Chlamydia trachomatis is the most prevalent sexually transmitted bacterium worldwide and the causative agent of trachoma. Its strains are classified according to their ompA genotypes, which are strongly linked to differential tissue tropism and disease outcomes [ocular disease, urogenital disease and lymphogranuloma venereum (LGV)]. While the genome-based species phylogenetic tree presents four main clades correlating with tropism/prevalence, namely ocular, LGV, urogenital T1 (more prevalent genotypes) and urogenital T2 (less prevalent genotypes), inter-clade exchange of ompA is considered a rare phenomenon probably mediating marked tropism alterations. An LGV epidemic, associated with the clonal expansion of the L2b genotype, has emerged in the last few decades, raising concerns particularly due to its atypical clinical presentation (ulcerative proctitis) and circulation among men who have sex with men (MSM). Here, we report an LGV outbreak, mostly affecting human immunodeficiency virus-positive MSM engaging in high-risk sexual practices, caused by an L2b strain with a rather unique non-LGV ompA signature that precluded the laboratory notification of this outbreak as LGV. C. trachomatis whole-genome capture and sequencing directly from clinical samples was applied to deeply characterize the genomic backbone of this novel LGV outbreak-causing clone. It revealed a chimeric genome structure due to the genetic transfer of ompA and four neighbouring genes from a serovar D/Da strain, likely possessing the genomic backbone associated with the more prevalent urogenital genotypes (T1 clade), to an LGV (L2b) strain. The hybrid L2b/D-Da strain presents the adhesin and immunodominant antigen MOMP (major outer membrane protein) (encoded by ompA) with an epitope repertoire typical of non-invasive genital strains, while keeping the genome-dispersed virulence fingerprint of a classical LGV strain. As previously reported for inter-clade ompA exchange among non-LGV clades, this novel C. trachomatis genomic mosaic involving a contemporary epidemiologically and clinically relevant LGV strain may have implications on its transmission, tissue tropism and pathogenic capabilities. The emergence of variants with epidemic and pathogenic potential highlights the need for more focused surveillance strategies to capture C. trachomatis evolution in action.

Background: Pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) have been increasingly available in Europe. Due to the high burden of HIV in key populations, these could benefit from their use. In 2016, in Portugal, an open, non-interval, prospective cohort study was established in a network of 26 community-based voluntary HIV/STI counseling and testing centers. Data collected included questions on PEP and PrEP knowledge and use. We aimed to estimate the proportion of PEP and PrEP knowledge and its use among key populations, visiting the centers between 2016 and 2019.Method and results: Individuals who self-identify as being among at least one key population for HIV, men who have sex with men (MSM), people who inject drugs (PWID), sex workers (SW), migrants, and male-to-female transgender individuals (MTF), responded to questions on PEP and PrEP knowledge and use while waiting for their test results between 2016 and 2019 (n = 12,893 for PEP; n = 10,973 for PrEP). Reported knowledge was low in all key populations for both tools: 15.7% of respondents reported knowing about PEP and 10.9% about PrEP over the course of 4 years. PEP was used by 1.8% and PrEP by 0.4% of the respondents, MSM being 88.9% of PrEP users, and 52.8% of PEP users. Multivariate logistic regression showed multiple factors associated with knowing the tools, including age, education, country of birth, gender, year of test, having a reactive HIV test in the same visit, reporting an STI or condomless sex in the last 12 months, and identifying with being MSM or SW.Conclusions: Knowledge and use of PEP and PrEP remain low among key populations in Portugal. The need remains to increase knowledge and use among those at risk for HIV infection.

Men who have sex with men (MSM) are at greater risk for sexually transmitted infections (STIs). Data on MSM chlamydia and gonorrhea prevalence estimates and associated risk factors are scarce. To our knowledge, this is the first study to describe the prevalence and the determinants of both chlamydia and gonorrhea infections in MSM in Portugal. We conducted a cross-sectional study using data from 1832 visits to CheckpointLX, a community-based center for screening blood-borne viruses and other STIs in MSM. Overall prevalence of chlamydia or gonorrhea in our sample was 16.05%, with 14.23% coinfection and 40.73% asymptomatic presentation among those testing positive. Anorectal infection was most common for chlamydia (67.26%), followed by urethral (24.78%) and oral (19.47%) infection. Oral infection was most common for gonorrhea (55.63%), followed by anal (51.25%) and urethral (17.50%) infection. In multivariate analyses, young age ( U = 94684, p = 0.014), being foreign-born (χ2 = 11.724, p = 0.003), reporting STI symptoms (χ2 = 5.316, p = 0.021), inhaled drug use (χ2 = 4.278, p = 0.039) and having a higher number of concurrent (χ2 = 18.769, p < 0.001) or total (χ2 = 5.988, p = 0.050) sexual partners were each associated with higher rates of chlamydia or gonorrhea infection. Young and migrant MSM are a vulnerable population to STIs, as are those who use inhaled drugs and those with a higher number of concurrent or total sexual partners. Although Portugal has no guidelines on chlamydia and gonorrhea screening, our results point toward a need for greater awareness about the importance of high-frequency screening for those at increased risk (i.e., every three to six months).

IntroductionConsistent use of PrEP reduces HIV transmission from sexual practices amongst men who have sex with men (MSM) up to 92% [1]. Lisbon MSM cohort study estimates point that 59.3% of their participants at entrance (1593 HIV negative MSM enrolled between April 2011 and May 2013) were eligible for PrEP [2], according to the 2014 USA PrEP guidelines [3]. Studies about PrEP acceptability and implementation support policies aimed at increasing and rolling out its use. Hence, the exploratory study about PrEP acceptability in MSM at Lisbon.Materials and MethodsA street-based intercept survey, adapted from Mantell et al. study [4], was the one used on MSM attending the 2014 Lisbon pride fair. The survey included socio-demographic data, PrEP awareness and readiness to use it, probability of MSM's social network to also use it, promptness to join PrEP-related studies, type of PrEP warranted and condomless anal sex practice in the last six months.ResultsA total of 110 HIV negative Portuguese MSM responded, with a median age of 33% and 84% of them identified themselves as gay. A majority of MSM were unaware of PrEP (59%); those that were aware, had heard of it trough CheckpointLx (31%), internet (22%) or health professionals (20%). 66% were likely or very likely to participate in PrEP-related studies. 57% of MSM were likely or very likely to use PrEP if available and reported that some, if not almost all of their social network, will do it too (70%). Type of PrEP preferred was oral, a pill a day (43%), followed by oral, intermittent intake (32%). Overall 41% of MSM had condomless anal sex practice in the last six months.ConclusionsIn this MSM Portuguese sample, a general willingness to adopt PrEP was predominant, specially the oral daily intake. Forty-one percent of participants had had condomless anal sex practice in the last six months and therefore fitted within the criteria to be on Pre-Exposure Prophylaxis (PrEP), according to MSM Risk Index in 2014 USA PrEP guidelines. PrEP, when available in Portugal, should be a powerful tool for HIV prevention in this key population.

Previously, we identified a Chlamydia trachomatis Lymphogranuloma venereum (LGV) recombinant strain possessing a unique non-LGV ompA genotype. Here, culture-independent genome sequencing confirms its circulation in Europe, Middle East and North America, and unveils genetic evidence of emergence of antibiotic resistance. Multi-country and systematic molecular surveillance is needed.