Use of a reliable PCR assay for the detection of Neisseria gonorrhoeae in Peruvian patients

Abstract

Neisseria gonorrhoeae is the most common sexually transmitted disease-causing bacterium worldwide. An in-house PCR assay targeting the carbamoyl-phosphate synthase subunit A (carA) gene was developed for the specific detection of N. gonorrhoeae in clinical specimens. Samples from 605 patients were cultured on selective medium and assayed by PCR in a double-blind fashion. Of 605 urethral/cervical samples analysed, 13 were PCR-positive, of which 11 were culture-positive. The PCR showed a sensitivity and specificity of 100% and 99.7% with these samples. PCR targeting the carA gene appears to be a reliable method for the detection of N. gonorrhoeae in clinical specimens.

Prevalence of <em>Neisseria gonorrhoeae</em> infection in symptomatic and asymptomatic women attending obstetrics and gynecology outpatient department at Lahore general hospital Lahore, Pakistan

“…The results are not in line with the finding of Mayta who reported that 1.7% of gonorrhoeae suspected asymptomatic woman were confirmed through PCR analysis (Fig. 3, 4) [20] . 4% of PID asymptomatic infected woman were declared as positive of Neisseria by molecular characteristics of Orf1 gene.…”

Conventional Agar-Based Culture Method, and Nucleic Acid Amplification Test (NAAT) of the cppB Gene for Detection of Neisseria gonorrhea in Pregnant Women Endocervical Swab Specimens

“…Although commercially available tests established upon nucleic acid amplification have greater sensitivity than conventional tests for detecting N. gonorrhea, specificity remains controversial, since intra- and interspecies genetic recombination take place frequently between members of the genus Neisseria. Cross-reactivity is common with most target sequences, including the 16S rRNA gene, and false-positive results with Neisseria meningitides , and Neisseria lactamase have been reported using cppB gene sequences (1). However, each of these tests has limitations, including variable sensitivities to inhibitors, cross-reactivity with other microorganisms, limited sensitivity, high costs, and equipment of public health laboratories.…”

“…However, each of these tests has limitations, including variable sensitivities to inhibitors, cross-reactivity with other microorganisms, limited sensitivity, high costs, and equipment of public health laboratories. In addition, their application is often restricted to specific specimen types due to limited validation of the assays (10, 13) cppB gene and 16S rRNA gene-based assays are used for confirmation, however, about 5% of N. gonorrhea strains do not carry the cppB plasmid, and not all 16S rRNA-based tests are sensitive and specific enough (1, 7). This can be a disadvantage in the use of this cppB gene for detection of Neisseria gonorrhea .…”

“…N. gonorrhea also causes disseminated infection, with complications that may result in ectopic pregnancy, tubal infertility, chronic pelvic pain or maternal transmission of gonorrhea, and also increases susceptibility to HIV. Gonorrhea primarily causes urethritis in males (1-3). Health complications resulting from gonorrhea disease occur mainly in women, and are largely assigned to the predominately asymptomatic nature of the lower genital tract infection.…”

“…This is largely due to bacterial autolysis, poor sampling techniques, and improper specimen storage and transport. Nucleic acid amplification tests (NAATs), have been shown to have both high sensitivity and specificity for the detection of N. gonorrhea (1, 7-10). Detection techniques such as NAATs which are independent of bacterial viability have a potential to limit false negative samples and in some geographic areas, NAATs are promptly substituting the culture method for the diagnosis of gonorrhea disease (8).…”