Congenital syphilis and fluorescent treponemal antibody test reactivity after the age of 1 year

CDC Laboratory Recommendations for Syphilis Testing, United States, 2024

This report provides new CDC recommendations for tests that can support a diagnosis of syphilis, including serologic testing and methods for the identification of the causative agent Treponema pallidum. These comprehensive recommendations are the first published by CDC on laboratory testing for syphilis, which has traditionally been based on serologic algorithms to detect a humoral immune response to T. pallidum. These tests can be divided into nontreponemal and treponemal tests depending on whether they detect antibodies that are broadly reactive to lipoidal antigens shared by both host and T. pallidum or antibodies specific to T. pallidum, respectively. Both types of tests must be used in conjunction to help distinguish between an untreated infection or a past infection that has been successfully treated. Newer serologic tests allow for laboratory automation but must be used in an algorithm, which also can involve older manual serologic tests. Direct detection of T. pallidum continues to evolve from microscopic examination of material from lesions for visualization of T. pallidum to molecular detection of the organism. Limited point-of-care tests for syphilis are available in the United States; increased availability of point-of-care tests that are sensitive and specific could facilitate expansion of screening programs and reduce the time from test result to treatment. These recommendations are intended for use by clinical laboratory directors, laboratory staff, clinicians, and disease control personnel who must choose among the multiple available testing methods, establish standard operating procedures for collecting and processing specimens, interpret test results for laboratory reporting, and counsel and treat patients. Future revisions to these recommendations will be based on new research or technologic advancements for syphilis clinical laboratory science.

The Clinical Characteristics and Serological Outcomes of Infants With Confirmed or Suspected Congenital Syphilis in Shanghai, China: A Hospital-Based Study

BACKGROUND

Congenital syphilis (CS) is the infection of an infant or fetus with Treponema pallidum. The aim of this study was to investigate the clinical features and outcomes of serology reversion in infants diagnosed with confirmed or suspected congenital syphilis (CS).

METHODS

Infants admitted to the neonatal department of Children's Hospital of Fudan University from 2013 to 2016 who met the case definition of CS or suspected CS were included in this study. Follow-up was performed in an outpatient clinic until reversion to non-reactivity of both toluidine red unheated serum test (TRUST) and Treponemal pallidum particle agglutination (TPPA). Follow-up data were collected until up to the end of 2019, when the last infant with CS reached 3 years of age.

RESULTS

In total, 682 infants were enrolled in this study, including 63 in the CS group and 619 in the suspected CS group. Forty-seven infants (74.6%) in the CS group had symptoms, and 57 (90.5%) had abnormal laboratory and/or long bone X-ray findings. By 6 months of age, TRUST results were negative in 53.3% of the infants with CS and in 100% of the infants with suspected CS. All the infants in the CS group returned to TRUST non-reactivity by 18 months of age. The TPPA results at 18 months of age showed that only 10.0% (3/30) of the patients in the CS group returned to non-reactivity, while a 99.6% (548/550) non-reactivity rate was observed in the suspected CS group. All the infants in the CS group returned to 19S-IgM-TPPA non-reactivity by 6 months of age.

CONCLUSIONS

Although CS is an burdensome disease that may cause fetal and neonatal death, CS responds well to treatment when diagnosed and treated promptly, even when symptoms or lab/X-ray findings are present at birth.

Brazilian Protocol for Sexually Transmitted Infections, 2020: congenital syphilis and child exposed to syphilis

The topics of congenital syphilis and children exposed to syphilis compose the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health in 2020. Such document was elaborated based on scientific evidence and validated in discussions with specialists. This article provides guidelines for syphilis in pregnant women and congenital syphilis clinical management, emphasizing the vertical transmission of Treponema pallidum prevention. Epidemiological and clinical aspects of these infections are presented and recommendations for managers in the programmatic and operational management of syphilis. The article also includes guidelines for health professionals in screening, diagnosing, and treating people with sexually transmitted infections and their sex partners, in addition to strategies for surveillance actions, prevention, and control of the disease.

Most congenital syphilis cases arise from test failures in prenatal care or inadequate or no treatment of maternal syphilis.

[Brazilian Protocol for Sexually Transmitted Infections 2020: congenital syphilis and child exposed to syphilis]

The topics of congenital syphilis and children exposed to syphilis are part of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health in 2020. The Protocol and Guidelines have been developed based on scientific evidence and validated in discussions with specialists. This article provides guidelines for clinical management of both syphilis in pregnant women and also congenital syphilis, emphasizing prevention of vertical transmission of Treponema pallidum. Epidemiological and clinical aspects of these infections are presented, as well as recommendations for health service managers regarding the programmatic and operational management of syphilis. The article also includes guidelines for health professionals on screening, diagnosing and treating people with sexually transmitted infections and their sex partners, in addition to strategies for syphilis surveillance, prevention and control actions.

Syphilis in Children

Syphilis, caused by Treponema pallidum, is transmitted both sexually and transplacentally. Untreated syphilis is a progressive disease that may result in death or disability in children and adults. Syphilis diagnosis requires 2-stage serologic testing for nontreponemal and treponemal antibodies. Congenital syphilis diagnosis requires careful review of maternal testing and treatment, comparison of maternal and neonatal nontreponemal antibody titers, and clinical evaluation of the neonate. In this review, we present the current epidemiology of syphilis, and the clinical manifestations, diagnosis, and management of syphilis as they relate to pediatric practice, specifically, congenital syphilis and acquired syphilis in adolescents and pregnant women.

Sensitivity of nPCR for four types of membrane protein DNA and of two pairs of primers for Tpp47 DNA of Treponema pallidum in whole blood of congenital syphilis newborns

BACKGROUND

Problems exist in congenital syphilis (CS) diagnosis and no single test can be used to diagnose CS.

OBJECTIVE

To know whether there exist differences of nested polymerase chain reaction (nPCR) sensitivity among four membrane protein DNA and of nPCR between two pairs of primers for Tpp47.

METHODS

We collected 30 CS patients as a study group, and 20 cases admitted to hospital for other reasons as a control group. The blood samples from newborns were left of blood for other examination, not special for the study. Following confirmed diagnosis, DNA was extracted from blood. nPCR examined for membrane protein DNA in both groups.

RESULTS

Sensitivity of nPCR for Tpp15, Tpp17, Tpp45, and Tpp47 (total) was 6/30, 3/30, 1/30, and 20/30, respectively. The sensitivity of nPCR for Tpp47 was highest among that of four types of membrane protein DNA. The nPCR sensitivity of two pairs of primers (a and b) for Tpp47 was 11/30 and 13/30, respectively. There was no significant difference between two pairs of primers for Tpp47, and total sensitivity of nPCR for Tpp47 combining Tpp47a with Tpp47b was up to 20/30.

CONCLUSION

Sensitivity of nPCR for Tpp47 was highest among that of four types of membrane protein DNA. Two pairs of primers for Tpp47 different bands could elevate nPCR sensitivity.

Contribution of a Comparative Western Blot Method to Early Postnatal Diagnosis of Congenital Syphilis

Serology has a pivotal role in the diagnosis of congenital syphilis (CS), but problems arise because of the passive transfer of IgG antibodies across the placenta. The aim of this study was to assess the diagnostic value of a comparative Western blot (WB) method finalized to match the IgG immunological profiles of mothers and their own babies at birth in order to differentiate between passively transmitted maternal antibodies and antibodies synthesized by the infants against Treponema pallidum Thirty infants born to mothers with unknown or inadequate treatment for syphilis were entered in a retrospective study, conducted at St. Orsola-Malpighi Hospital, Bologna, Italy. All of the infants underwent clinical, instrumental, and laboratory examinations, including IgM WB testing. For the retrospective study, an IgG WB assay was performed by blotting T. pallidum antigens onto nitrocellulose sheets and incubating the strips with serum specimens from mother-child pairs. CS was diagnosed in 11 out of the 30 enrolled infants; 9/11 cases received the definitive diagnosis within the first week of life, whereas the remaining two were diagnosed later because of increasing serological test titers. The use of the comparative IgG WB testing performed with serum samples from mother-child pairs allowed a correct CS diagnosis in 10/11 cases. The CS diagnosis was improved by a strategy combining comparative IgG WB results with IgM WB results, leading to a sensitivity of 100%. The comparative IgG WB test is thus a welcome addition to the conventional laboratory methods used for CS diagnosis, allowing identification and adequate treatment of infected infants and avoiding unnecessary therapy of uninfected newborns.

Current standards for diagnosis of syphilis: comparing the russian and foreign guidelines (part I)

Despite the abundance of existing laboratory methods the diagnosis of syphilis still faces many challenges. Though direct detection of T. pallidum plays an important role in early manifest forms of the disease, serological tests remain the mainstay of diagnosis. Traditional syphilis screening algorithm based on nontreponemal tests with subsequent confirmation using treponemal tests is a standard worldwide. Recently, the ability to automate the treponemal tests promotes the increasingly widespread implementation of reverse algorithm when these tests are used for syphilis screening. None of the current serological algorithms are able to reliably differentiate between active and previously treated syphilis, which causes uncertainty in the management of patients. There is no «gold standard» for the diagnosis of neurosyphilis, ocular, auricular and visceral syphilis. The interpretation of serological tests in children born to seropositive mothers is also complicated. Diagnosis of congenital syphilis in newborns and, consequently, the prescription of antibiotic therapy often depends on assessment of the adequacy of maternal treatment during pregnancy, which leads to subjective decisions. This article provides a comparative analysis of the «Federal guidelines for the management of patients with syphilis» and their foreign analogues, discusses significant peculiarities of these guidelines and reviews current concerns and controversies in syphilis diagnosis.

Recent trends in the serologic diagnosis of syphilis

Complexities in the diagnosis of syphilis continue to challenge clinicians. While direct tests (e.g., microscopy or PCR) are helpful in early syphilis, the mainstay of diagnosis remains serologic tests. The traditional algorithm using a nontreponemal test (NTT) followed by a treponemal test (TT) remains the standard in many parts of the world. More recently, the ability to automate the TT has led to the increasingly widespread use of reverse algorithms using treponemal enzyme immunoassays (EIAs). Rapid, point-of-care TTs are in widespread use in developing countries because of low cost, ease of use, and reasonable performance. However, none of the current diagnostic algorithms are able to distinguish current from previously treated infections. In addition, the reversal of traditional syphilis algorithms has led to uncertainty in the clinical management of patients. The interpretation of syphilis tests is further complicated by the lack of a reliable gold standard for syphilis diagnostics, and the newer tests can result in false-positive reactions similar to those seen with older tests. Little progress has been made in the area of serologic diagnostics for congenital syphilis, which requires assessment of maternal treatment and serologic response as well as clinical and laboratory investigation of the neonate for appropriate management. The diagnosis of neurosyphilis continues to require the collection of cerebrospinal fluid for a combination of NTT and TT, and, while newer treponemal EIAs look promising, more studies are needed to confirm their utility. This article reviews current tests and discusses current controversies in syphilis diagnosis, with a focus on serologic tests.

Canadian Public Health Laboratory Network laboratory guidelines for congenital syphilis and syphilis screening in pregnant women in Canada

Despite universal access to screening for syphilis in all pregnant women in Canada, cases of congenital syphilis have been reported in recent years in areas experiencing a resurgence of infectious syphilis in heterosexual partnerships. Antenatal screening in the first trimester continues to be important and should be repeated at 28 to 32 weeks and again at delivery in women at high risk of acquiring syphilis. The diagnosis of congenital syphilis is complex and is based on a combination of maternal history and clinical and laboratory criteria in both mother and infant. Serologic tests for syphilis remain important in the diagnosis of congenital syphilis and are complicated by the passive transfer of maternal antibodies which can affect the interpretation of reactive serologic tests in the infant. All infants born to mothers with reactive syphilis tests should have nontreponemal tests (NTT) and treponemal tests (TT) performed in parallel with the mother's tests. A fourfold or higher titre in the NTT in the infant at delivery is strongly suggestive of congenital infection but the absence of a fourfold or greater NTT titre does not exclude congenital infection. IgM tests for syphilis are not currently available in Canada and are not recommended due to poor performance. Other evaluation in the newborn infant may include long bone radiographs and cerebrospinal fluid tests but all suspect cases should be managed in conjunction with sexually transmitted infection and/or pediatric experts.

Maternal titers after adequate syphilotherapy during pregnancy

BACKGROUND

We aimed to construct a timeline for nontreponemal titer decline specific to pregnancy and evaluate factors associated with inadequate decline by delivery.

METHODS

This was a retrospective medical records review from September 1984 to June 2011 of women diagnosed with syphilis after 18 weeks of gestation. Women were treated according to stage of syphilis per Centers for Disease Control and Prevention guidelines. Patients with both pretreatment and delivery titers were included for data analysis. Demographics, stage of syphilis, maternal titers, delivery, and infant outcomes were recorded. Standard statistical analyses were performed for categorical and continuous data. The titer decline was analyzed using mixed-effects regression modeling.

RESULTS

A total of 166 patients met inclusion criteria. Mean gestational age at treatment was 29.1 ± 5 weeks, and 93 (56%) women were diagnosed with early-stage syphilis. For all stages of syphilis, maternal titers declined after syphilotherapy. Pretreatment titers were higher and declined more rapidly in primary and secondary disease than in latent-stage disease and syphilis of unknown duration. Sixty-three (38%) patients achieved a 4-fold decline by delivery. Patients without a 4-fold decline by delivery were older (24.6 vs 21.5 years; P < .001), treated later in pregnancy (30.3 vs 27.3 weeks; P < .001), diagnosed with latent syphilis or syphilis of unknown duration, and had less time from treatment to delivery (7.8 vs 11.1 weeks; P < .001).

CONCLUSIONS

Maternal serologic response during pregnancy after adequate syphilotherapy varied by stage of disease. Failure to achieve a 4-fold decline in titers by delivery is more a reflection of treatment timing than of treatment failure.

Progression of ultrasound findings of fetal syphilis after maternal treatment

OBJECTIVE

The purpose of this study was to evaluate ultrasound findings of fetal syphilis and to describe their progression after maternal treatment.

STUDY DESIGN

This was a retrospective cohort study from September 1981 to June 2011 of seropositive women after 18 weeks of gestation who had an ultrasound before treatment to evaluate for fetal syphilis. Only those women who received treatment after the initial ultrasound scan, but before delivery, were included. If the initial ultrasound scan was abnormal, serial sonography was performed until resolution of the abnormality or delivery. Patient demographics, ultrasound findings, stage of syphilis, delivery, and infant outcomes were recorded. Standard statistical analyses were performed. Kaplan-Meier estimates were constructed to estimate time to resolution.

RESULTS

Two hundred thirty-five women met the inclusion criteria; 73 of them (30%) had evidence of fetal syphilis on initial ultrasound scan. Abnormalities included hepatomegaly (79%), placentomegaly (27%), polyhydramnios (12%), ascites (10%) and abnormal middle cerebral arterial Doppler assessment (33%). After treatment, middle cerebral arterial Doppler assessment abnormalities, ascites, and polyhydramnios resolved first, followed by placentomegaly and finally hepatomegaly. Infant outcomes were available for 173 deliveries; of these, 32 infants (18%) were diagnosed with congenital syphilis. Congenital syphilis was more common when antenatal ultrasound abnormalities were present (39% vs 12%; P < .001). Infant examination findings at delivery were similar between women with and without an abnormal pretreatment ultrasound scan. However, in those infants with congenital syphilis, hepatomegaly was the most frequent abnormality found, regardless of antenatal ultrasound findings.

CONCLUSION

Sonographic signs of fetal syphilis confer a higher risk of congenital syphilis at delivery for all maternal stages. Hepatomegaly develops early and resolves last after antepartum treatment.

Syphilis in Children: Congenital and Acquired

Syphilis rates in women and congenital syphilis rates have declined steadily in the United States in recent years. However, syphilis remains a worldwide public health problem, with more than 12 million cases in adults and more than half a million pregnancies affected yearly. Prenatal screening and treatment programs are limited or nonexistent in many developing countries. The genome of Treponema pallidum, one of the smallest among prokaryotes, has been sequenced, but methods for continuous in vitro cultivation of the microbe remain elusive. There are no promising candidates for future vaccines at this time. Serologic testing, for both specific treponemal and nontreponemal antibodies, continues to be a primary means of diagnosis. Penicillin remains the drug of choice for congenital and acquired syphilis in childhood. The diagnosis of syphilis beyond early infancy raises concerns for possible child sexual abuse, although progression of congenital syphilis may account for some cases. Syphilis is a potentially eradicable disease, but this can be achieved only with sustained international will and cooperation to fund the necessary screening and treatment programs.