ABSTRACT
BACKGROUND: Escherichia coli is the most common pathogenic bacteria that frequently causes life-threatening opportunistic human infections, diarrhea, and septicemia in immunocompromised hosts. METHODS: This study aimed to establish a loop-mediated isothermal amplification (LAMP) method for the rapid and sensitive detection of a hypothetical protein from an E. coli-specific gene (GenBank ID: 13702648). The gene was obtained through local and online BLAST, and specific primers were designed for this gene. Reaction conditions were optimized at 65ºC for 30 minutes and 80ºC for 2 minutes, whereas the reaction system contained 5.2 mM Mg2+, 8 U of Bst 2.0 DNA polymerase, 1.4 mM deoxyribonucleotide, and 0.2 and 1.6 µM of the outer and inner primers, respectively. The LAMP method was evaluated using 240 strains of E. coli and 150 strains of non-E. coli. RESULTS: Positive reactions were observed on all 240 strains of E. coli while all non-E. coli strains were negative. Plasmids with the specific gene and mice blood with E. coli were used for sensitivity analysis. The detection limit of LAMP was 100 bacterium/reaction. CONCLUSIONS: Results showed that the LAMP targeted to the hypothetical protein (GenBank ID: 13702648) is a fast, specific, sensitive, inexpensive, and suitable method for the detection of E. coli.
Subject(s)
Clinical Laboratory Techniques/methods , Escherichia coli/genetics , Nucleic Acid Amplification Techniques , Animals , DNA Primers/genetics , Diarrhea/microbiology , Humans , Immunocompromised Host , Limit of Detection , Mice , Plasmids/genetics , Polymerase Chain Reaction , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
AIM: The purpose of this study was to investigate relationships between green tea consumption and gastric cancer development. METHODS: A population-based case-control study including 200 cases and 200 controls was conducted in the southwest area of China from May 2010 to February 2011. A self-designed questionnaire was used to collect data on factors influencing gastric cancer development, including tea drinking, conditional logistic regression being used to calculate odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs). RESULTS: Cases with higher economic status had a reduced risk of gastric cancer, while those with cancer family history, drinking and smoking showed increased risk. Hot and very hot tea temperature was significantly related to high risk of gastric cancer with ORs (95%Cl) of 1.82 (1.03-3.52) and 3.07 (1.78-7.36), respectively. Further analysis indicated elevated risk of gastric cancer in former drinkers, former smokers and current drinkers when the measured tea temperature was hot. CONCLUSION: Drinking tea at high temperature increases the gastric cancer risk, especially in drinkers and smokers.
