scholarly journals Direct Detection of Shiga Toxigenic Escherichia coliStrains Belonging to Serogroups O111, O157, and O113 by Multiplex PCR

1999 ◽  
Vol 37 (10) ◽  
pp. 3362-3365 ◽  
Author(s):  
Adrienne W. Paton ◽  
James C. Paton

Shiga toxigenic Escherichia coli (STEC) strains are a diverse group of organisms associated with severe gastrointestinal and systemic diseases in humans. Within the STEC family,eae-positive STEC strains, particularly those belonging to serogroups O157 and O111, appear to have greater virulence for humans. However, in spite of being eae negative, STEC strains belonging to serogroup O113 have frequently been associated with cases of severe STEC disease, including hemolytic-uremic syndrome (HUS). We have developed a modified multiplex PCR assay for detection of STEC strains belonging to these three serogroups in cultures of feces by using primers specific for portions of the genetic loci (rfb) encoding biosynthesis of the respective O antigen. These primers direct amplification of PCR products of 259, 406, and 593 bp for serogroups O157, O111, and O113, respectively. The assay was validated by testing 40 previously characterized STEC strains, with 100% agreement. It also detected STEC strains of the appropriate genotype in primary fecal cultures from 13 patients with HUS or bloody diarrhea. Thirty other primary fecal cultures from patients without evidence of STEC infection were negative.

1998 ◽  
Vol 36 (2) ◽  
pp. 598-602 ◽  
Author(s):  
Adrienne W. Paton ◽  
James C. Paton

Shiga toxigenic Escherichia coli (STEC) comprises a diverse group of organisms capable of causing severe gastrointestinal disease in humans. Within the STEC family, certain strains appear to be of greater virulence for humans, for example, those belonging to serogroups O111 and O157 and those with particular combinations of other putative virulence traits. We have developed two multiplex PCR assays for the detection and genetic characterization of STEC in cultures of feces or foodstuffs. Assay 1 utilizes four PCR primer pairs and detects the presence of stx 1,stx 2 (including variants ofstx 2), eaeA, and enterohemorrhagicE. coli hlyA, generating amplification products of 180, 255, 384, and 534 bp, respectively. Assay 2 uses two primer pairs specific for portions of the rfb (O-antigen-encoding) regions of E. coli serotypes O157 and O111, generating PCR products of 259 and 406 bp, respectively. The two assays were validated by testing 52 previously characterized STEC strains and observing 100% agreement with previous results. Moreover, assay 2 did not give a false-positive O157 reaction with enteropathogenic E. colistrains belonging to clonally related serogroup O55. Assays 1 and 2 detected STEC of the appropriate genotype in primary fecal cultures from five patients with hemolytic-uremic syndrome and three with bloody diarrhea. Thirty-one other primary fecal cultures from patients without evidence of STEC infection were negative.


2016 ◽  
Vol 1 (2) ◽  
pp. 38-42 ◽  
Author(s):  
Khairun Nessa ◽  
Dilruba Ahmed ◽  
Johirul Islam ◽  
FM Lutful Kabir ◽  
M Anowar Hossain

A multiplex PCR assay was evaluated for diagnosis of diarrheagenic Escherichia coli in stool samples of patients with diarrhoea submitted to a diagnostic microbiology laboratory. Two procedures of DNA template preparationproteinase K buffer method and the boiling method were evaluated to examine isolates of E. coli from 150 selected diarrhoeal cases. By proteinase K buffer method, 119 strains (79.3%) of E. coli were characterized to various categories by their genes that included 55.5% enteroaggregative E. coli (EAEC), 18.5% enterotoxigenic E. coli (ETEC), 1.7% enteropathogenic E. coli (EPEC), and 0.8% Shiga toxin-producing E. coli (STEC). Although boiling method was less time consuming (<24 hrs) and less costly (<8.0 US $/ per test) but was less efficient in typing E. coli compared to proteinase K method (41.3% vs. 79.3% ; p<0.001). The sensitivity and specificity of boiling method compared to proteinase K method was 48.7% and 87.1% while the positive and negative predictive value was 93.5% and 30.7%, respectively. The majority of pathogenic E. coli were detected in children (78.0%) under five years age with 53.3% under one year, and 68.7% of the children were male. Children under 5 years age were frequently infected with EAEC (71.6%) compared to ETEC (24.3%), EPEC (2.7%) and STEC (1.4%). The multiplex PCR assay could be effectively used as a rapid diagnostic tool for characterization of diarrheagenic E. coli using a single reaction tube in the clinical laboratory setting.Bangladesh J Med Microbiol 2007; 01 (02): 38-42


2020 ◽  
Vol 12 (2) ◽  
pp. 212-217 ◽  
Author(s):  
Juan Du ◽  
Shujing Wu ◽  
Liyuan Niu ◽  
Junguang Li ◽  
Dianbo Zhao ◽  
...  

Unfunctionalized flower-shaped AuNPs is used as colorimetric sensor for PCR product detection by naked eyes.


2013 ◽  
Vol 5 (2) ◽  
pp. 59-66 ◽  
Author(s):  
Sushmita Roy ◽  
SM Shamsuzzaman ◽  
Kazi Z Mamun

Objective: Multiplex PCR assay was used for diagnosis of diarrheagenic Escherichia coli (DEC) in stool samples of children (under 5 years) with acute diarrhea.  Methods: Samples were collected from January 2011 to December 2011, from Dhaka Medical College Hospital and Dhaka Shishu Hospital. Multiplex PCR with five specific primer pairs to detect enteropathogenic E. coli (eae, bfp), enterotoxigenic E. coli (lt, st) and enteroaggregative E. coli (aat) were used. However, enteroinvasive E. coli, enterohemorrhagicE. coli and diffusely adhererentE. coli were not sought. Result: In total, 135 (67.5%) E. coli were isolated from 200 stool samples. The prevalence of DEC was 68 (34%). Among DEC, most frequently isolated pathotype was EPEC 40 (58.82%), followed by ETEC 24 (35.29%) and EAggEC 18 (26.47%). Among the EPEC, 5 (12.5%) were typical EPEC. Among the 68 DEC positive cases, 22 samples contained more than one pathogenic gene in various combinations. Among the combination of DEC, EPEC+ETEC combination was 6 (27.27%) followed by ETEC+EAggEC 4 (18.18%), EPEC+EAggEC and ETEC+EPEC+EAggEC were both in 3 (13.6%). Conclusion:This study shows that DEC is a common cause of childhood diarrhea in Dhaka city of Bangladesh. By using multiplex PCR assay, DEC can be diagnosed in one PCR reaction that makes a conclusive diagnosis of diarrhea. DOI: http://dx.doi.org/10.3126/ajms.v5i2.8576 Asian Journal of Medical Science, Volume-5(2) 2014: 59-66


2004 ◽  
Vol 132 (1) ◽  
pp. 61-65 ◽  
Author(s):  
R. HORVÁTH ◽  
M. DENDIS ◽  
J. SCHLEGELOVÁ ◽  
F. RŮŽIČKA ◽  
J. BENEDÍK

The original method for molecular typing of E. coli strains was developed using the polymorphism in chromosomal sequences of bacterial interspersed mosaic elements (BIMEs) detected by multiplex PCR and analysed by AFLP assay. The applicability of the method in the epidemiology of E. coli was tested on a group of 524 strains of human and veterinary origin. In the studied group 18 different genotypes were detected. Significant differences were found in the frequencies of the genotypes among various groups of strains, suggesting the method could be a promising tool in the epidemiology of E. coli.


1970 ◽  
Vol 29 (6) ◽  
Author(s):  
Hossein Ali Rahdar ◽  
Mohammad Reza Salehi ◽  
Abass Bahador ◽  
Seyedesomaye Jasemi ◽  
Morteza Karami-Zarandi ◽  
...  

Background: Nocardia, Streptomyces and Rhodococcus are life threatening opportunistic pathogens under immunodeficiency conditions, particularly among patients infected with HIV. Rapid and accurate detection of these infections can improve immune health quality, patient management and appropriate treatment. The aim of this study was to design a novel multiplex-PCR assay for rapid diagnosis of these three organisms directly from bronchoalveolar lavage (BAL) specimens of patients infected with HIV.Methods: The genus specific primers were designed for directdetection of Nocardia, Streptomyces and Rhodococcus in a single tube multiplex PCR. This PCR specifically amplified the target genes from pure cultures. It subsequently was applied on BAL specimens of 29 HIV positive patients that had previously been culture negative for actinomycete bacteria, of which Nocardia, Streptomyces and Rhodococcus are members.Results: Of 29 respiratory clinical specimens, there were positive for Nocardia spp. and one was positive for Streptomyces spp using the multiplex PCR assay. The sequencing of the PCR products identified the species as Nocardia cyriacigeorgica (n=2), Nocardia farcinica and Streptomyces albus.Conclusion: This novel multiplex PCR assay yielded reliable results for accurate identification of Nocardia, Streptomyces and Rhodococcus from BAL while the results of bacterial culture were negative. 


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