Specific and Sensitive Detection of Neisseria gonorrhoeae in Clinical Specimens by Real-Time PCR (original) (raw)
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Development of a SYBR Green real-time PCR-based assay system for detection of Neisseria gonorrhoeae
Journal of the Medical Sciences (Berkala Ilmu Kedokteran)
Diagnosis of Neisseria gonorrhoeae infection is needed for patient therapy and for reducing this bacterial transmission in the population. The culture method is a gold standard method for N. gonorrhoeae detection, however it has low sensitivity. Among molecular methods with high sensitivity and specificity, SYBR Green real-time PCR is the potential method for N. gonorrhoeae detection. In this study, we developed an SYBR Green real-time PCR-based system assay for N. gonorrhoeae detection. Several PCR conditions were optimized and analyzed including primer annealing temperature, DNA template volume, the limit of detection (LoD), cross-reaction with others (bacteria, viruses, fungus, protozoa), and quality assurance. The results showed that the annealing temperature and DNA template volume were 60oC and 5 µL, respectively. The LoD was 29 DNA copies corresponding to 3 bacterial cells per reaction. No cross-reaction was detected for other bacteria, viruses, fungus and protozoa. The exter...
Journal of clinical microbiology, 2000
Typing of gonococcal strains is a valuable tool for the biological confirmation of sexual contacts. We have developed a typing method based on DNA sequencing of two overlapping por gene fragments generated by a heminested PCR. We compared sequencing of the por gene (POR sequencing) and typing of the opa gene (OPA typing) for the characterization of strains from 17 sexual partnerships. Both methods were highly discriminatory. A different genotype was detected in 15 of the 17 epidemiologically unconnected couples by POR sequencing and in 16 of the 17 couples by OPA typing with restriction enzyme HpaII. Within partnerships, identical genotypes were obtained from 16 of the 17 known sex contacts by POR sequencing and from 15 of the 17 by OPA typing. Compared to OPA typing, which relies on interpretation of bands in a gel, DNA sequence data offer the advantage of being objective and portable. As costs for sequencing decline, the method should become affordable for most laboratory personne...
Diagnosis of NEISSERIA GONORRHOEAE using 1 molecular beacon
Neisseria gonorrhoeae is an important STI causing pathogen worldwide. Due to absence of an affordable diagnostic assay, routine screening of gonococcal infection becomes impossible in developing countries where infection rates are maximum. Treatment is given on the basis of symptoms alone which leads to spread of infection. Thus, development of a rapid, sensitive, specific, PCR based visual diagnostic assay suitable for developing countries, required for better disease management is aimed in present study. Endocervical swabs were collected from patients visiting gynecology department of various hospitals in Delhi. In-house PCR based assay was developed and modified to visual assay using molecular beacon for end-point detection. It was evaluated against Roche Amplicor NG kit and rmp gene. Specificity of beacon was confirmed by competition experiments. Diagnostic test was 98.21% specific and 99.59% sensitive whereas negative and positive predicted value were 99.40% and 98.78% respectively. We also observed that twice the concentration (2X) of pre-mix was stable at 4°C for 4 months and dry swab samples gave concordant results with that of wet swabs. These features make the test best suitable for routine diagnosis of genital infections in developing countries