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.

Prevalence and Predictors of Oral Treponema pallidum Detection by Quantitative Polymerase Chain Reaction in Early Syphilis.

BACKGROUND: Treponema pallidum prevalence and burden at oral and lesion sites in adults with early syphilis were assessed by quantitative polymerase chain reaction (qPCR). Factors associated with oral shedding were also examined. METHODS: Pretreatment oral and lesion swabs were collected from adults with early syphilis in a US multicenter syphilis treatment trial. Oral swabs were collected in the presence and absence of oral lesions. Following DNA extraction, qPCR and whole-genome sequencing (WGS) were performed to assess burden and strain variability. RESULTS: All 32 participants were male, mean age was 35 years, and 90.6% with human immunodeficiency virus (HIV). T. pallidum oral PCR positivity varied by stage: 16.7% primary, 44.4% secondary, and 62.5% in early latent syphilis. Median oral T. pallidum burden was highest in secondary syphilis at 63.2 copies/µL. Lesion PCR positivity was similar in primary (40.0%) and secondary syphilis (38.5%). Age 18-29 years was significantly associated with oral shedding (vs age 40+ years) in adjusted models. WGS identified 2 distinct strains. CONCLUSIONS: T. pallidum DNA was directly detected at oral and lesion sites in a significant proportion of men with early syphilis. Younger age was associated with oral shedding. Ease of oral specimen collection and increased PCR availability suggest opportunities to improve syphilis diagnostic testing. Clinical Trials Registration. NCT03637660.

Evaluation of Automated Processing of Electronically Reported Serological Tests for Syphilis Using Current and Historical Syphilis Results Compared With Traditional Reactor Grid Processing in Florida.

BACKGROUND: Syphilis in Florida increased 49% from 2016 to 2020. Moreover, many serological tests for syphilis (STS) do not indicate current infection. Traditionally, syphilis surveillance systems used reactor grids, a method for prioritizing STS for investigation based on age, nontreponemal titer, and/or sex. In 2022, Florida's sexually transmitted disease surveillance system implemented an automated method for processing electronically reported STS (eSTS), expanding upon the reactor grid, using an individual's current STS (treponemal and nontreponemal), treatment history, and historical STS results aiming for more efficiently processing eSTS. We compared the new method of processing eSTS results against the reactor grid and determined potential value in time/cost savings of this change. METHODS: All eSTSs (n = 4144) from January 2, 2023 to January 8, 2023, were compared by how the logic-based method processed test results versus how the reactor grid processed test results. Each method was compared using measurements of accuracy (e.g., sensitivity/specificity). Time and cost savings in eSTS processing were estimated. RESULTS: Using the surveillance case definition as reference, the accuracy of the logic-based method for processing eSTS was nearly double (82.3% vs. 43.6%), had greater specificity (79.0% vs. 33.0%), and increased positive predictive value (47.5% vs. 22.0%) when compared with the reactor grid method. Sensitivity (99.5% vs. 98.6%) and negative predictive value (99.9% vs. 99.2%) remained similar. The logic-based method is estimated to save 7783 hours annually (~$185,000). CONCLUSIONS: Processing eSTS based on current and historical STS results is significantly more accurate than using a reactor grid. Moreover, these improvements save time and resources that can be better allocated to other program prevention activities.

A Novel Treponema pallidum Subspecies pallidum Strain Associated With a Painful Oral Lesion Is a Member of a Potentially Emerging Nichols-Related Subgroup.

BACKGROUND: Early syphilitic lesions are typically painless; however, several recent case studies have included patients with tender lesions and no evidence of concurrent infections. Here we present the manifestations and serological and molecular findings of a patient from New York State with a painful tongue lesion. METHODS: The diagnosis of syphilis was based on a combination of physical examination, serologic, pathologic, and immunohistochemical findings. DNA obtained from a formalin-fixed, paraffin-embedded biopsy was used to characterize the infecting pathogen using polymerase chain reaction, multilocus sequence typing, and whole-genome sequencing methods. RESULTS: Polymerase chain reaction and multilocus sequence typing of the biopsy specimen confirmed infection with T. pallidum subspecies pallidum ( T. pallidum ) of the Nichols cluster. Whole-genome sequencing analysis of this strain (herein called NYMC01) showed that it contained 17 unique single nucleotide variations and 4 more complex genetic differences; this novel genotype matched only 2 specimens, both from a patient in Seattle, Washington. The presence of this rare genotype in 2 geographically distinct locations suggests the potential emergence and spread of a new subgroup of the Nichols cluster. CONCLUSIONS: To our knowledge, this is the first genomic sequence obtained from a T. pallidum strain linked to a painful lesion, and the third description of whole-genome sequencing of T. pallidum from formalin-fixed, paraffin-embedded tissue. Analysis of additional specimens may reveal that the NYMC01-related genotype represents an emerging T. pallidum subgroup and may also aid in determining whether the painful clinical presentation of primary syphilis is related to specific T. pallidum genotypes.

HIV Infection Modifies the Role of Prior Treponema pallidum Infection in the Clinical Presentation of Early Syphilis Among Adult Patients From Sexually Transmitted Infection Clinics in Peru.

BACKGROUND: We aimed to compare the clinical presentations (symptomatic vs. asymptomatic) with prior Treponema pallidum infection status (first infection vs. reinfection) among people with early syphilis. METHODS: We used data from PICASSO, a cohort study in Peru that enrolled people with active syphilis from May 2019 to August 2021. Study participants had early syphilis and a prior syphilis serological test result within the prior 12 months to determine prior T. pallidum infection status. We calculated prevalence ratios (PRs) of symptomatic clinical presentation (primary or secondary syphilis) by prior T. pallidum infection status, stratified by HIV infection status. In addition, we explored the association of prior T. pallidum infection status and lesion presentation, stratified by primary and secondary syphilis cases, using the Fisher exact test. RESULTS: We include 84 T. pallidum reinfection cases and 61 first infection cases. We found increased frequency of symptomatic clinical presentation among first-infection cases (39% vs. 20%; PR, 1.94; P = 0.014). This association was stronger among persons living without HIV infection (38% vs. 7%; adjusted PR, 6.63; P = 0.001) in comparison to those living with HIV infection (45% vs. 34%; adjusted PR, 1.38; P = 0.458). Among secondary syphilis cases, more participants from the reinfection group reported that their lesions improved 1 week after treatment (100% vs. 29%, P = 0.045) compared with those with a first infection. Among the primary syphilis cases, all participants reported that their lesions improved 1 week after treatment. CONCLUSIONS: Prior syphilis was associated with a decreased prevalence of symptomatic reinfection, especially among persons not living with HIV infection.

"Syphilitic Hepatitis": A Comprehensive Review of Clinical Features, Diagnostic Approaches, and Management Considerations.

Syphilitic hepatitis is a very rare presentation of syphilis infection, characterized by inflammation of the liver due to the invasion of hepatic tissue by the bacterium Treponema pallidum. This review article provides an in-depth analysis of the existing body of information pertaining to syphilitic hepatitis. The article primarily concentrates on key aspects such as the epidemiology, clinical manifestations, diagnostic methods, and therapeutic approaches associated with this condition. Despite its rarity, awareness of syphilitic hepatitis is vital for accurate diagnosis and appropriate intervention. The clinical presentations frequently exhibit similarities with many liver illnesses, hence presenting difficulties in making an accurate diagnosis. Common symptoms include fatigue, stomach pain, and jaundice. Diagnostic procedures encompass the use of serological assays, including rapid plasma reagin (RPR) and fluorescent treponemal antibody absorption (FTA-ABS), in conjunction with imaging modalities to evaluate hepatic engagement. The primary therapeutic approach is the prompt initiation of antibiotic therapy, with a particular emphasis on penicillin, to eradicate the causative bacterial infection and facilitate the restoration of liver function. Failure to swiftly manage this condition may result in substantial morbidity. In summary, syphilitic hepatitis is a very uncommon but medically relevant manifestation of syphilis infection. The significance of increased clinical suspicion, precise diagnostic techniques, and prompt antibiotic administration is emphasized in this review since these are crucial in reducing the potentially severe outcomes associated with this illness.

Sudden hearing loss secondary to syphilis.

BACKGROUND: Syphilis is a sexually transmitted disease caused by the spirochete Treponema pallidum, whose incidence has increased significantly in recent years. Some patients may develop sudden hearing loss (SHL) against the background of otosyphilis. OBJECTIVES: The objective of our study was to determine whether routine lues serology is useful in patients presenting with sudden hearing loss. METHODS: For this purpose, all cases of SHL treated in our hospital during a period of 6 years were propectively collected. The frequency of positivity for syphilis in these patients, the treatment received, and their evolution were determined. RESULTS: Of the total number of patients evaluated during that period, 71 underwent serological screening for syphilis, of whom 2 (2.8 %) presented positive screening antibodies. In one of them, the RPR was normal and had been treated with lues a few years before. After treatment there was no improvement. The other patient, diagnosed with otosyphilis with unconfirmed suspected neurological disease, showed normalization of hearing after specific treatment. CONCLUSIONS: Since it is a potentially curable disease, despite the low overall frequency of syphilis in patients with SHL it is advisable to perform serological screening for syphilis in high risk patients (e.g., incarceration, multiple recent sexual partners, men who have sex with men) or atypical clinical presentation (e.g., concurrent neuropathies).

[Surgical treatment of a patient with syphilitic aortitis]. / Khirurgicheskoe lechenie patsienta s sifiliticheskim aortitom.

Syphilitic aortitis is a rare disease caused by Treponema pallidum affecting the aorta and leading to inflammation. Syphilitic aortitis is one of the causes of aortic aneurysms. This article presents surgical treatment of a patient with syphilitic aortitis and thoracic aortic aneurysm. This clinical case confirms the difficulties of surgical treatment.

In Vitro Isolation of Treponema pallidum subsp. pallidum From Fresh and Frozen Needle Aspirates of Primary Experimental Syphilis Lesions.

ABSTRACT: Isolation of Treponema pallidum subsp. pallidum strains still relies on rabbit intratesticular inoculation of clinical samples. In this article, we report an alternative isolation approach based on the inoculation of fresh and frozen needle aspirates of primary experimental lesions into culture plates suitable for in vitro propagation of the syphilis agent.

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.

Diagnostic tools for neurosyphilis: a systematic review.

PURPOSE: Increasing incidences of syphilis highlight the preoccupation with the occurrence of neurosyphilis. This study aimed to understand the current diagnostic tools and their performance to detect neurosyphilis, including new technologies and the variety of existing methods. METHODS: We searched databases to select articles that reported neurosyphilis diagnostic methods and assessed their accuracy, presenting sensitivity and specificity values. Information was synthesized in tables. The risk of bias was examined using the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy recommendations. RESULTS: Fourteen studies were included. The main finding was a remarkable diversity of tests, which had varied purposes, techniques, and evaluation methodologies. There was no uniform criterion or gold standard to define neurosyphilis. The current basis for its diagnosis is clinical suspicion and cerebrospinal fluid analysis. There are new promising tests such as PCR tests and chemokine measurement assays. CONCLUSIONS: The diagnosis of neurosyphilis is still a challenge, despite the variety of existing and developing tests. We believe that the multiplicity of reference standards adopted as criteria for diagnosis reveals the imprecision of the current definitions of neurosyphilis. An important next step for the scientific community is to create a universally accepted diagnostic definition for this disease.

Unusual erythematous plaque with white scales, a case of acquired syphilis in a child and literature review.

BACKGROUND: Syphilis in children is uncommon with the mode of infection for this rare condition likely being congenital or acquired. While most acquired cases of syphilis in children result from sexual abuse, children can also be infected with syphilis through kissing, breastfeeding, sharing of daily necessities or pre-chewed food. Here, we report a case of acquired secondary syphilis in a child due to consumption of pre-chewed-food and provide a review of the literature on the characteristics of acquired syphilis in preschool children. CASE PRESENTATION: A 3-year-old girl presented with erythematous plaques and scales on her head, neck, and thighs as well as flat red papules with a moist, well circumscribed surface covered with a grayish-white film. The grandmother who cared for the girl was in the habit of pre-chewing food before giving it to the girl. The child and grandmother tested positive for RPR. The girl, who was not sexually abused, was diagnosed with acquired secondary syphilis, resulting from the transmission of pre-chewed food from her grandmother. CONCLUSIONS: Our case report and literature review reveal that close contact among family members can result in the transmission of syphilis. We recommend that pre-chewing food should be discouraged by caregivers when caring for their children to avoid disease transmission.

Unusual clinical manifestation and challenging serological interpretation of syphilis: insights from a case report.

BACKGROUND: The clinical manifestations of recent syphilis can be variable, with typical and atypical patterns. Several conditions may cause atypical clinical aspects, including human immunodeficiency virus (HIV) co-infection. Besides the clinical features, co-infections may completely alter syphilis serological tests, causing interpretative difficulties and diagnostic delays. Aim of the work is to describe the difficulties encountered during the diagnostic evaluation of atypical skin manifestations and of the serology for syphilis of an HIV-infected patient who had contracted it several times. CASE PRESENTATION: In 2020, a 52-year old HIV-positive bisexual male patient was admitted to our department with a 4-month history of moderately itchy cutaneous lesions localized at his neck, trunk and arms. In 2013, the patient presented with a classic syphilitic roseola of the trunk and a secondary syphilis was diagnosed, with increased levels of rapid plasma reagin (RPR), Treponema pallidum hemagglutination assay (TPHA), anti-Treponema pallidum IgM and IgG Index. A second episode occurred in 2018, as a primary syphilis with multiple ulcerative lesions of the penis, and increased levels of RPR, IgG and IgM. In 2019, a further episode of secondary syphilis was treated with Doxycycline. In 2020, erythematous and papular lesions with vesicular components and urticarial erythema multiforme (EM)-like lesions were present at the neck, trunk and arms. Serological tests and Nucleic Acid Amplification Test (NAAT) for Treponema Pallidum were performed, as well as a cutaneous biopsy with histological and immunohistochemical evaluation of one lesion. NAAT was negative for T. pallidum. Serological test results were discordant with a new syphilis infection, showing only increased levels of RPR and anti-Treponema IgG. The cutaneous biopsy revealed a non specific histological pattern, while the immunohistochemical evaluation with anti-spirochetal antibodies was mandatory for the diagnosis of recent syphilis, showing clusters of rod-shaped elements, some of which with spiral form, focally present at the epidermis and adnexal structures. CONCLUSIONS: Nowadays, syphilis may present with atypical clinical and serological features. Physicians should be aware of these possible alterations and consider syphilis even in case of uncommon clinical aspect and unclear serological tests. Cutaneous biopsy and immunohistochemical exam may be mandatory for the diagnosis.

Oral forms of secondary syphilis: An illustration of the pitfalls set by the great imitator.

INTRODUCTION: Syphilis is reemerging in certain populations, such as in men who have sex with men in particular. Oral manifestations are not uncommon and can render diagnosis difficult, particularly if occurring in isolation. MATERIALS AND METHODS: We recovered clinical data for all patients receiving a diagnosis of secondary syphilis who were referred to the National Reference Center for Syphilis in Paris, France, from January 2000 to July 2019. We selected patients presenting oral symptoms only and analyzed their general characteristics, time to diagnosis, and clinical presentations. RESULTS: Secondary syphilis was diagnosed in 206 patients, 38 of whom (18%) presented oral manifestations, which were isolated in 14 patients (37%). The main oral manifestations were subacute erosive or ulcerative lesions (55%), mucous patches on the tongue (53%), and nodular (10%) and leukokeratotic lesions (5%). Mean time to diagnosis was 4.5 months, but was significantly longer for patients with isolated oral symptoms (8.8 vs 1.8 months; P = .02). CONCLUSION: Oral presentations of secondary syphilis are frequent and challenging for diagnosis, even in patients with epidemiologic risk factors. Clinicians confronted with subacute oral lesions in such patients should bear in mind the possibility of this contagious, curable, and sometimes severe disease.

Syphilis infection and epidemiological characteristics in Haidian District, Beijing, China, 2013-2018.

OBJECTIVES: This study aimed to investigate the epidemiological characteristics of syphilis between 2013 and 2018 in the Haidian District of Beijing in China. In addition, this study suggests potential strategies to control the spread of syphilis infection. STUDY DESIGN: Observational study. METHODS: Data were collected from the Infectious Disease Reporting System at medical institutions within the Haidian District of Beijing between 2013 and 2018. Epidemiological methods, combined with Chi-squared test, were used to analyse the distribution of syphilis in terms of time, region, population and development stage. RESULTS: In total, 3048 patients with syphilis were reported in the Haidian District between 2013 and 2018, with an average annual prevalence of 14.26 per 100,000 population. The prevalence of syphilis was higher in rural than urban regions, and the sex ratio of male-to-female was 1.52:1. Patients aged 20-29 years accounted for 22.60% (689/3048) of the total cases. In terms of occupational distributions, the highest proportion (30.61%; 933/3048) was seen in individuals who were homemakers or unemployed. Latent syphilis was present in 66.83% (2037/3048) of patients and accounted for an increased proportion of syphilis cases each year. CONCLUSIONS: Syphilis was epidemic in the Haidian District of Beijing between 2013 and 2018. High prevalence was seen in young and middle-aged males living in urban areas. The prevalence of syphilis has been increasing since 2016; thus, public health policies and intervention strategies need to be strengthened to curb the spread of infection.

Multiplex Mediator Displacement Loop-Mediated Isothermal Amplification for Detection of Treponema pallidum and Haemophilus ducreyi.

Yaws, a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue, manifests as ulcerative skin lesions. Nucleic acid amplification tests, like loop-mediated isothermal amplification (LAMP), are versatile tools to distinguish yaws from infections that cause similar skin lesions, primarily Haemophilus ducreyi. We developed a novel molecular test to simultaneously detect T. pallidum and H. ducreyi based on mediator displacement LAMP. We validated the T. pallidum and H. ducreyi LAMP (TPHD-LAMP) by testing 293 clinical samples from patients with yaws-like lesions. Compared with quantitative PCR, the TPHD-LAMP demonstrated high sensitivity and specificity for T. pallidum (84.7% sensitivity, 95.7% specificity) and H. ducreyi (91.6% sensitivity, 84.8% specificity). This novel assay provided rapid molecular confirmation of T. pallidum and H. ducreyi DNA and might be suitable for use at the point of care. TPHD-LAMP could support yaws eradication by improving access to molecular diagnostic tests at the district hospital level.

Ocular and neurosyphilis: epidemiology and approach to management.

PURPOSE OF REVIEW: In the context of a resurgence of syphilis worldwide, it can be anticipated that a rise in cases of ocular, otic, and neurosyphilis will also be seen. This article reviews the current epidemiology, manifestations, and approach to management and treatment. RECENT FINDINGS: Although studies continue investigating alternate approaches and new diagnostic tests for ocular and neurosyphilis, few data exist to change current diagnostic algorithms and approaches to diagnosis, management, or follow up. SUMMARY: The diagnosis of neurologic and eye/ear involvement with syphilis may be delayed because of a lack of specificity of findings, low suspicion for syphilis, fluctuation in symptoms, and/or similarities in presentation to other diseases. A high index of suspicion for syphilis and re-education about the protean manifestations of syphilis by all clinicians is required provide timely diagnosis and management of ocular, otic, and neurosyphilis.

Estimating the syphilis incidence and diagnosis rate in Japan: a mathematical modelling study.

OBJECTIVES: The reported number of syphilis cases is increasing in Japan. In this study, we aimed to estimate both the incidence of infection and diagnosis-and-reporting rate using a mathematical model that captures the time course of infection. METHODS: We analysed yearly notification data from 1961 to 2016 and stratified according to clinical stage and sex. We built a compartmental ordinary differential equations model to describe the natural epidemiological course of syphilis in which the incidence of infection and diagnosis-and-reporting rate were included as time-varying parameters that we estimated via the maximum likelihood method. RESULTS: From 2008 to 2016, the estimated number of new syphilis cases among men and women was 1070 (95% CI 1037 to 1104) and 302 (95% CI 287 to 318), respectively, which was increased from the previous period (1999-2007) with 269 (95% CI 256 to 282) and 71 (95% CI 64 to 78) cases, respectively. The diagnosis-and-reporting rate did not vary greatly over time. We estimated the number of undiagnosed syphilis cases from either incubating or early clinical (ie, primary or secondary) infections in 2016 to be 262 (95% CI 249 to 275) and 79 (95% CI 74 to 84) for men and women, respectively. CONCLUSIONS: The recent increase in reported cases of syphilis is owing to an increase in the number of infections. We found no evidence of time-dependent improvement in detection or reporting.

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.