Resurgence of congenital syphilis: new strategies against an old foe

Providing adolescent-friendly sexually transmitted infection screening and treatment services

PURPOSE OF REVIEW

There are high rates of sexually transmitted infections (STIs) worldwide. Adolescents and young adults (AYA) ages 15-24 years remain one of the populations that is most vulnerable to STIs. The goal of this review is to summarize recent international updates in adolescent STI screening and treatment.

RECENT FINDINGS

Normalizing sexual history taking and STI testing, and advocating for adolescents to receive comprehensive sexuality education improves stigma surrounding sexual health. The global rise in syphilis is pervasive and includes high rates of infection among AYA and women of reproductive age - universal screening may be indicated depending on local epidemiology. Gonococcal antimicrobial resistance remains a significant public health concern worldwide, thus judicious use of antimicrobials and reporting cases of resistance is crucial. Sexual health services are increasingly using virtual platforms, which may be an effective strategy for STI testing and treatment among AYA.

SUMMARY

Specific areas of focus to address the STI epidemic among AYA include reducing stigma surrounding sexual health, screening, and treatment of STIs, especially with the global rise in syphilis and high rates of gonorrhea resistance, in addition to increased use of telehealth services as effective education and intervention strategies.

High Prevalence of Syphilis among Young Pregnant Women in the Brazilian Amazon: A Cross-Sectional Study Based on Clinical Records in a Public Health Reference Unit in the City of Belém

BACKGROUND

Syphilis remains a significant global public health concern, and one of its consequences in pregnant women is the potential occurrence of congenital syphilis due to Treponema pallidum infection. This study determined the prevalence of syphilis among pregnant women undergoing prenatal care in a neighborhood on the outskirts of the city of Belém, Brazilian Amazon.

METHODS

This cross-sectional study used data from clinical records of 611 pregnant women who underwent prenatal care at a public health unit in 2019 and 2020. The reagent result for VDRL was used as an indicator of syphilis. Odds Ratio and chi-square tests were used to evaluate the association of information from pregnant women with syphilis.

RESULTS

The overall prevalence of syphilis was 5.2 % (32/611; 95 % CI: 3.5-7.0 %). Age under 23 years was identified as a risk factor for syphilis.

CONCLUSIONS

The prevalence of syphilis among pregnant women in the outskirts of Belém is high, especially among younger women. There is an urgent need to intensify innovative sexual and reproductive health education initiatives and emphasize the importance of consistent practice of preventive measures against syphilis and other STIs in the Amazon region, especially in the young population.

Increase in congenital syphilis in a tertiary-care centre from Madrid, Spain: Back to the classics

Globally, an increase in sexually transmitted diseases worldwide has been reported, including acquired Treponema pallidum infection. Congenital syphilis is the mother-to-child transmission syphilis infection, experiencing an increase in cases returning to incidence rates of years ago. We report three cases of symptomatic congenital syphilis occurring in a tertiary-care hospital in Madrid (Spain). Cases were diagnosed by serology and molecular biology methods. The use of molecular techniques in specimens such as skin lesion, subplacental exudate swabs, bronchoalveolar aspirate, or cerebrospinal fluid could favour the diagnosis of this clinical entity, especially in symptomatic newborns with systemic involvement.

Congenital Syphilis: A Re-Emerging but Preventable Infection

Congenital syphilis presents a significant global burden, contributing to fetal loss, stillbirth, neonatal mortality, and congenital infection. Despite the target established in 2007 by the World Health Organization (WHO) of fewer than 50 cases per 100,000 live births, the global incidence is on the rise, particularly in low- and middle-income regions. Recent data indicate a rate of 473 cases per 100,000 live births, resulting in 661,000 total cases of congenital syphilis, including 355,000 adverse birth outcomes such as early fetal deaths, stillbirths, neonatal deaths, preterm or low-birth-weight births, and infants with clinical congenital syphilis. Alarmingly, only 6% of these adverse outcomes occurred in mothers who were enrolled, screened, and treated. Unlike many neonatal infections, congenital syphilis is preventable through effective antenatal screening and treatment of infected pregnant women. However, despite available screening tools, affordable treatment options, and the integration of prevention programs into antenatal care in various countries, congenital syphilis remains a pressing public health concern worldwide. This review aims to summarize the current epidemiology, transmission, and treatment of syphilis in pregnancy, as well as to explore global efforts to reduce vertical transmission and address the reasons for falling short of the WHO elimination target.

Congenital Syphilis Prevention Challenges, Pacific Coast of Colombia, 2018-2022

High incidences of congenital syphilis have been reported in areas along the Pacific coast of Colombia. In this retrospective study, conducted during 2018-2022 at a public hospital in Buenaventura, Colombia, we analyzed data from 3,378 pregnant women. The opportunity to prevent congenital syphilis was missed in 53.1% of mothers because of the lack of syphilis screening. Characteristics of higher maternal social vulnerability and late access to prenatal care decreased the probability of having >1 syphilis screening test, thereby increasing the probability of having newborns with congenital syphilis. In addition, the opportunity to prevent congenital syphilis was missed in 41.5% of patients with syphilis because of the lack of treatment, which also increased the probability of having newborns with congenital syphilis. We demonstrate the urgent need to improve screening and treatment capabilities for maternal syphilis, particularly among pregnant women who are more socially vulnerable.

Neurosyphilis: insights into its pathogenesis, susceptibility, diagnosis, treatment, and prevention

Background and aim

Invasion of the central nervous system by Treponema pallidum can occur at any stage of syphilis. In the event that T. pallidum is not cleared promptly, certain individuals may experience progression to neurosyphilis, which manifests as cognitive and behavioral abnormalities, limb paralysis, and potentially fatal outcomes. Early identification or prevention of neurosyphilis is therefore crucial. The aim of this paper is to conduct a critical and narrative review of the latest information focusing exclusively to the pathogenesis and clinical management of neurosyphilis.

Methodology

To compile this review, we have conducted electronic literature searches from the PubMed database relating to neurosyphilis. Priority was given to studies published from the past 10 years (from 2013 to 2023) and other studies if they were of significant importance (from 1985 to 2012), including whole genome sequencing results, cell structure of T. pallidum, history of genotyping, and other related topics. These studies are classic or reflect a developmental process.

Results

Neurosyphilis has garnered global attention, yet susceptibility to and the pathogenesis of this condition remain under investigation. Cerebrospinal fluid examination plays an important role in the diagnosis of neurosyphilis, but lacks the gold standard. Intravenous aqueous crystalline penicillin G continues to be the recommended therapeutic approach for neurosyphilis. Considering its sustained prominence, it is imperative to develop novel public health tactics in order to manage the resurgence of neurosyphilis.

Conclusion

This review gives an updated narrative description of neurosyphilis with special emphasis on its pathogenesis, susceptibility, diagnosis, treatment, and prevention.

Crossing the Barrier: A Comparative Study of Listeria monocytogenes and Treponema pallidum in Placental Invasion

Vertically transmitted infections are a significant cause of fetal morbidity and mortality during pregnancy and pose substantial risks to fetal development. These infections are primarily transmitted to the fetus through two routes: (1) direct invasion and crossing the placenta which separates maternal and fetal circulation, or (2) ascending the maternal genitourinary tact and entering the uterus. Only two bacterial species are commonly found to cross the placenta and infect the fetus: Listeria monocytogenes and Treponema pallidum subsp. pallidum. L. monocytogenes is a Gram-positive, foodborne pathogen found in soil that acutely infects a wide variety of mammalian species. T. pallidum is a sexually transmitted spirochete that causes a chronic infection exclusively in humans. We briefly review the pathogenesis of these two very distinct bacteria that have managed to overcome the placental barrier and the role placental immunity plays in resisting infection. Both organisms share characteristics which contribute to their transplacental transmission. These include the ability to disseminate broadly within the host, evade immune phagocytosis, and the need for a strong T cell response for their elimination.

Antimicrobial susceptibility of Treponema pallidum subspecies pallidum: an in-vitro study

BACKGROUND

The increasing incidence of syphilis and the limitations of first-line treatment with penicillin, particularly in neurosyphilis, neonatal syphilis, and pregnancy, highlight the need to expand the therapeutic repertoire for effective management of this disease. We assessed the in-vitro efficacy of 18 antibiotics from several classes on Treponema pallidum subspecies pallidum (T pallidum), the syphilis bacteria.

METHODS

Using the in-vitro culture system for T pallidum, we exposed the pathogen to a concentration range of each tested antibiotic. After a 7-day incubation, the treponemal burden was evaluated by quantitative PCR targeting the T pallidum tp0574 gene. The primary outcome was the minimum inhibitory concentration (MIC) at which the quantitative PCR values were not significantly higher than the inoculum wells. We also investigated the susceptibility of macrolide-resistant strains to high concentrations of azithromycin, and the possibility of developing resistance to linezolid, a proposed candidate for syphilis treatment.

FINDINGS

Amoxicillin, ceftriaxone, several oral cephalosporins, tedizolid, and dalbavancin exhibited anti-treponemal activity at concentrations achievable in human plasma following regular dosing regimens. The experiments revealed a MIC for amoxicillin at 0·02 mg/L, ceftriaxone at 0·0025 mg/L, cephalexin at 0·25 mg/L, cefetamet and cefixime at 0·0313 mg/L, cefuroxime at 0·0156 mg/L, tedizolid at 0·0625 mg/L, spectinomycin at 0·1 mg/L, and dalbavancin at 0·125 mg/L. The MIC for zoliflodacin and balofloxacin was 2 mg/L. Ertapenem, isoniazid, pyrazinamide, and metronidazole had either a poor or no effect. Azithromycin concentrations up to 2 mg/L (64 times the MIC) were ineffective against strains carrying mutations associated to macrolide resistance. Exposure to subtherapeutic doses of linezolid for 10 weeks did not induce phenotypic or genotypic resistance.

INTERPRETATION

Cephalosporins and oxazolidinones are potential candidates for expanding the current therapeutic repertoire for syphilis. Our findings warrant testing efficacy in animal models and, if successful, clinical assessment of efficacy.

FUNDING

European Research Council.