Epidemiology of Bacterial Enteric Pathogens in Rural Thailand: Application of a Dna Hybridization Assay to Detect Enterotoxigenic Escherichia Coli

1985 ◽  
pp. 53-63
Author(s):  
P. Echeverria ◽  
C. Tirapat ◽  
C. Charoenkul ◽  
S. Yangratoke ◽  
W. Chaicumpa
Keyword(s):  
Escherichia Coli ◽  
Dna Hybridization ◽  
Enteric Pathogens ◽  
Enterotoxigenic Escherichia Coli ◽  
Hybridization Assay ◽  
Rural Thailand

scholarly journals Comparison of virulence markers and antibiotic resistance in enterotoxigenic Escherichia coli isolated ten years apart in Tehran

2010 ◽  
Vol 5 (04) ◽  
pp. 248-254 ◽  
Author(s):  
Nader Shahrokhi ◽  
Saeid Bouzari ◽  
Anis Jafari
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Dna Hybridization ◽  
Pathogenic Bacteria ◽  
Enterotoxigenic Escherichia Coli ◽  
Significant Shift ◽  
Bacterial Populations ◽  
Virulence Markers ◽  
Class 1 ◽  
Resistance Patterns

Introduction: Enterotoxigenic Escherichia coli (ETEC) causes diarrhoea by producing heat-labile (LT) or heat-stable (ST) enterotoxins after colonizing the small intestine by means of colonization factors (CFs). Although detection of the toxins is sufficient for verification of ETEC isolates, toxin-positive strains may be further analyzed for the presence of CFs. Antibiotics may shorten the duration of diarrhoea caused by ETEC, but the rapid emergence of resistant strains limits their usefulness. Methodology: ETEC isolates collected 10 years apart were compared for the prevalence of toxin types, CFs and antibiotic resistance. DNA/DNA hybridization with digoxigenin (DIG)-labeled probes was used for the detection of toxin types, and CF-typing was performed by DNA hybridization using DIG-labeled probes for cfaD and CS6 with slide agglutination. Disk diffusion was used to determine antibiotic resistance. The presence of class 1 integrons was detected by PCR. Results: ST-positive isolates were the most prevalent among the isolates from 1988, but a significant shift towards LT-gene carriage was observed in the 1998 group. CFA/I and CFA/IV were the most common CF types within both groups. The most prevalent resistance patterns among these isolates were ACSTSXT followed by ASTSXT and ASSXT. Conclusion: Our study of the two groups of isolates showed that the rate of LT and ST gene carriage, as well as antibiotic resistance markers, has changed in the ten years separating the two bacterial populations. These variations show the importance of monitoring pathogenic bacteria to obtain a near realistic picture of the circulating bacterial pathogens.

scholarly journals Etiology of acute diarrhea in children in Shanghai, 2015-2018

2019 ◽  
Author(s):  
Hailing Chang ◽  
Jiayin Guo ◽  
Zhongqiu Wei ◽  
Zheng Huang ◽  
Chuning Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Acute Diarrhea ◽  
Enteric Bacteria ◽  
Enterohemorrhagic Escherichia Coli ◽  
Enteric Pathogens ◽  
Enterotoxigenic Escherichia Coli ◽  
Salmonella Spp ◽  
Shigella Spp ◽  
Fresh Stool

Abstract Background Diarrhea is still a major cause of childhood morbidity and mortality worldwide. This hospital-based study aimed to monitor the consecutive epidemiological trend of etiology in children with acute diarrhea in Shanghai.Methods Outpatient children with diarrhea were prospectively enrolled within 7 days after onset of diarrheal symptoms during 2015-2018. Fresh stool samples were collected for testing enteropathogens. Enteric bacteria were identified and typed through culture and serotyping. Enteric viruses were identified through real-time PCR assay. hadResults Enteric pathogens were identified in 1572 (58.4%) of the 2692 enrolled children with acute diarrhea. Viruses were more frequently detected than bacteria (41.3% versus 25.0%), and co-infection with 2 or more pathogens was found in 13% of outpatients. Nontyphoidal Salmonella spp . (NTS) was the most common bacteria with 10.3% of isolate rate, followed by enteropathogenic Escherichia coli (EPEC) (6.5%), enteroaggregative Escherichia coli (EAEC) (6.2%), Campylobacter spp . (3.6%), enterotoxigenic Escherichia coli (ETEC) (1.1%), Shigella spp . (0.2%), and enterohemorrhagic Escherichia coli (EHEC) (0.1%). Rotavirus was the most common virus with 16.0% of detection rate, followed by norovirus (15.5%), adenovirus (7.2%), sapovirus (3.0%) and astrovirus (2.7%).Conclusions Infectious diarrhea remains the major cause of diarrhea in children in Shanghai. Rotavirus, norovirus and NTS were the major enteric pathogens responsible for diarrhea in Shanghainese children. Improving uptake of rotavirus vaccine and strengthening prevention of foodborne pathogens will be helpful to reduce the burden of diarrheal diseases in children in Shanghai.

Identification by DNA Hybridization of Enterotoxigenic Escherichia coli in a Longitudinal Study of Villages in Thailand

1985 ◽  
Vol 151 (1) ◽  
pp. 124-130 ◽  
Author(s):  
P. Echeverria ◽  
J. Seriwatana ◽  
D. N. Taylor ◽  
C. Tirapat ◽  
W. Chaicumpa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Longitudinal Study ◽  
Dna Hybridization ◽  
Enterotoxigenic Escherichia Coli

Sensitive and simple detection of Escherichia coli strain based on time-resolved fluorescence DNA hybridization assay

2010 ◽  
Vol 664 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Min Ruan ◽  
Cheng-Gang Niu ◽  
Pin-Zhu Qin ◽  
Guang-Ming Zeng ◽  
Zhao-Hui Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Hybridization ◽  
Coli Strain ◽  
Hybridization Assay ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Simple Detection

Increased Reliability in Detection of Enterotoxigenic Escherichia coli by DNA Colony Hybridization1

1987 ◽  
Vol 50 (6) ◽  
pp. 487-489 ◽  
Author(s):  
VALERIE MITCHELL DAVIS
Keyword(s):  
Escherichia Coli ◽  
Dna Hybridization ◽  
False Negative ◽  
Enterotoxigenic Escherichia Coli ◽  
Hybridization Method ◽  
X Ray ◽  
Genes Encoding ◽  
Autoradiographic Analysis ◽  
Labeled Probe ◽  
Pathogenic Determinant

Previously a DNA hybridization assay was designed to detect the presence of and to enumerate enterotoxigenic foodborne Escherichia coli. The determinative step in the method involves autoradiographic analysis of the DNA from foodborne isolates after hybridization with a 32P-labeled probe specific for an enterotoxin gene. Dark spots appearing on the X-ray film after exposure indicate which colonies carry genes encoding the pathogenic determinant. A problem with this assay is the tendency of some colonies to detach from the nitrocellulose filters during hybridization or washing to remove the unbound probe DNA; this results in a false-negative interpretation in up to 60% of the samples processed at 80°C. By lowering the temperature to 70°C and increasing the incubation time to 3 h during in vacuo baking of filters, detachment (flotation) of colonies is reduced to about 37%. At 65°C only 2% of the colonies came off the filter after in vacuo baking of filters for 24 h. Another problem has been the inadequacy of exposure of X-ray film at −20°C when a −70°C freezer is not available. This problem can be alleviated by exposing the X-ray film in cassette holders “sandwiched” between slabs of dry ice (CO2 ice has a temperature of −78.5°C). These modifications improve the reliability and accuracy of this DNA colony hybridization method.

A Colorimetric DNA Hybridization Method for the Detection of Escherichia coli in Foods

1991 ◽  
Vol 54 (4) ◽  
pp. 249-255 ◽  
Author(s):  
HSIEN-YEH HSU ◽  
SAMUEL W. CHAN ◽  
DAVID I. SOBELL ◽  
DONALD N. HALBERT ◽  
E. PATRICK GROODY
Keyword(s):  
Escherichia Coli ◽  
Dna Hybridization ◽  
False Negative ◽  
False Negative Rate ◽  
Culture Method ◽  
Hybridization Assay ◽  
Hybridization Method ◽  
E Coli ◽  
Probe Target ◽  
Negative Rate

A colorimetric DNA hybridization assay has been developed for the rapid detection of Escherichia coli in foods. The method employs two oligonucleotide probes which are specific for the 16S ribosomal RNA of E. coli. Probes are added to lysates of test cultures and allowed to hybridize to target rRNA if present. The probe-target complex is captured via hybridization to a polystyrene dipstick. The immobilized target is detected using an antibody-horseradish peroxidase conjugate which binds to the immobilized probe-target complex. The probe-target-antibody complex generates a colorimetric signal when exposed to a substrate/chromogen mixture. A total of 233 E. coli isolates representing typical, toxigenic, invasive, hemorrhagic serotype 0157:H7, and other pathogenic strains all resulted in a positive assay signal. Dose-response experiments indicate the sensitivity of the assay is approximately 1 × 106 CFU/ml. Specificity of the assay was determined by testing 207 strains of non-E. coli species at 109 CFU/ml. All of the non-E. coli organisms tested were negative with the exception of Escherichia fergusonii and Shigella species. A total of 345 enriched samples including inoculated, uninoculated, and naturally-contaminated foods was tested for the presence of E. coli by the hybridization assay and a conventional cultural method. The false-negative rate for the hybridization assay was 1.2%. By comparison, the false-negative rate for the culture method in these studies was 23.4%. Based on these data, the DNA hybridization method is significantly more accurate than conventional methods for the detection of E. coli in foods.

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