Serovar distribution of Chlamydia trachomatis isolates collected from the cervix: use of the polymerase chain reaction and restriction endonuclease digestion.

In order to study the distribution of Chlamydia trachomatis serovars isolated from the cervix of patients attending the gynaecology out-patients clinic of Safdarjang Hospital, New Delhi, India, gene typing was performed using restriction fragment length polymorphism (RFLP) analysis of a polymerase chain reaction (PCR)-amplified portion of the major outer membrane protein (MOMP). A set of primers were used to amplify a 540 bp gene fragment which encompasses the four hypervariable regions of the MOMP. EcoR1 and Xbal double digestion of the product gave distinctive patterns for the genital serovars (D-K) as demonstrated on 12% polyacrylamide gel stained with ethidium bromide. PCR and RFLP were used to genotype 50 clinical isolates and their respective control serovars. Clinical isolates demonstrated the same banding pattern as the control strain of C. trachomatis. The serovars isolated were D (39.13%), E (28.26%), G (15.25%), I (10.86%) and F (6.5%), representing 92% of those investigated.