scholarly journals Evaluation of a PCR Primer Based on the Isocitrate Dehydrogenase Gene for Detection of Helicobacter pyloriin Feces

2000 ◽  
Vol 38 (10) ◽  
pp. 3755-3758 ◽  
Author(s):  
Frauke C. Argyros ◽  
Mayurika Ghosh ◽  
Lili Huang ◽  
Naoko Masubuchi ◽  
David R. Cave ◽  
...  

In order to improve detection and identification ofHelicobacter pylori in highly contaminated samples, we evaluated new specific primers based on the DNA base sequence within the isocitrate dehydrogenase (icd) gene to amplify a 1,200-bp DNA segment. The specificity of the icd primer was tested against DNA derived from various bacteria, including 7Helicobacter species and a panel of 1 gram-variable, 2 gram-positive, and 16 gram-negative bacteria, as well as DNA from houseflies and feces from H. pylori-negative patients. The primers permitted the detection of all clinical H. pyloriisolates tested, but no reactions were observed with negative controls. Several procedures for DNA extraction from feces were evaluated using PCR with icd primers. The lower limits of detection ofH. pylori DNA from two different sources containing the same number of H. pylori organisms, a pure culture and feces spiked with H. pylori, were established for each extraction method tested. The results were 8.0 × 103CFU/ml for cultures of pure H. pylori, and 8.0 × 106 CFU/ml for H. pylori from feces, using the phenol-chloroform method; 8.0 × 102 and 7.0 × 103 CFU/ml, respectively, for a glass matrix and chaotropic solution protocol; 8.0 × 102 and 7.0 × 103 CFU/ml, respectively, for the QIAamp tissue kit; and 5.0 × 102 and 5.0 × 103 CFU/ml, respectively, for the XTRAX DNA extraction kit. We conclude that the use of the icd gene as a primer for PCR represents a specific and sensitive assay for detection of H. pylori in highly contaminated samples.

2019 ◽  
Vol 19 (3) ◽  
pp. 274-278 ◽  
Author(s):  
Saba Fakhrieh Asl ◽  
Mehrnaz Pourvahedi ◽  
Ali Mojtahedi ◽  
Mohammad Shenagari

Objective:Helicobacter pylori is a Gram-negative bacterium which has a serious effect on up to half of the world’s population and has been related to different gastric diseases. The goal of this study was to assess the frequency of babA, cagE and cagA genotypes among H. pylori strains isolated from gastric biopsies of endoscopic patients in the north of Iran.Methods:The present study was performed on 90 strains of H. pylori isolated from patients with gastric diseases (Gastric ulcer (GU), Duodenal ulcer (DU), Gastritis (G), Non-ulcer dyspepsia (NUD) and Gastric adenocarcinoma (GC)). DNA was extracted from all isolated strains and PCR method was performed to detect the prevalence of babA2, cagE and cagA genes using specific primers.Results:Among 90 samples of H. pylori, babA2, cagE, and cagA genes were detected in 42.2%, 30% and 82.2% of strains respectively. The statistical analysis showed that the prevalence of cagA gene in GU, G, DU, and NUD was significantly higher than other genes. Moreover, cagA, and babA2 genes were significantly more prevalent in GC patients compared to cagE gene. Our isolates exhibited 8 distinct arrangements of virulence patterns. The occurrence of cagA (35.6%) was the most prevalent pattern followed by cagA/babA2 (20%) and cagA/babA2/cagE (14.4%).Conclusion:In summary, as first report from Guilan province in the north of Iran, we showed significant association between the presence of babA2, cagE, and cagA genes in different types of gastric disorders.


2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Ana Valero-Rello ◽  
Desiree Henares ◽  
Lesly Acosta ◽  
Mireia Jane ◽  
Iolanda Jordan ◽  
...  

ABSTRACTThis study aimed to validate a comprehensive diagnostic protocol based on real-time PCR for the rapid detection and identification ofBordetella pertussis,Bordetella parapertussis, andBordetella holmesii, as well as its implementation in the diagnostic routine of a reference children’s hospital. The new algorithm included a triplex quantitative PCR (qPCR) targeting IS481gene (inB. pertussis,B. holmesii, and someBordetella bronchisepticastrains), pIS1001(B. parapertussis-specific) andrnaseP as the human internal control. Two confirmatory singleplex tests forB. pertussis(ptxA-Pr) andB. holmesii(hIS1001) were performed if IS481was positive. Analytical validation included determination of linear range, linearity, efficiency, precision, sensitivity, and a reference panel with clinical samples. Once validated, the new algorithm was prospectively implemented in children with clinical suspicion of whooping cough presenting to Hospital Sant Joan de Deu (Barcelona, Spain) over 12 months. Lower limits of detection obtained were 4.4, 13.9, and 27.3 genomic equivalents/ml of sample for IS481(onB. pertussis), pIS1001and hIS1001, and 777.9 forptxA-Pr. qPCR efficiencies ranged from 86.0% to 96.9%. Intra- and interassay variabilities were <3% and <5%, respectively. Among 566 samples analyzed,B. pertussis,B. holmesii, andB. parapertussiswere detected in 11.1%, 0.9% (only in females >4 years old), and 0.2% of samples, respectively. The new algorithm proved to be a useful microbiological diagnostic tool for whooping cough, demonstrating a low rate of other non-pertussisBordetellaspecies in our surveilled area.


Author(s):  
Eun-Sook Lee ◽  
So-Yang Cha ◽  
Jong-Soon Jung

Abstract DNA extraction methods were evaluated to reduce PCR inhibitors and quantify Helicobacter pylori directly from water samples using real-time PCR. Three nucleic acid extraction methods were evaluated for different types of water samples. While the QIAamp DNA mini kit for tissue was suitable for DNA extraction from treated water, the QIAamp DNA stool mini kit was still efficient in analyzing samples from river water after heavy rain and with high concentration of PCR inhibitors. The FastDNA SPIN Kit for Soil could extract DNA effectively from microbes in river and stream waters without heavy rain. Immunomagnetic separation (IMS) was used prior to DNA extraction and was a useful tool for reducing PCR inhibitors in influent and stream samples. H. pylori in various waters could be quantified directly by real-time PCR while minimizing the effect of PCR inhibitors by an appropriate method through the evaluation of DNA extraction methods considering the characteristics of the matrix water. The findings of the present study suggest that the types or characteristics of water sample by source and precipitation are an important factor in detecting H. pylori and they can be applied when detecting and monitoring of other pathogens in water.


2001 ◽  
Vol 69 (8) ◽  
pp. 4774-4781 ◽  
Author(s):  
Michael A. Heneghan ◽  
Ciaran F. McCarthy ◽  
Daiva Janulaityte ◽  
Anthony P. Moran

ABSTRACT Lewis (Le) antigens have been implicated in the pathogenesis of atrophic gastritis and gastric cancer in the setting ofHelicobacter pylori infection, and H. pylori-induced anti-Le antibodies have been described that cross-react with the gastric mucosa of both mice and humans. The aim of this study was to examine the presence of anti-Le antibodies in patients with H. pylori infection and gastric cancer and to examine the relationships between anti-Le antibody production, bacterial Le expression, gastric histopathology, and host Le erythrocyte phenotype. Anti-Le antibody production and H. pylori Le expression were determined by enzyme-linked immunosorbent assay, erythrocyte Le phenotype was examined by agglutination assays, and histology was scored blindly. Significant levels of anti-Lex antibody (P < 0.0001, T = 76.4, DF = 5) and anti-Ley antibody (P < 0.0001, T = 73.05, DF = 5) were found in the sera of patients with gastric cancer and other H. pylori-associated pathology compared with H. pylori-negative controls. Following incubation of patient sera with synthetic Le glycoconjugates, anti-Lex and -Ley autoantibody binding was abolished. The degree of the anti-Lex and -Leyantibody response was unrelated to the host Le phenotype but was significantly associated with the bacterial expression of Lex (r = 0.863,r 2 = 0.745, P < 0.0001) and Ley (r = 0.796,r 2 = 0.634, P < 0.0001), respectively. Collectively, these data suggest that anti-Le antibodies are present in most patients with H. pyloriinfection, including those with gastric cancer, that variability exists in the strength of the anti-Le response, and that this response is independent of the host Le phenotype but related to the bacterial Le phenotype.


1998 ◽  
Vol 57 (6) ◽  
pp. R6281-R6284 ◽  
Author(s):  
Katrin Kneipp ◽  
Harald Kneipp ◽  
V. Bhaskaran Kartha ◽  
Ramasamy Manoharan ◽  
Geurt Deinum ◽  
...  

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