Therapy For Syphilis Research Articles

Clinical and laboratory characteristics of asymptomatic and symptomatic neurosyphilis in HIV-infected patients: A retrospective study in China.

There are high rates of human immunodeficiency virus (HIV) and Treponema pallidum coinfection, HIV can increase the incidence and disability rate of neurosyphilis. However, there is a lack of data about the risk factors associated with the development of symptomatic neurosyphilis (SNS). We retrospectively reviewed the medical records of inpatients with concurrent syphilis and HIV infection who underwent a lumbar puncture and completed cerebrospinal fluid (CSF) examination. Sixty inpatients were consecutively enrolled from Beijing Ditan Hospital between January 2015 and March 2023. The clinical and laboratory features were evaluated between the SNS and asymptomatic neurosyphilis (ANS) groups. All patients were male, 25% (15/60) patients were diagnosed with ANS, and 75% (45/60) patients were diagnosed with SNS. Meningovascular neurosyphilis was the most prevalent clinical form in this study. Age, CD4 cell count, highly active antiretroviral therapy use, and serum HIV viral load showed no statistically significant differences between the 2 groups. The SNS group lacked early detection of syphilis (P < .001) and did not get previous adequate therapy for syphilis (P < .001) than the ANS group, as well as a higher initial serum toluidine red unheated serum test (TRUST) titer, current serum TRUST titer, CSF white blood cell count (WBC), protein concentration, and CSF TRUST titer (P = .014, P = .042, P = .01, P = .007, and P = .007, respectively). In multivariable logistic regression, high CSF WBC count (odds ratio = 1.08; P = .032) and previous treatment of syphilis (odds ratio = 0.01; P = .049) related to the SNS. Lack of antisyphilis treatment in the early stage of syphilis and a higher CSF WBC count are related risk factors for SNS in HIV-infected patients. Meningovascular neurosyphilis should get more attention in young patients with cryptogenic stroke.

Lack of Serological Response by Delivery to Syphilis Treatment Does Not Impact Pregnancy Outcomes.

Objectives: Maternal syphilis can lead to serious adverse pregnancy outcomes, including neonatal death. A 4-fold decline in blood non-treponemal titer at six months after the treatment of syphilis compared to the baseline is considered as an adequate serological response. However, the duration of normal human gestation does not allow the ascertainment of an adequate serological response. Aim: The aim of this study was to assess correlations between the lack of a 4-fold decrease in non-treponemal titer by delivery after syphilis treatment and fetal and newborns' condition and serological outcomes. Methods: Fourteen pregnant patients (gestational age 16-22 weeks) diagnosed with early syphilis (secondary or latent) were treated with intramuscular benzathine penicillin and subsequently monitored clinically, serologically, and ultrasonographically at monthly intervals. Based on the non-treponemal test results at delivery, patients were stratified into two groups: those with a 4-fold decline in titers and those without such a decline. All newborns were clinically and serologically assessed for congenital syphilis at birth and then monitored until serological tests became negative. Results: Fifty percent of the included women did not achieve a 4-fold decline in non-treponemal titer by delivery. Patients from the group showing a 4-fold decline in RPR titer at delivery and those without such a decline did not differ in basic demographic and clinical characteristics or in ultrasound parameters used for fetal assessment. Based on the clinical and laboratory assessments of newborns on the day of delivery and during a 6-month follow-up, none were diagnosed with congenital syphilis or required treatment for syphilis. Conclusions: The lack of an adequate serological response to syphilis therapy by delivery among patients treated between 16 and 22 weeks of pregnancy does not appear to be associated with adverse fetal and neonatal outcomes.

Typing of Treponema pallidum in a Brazilian sample and follow-up of treatment using molecular assays.

Syphilis remains a significant public health concern, with serological assays being the primary method for diagnosis. However, molecular techniques have proven to be reliable tools for the diagnosis and understanding of the transmission dynamics of Treponema pallidum infection. This study aimed to evaluate the efficacy of syphilis treatment using molecular assays, perform Enhanced Centers for Disease Control and Prevention (ECDC) typing, and analyze resistance (macrolide and doxycycline) in the T. pallidum isolate. PCR assay amplified treponemal DNA only from the lesion sample, whereas qPCR was able to amplify DNA in both lesion and blood samples before treatment. Throughout the treatment follow-up, qPCR effectively did not identify treponemal DNA in the blood for up to one to two weeks after treatment. ECDC typing revealed the genotype 14 e/g in the Brazilian T. pallidum isolate, and the presence of the A2058G mutation in 23S rRNA gene, indicating macrolide resistance. Although, the G1058C mutation in 16S rRNA gene was not detected. Notably, qPCR demonstrated its potential for diagnosing T. pallidum in blood samples, even when the treponemal DNA levels were low, enabling more accurate and sensitive diagnosis and guiding better syphilis therapy. In addition, to the best of our knowledge, this study represents the first identification of subtype 14 e/g and azithromycin resistance in a Brazilian T. pallidum isolate.

Insights into ocular syphilis in Nepal.

This study aims to elucidate the demographic characteristics, clinical features, diagnostic approaches, and medical management of patients with ocular syphilis, known as 'the great masquerader,' at a tertiary eye care center in Nepal. We conducted a retrospective review involving 15 eyes from ten patients with ocular syphilis treated at a uveitis referral center between 2020 and 2022. Lumbar puncture was performed if neurosyphilis was suspected. Treatment success was defined as the absence of ocular inflammation in both eyes and a decrease in Veneral disease research laboratory (VDRL) titres after completing therapy. A total of 15 eyes of 10 patients were diagnosed with syphilitic uveitis based on positive treponemal and non-treponemal serological tests. The mean age of the patient was 39.9years (range 22-54years) with an equal distribution between males and females. HIV coinfection was not found in any of the patients. Syphilitic uveitis was the primary presentation in nine patients (90%), while one patient presented with recurrent nodular scleritis. Ocular involvement was bilateral in 50% (5 patients). The mean duration between the initial symptom and the first presentation was 8.7weeks (range: 4days to 24weeks). The most common ocular findings was panuveitis (6 eyes). Eight patients with early syphilis received weekly intramuscular injections of benzathine penicillin G for 3 weeks whereas 2 patients with neurosyphilis were treated with intravenous ceftriaxone 1 gm twice a day for 14 days. Signs and symptoms of majority of patients improved with systemic therapy for syphilis. Syphilitic uveitis should be included in the differential diagnosis of any form of ocular inflammation.

Challenges in The Management of Ocular Syphilis in Human Immunodeficiency Virus Patient: A Case Report

Background: The incidence rate of syphilis has been increasing in recent years. Ocular syphilis can manifest at any stage of syphilis, either with or without Human Immunodeficiency Virus (HIV) co-infection. Case Illustration: A 52-year-old man presented with a complaint of blurred vision persisting for the past 6 months. Visual examination revealed NLP (no light perception) in the right eye and 6/30 in the left eye. Syphilis serology testing was positive. Patient were diagnosed with latent syphilis with ocular syphilis, along with stage I HIV infection. Patient were treated with benzathine penicillin also with antiretroviral therapy for the HIV infection. Conclusion: Syphilis and HIV often occur together and can influence each other. Syphilitic ulcers can serve as the port of entry for HIV infection. In HIV-infected individuals with syphilis, the symptoms of syphilis can be varied due to the immunocompromised state. Benzathine penicillin G is a first-line therapy for ocular syphilis.

A comparative retrospective study on syphilis serology in HIV-positive and negative individuals before and after therapy

Syphilis serological tests are crucial for diagnosing and evaluating syphilis therapy. Human immunodeficiency virus (HIV) infection can alter syphilis serologies, making manifestations more atypical and increasing complications. This study aims to compare treponemal and nontreponemal titers before and after therapy between HIV-positive and negative patients. From January 2018 to December 2021, we retrospectively evaluated patients diagnosed with early and latent syphilis using quantitative nontreponemal and treponemal serologies (VDRL and TPHA) and categorized them as HIV-positive or negative. Baseline and post-therapy (1 month and last follow-up within 2 years) VDRL and TPHA titers were recorded. Twenty-nine HIV-negative and 28 HIV-positive patients met the inclusion criteria. Baseline VDRL and TPHA titers differed significantly between both groups, particularly in early syphilis, with the median baseline VDRL titer higher in the HIV-positive group. At 1-month and the last follow-up after therapy, VDRL titers continued to differ significantly, underscoring the impact of HIV coinfection on treatment response. Notably, TPHA titers exhibited significant differences between the two groups only at the last follow-up in overall syphilis. The HIV-positive group showed a higher percentage of patients failing to achieve a serological cure (60.7% vs. 58.6%). HIV coinfection in syphilis patients affects both nontreponemal and treponemal titers and elevates the treatment failure risk. This study highlights the importance of periodic syphilis serology tests in coinfected individuals to ensure treatment effectiveness, detect reinfection promptly, and prevent complications.

A 4-fold or greater decrease in TPPA titers may indicate effective BPG treatment in primary syphilis

BackgroundIn the majority of clinical environments, the treponema pallidum particle agglutination (TPPA) test is known for its higher specificity compared to the rapid plasma reagin (RPR) test and is commonly employed for the diagnosis of syphilis, but their use for serological monitoring after syphilis therapy is controversial. ObjectivesWe aim to evaluate whether the TPPA titers is suitable for monitoring syphilis treatment efficacy. MethodsAt first, 232 patients with primary syphilis were recruited. Serological testing was performed at baseline (initial visit) and at 6 months (±1 month) after benzathine penicillin G (BPG) treatment. Second, New Zealand white male rabbits were infected with Treponema pallidum (T. pallidum) to evaluate the changes in TPPA titers after BPG therapy. Finally, we compared the TPPA titers in the culture supernatant of rabbit splenocytes stimulated with T. pallidum with or without BPG. ResultsAfter 6 months of treatment, 150 (64.7%) of 232 primary syphilis patients achieved serological cure, and 82 (35.3%) had adverse outcomes. Among 110 patients with TPPA titers decreased by more than fourfold, 109 of them were serological cure patients (≥4-fold decrease in RPR titers) (P ＜ 0.0001). In the rabbit model of syphilis, the TPPA titers was significantly decreased in the treatment subgroup (P = 0.016) and remained constant (±2-fold) or increased (≥4-fold) in the nontreatment subgroup. In addition, T. pallidum resulted in a positive TPPA titers in the culture supernatant of splenocytes (median titers was 1: 80), while BPG could directly reduce the TPPA titers in the culture supernatant (median titers was 1: 40) (P = 0.032). ConclusionsA 4-fold or greater decrease in TPPA titers may indicate effective treatment in primary syphilis. Combining TPPA titers with RPR titers results may potentially aid in the early diagnosis of syphilis.

Higher Serologic Responses of Early Syphilis to Single-dose Benzathine Penicillin G Plus Doxycycline Versus Single-dose Benzathine Penicillin G Alone Among People With HIV.

Single-dose benzathine penicillin G (BPG) is the preferred therapy for early syphilis, but poorer serologic responses have been observed among people with human immunodeficiency virus (PWH). No enhanced regimen has previously been shown to improve serologic outcomes of early syphilis. We conducted a retrospective study to compare the treatment responses to single-dose BPG combined with 7-day doxycycline versus BPG alone in PWH who presented with early syphilis. Rapid plasma reagin (RPR) titers were determined every 3-6 months for all included PWH. Serologic response was defined as at least a 4-fold decline in RPR titers at month 12. During January 2018 to March 2022, 223 PWH with 307 episodes of early syphilis received single-dose BPG plus doxycycline and 347 PWH with 391 episodes received BPG alone. The median age was 36 years and baseline CD4 count was 600 cells/mm3. In the intention-to-treat with last-observation-carried-forward analysis, PWH receiving BPG plus doxycycline had a significantly higher serologic response rate at 12 months of treatment than those receiving BPG alone (79.5% vs 70.3%, respectively; P = .006). The factors associated with 12-month serologic response were RPR titer (per 1-log2 increase, adjusted odds ratio [AOR], 1.25; 95% confidence interval [CI], 1.15-1.35) and receipt of BPG plus doxycycline (AOR, 1.71; 95% CI, 1.20-2.46). In the subgroup analyses, BPG plus doxycycline was consistently associated with a better serologic response than BPG alone at month 12. Among PWH with early syphilis, single-dose BPG plus doxycycline achieved higher serologic responses than BPG alone during a 12-month follow-up period.

Association between treatment failure in patients with early syphilis and penicillin resistance-related gene mutations of Treponema pallidum: Protocol for a multicentre nested case-control study.

The widespread occurrence of syphilis remains a global public health problem. Although penicillin has been recommended as the first-line therapy for syphilis for more than 70 years, treatment failure occurs in 10-20% of patients with early syphilis. Recent studies have reported varied single-nucleotide polymorphisms (SNPs) of Treponema pallidum related to penicillin resistance. The clinical relevance of these SNPs to treatment failure in patients with early syphilis is unresolved. In this work, a protocol is developed to evaluate the association between treatment failure in patients with early syphilis and penicillin resistance-related gene mutations of T. pallidum. A multicentre nested case-control study is designed, and patients who are diagnosed with early syphilis and treated with penicillin will be recruited for the study cohort. Before the first treatment, baseline information and biological specimens will be collected from the subjects, and serological tests for syphilis will be performed. Each participant will be followed up at 1, 3, 6, 9, and 12 months after the first treatment, and the clinical manifestations and serum non-treponemal test titres will be evaluated at each follow-up. Patients who will fail treatment are defined as cases, and those who will respond to treatment are defined as controls. Tests for SNPs related to penicillin-binding proteins and Tp47 will be performed in these cases and controls. Survival analysis is used performed to identify gene mutations of T. pallidum related to penicillin resistance and their combinations associated with treatment failure. This protocol provides a practical clinical study design that illustrates the role of gene mutations of T. pallidum related to penicillin resistance in the treatment outcome of patients with early syphilis.

HF01-20 THE CODPIECE: A NOT SO FISHY HISTORY OF FORM AND FUNCTION

You have accessJournal of UrologyCME1 Apr 2023HF01-20 THE CODPIECE: A NOT SO FISHY HISTORY OF FORM AND FUNCTION Kristina Suson and Janae Preece Kristina SusonKristina Suson More articles by this author and Janae PreeceJanae Preece More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003243.20AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The codpiece, from the slang “cod” for scrotum, sprang into fashion in the 1500s and continues to be represented in art today. We chose to investigate its origins, focusing on its function and representation in the arts through today. METHODS: A review of primary and secondary sources was performed, focusing on function, and historical and cultural relevance. RESULTS: In the 1400s, male attire included a long shirt to cover the upper body, separate hosiery on each leg, and a coat or cape over both. As the shirts shortened, the genitals became increasingly exposed. In 1463, English law mandated they be covered. The earliest codpieces were a triangle of cloth attached to each hose and doublet, but soon that gave way to more padded, formed cloth. They grew into a figurative extension of the man’s outward virility; no longer limited to the “cod,” they eventually assumed the form of an erect phallus. In addition to its function of “modesty,” the more voluminous codpieces sometimes served as a pocket. They also protected the phallus from objects dangling from the wearer’s belt, while metal codpieces were paired with armor for the battlefield. Codpieces also performed a medical function. Medical therapy for syphilis, rampant in the late 1400s, was limited to topical applications. The phallus, wrapped in bandages, was covered by a codpiece, holding the treatment in place and protecting outerwear. Similar garments containing secretions associated with sexually transmitted infections persisted into the 1900s, with gonorrhea aprons. Detachable codpieces are still used today in some jock straps. In art, few codpieces are as recognizable as King Henry VIII’s. Legend has it, there was a wooden statue of the king featuring a mechanized swinging codpiece, while women stuck pins in his codpiece to promote fertility. The codpiece’s artistic reach extended far beyond England, popping up in famous Renaissance works around Europe. Not limited to the visual arts, there are numerous references in in plays, poetry, and other manuscripts. Western fascination with the codpiece has not entirely withered. It now has secured a place in superhero lore; Superman famously sports a codpiece, while a DC Comics super villain named Codpiece fashions his garment into a large weapon. Recently, several high end ateliers have incorporated the codpiece into their offerings. CONCLUSIONS: The codpiece has firmly erected itself in Western culture, from the 15th century through today, serving not only to protect a man’s modesty and manhood, but also to entertain through the visual arts, literature, motion pictures, and couture. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e263 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kristina Suson More articles by this author Janae Preece More articles by this author Expand All Advertisement PDF downloadLoading ...

Syphilis in pregnancy at Public Health Centre III North Denpasar

Introduction: Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. Syphilis in pregnancy is often asymptomatic, so early detection of syphilis is needed to prevent a poor pregnancy outcome and transmission of infection to the baby.&#x0D; Case: A 25-year-old woman, pregnant with her second child at 24 weeks of gestation, came without any health complaint for a routine prenatal check-up. On syphilis screening, reactive TPHA and RPR titer of 1:2 were found. The patient was diagnosed with syphilis infection in pregnancy. The patient has been treated with Benzathine Benzylpenicillin 2.4 million IU intramuscular injection once a week for 3 consecutive weeks.&#x0D; Conclusion: Syphilis is a sexually transmitted infection that infects pregnant women. Treponemal transmission in pregnant women was detected early in the ninth week of pregnancy. The diagnosis of syphilis was made by dark-field microscopy, treponemal antibody tests (TPHA, FTA-ABS), and non-treponemal antibody tests (VDRL, RPR). Penicillin is the gold standard therapy for syphilis in pregnant women.

Secondary syphilis with stage III HIV in an adolescent deaf male with a history of sexual relationship with men: a case report

Introduction: Syphilis is an infection caused by Treponema pallidum of the spirochaete family.&#x0D; Case: A 19-year-old Balinese came with a complaint of red spots on the palms of the hands and feet one month ago. The patient has a hearing disability and is currently enrolled in a special-needs school in Denpasar. VDRL examination with reactive results with titer 1:256 and TPHA reactive with TPHA titer 1:5120. The patient received benzathine penicillin G 2.4 million units intramuscularly. Significant improvement was obtained, and the serological test was decreased.&#x0D; Discussion: Syphilis transmits through sexual contact, vertically from pregnant women to their fetuses, through needle sharing. People with hearing disabilities and adolescents are considered vulnerable as objects of harassment and sexual violence.&#x0D; Conclusion: People with disabilities and adolescents are vulnerable to sexually transmitted diseases. Information on reproductive health and sexually transmitted diseases need to be more readily available for people with disabilities. Secondary syphilis therapy with a single dose of benzathine penicillin is effective from clinical or serological observations.

Effect of unintended short-term 3.0 g/day amoxicillin and probenecid treatment for early syphilis on patients with HIV-1 infection.

Standard therapy for early syphilis involves intramuscular injections of penicillin G, which frequently faces shortages in several countries. Fourteen-day amoxicillin therapy has been suggested as an alternative to benzathine penicillin G, but the optimal duration of amoxicillin therapy remains unclear and could theoretically be shortened to less than 14 days. The aim of this study was to explore the effectiveness of short-term amoxicillin therapy for early syphilis. We retrospectively explored the effectiveness of short-term amoxicillin therapy for early syphilis. The treatment data of patients who had received amoxicillin therapy for less than 14 days for unintended reasons were reviewed. Diagnosis was confirmed based on either the physician's description or clinical presentation. Successful treatment was defined as a fourfold or greater decline in the rapid plasma reagin titer or sero-reversion to negative within 12 months. Of 295 patients, 8 received short-term amoxicillin treatment. All were men who had sex with men and people living with human immunodeficiency virus. Their median age, CD4 count, and treatment duration were 34 years (range, 26-40), 258/mL (range, 112-930), and 9.5 days (range, 5-11), respectively. One patient had primary syphilis, six had secondary syphilis, and one had early latent syphilis. All patients, except one who showed reinfection, demonstrated a serological response within 4 months. The median time for serological response was 112 days. The results indicate that early syphilis could potentially be treated with 5-11 days of amoxicillin therapy combined with probenecid. This suggests that short-term amoxicillin therapy might be a sufficient treatment for early syphilis instead of the standard 14-day course.

LABORATORY DIAGNOSTICS OF SYPHILIS IN THE ULYANOVSK REGION

Currently, a wide range of methods are used to diagnose syphilis, however, unfortunately, none of them has 100% sensitivity and specificity. Domestic and foreign researchers agree on the need for comprehensive research. Complex systems used in the Ulyanovsk region for laboratory diagnosis of syphilis, performed in medical organizations in accordance with the order of the Ministry of Health of the Russian Federation "On improving serological diagnosis of syphilis" provide ample opportunities to solve many topical clinical and diagnostic problems in screening, diagnosis and control of the effectiveness of syphilis therapy.

Syphilis in pregnancy at Public Health Centre III North Denpasar

Introduction: Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. Syphilis in pregnancy is often asymptomatic, so early detection of syphilis is needed to prevent a poor pregnancy outcome and transmission of infection to the baby.Case: A 25-year-old woman, pregnant with her second child at 24 weeks of gestation, came without any health complaint for a routine prenatal check-up. On syphilis screening, reactive TPHA and RPR titer of 1:2 were found. The patient was diagnosed with syphilis infection in pregnancy. The patient has been treated with Benzathine Benzylpenicillin 2.4 million IU intramuscular injection once a week for 3 consecutive weeks.Conclusion: Syphilis is a sexually transmitted infection that infects pregnant women. Treponemal transmission in pregnant women was detected early in the ninth week of pregnancy. The diagnosis of syphilis was made by dark-field microscopy, treponemal antibody tests (TPHA, FTA-ABS), and non-treponemal antibody tests (VDRL, RPR). Penicillin is the gold standard therapy for syphilis in pregnant women.

Neosilbersalvarsannatriutn, its physicochemical and pharmaco-therapeutic properties in the light of the literature

Under the conditions of the time we are going through, Russian doctors, with extremely insignificant exceptions, still continue to be just outside contemplators of the powerful successes in syphilis therapy that have been achieved in recent years in the West, and have so far been deprived of the opportunity to actively participate in the undoubtedly close completion of the ultimate goal of our therapeutic quests overcoming the formidable scourge of mankind.

I. Kyrle. Syphilis. The current state of the doctrine of pathology and its therapy. Translated. from the 2nd it. ed, Dr. A. N. Domnikova, ed. prof. E. F. Fridman. Petrograd, 1923.58 p.

Dr. Kyrle's book, containing 6 lectures on the pathology and therapy of syphilis for practitioners, acquaints the reader with the current state of the teaching about this disease, which has always had great social significance. The author sets out here in a concise and clear form everything that is necessary to know about the pathogenesis, methods of early diagnosis and methods of treating syphilis to every doctor involved in its treatment.

Secondary syphilis with stage III HIV in an adolescent deaf male with a history of sexual relationship with men: a case report

Introduction: Syphilis is an infection caused by Treponema pallidum of the spirochaete family.Case: A 19-year-old Balinese came with a complaint of red spots on the palms of the hands and feet one month ago. The patient has a hearing disability and is currently enrolled in a special-needs school in Denpasar. VDRL examination with reactive results with titer 1:256 and TPHA reactive with TPHA titer 1:5120. The patient received benzathine penicillin G 2.4 million units intramuscularly. Significant improvement was obtained, and the serological test was decreased.Discussion: Syphilis transmits through sexual contact, vertically from pregnant women to their fetuses, through needle sharing. People with hearing disabilities and adolescents are considered vulnerable as objects of harassment and sexual violence.Conclusion: People with disabilities and adolescents are vulnerable to sexually transmitted diseases. Information on reproductive health and sexually transmitted diseases need to be more readily available for people with disabilities. Secondary syphilis therapy with a single dose of benzathine penicillin is effective from clinical or serological observations.

Sifilis u trudnoći

Early syphilis has been increasing in the Republic of Serbia since 2010 and its infectivity for sexual partners lasts for a year from the moment of infection. The exception is pregnant women who, if left untreated, can transmit the infection to the fetus within four years of infection. Syphilis in pregnancy can cause miscarriage, stillbirth, low birth weight or congenital syphilis. The aim of this paper is to present the clinical manifestations, laboratory diagnostics and therapy of syphilis in pregnancy, as well as to sensitize medical workers to this disease and the introduction of mandatory serological screening tests for syphilis in all pregnant women.

In Vitro Susceptibility of Treponema pallidum subsp. pallidum to Doxycycline.

Doxycycline is regarded as an effective therapy for early syphilis, and there is increasing interest in using doxycycline for prophylaxis of this infection. However, the MIC of doxycycline for Treponema pallidum subsp. pallidum has not been reported previously. In this study, an in vitro culture system was utilized to determine that the MIC of doxycycline is 0.06 to 0.10 μg/ml for four strains of T. pallidum subsp. pallidum (Nichols, SS14, UW231B, and UW249B). The Nichols strain cultured in vitro with doxycycline was also tested for infectivity in rabbits, and the minimum bactericidal concentration (MBC) was found to be ≤0.1 μg/ml using this method. The low MIC and MBC values are consistent with the previously demonstrated clinical efficacy of doxycycline for the treatment of early syphilis. This study represents the first report of the in vitro susceptibility of T. pallidum to doxycycline, and the resulting information may be useful in the consideration of doxycycline for use in prevention of syphilis.