Detection of Chlamydia trachomatis DNA in cervical samples with regard to infection by human papillomavirus

The correlation between human papillomavirus (HPV) and Chlamydia, trachomatis infections was evaluated in 144 patients with normal cytology or with atypical squamous cells of undetermined significance (ASCUS).

Cervical samples were analysed using polymerase chain reaction (PCR) and non-radioactive Southern blot analysis. Specificity and sensitivity of two C. trachomatis PCR systems: major outer membrane protein (MOMP)-PCR and plasmid-PCR were determined. Southern blot hybridization of the PCR amplicons was done using 5' and 3' biotinylated oligonucleotide probes.

All cervical samples were tested by the plasmid-PCR due to a 10 times higher sensitivity compared to the MOMP-PCR. To determine the specificity of our C. trachomatis primer sets different bacteria and viruses which can cause urogenital infections were analysed. Comparison of the probes revealed an increased sensitivity of the 5' and 3' double-biotinylated probe vs. the 5' biotinylated probe. The infection rate of C. trachomatis in cervical samples of HPV-positive patients was 10.3% (three out of 29) vs. 1.7% (two out of 115; P< or =0.05) in HPV-negative patients. In patients HPV-X (unsequenced HPV-types) positive the rate was 14.3% (one out of seven) vs. 2.9% (four out of 137: P = 0.2) in HPV-X negative patients. In high risk (HR) HPV-positive cervical samples the infection rate was 9.1% (two out of 22) vs. 2.5% (three out of 122; P = 0.14) in HR HPV-negative samples. Chlamydia trachomatis frequency of patients with cytological changes (ASCUS) was 27.3% (three out of 11) vs. 1.5% (two out of 1 33) in patients with normal cytology (P = 0.003). The highest prevalence rate of C. trachomatis-positive cervical samples (50%; one out of two) was found in HR HPV-positive patients with cytological changes (ASCUS) vs. 5% (one out of 20) in HR HPV-positive patients with normal cytology (P = 0.17). Patients negative for HPV and positive for ASCIIS have a C. trachomatis rate of 22.2% (two out of nine) vs. HPV-negative patients with normal cytology (none out of 106; P = 0.006) and vs. HR HPV-negative patients with normal cytology (0.9%; one out of 113; P = 0.014).

There appears to be a correlation between cervical HPV and cervical C. trachomatis infections. The prevalence rate of C. trachomatis was significantly higher in patients with abnormal cytology (ASCUS) vs. normal cytology.