(1.14%) stool specimens.A significanl difference was seen between detection rale of isolated bacteria from age groups 18-23 months and other age groups(P=0.004).Out of considered virulence genes.only 1 of the isolated strains(0.16%)he stx,and eaeA genes were seen and also all isolated hacleria had resistance to penicillin,ampicillin and erythromycin antibiotics.Conclusions:We found thai children < 2 years of age were at highest risk of infection with E.coli O157:H7.Regarding severity of E.coli O157:H7 pathogenesis,low infectious dose and lack of routine assay for detection ol these bacleria in clinical laboratory,further and completed studies on diagnosis and genolyping of this E.coli O157:H7 strain has been recommended.
基金Supported by the Key Military Medical Science and Technique Program during the 10~(th) Five Year Plan Period, No. 01L006
文摘AIM： To establish the rapid, specific, and sensitive method for detecting O157：H7 with DNA microchips. METHODS： Specific oligonucleotide probes （26-28 nt） of bacterial antigenic and virulent genes of E. coliO157：H7 and other related pathogen genes were pre-synthesized and immobilized on a solid support to make microchips. The four genes encoding O157 somatic antigen （rfbE）, H7 flagellar antigen （fliC） and toxins （SLT1, SLT2） were monitored by multiplex PCR with four pairs of specific primers. Fluorescence-Cy3 labeled samples for hybridization were generated by PCR with Cy3-1abeled single prime. Hybridization was performed for 60 min at 45 ℃. Microchip images were taken using a confocal fluorescent scanner. RESULTS： Twelve different bacterial strains were detected with various combinations of four virulent genes. All the O157：H7 strains yielded positive results by multiplex PCR. The size of the PCR products generated with these primers varied from 210 to 678 bp. All the rfbE/fliC/SLT1/SLT2 probes specifically recognized Cy3-1abeled fluorescent samples from O157：H7 strains, or strains containing O157 and H7 genes. No cross hybridization of O157：H7 fluorescent samples occurred in other probes. Non-O157：H7 pathogens failed to yield any signal under comparable conditions. If the Cy3-1abeled fluorescent product of O157 single PCR was diluted 50-fold, no signal was found in agarose gel electrophoresis, but a positive signal was found in microarray hybridization. CONCLUSION： Microarray analysis of O157：H7 is a rapid, specific, and efficient method for identification and detection of bacterial pathogens.
