Lodhia Zohra, Costa Da Silva Jorge, Correia Cristina, Cordeiro Dora, João Inês, Carreira Teresa, Schäfer Sandra, Aliyeva Elzara, Portugal Clara, Monge Isabel, Gonçalves Elsa, Matos Susana, Dias Ana Paula, Côrte-Real Rita, Carpinteiro Dina, Duarte Sílvia, Vieira Luís, Gomes João Paulo, Borges Vítor, Borrego Maria José
National Reference Laboratory (NRL) for Sexually Transmitted Infections (STI), Department of Infectious Diseases, National Institute of Health (Instituto Nacional de Saúde Doutor Ricardo Jorge, INSA, IP), Lisbon, Portugal.
Clinical Pathology Department, Unidade Local de Saúde Amadora Sintra, Amadora, Portugal.
J Antimicrob Chemother. 2025 Apr 2;80(4):1072-1079. doi: 10.1093/jac/dkaf036.
To survey genetic markers of potential antimicrobial resistance (AMR) to macrolides and fluoroquinolones among Chlamydia trachomatis-positive samples from the collection of the Portuguese National Reference Laboratory for Sexually Transmitted Infections (STIs), and explore a multiplex PCR approach coupled with NGS to provide complementary information regarding a strain's genomic backbone.
A total of 502 C. trachomatis-positive samples, mostly anorectal exudates, were subjected to PCR and sequencing of five targets, including loci potentially driving AMR (23S rRNA, gyrA and parC) and loci potentially informative about a strain's genomic backbone with emphasis on differentiation of lymphogranuloma venereum (LGV)/non-LGV and L2/L2b (a 9 bp insertion in pmpH, a 74 bp insertion upstream from CT105 and the polymorphic CT442).
No samples evidenced 23S rRNA mutations recognizably linked to macrolide resistance. Three samples harboured the Ser83Ile mutation in GyrA putatively driving fluoroquinolone resistance: two recombinant L2-L2b/D-Da (0.4%) and one L2 (0.2%). The screened regions in pmpH, upstream CT105 and CT442 were fully concordant with LGV/non-LGV differentiation. As expected, the pmpH L2b-specific genetic trait locus was detected in all L2b and recombinant L2-L2b/D-Da ompA genotypes, but also in 96.0% of L2 specimens, which also likely possess an L2b genomic backbone. The insertion upstream from CT105 exhibited full LGV specificity, constituting a promising target for the development of rapid LGV diagnostic assays.
This study contributes to enhancing the knowledge of C. trachomatis molecular epidemiology, suggesting that the known genetic determinants of AMR are not disseminated in clinical C. trachomatis strains, and presents an exploratory approach that can be suitable for LGV/non-LGV and L2/L2b genomic background differentiation.
在葡萄牙国家性传播感染参考实验室收集的沙眼衣原体阳性样本中，调查对大环内酯类和氟喹诺酮类潜在抗菌药物耐药性（AMR）的遗传标记，并探索一种多重PCR方法结合二代测序（NGS），以提供有关菌株基因组主干的补充信息。
总共502份沙眼衣原体阳性样本，主要为肛门直肠分泌物，对五个靶点进行了PCR和测序，包括可能驱动AMR的位点（23S rRNA、gyrA和parC）以及可能提供有关菌株基因组主干信息的位点，重点是区分性病性淋巴肉芽肿（LGV）/非LGV和L2/L2b（pmpH中9 bp插入、CT105上游74 bp插入以及多态性CT442）。
没有样本显示出与大环内酯耐药性明显相关的23S rRNA突变。三个样本在GyrA中存在Ser83Ile突变，推测该突变驱动氟喹诺酮耐药性：两个重组L2-L2b/D-Da（0.4%）和一个L2（0.2%）。pmpH、CT105上游和CT442中的筛选区域与LGV/非LGV区分完全一致。正如预期的那样，在所有L2b和重组L2-L2b/D-Da ompA基因型中检测到了pmpH L2b特异性遗传特征位点，但在96.0%的L2样本中也检测到了该位点，这些样本可能也具有L2b基因组主干。CT105上游的插入显示出完全的LGV特异性，是开发快速LGV诊断检测方法的一个有前景的靶点。
本研究有助于增进对沙眼衣原体分子流行病学的了解，表明已知的AMR遗传决定因素在临床沙眼衣原体菌株中并未传播，并提出了一种适用于LGV/非LGV和L2/L2b基因组背景区分的探索性方法。
