Background Chlamydia trachomatis (CT) can infect the anorectum producing various signs and symptoms. There is scarce literature regarding the differences between LGV and non-LGV CT anorectal manifestations. We compare the clinical spectrum of LGV and non-LGV infections. Methods Patients over 18 years with presumptive infectious anorectal symptoms were examined in two healthcare centres in Buenos Aires. The patients were studied and treated according to current sexually transmitted infection guidelines. Anorectal swabs were collected to detect and genotype CT. Results A three-year-long study on 317 patients with anorectal symptoms showed 45.11% CT infection (85% LGV strains). Of 140 samples, 92 were sequenced: 80/119 LGV (L2b 45%, L1 32.5% and L2 22.5%) and 12/21 non-LGV. Older age and HIV+ status were significantly higher in the LGV group. Anal discharge, bleeding, severe proctitis and anal ulcers were more common in the LGV group. Multivariate logistic regression analysis revealed that HIV infection, anorectal bleeding and oro-anal sex are independent predictors of LGV infection. Conclusions In patients with anorectal symptoms, LGV serovars predominate over non-LGV ones. Clinical manifestations are not pathognomonic of a specific biovar. If genotyping is not available, having clinical predictors may help to presume an LGV infection and define length of treatment.

More than L2b in rectal lymphogranuloma venereum We declare no competing interests. The hospital's ethical committee approved the study protocol under number 201723. This study has been partly supported by Universidad de Buenos Aires grant UBACyT 20020150100223BA. ACE and KAB contributed equally. The funder of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report. All authors had full access to all the data in the study and had final responsibility for the decision to submit for publication. KAB, ACE, LLR, LSL, and MRF verified the data.