Molecular characterization of Treponema pallidum isolates from Brazil.

Syphilis remains a public health concern in Brazil, and the data on the characterization and resistance of Treponema pallidum in Brazil is limited. The present study aimed to detect Treponema DNA in the lesions and blood samples obtained from individuals diagnosed with syphilis. The Brazilian isolates were submitted to the Enhanced Centers for Disease Control and Prevention (ECDC) scheme and also analyzed for resistance gene. Treponemal DNA from 18 lesions and 18 blood specimens were submitted for amplification using Polymerase Chain Reaction (PCR) and Polymerase Chain Reaction in Real Time (RT-PCR). Eight samples from lesions and eight from blood were positive in the RT-PCR analysis. Eight lesions and three blood samples were positive using PCR. Two samples exhibited azithromycin resistance. The Brazilian isolate types 14d/g, 14 d/c, 15d/c, and 15d/e were identified using the ECDC scheme. The three subtypes 14d/c, 15d/c, and 15d/e have been identified in Brazil for the first time.

Redefining the treponemal history through pre-Columbian genomes from Brazil.

The origins of treponemal diseases have long remained unknown, especially considering the sudden onset of the first syphilis epidemic in the late 15th century in Europe and its hypothesized arrival from the Americas with Columbus' expeditions1,2. Recently, ancient DNA evidence has revealed various treponemal infections circulating in early modern Europe and colonial-era Mexico3-6. However, there has been to our knowledge no genomic evidence of treponematosis recovered from either the Americas or the Old World that can be reliably dated to the time before the first trans-Atlantic contacts. Here, we present treponemal genomes from nearly 2,000-year-old human remains from Brazil. We reconstruct four ancient genomes of a prehistoric treponemal pathogen, most closely related to the bejel-causing agent Treponema pallidum endemicum. Contradicting the modern day geographical niche of bejel in the arid regions of the world, the results call into question the previous palaeopathological characterization of treponeme subspecies and showcase their adaptive potential. A high-coverage genome is used to improve molecular clock date estimations, placing the divergence of modern T. pallidum subspecies firmly in pre-Columbian times. Overall, our study demonstrates the opportunities within archaeogenetics to uncover key events in pathogen evolution and emergence, paving the way to new hypotheses on the origin and spread of treponematoses.

Intrathecal Synthesis Index of Specific Anti-Treponema IgG: a New Tool for the Diagnosis of Neurosyphilis.

Neurosyphilis (NS) diagnosis is challenging because clinical signs are diverse and unspecific, and a sensitive and specific laboratory test is lacking. We tested the performance of an antibody index (AI) for intrathecal synthesis of specific anti-Treponema IgG by enzyme-linked immunosorbent assay (ELISA) for NS diagnosis. We conducted a retroprospective monocentric study including adults with neurological symptoms who had serum and cerebral spinal fluid (CSF) samples collected between 2006 and 2021. Two NS definitions were used. NS1 included patients with neurological symptoms, positive Treponema pallidum particle agglutination (TPPA) serology, and CSF-TPPA of ≥320, as well as CSF-leukocytes of >5 cells/mm3 and/or CSF-protein of >0.45 g/L and/or a reactive CSF-VDRL/RPR test. NS2 included patients with acute ocular and/or otologic symptoms, positive TPPA serology, and a response to NS treatment. Controls were patients with central nervous system disorders other than neurosyphilis. Anti-Treponema pallidum IgG were measured simultaneously in serum and CSF, and AI was calculated according to Reiber diagram. We assessed the AI test area under the curve (AUC), sensitivity/specificity, and estimated positive and negative predictive values. In total, 16 NS1 patients, 11 NS2 patients, and 71 controls were included. With an AI of ≥1.7 as a positive test for NS diagnostic, specificity was 98.6% (95% confidence interval [CI 95%] of 92.4 to 100.0) and sensitivity was 81.3% (CI 95% of 54.4 to 96.0) for NS1 and 98.6% (CI 95% 92.4 to 100.0) and 27.3% (CI 95% 6.0 to 61.0), respectively, for NS2. Positive and negative predictive values were >95% for NS1 and >85% for NS2, for prevalence above and below 20%. Measuring an AI for intrathecal synthesis of specific anti-Treponema pallidum IgG is a new promising tool highly specific for NS diagnosis. IMPORTANCE In the context of a lack of a gold standard for the diagnosis of neurosyphilis due to either nonspecific or nonsensitive tests, we present in this article a new promising tool highly specific for NS diagnosis. This new test involves measuring an intrathecal synthesis index of specific anti-Treponema IgG by ELISA.

Treponema pallidum genome sequencing from six continents reveals variability in vaccine candidate genes and dominance of Nichols clade strains in Madagascar.

In spite of its immutable susceptibility to penicillin, Treponema pallidum (T. pallidum) subsp. pallidum continues to cause millions of cases of syphilis each year worldwide, resulting in significant morbidity and mortality and underscoring the urgency of developing an effective vaccine to curtail the spread of the infection. Several technical challenges, including absence of an in vitro culture system until very recently, have hampered efforts to catalog the diversity of strains collected worldwide. Here, we provide near-complete genomes from 196 T. pallidum strains-including 191 T. pallidum subsp. pallidum-sequenced directly from patient samples collected from 8 countries and 6 continents. Maximum likelihood phylogeny revealed that samples from most sites were predominantly SS14 clade. However, 99% (84/85) of the samples from Madagascar formed two of the five distinct Nichols subclades. Although recombination was uncommon in the evolution of modern circulating strains, we found multiple putative recombination events between T. pallidum subsp. pallidum and subsp. endemicum, shaping the genomes of several subclades. Temporal analysis dated the most recent common ancestor of Nichols and SS14 clades to 1717 (95% HPD: 1543-1869), in agreement with other recent studies. Rates of SNP accumulation varied significantly among subclades, particularly among different Nichols subclades, and was associated in the Nichols A subclade with a C394F substitution in TP0380, a ERCC3-like DNA repair helicase. Our data highlight the role played by variation in genes encoding putative surface-exposed outer membrane proteins in defining separate lineages, and provide a critical resource for the design of broadly protective syphilis vaccines targeting surface antigens.

Global phylogeny of Treponema pallidum lineages reveals recent expansion and spread of contemporary syphilis.

Syphilis, which is caused by the sexually transmitted bacterium Treponema pallidum subsp. pallidum, has an estimated 6.3 million cases worldwide per annum. In the past ten years, the incidence of syphilis has increased by more than 150% in some high-income countries, but the evolution and epidemiology of the epidemic are poorly understood. To characterize the global population structure of T. pallidum, we assembled a geographically and temporally diverse collection of 726 genomes from 626 clinical and 100 laboratory samples collected in 23 countries. We applied phylogenetic analyses and clustering, and found that the global syphilis population comprises just two deeply branching lineages, Nichols and SS14. Both lineages are currently circulating in 12 of the 23 countries sampled. We subdivided T. p. pallidum into 17 distinct sublineages to provide further phylodynamic resolution. Importantly, two Nichols sublineages have expanded clonally across 9 countries contemporaneously with SS14. Moreover, pairwise genome analyses revealed examples of isolates collected within the last 20 years from 14 different countries that had genetically identical core genomes, which might indicate frequent exchange through international transmission. It is striking that most samples collected before 1983 are phylogenetically distinct from more recently isolated sublineages. Using Bayesian temporal analysis, we detected a population bottleneck occurring during the late 1990s, followed by rapid population expansion in the 2000s that was driven by the dominant T. pallidum sublineages circulating today. This expansion may be linked to changing epidemiology, immune evasion or fitness under antimicrobial selection pressure, since many of the contemporary syphilis lineages we have characterized are resistant to macrolides.

Phylogenetic and genetic characterization of Treponema pallidum strains from syphilis patients in Japan by whole-genome sequence analysis from global perspectives.

Japan has had a substantial increase in syphilis cases since 2013. However, research on the genomic features of the Treponema pallidum subspecies pallidum (TPA) strains from these cases has been limited. Here, we elucidated the genetic variations and relationships between TPA strains in Japan (detected between 2014 and 2018) and other countries by whole-genome sequencing and phylogenetic analyses, including syphilis epidemiological surveillance data and information on patient sexual orientation. Seventeen of the 20 strains in Japan were SS14- and the remaining 3 were Nichols-lineage. Sixteen of the 17 SS14-lineage strains were classified into previously reported Sub-lineage 1B. Sub-lineage 1B strains in Japan have formed distinct sub-clusters of strains from heterosexuals and strains from men who have sex with men. These strains were closely related to reported TPA strains in China, forming an East-Asian cluster. However, those strains in these countries evolved independently after diverging from their most recent common ancestor and expanded their genetic diversity during the time of syphilis outbreak in each country. The genetic difference between the TPA strains in these countries was characterized by single-nucleotide-polymorphism analyses of their penicillin binding protein genes. Taken together, our results elucidated the detailed phylogenetic features and transmission networks of syphilis.

Parameters Affecting Continuous In Vitro Culture of Treponema pallidum Strains.

The bacterium that causes syphilis, Treponema pallidum subsp. pallidum, has now been cultured in vitro continuously for periods exceeding 3 years using a system consisting of coculture with Sf1Ep rabbit epithelial cells in TpCM-2 medium and a low-oxygen environment. In addition, long-term culture of several other syphilis isolates (SS14, Mexico A, UW231B, and UW249B) and the T. pallidum subsp. endemicum Bosnia A strain has been achieved. During in vitro passage, T. pallidum subsp. pallidum exhibited a typical bacterial growth curve with logarithmic and stationary phases. Sf1Ep cells are required for sustained growth and motility; however, high initial Sf1Ep cell numbers resulted in reduced multiplication and survival. Use of Eagle's minimal essential medium as the basal medium was not effective in sustaining growth of T. pallidum subsp. pallidum beyond the first passage, whereas CMRL 1066 or M199 supported long-term culture, confirming that additional nutrients present in these more complex basal media are required for long-term culture. T. pallidum subsp. pallidum growth was dependent upon the presence of fetal bovine serum, with 20% (vol/vol) being the optimal concentration. Omission of reactive oxygen species scavengers dithiothreitol, d-mannitol, or l-histidine did not dramatically affect survival or growth. Additionally, T. pallidum subsp. pallidum can be successfully cultured in a Brewer jar instead of a specialized low-oxygen incubator. Phosphomycin or amphotericin B can be added to the medium to aid in the prevention of bacterial or fungal contamination, respectively. These results help define the parameters of the T. pallidum subsp. pallidum culture system that are required for sustained, long-term survival and multiplication.IMPORTANCE Syphilis is caused by the bacterium Treponema pallidum subsp. pallidum Until recently, this pathogen could only be maintained through infection of rabbits or other animals, making study of this important human pathogen challenging and costly. T. pallidum subsp. pallidum has now been successfully cultured for over 3 years in a tissue culture system using a medium called TpCM-2. Here, we further define the growth requirements of this important human pathogen, promoting a better understanding of the biology of this fastidious organism.

Characterisation of the novel clinical isolate X-4 containing a new tp0548 sequence-type.

OBJECTIVES: A novel tp0548 sequence-type was identified in one clinical isolate (X-4) from a patient diagnosed with primary syphilis in Xiamen, China. To precisely define and characterise a new clinical isolate, we performed further genome-scale molecular analysis. METHODS: The pooled segment genome sequencing method followed by Illumina sequencing was performed. RESULTS: This novel sequence-type contained a unique nucleotide substitution 'T' at position 167 and belonged to the SS14-like clade of TPA strains, as determined by phylogenetic analysis. Multi-locus sequence analysis of nine chromosomal loci demonstrated that the X-4 isolate was clustered within a monophyletic group of TPA strains. Whole-genome phylogenetic analysis subsequently corroborated the TPA strain classification of the X-4 isolate and revealed that the isolate was closely related to the SS14 strain, with 42 single-nucleotide variations and 12 insertions/deletions. In addition, high intrastrain heterogeneity in the length of the poly G/C tracts was found in the TPAChi_0347 locus, which might indicate that this gene of the X-4 isolate is likely involved in phase variation events. The length heterogeneity of the poly A/T tracts was lower than the genetic variability of the poly G/C tracts, and all the observed intrastrain variations fell within coding regions. CONCLUSION: The novel tp0548 sequence-type was determined to belong to a new TPA isolate, X-4. The identification of variable length in homopolymetic tracts (G/C and A/T) could provide a snapshot of the genes that potentially involved in genotype-phenotype variations. These findings provide an unequivocal characterisation for better understanding the molecular variation of this emerging isolate.

Analysis of Treponema pallidum Strains From China Using Improved Methods for Whole-Genome Sequencing From Primary Syphilis Chancres.

BACKGROUND: Whole-genome sequencing (WGS) of Treponema pallidum subspecies pallidum (TPA) has been constrained by the lack of in vitro cultivation methods for isolating spirochetes from patient samples. METHODS: We built upon recently developed enrichment methods to sequence TPA directly from primary syphilis chancre swabs collected in Guangzhou, China. RESULTS: By combining parallel, pooled whole-genome amplification with hybrid selection, we generated high-quality genomes from 4 of 8 chancre-swab samples and 2 of 2 rabbit-passaged isolates, all subjected to challenging storage conditions. CONCLUSIONS: This approach enabled the first WGS of Chinese samples without rabbit passage and provided insights into TPA genetic diversity in China.

No bejel among Surinamese, Antillean and Dutch syphilis diagnosed patients in Amsterdam between 2006-2018 evidenced by multi-locus sequence typing of Treponema pallidum isolates.

BACKGROUND: Treponema pallidum subspecies pallidum (TPA) and subsp. endemicum (TEN) are the causative agents of syphilis and bejel, respectively. TEN shows similar clinical manifestations and is morphologically and serologically indistinguishable from TPA. Recently, bejel was found outside of its assumed endemic areas. Using molecular typing we aimed to discover bejel and characterize circulating TPA types among syphilis cases with Surinamese, Antillean and Dutch ethnicity in Amsterdam. METHODS: DNA was extracted from 137 ulcer swabs, which tested positive in the in-house diagnostic PCR targeting the polA gene. Samples were collected between 2006 and 2018 from Surinamese, Antillean and Dutch patients attending the Amsterdam STI clinic. Multilocus sequence typing was performed by partial sequence analysis of the tp0136, tp0548 and tp0705 genes. In addition, the 23S rRNA loci were analyzed for A2058G and A2059G macrolide resistance mutations. RESULTS: We found 17 distinct allelic profiles in 103/137 (75%) fully typed samples, which were all TPA and none TEN. Of the strains, 82.5% were SS14-like and 17.5% Nichols-like. The prevalence of Nichols-like strains found in this study is relatively high compared to nearby countries. The most prevalent types were 1.3.1 (42%) and 1.1.1 (19%), in concordance with similar TPA typing studies. The majority of the TPA types found were unique per country. New allelic types (7) and profiles (10) were found. The successfully sequenced 23S rRNA loci from 123/137 (90%) samples showed the presence of 79% A2058G and 2% A2059G mutations. CONCLUSIONS: No TEN was found in the samples from different ethnicities residing in Amsterdam, the Netherlands, so no misdiagnoses occurred. Bejel has thus not (yet) spread as a sexually transmitted disease in the Netherlands. The strain diversity found in this study reflects the local male STI clinic population which is a diverse, mixed group.

The pan-genome of Treponema pallidum reveals differences in genome plasticity between subspecies related to venereal and non-venereal syphilis.

BACKGROUND: Spirochetal organisms of the Treponema genus are responsible for causing Treponematoses. Pathogenic treponemes is a Gram-negative, motile, spirochete pathogen that causes syphilis in human. Treponema pallidum subsp. endemicum (TEN) causes endemic syphilis (bejel); T. pallidum subsp. pallidum (TPA) causes venereal syphilis; T. pallidum subsp. pertenue (TPE) causes yaws; and T. pallidum subsp. Ccarateum causes pinta. Out of these four high morbidity diseases, venereal syphilis is mediated by sexual contact; the other three diseases are transmitted by close personal contact. The global distribution of syphilis is alarming and there is an increasing need of proper treatment and preventive measures. Unfortunately, effective measures are limited. RESULTS: Here, the genome sequences of 53 T. pallidum strains isolated from different parts of the world and a diverse range of hosts were comparatively analysed using pan-genomic strategy. Phylogenomic, pan-genomic, core genomic and singleton analysis disclosed the close connection among all strains of the pathogen T. pallidum, its clonal behaviour and showed increases in the sizes of the pan-genome. Based on the genome plasticity analysis of the subsets containing the subspecies T pallidum subsp. pallidum, T. pallidum subsp. endemicum and T. pallidum subsp. pertenue, we found differences in the presence/absence of pathogenicity islands (PAIs) and genomic islands (GIs) on subsp.-based study. CONCLUSIONS: In summary, we identified four pathogenicity islands (PAIs), eight genomic islands (GIs) in subsp. pallidum, whereas subsp. endemicum has three PAIs and seven GIs and subsp. pertenue harbours three PAIs and eight GIs. Concerning the presence of genes in PAIs and GIs, we found some genes related to lipid and amino acid biosynthesis that were only present in the subsp. of T. pallidum, compared to T. pallidum subsp. endemicum and T. pallidum subsp. pertenue.

Molecular diversity of Treponema pallidum subspecies pallidum isolates in Amsterdam, the Netherlands.

OBJECTIVES: The prevalence of syphilis, caused by the spirochete Treponema pallidum subsp. pallidum (TPA), remains high despite the availability of effective antibiotics. In the Netherlands, most syphilis cases are found among men who have sex with men (MSM). We studied the distribution of TPA strain types by molecular characterisation and related this to available characteristics. In addition, resistance to macrolides was assessed. METHODS: TPA DNA was extracted from 136 genital ulcer swab or skin lesions samples deriving from 135 patients diagnosed with syphilis in 2016 and 2017 at the Public Health Service in Amsterdam, the Netherlands. Molecular typing was done according to the enhanced CDC method (E-CDC), in which three genetic regions of the arp, tpr and tp0548 genes are analysed by gel electrophoresis of the arp and tpr regions and by sequence analysis for the tp0548 region. Part of the 23S rDNA locus was sequenced to determine the presence of macrolide resistance-associated mutations. RESULTS: Full E-CDC strain types could be determined for 99/136 (73%) DNA samples, which tested positive in a diagnostic PCR targeting the polA gene. Types differed within one patient of whom two samples were available. No association was found between the demographic and clinical characteristics and the TPA types. The most prevalent type was 14d/g, found in 23 of the 99 (23%) fully typed samples. Part of the 23S rDNA locus was successfully sequenced for 93/136 (68%) samples and 83 (88%) contained the A2058G mutation. No A2059G mutation was found. CONCLUSIONS: A broad strain distribution was found. Few subtypes were clonally expanded, and most other subtypes were rare. Detection of the most prevalent strain type, 14d/g, is in concordance with other TPA typing studies. The high prevalence of genetic macrolide resistance indicates that azithromycin is not an alternative treatment option.

Enhanced molecular typing and macrolide and tetracycline-resistance mutations of Treponema pallidum in Barcelona.

Aim: To describe the molecular types of Treponema pallidum and the proportion of macrolide and tetracycline resistance mutations in Barcelona. Materials & methods: Molecular type was determined using the Enhanced-CDC Typing system and antibiotic resistance was determined by sequencing the 23S and 16S rRNA genes. Results: A total of 183 patients were enrolled and 213 specimens (99 ulcers, 114 bloods) were collected. Sixty-two (70.5%) of 88 ulcers and 0 (0%) of bloods T. pallidum-DNA containing samples were fully typed. Up to 21 different strain types were identified (14d/g in 27.4%; 14f/g in 14.5%). Macrolide resistance mutations were present in 95% and tetracycline in 0%. Conclusion: Several different strains co-exist in Barcelona with a high proportion of macrolide resistance and absence of tetracycline resistance.

Genomic epidemiology of syphilis reveals independent emergence of macrolide resistance across multiple circulating lineages.

Syphilis is a sexually transmitted infection caused by Treponema pallidum subspecies pallidum and may lead to severe complications. Recent years have seen striking increases in syphilis in many countries. Previous analyses have suggested one lineage of syphilis, SS14, may have expanded recently, indicating emergence of a single pandemic azithromycin-resistant cluster. Here we use direct sequencing of T. pallidum combined with phylogenomic analyses to show that both SS14- and Nichols-lineages are simultaneously circulating in clinically relevant populations in multiple countries. We correlate the appearance of genotypic macrolide resistance with multiple independently evolved SS14 sub-lineages and show that genotypically resistant and sensitive sub-lineages are spreading contemporaneously. These findings inform our understanding of the current syphilis epidemic by demonstrating how macrolide resistance evolves in Treponema subspecies and provide a warning on broader issues of antimicrobial resistance.

Bejel, a Nonvenereal Treponematosis, among Men Who Have Sex with Men, Japan.

Bejel, an endemic treponematosis caused by infection with Treponema pallidum subspecies endemicum, has not been reported in eastern Asia and the Pacific region. We report local spread of bejel among men who have sex with men in Japan. Spread was complicated by venereal syphilis.

Identification of positively selected genes in human pathogenic treponemes: Syphilis-, yaws-, and bejel-causing strains differ in sets of genes showing adaptive evolution.

BACKGROUND: Pathogenic treponemes related to Treponema pallidum are both human (causing syphilis, yaws, bejel) and animal pathogens (infections of primates, venereal spirochetosis in rabbits). A set of 11 treponemal genome sequences including those of five Treponema pallidum ssp. pallidum (TPA) strains (Nichols, DAL-1, Mexico A, SS14, Chicago), four T. p. ssp. pertenue (TPE) strains (CDC-2, Gauthier, Samoa D, Fribourg-Blanc), one T. p. ssp. endemicum (TEN) strain (Bosnia A) and one strain (Cuniculi A) of Treponema paraluisleporidarum ecovar Cuniculus (TPeC) were tested for the presence of positively selected genes. METHODOLOGY/PRINCIPAL FINDINGS: A total of 1068 orthologous genes annotated in all 11 genomes were tested for the presence of positively selected genes using both site and branch-site models with CODEML (PAML package). Subsequent analyses with sequences obtained from 62 treponemal draft genomes were used for the identification of positively selected amino acid positions. Synthetic biotinylated peptides were designed to cover positively selected protein regions and these peptides were tested for reactivity with the patient's syphilis sera. Altogether, 22 positively selected genes were identified in the TP genomes and TPA sets of positively selected genes differed from TPE genes. While genetic variability among TPA strains was predominantly present in a number of genetic loci, genetic variability within TPE and TEN strains was distributed more equally along the chromosome. Several syphilitic sera were shown to react with some peptides derived from the protein sequences evolving under positive selection. CONCLUSIONS/SIGNIFICANCE: The syphilis-, yaws-, and bejel-causing strains differed relative to sets of positively selected genes. Most of the positively selected chromosomal loci were identified among the TPA treponemes. The local accumulation of genetic variability suggests that the diversification of TPA strains took place predominantly in a limited number of genomic regions compared to the more dispersed genetic diversity differentiating TPE and TEN strains. The identification of positively selected sites in tpr genes and genes encoding outer membrane proteins suggests their role during infection of human and animal hosts. The driving force for adaptive evolution at these loci thus appears to be the host immune response as supported by observed reactivity of syphilitic sera with some peptides derived from protein sequences showing adaptive evolution.

Molecular detection of Treponema pallidum subspecies pallidum in 150-year-old foetal remains, southeastern France.

PURPOSE: Syphilis, caused by Treponema pallidum subspecies pallidum , is considered as an old disease affecting humans; traces of such infections, including congenital syphilis, are potentially identifiable in archaeological samples. The aim of this research was to perform macroscopic and molecular investigations of T. pallidum on six infant remains, buried between 1837 and 1867, from the cemetery of 'Les Crottes' in Marseille city (southeastern France). METHODOLOGY: Pathological analysis of bones from individuals, aged from the twenty-ninth week of amenorrhea to 4-9 months, was performed. Samples served also as a source of ancient DNA (aDNA) for PCR-based molecular investigations targeting T. pallidum DNA; all samples were also tested for Mycobacterium tuberculosis and Plasmodium falciparum DNA. Sequences characterized were cloned and sequenced, and compared to those available in databases.Results/Key findings. All samples tested displayed widespread osteoporotic lesions across the skeleton possibly related to some metabolic or infectious disorders. Subsequent molecular analysis revealed that one individual, SP332 (unborn, 29 amenorrhea weeks, inhumation date 1864-1866), exhibited positive signals for the five T. pallidum amplification systems tested; sequence analysis provided strong evidence for the effective detection of T. pallidum subspecies pallidum DNA. CONCLUSIONS: Individual SP332 is the first PCR-confirmed palaeopathological case of syphilis identified in France, and the youngest specimen ever to be diagnosed with certainty for congenital syphilis. Future research aimed at better characterizing this 150-year-old treponeme genome and exploring new archaelogical cases of syphilis in the very young should contribute to a better comprehension of the disease's history.

Circulation of Distinct Treponema pallidum Strains in Individuals with Heterosexual Orientation and Men Who Have Sex with Men.

Human treponematosis is caused by various pathogenic Treponema pallidum subspecies, including T. pallidum subsp. pallidum, T. pallidum subsp. pertenue, T. pallidum subsp. endemicum, and Treponema carateum The global prevalence of syphilis has been increasing since the 2000s. Men account for more than 90% of the cases, with the majority being men who have sex with men (MSM). In Japan, the increase in the number of syphilis patients began in 2011, a 10-year delay from the global trend. In 2017, a total of 5,829 syphilis cases (3,934 men and 1,895 women) were reported, with an outstanding increase in cases among young adult women; the number reported for women age 15 to 20 years was 1,100. Hence, a molecular epidemiological study was conducted on circulating T. pallidum strains using two strain typing methods, the enhanced CDC method and sequencing-based molecular typing. Clinical specimens from 95 adults suspected of syphilis were collected from September 2013 to August 2017 in Osaka, Japan. T. pallidum DNA was detected in specimens from 25 males and 11 females, including seven MSM. The majority of the heterosexual patients (66.7% and 90.9% of males and females, respectively) were positive for 14d/f-SSR8. In contrast, the genotypes identified in the MSM group were significantly divergent. T. pallidum subsp. endemicum was notably identified in two MSM patients. Macrolide-sensitive or Nichols-like strains were significantly associated with the MSM group. These data suggest that distinct T. pallidum strains were circulating in the heterosexual and MSM groups. Our findings imply that independent factors may contribute to the increased syphilis prevalence in heterosexual and MSM populations.

Multilocus Sequence Typing of Treponema pallidum subsp. pallidum in Cuba From 2012 to 2017.

BACKGROUND: The increased prevalence of syphilis in Cuba prompted us to map the circulating Treponema pallidum subsp. pallidum allelic profiles in this geographic region. METHODS: Samples were collected from 2012 to 2017, from 83 male patients with ulcers or skin lesions, and were examined using multilocus sequence typing. Additionally, we analyzed the 23S rDNA and 16S rDNA regions for the presence of possible mutations leading to macrolide and tetracycline resistance. RESULTS: Among 94% of fully typed strains, we found 7 different allelic profiles, of which 4 had not been previously described. More than 87% of patients were infected with the T. pallidum SS14-like group and only 8.2% with T. pallidum Nichols-like group. As in other countries, the 1.3.1 allelic profile (ie, SS14-like) was the most common. In addition, 1 of the newly described allelic profiles represents T. pallidum strains that arose by recombination events between members of different T. pallidum subgroups. More than 90% of patients were infected with treponemes harboring the A2058G mutation. However, we found no potential tetracycline-resistant T. pallidum mutations. CONCLUSIONS: Our results suggest that, in Cuba, tetracycline antibiotics could be used to treat syphilis in penicillin-allergic patients instead of macrolides.

Molecular Typing and Macrolide Resistance Analyses of Treponema pallidum in Heterosexuals and Men Who Have Sex with Men in Japan, 2017.

In recent years, syphilis notifications have increased dramatically in Japan. We carried out molecular typing and macrolide resistance analyses of Treponema pallidum subsp. pallidum samples collected from patients at four clinics and a hospital in Tokyo and Osaka prefectures in 2017. The macrolide resistant strain type 14d/f (SS14-like clade) was found in significantly more cases of syphilis among heterosexuals than in those among men who have sex with men (MSM); i.e., 79% (31/39) of the strains from heterosexuals were 14d/f compared to 37% (7/19) of those from MSM (odds ratio [OR], 6.6; 95% confidence interval [CI], 1.7 to 26.7; P = 0.002). In addition, 83% (50/60) of the strains were identified as macrolide resistant with an A2058G mutation in the 23S rRNA gene; 90% (35/39) of the strains from heterosexuals were macrolide resistant compared to 58% (11/19) of those from MSM. The odds of having the resistant mutation were considerably higher in the former (OR, 6.4; 95% CI, 1.3 to 33.5; P = 0.02). Heterosexual women and heterosexual men showed similar distributions, and the association remained the same when restricted to men. The strain type distribution and the prevalence of macrolide resistance differed substantially between syphilis strains from heterosexual cases and from MSM cases, suggesting distinct epidemiologic profiles for the two communities and providing important insight into the dynamics of syphilis in Japan.