| 1. |
- Jurstrand, Margaretha, et al.
(author)
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Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted disease patients in Sweden
- 2001
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In: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 39:11, s. 3915-3919
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Journal article (peer-reviewed)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.
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| 2. |
- Klint, Markus, et al.
(author)
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High-resolution genotyping of Chlamydia trachomatis strains by multilocus sequence analysis
- 2007
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In: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 45:5, s. 1410-1414
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Journal article (peer-reviewed)abstract
- Genotyping of Chlamydia trachomatis is limited by the low sequence variation in the genome, and no adequatemethod is available for analysis of the spread of chlamydial infections in the community. We have developeda multilocus sequence typing (MLST) system based on five target regions and compared it with analysis ofompA, the single gene most extensively used for genotyping. Sequence determination of 16 reference strains,comprising all major serotypes, serotypes A to L3, showed that the number of genetic variants in the fiveseparate target regions ranged from 8 to 16. The genetic variation in 47 clinical C. trachomatis isolates ofrepresentative serotypes (14 serotype D, 12 serotype E, 11 serotype G, and 10 serotype K strains) was analyzed;and the MLST system detected 32 variants, whereas 12 variants were detected by using ompA analysis.Specimens of the predominant serotype, serotype E, were differentiated into seven genotypes by MLST but intoonly two by ompA analysis. The MLST system was applied to C. trachomatis specimens from a population ofmen who have sex with men and was able to differentiate 10 specimens of one predominant ompA genotype Gvariant into four distinct MLST variants. To conclude, our MLST system can be used to discriminate C.trachomatis strains and can be applied to high-resolution molecular epidemiology.
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