Distribution of Chlamydia trachomatis omp A genotypes in patients attending a sexually transmitted disease outpatient clinic in New Delhi, India.

BACKGROUND &

OBJECTIVES

Limited data are available on the typing of Chlamydia trachomatis in India. Serovars D to K of C. trachomatis are chiefly responsible for urogenital infections. Thus, this study was conducted to determine the distribution of C. trachomatis serovars in patients with urogenital infections and to characterize omp A gene of the detected C. trachomatis isolates by sequence analysis. Presence of other co-infections was also evaluated.

METHODS

Endocervical swabs were collected from 324 women and urethral swabs/urine were collected from 193 men attending the sexually transmitted diseases outpatient clinic. The samples were screened for C. trachomatis by cryptic plasmid PCR and omp A gene PCR. Genotyping was performed by PCR-restriction fragment length polymorphism (RFLP) and sequencing of the omp A gene. Samples were screened for genital mycoplasmas, Neisseria gonorrhoeae, Treponema pallidum and human immunodeficiency virus (HIV).

RESULTS

C. trachomatis was found in 15.0 per cent men and 10.8 per cent women. Serovar D was the most prevalent followed by serovars E, F, I and G. Twenty two C. trachomatis isolates were selected for omp A gene sequencing. No mixed infection was found. Variability in omp A sequences was seen in 31.8 per cent cases. Both PCR-RFLP and omp A gene sequencing showed concordant results. The presence of Ureaplasma spp. and Mycoplasma hominis was observed in 18.7 and 9.5 per cent patients, respectively. Co-infection of C. trachomatis was significantly associated with Ureaplasma urealyticum and HIV.

INTERPRETATION &

CONCLUSIONS

The high occurence of C. trachomatis infections warrants its screening in addition to other sexually transmitted infections namely U. urealyticum and HIV. Genotyping of the omp A gene may provide additional information for vaccine development.