A Semi-Nested Polymerase Chain Reaction for Amplification of Chlamydia trachomatis Omp1 Gene

Kim, Bo rahm; Lee, Gil ho

Abstract

PURPOSE: Chlamydia trachomatis(CT) infection is the most common bacterial sexually transmitted disease. Because of vague symptoms and delayed diagnosis, untreated infection can be transmitted to sexual partners and progress to infertility, pelvic inflammatory disease and ectopic pregnancy. Genotyping and serotyping for CT are very important to establish contact networks and for epidemiological and evolutionary studies. Cryptic plasmid and omp1 genes are targets for the detection of CT. Although the plasmid is a good target for amplification, it is very difficult to analyze sequences from the plasmid amplicons. The omp1 gene is an ideal target for sequence analysis because of large and publicized data deposits on the internet. However, very few studies have been published using a polymerase chain reaction(PCR) for the detection of the chlamydial omp1 gene in Korea. The purpose of this study was to detect CT infection with semi-nested amplification of the chlamydial omp1 gene.
MATERIALS AND METHODS
Genomic DNA was extracted from the urethral swabs of 20 patients with urethritis or idiopathic chronic prostatitis, and from the vaginal swabs of 80 patients attending the gynecology clinic due to various vaginal symptoms. The primers were designed on omp1 genes from 12 CT and 2 sequences of lymphogranuloma venereum. The estimated products from the first and second rounds of PCR were 656 and 100 bp, respectively.
RESULTS
With the 1st PCR bands there were confusing and non-specific bands, but all the specific PCR products from the 1st and 2nd amplifications with new primer sets were identified. CT was identified in 2 of 20 male patients (10%) and 4 of 80 female patients (5%).
CONCLUSIONS
CT infections were detected from patients with semi-nested amplifications of the chlamydial omp1 gene. The semi-nested PCR method may be a more sensitive and specific test than first round PCR.