Characterization of Chlamydia trachomatis omp1 Genotypes among Sexually Transmitted Disease Patients in Sweden

Abstract

A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n ‫؍‬ 6) and H (n ‫؍‬ 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. This omp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.

Distribution Study ofChlamydia trachomatisSerovars among High-Risk Women in China Performed Using PCR-Restriction Fragment Length Polymorphism Genotyping

“…The genotyping methods are more sensitive and specific than serotyping for C. trachomatis serovar identification (12,13). Many studies have shown the feasibility of deducing the serotypes of C. trachomatis clinical isolates using PCR-based RFLP or sequencing of the amplified omp1 gene, which encodes the MOMP (8,10,15).…”

“…Variable domains are coded by the omp1 gene, and their nucleotide sequences exhibit distinct variations in different serovars. Subsequently, they have become widely used for the genotyping of C. trachomatis isolates (1,12). Typically, C. trachomatis serovars A through C are found associated with trachoma, serovars D through K are associated with urogenital infections, and serovars L1 through L3 are associated with the systemic disease lymphogranuloma venereum (13,18,26).…”

High-Resolution Genotyping of Chlamydia trachomatis Strains by Multilocus Sequence Analysis

“…However, when it is applied to nonselected populations, the limited resolution of ompA sequencing restricts the amount of epidemiological information that can be obtained (6). This is especially true, given that the single serotype E comprises almost half of all urogenital chlamydial infections, and within this serotype, one genotypic variant appears to predominate (3,4,6). There is therefore an obvious need to develop better methods for evaluation of the molecular epidemiology of chlamydial infections.…”

Lymphogranuloma Venereum in Australia: AnorectalChlamydia trachomatisSerovar L2b in Men Who Have Sex with Men

“…Furthermore, all positive samples underwent PCR and sequencing targeting the omp1 gene as described by Jurstrand et al (9). Sequencing was performed in both directions to ensure sufficient sequence overlap and fidelity on an ABI Prism 3730 automated sequencer at the SUPAMAC facility (Royal Prince Alfred Hospital, Sydney, Australia).…”