Evaluation of a high resolution genotyping method for Chlamydia trachomatis using routine clinical samples.

Area of Science:

• Microbiology
• Epidemiology
• Genetics

Background:

• Genital chlamydia is the most common STI in the UK, caused by C. trachomatis.
• Common C. trachomatis strains include lymphogranuloma venereum (LGV) and genitourinary genotypes D-K.
• Existing genotyping methods like ompA sequencing and MLST lack the resolution for detailed local epidemiology.

Purpose of the Study:

• To evaluate the utility of multi-locus VNTR analysis and ompA sequencing (MLVA-ompA) for high-resolution genotyping of C. trachomatis.
• To study the local epidemiology of C. trachomatis infections in Southampton.

Main Methods:

• One hundred fifty-seven C. trachomatis-positive endocervical swabs were analyzed.
• Samples were tested for C. trachomatis using PCR and genotyped using the MLVA-ompA technique.
• C. trachomatis isolation in cell culture was attempted for all samples.

Main Results:

• 59% of samples were successfully genotyped by MLVA-ompA.
• The most frequent ompA genotypes were D (20%), E (41%), and F (16%).
• Numerous MLVA subtypes were identified within these common genotypes, indicating significant genetic diversity.

Conclusions:

• MLVA-ompA provides high-resolution genotyping for C. trachomatis.
• The identified MLVA subtypes may correlate with demographic factors, sexual behavior, and social networks.
• This detailed genotyping can improve local STI epidemiology and contact tracing efforts.