Prevalence of Chlamydia trachomatis Sequence Types 4 and 80 in Infertile Couples in North Khorasan, Iran

Background: Chlamydial infections could lead to ectopic pregnancy and infertility. Considering the high prevalence of infertility in Iran and little information about the role of urogenital bacterial infections in this disease, this study aimed to evaluate the prevalence and sequence types of Chlamydia trachomatis in the urogenital tract of infertile couples in North Khorasan. Materials Methods: Cervical or urethral swabs collected from infertile patients referring to two private clinics and the infertility center of Bent Al-Hoda hospital in Bojnurd during 2017-2021 were tested for C. trachomatis. These specimens were evaluated using PCR for C. trachomatis orf8 gene. Multi-locus sequence typing (MLST) was performed on positive samples using PCR amplification of seven housekeeping genes (GlyA, leuS, lysS, mdhC, pdhA, pykF, and yhbG) following a previously described protocol. Findings: Out of 268 samples tested, 44 (16.4%) samples were positive for C. trachomatis. Among which, 35 cases were obtained from women, and nine samples were from men. Of the 44 positive samples, 10 cases were not typable. Only two sequence types were detected among 34 typeable isolates: 25 (73.5%) isolates belonged to ST80, and nine (26.5%) samples belonged to ST4. Conclusion: The high prevalence of ST4 and ST80 in most symptomatic infertile patients may be attributed to the higher pathogenicity of these types in the urogenital tract. However, our sample size was insufficient to draw such a conclusion.,  Further research on the prevention and treatment of Chlamydial infections could potentially help to reduce infertility in Iran.