Mother-to-child transmission of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in HIV-infected pregnant women in South Africa

Design of a novel multi-epitope vaccine candidate against Chlamydia trachomatis using structural and nonstructural proteins: an immunoinformatics study

Chlamydia trachomatis (C. trachomatis) is an obligate intracellular bacterium which causes eye and sexually transmitted infections. During pregnancy, the bacterium is associated with preterm complications, low weight of neonates, fetal demise and endometritis leading to infertility. The aim of our study was design of a multi-epitope vaccine (MEV) candidate against C. trachomatis. After protein sequence adoption from the NCBI, potential epitopes toxicity, antigenicity, allergenicity, MHC-I and MHC-II binding, cytotoxic T lymphocytes (CTLs), Helper T lymphocytes (HTLs) and interferon-γ (IFN-γ)- induction were predicted. The adopted epitopes were fused together using appropriate linkers. In the next step, the MEV structural mapping and characterization, three-dimensional (3D) structure homology modeling and refinement were also performed. The MEV candidate interaction with the toll-like receptor 4 (TLR4) was also docked. The immune responses simulation was assessed using the C-IMMSIM server. Molecular dynamic (MD) simulation verified the structural stability of the TLR4-MEV complex. The Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) approach demonstrated the MEV high affinity of binding to the TLR4, MHC-I and MHC-II. The MEV construct was also stable and water soluble and had enough antigenicity and lacked allergenicity with stimulation of T cells and B cells and INF-γ release. The immune simulation confirmed acceptable responses of both the humoral and cellular arms. It is proposed that in vitro and in vivo studies are needed to evaluate the findings of this study.Communicated by Ramaswamy H. Sarma.

Implementation considerations for a point-of-care Neisseria gonorrhoeae rapid diagnostic test at primary healthcare level in South Africa: a qualitative study

BACKGROUND

South Africa maintains an integrated health system where syndromic management of sexually transmitted infections (STI) is the standard of care. An estimated 2 million cases of Neisseria gonorrhoeae (N. gonorrhoeae) occur in South Africa every year. Point-of-care diagnostic tests (POCT) may address existing STI control limitations such as overtreatment and missed cases. Subsequently, a rapid lateral flow assay with fluorescence-based detection (NG-LFA) with a prototype reader was developed for N. gonorrhoeae detection showing excellent performance and high usability; however, a better understanding is needed for device implementation and integration into clinics.

METHODS

A qualitative, time-series assessment using 66 in-depth interviews was conducted among 25 trained healthcare workers involved in the implementation of the NG-LFA. Findings were informed by the Normalization Process Theory (NPT) as per relevant contextual (strategic intentions, adaptive execution, and negotiation capacity) and procedural constructs (coherence, cognitive participation, collective action, reflexive monitoring) to examine device implementation within primary healthcare levels. Interviews were audio-recorded, transcribed, and then analyzed using a thematic approach guided by NPT to interpret results.

RESULTS

Overall, healthcare workers agreed that STI POCT could guide better STI clinical decision-making, with consideration for clinic integration such as space constraints, patient flow, and workload. Perceived NG-LFA benefits included enhanced patient receptivity and STI knowledge. Further, healthcare workers reflected on the suitability of the NG-LFA given current limitations with integrated primary care. Recommendations included sufficient STI education, and appropriate departments for first points of entry for STI screening.

CONCLUSIONS

The collective action and participation by healthcare workers in the implementation of the NG-LFA revealed adaptive execution within the current facility environment including team compositions, facility-staff receptivity, and STI management experiences. User experiences support future clinic service integration, highlighting the importance of further assessing patient-provider communication for STI care, organizational readiness, and identification of relevant departments for STI screening.

Fused Enzyme Glucose-6-Phosphate Dehydrogenase::6-Phosphogluconolactonase (G6PD::6PGL) as a Potential Drug Target in Giardia lamblia, Trichomonas vaginalis, and Plasmodium falciparum

Several microaerophilic parasites such as Giardia lamblia, Trichomonas vaginalis, and Plasmodium falciparum are major disease-causing organisms and are responsible for spreading infections worldwide. Despite significant progress made in understanding the metabolism and molecular biology of microaerophilic parasites, chemotherapeutic treatment to control it has seen limited progress. A current proposed strategy for drug discovery against parasitic diseases is the identification of essential key enzymes of metabolic pathways associated with the parasite's survival. In these organisms, glucose-6-phosphate dehydrogenase::6-phosphogluconolactonase (G6PD:: 6PGL), the first enzyme of the pentose phosphate pathway (PPP), is essential for its metabolism. Since G6PD:: 6PGL provides substrates for nucleotides synthesis and NADPH as a source of reducing equivalents, it could be considered an anti-parasite drug target. This review analyzes the anaerobic energy metabolism of G. lamblia, T. vaginalis, and P. falciparum, with a focus on glucose metabolism through the pentose phosphate pathway and the significance of the fused G6PD:: 6PGL enzyme as a therapeutic target in the search for new drugs.

Case series and literature review of chlamydial ophthalmia neonatorum in Botswana

BACKGROUND

We describe 12 cases of chlamydial ophthalmia neonatorum and the current scientific evidence on its prevention and treatment. The data presented were obtained from the "Maduo" study, a prospective observational study of the relationship between curable sexually transmitted infections and adverse neonatal outcomes at four antenatal clinics in Gaborone, Botswana.

METHODS

Infants of mothers with perinatal chlamydia infection were evaluated for chlamydial ophthalmia neonatorum based on clinical presentation of conjunctivitis or positive test via GeneXpert CT/NG assay. Data on 29 infants born to mothers with postnatal C. trachomatis infection were analysed.

RESULTS

12 infants were diagnosed with chlamydial ophthalmia neonatorum. Eight of those cases were confirmed with the GeneXpert CT/NG assay while four were identified as probable cases based on clinical history and presentation. Overall, nine infants presented with signs of conjunctivitis, while three who had a positive diagnostic test result had asymptomatic infection. All but one infant had received ocular 1% tetracycline prophylaxis at birth, and four infants had signs suggestive of chlamydial pneumonia at presentation. Two out of five symptomatic cases whose mothers reported completion of their treatment course with erythromycin had lingering symptoms.

CONCLUSIONS

Our findings affirm that the current prophylaxis and treatment modalities for chlamydial ophthalmia neonatorum are inadequate. To the extent feasible in low- and middle-income countries, we recommend implementation of routine C. trachomatis screening and treatment in pregnant women.

Global prevalence of Neisseria gonorrhoeae infection in pregnant women: a systematic review and meta-analysis

BACKGROUND

Neisseria gonorrhoeae infection (gonorrhoea) is associated with several pregnancy complications, including preterm labour, spontaneous abortion, stillbirth, miscarriage, growth retardation, and intrauterine death.

OBJECTIVES

We performed a systematic review and meta-analysis to estimate the global and regional prevalence of gonorrhoea in pregnant women as a scientific basis for further studies.

DATA SOURCES

We systematically searched PubMed/MEDLINE, Web of Science, Embase, Scopus, and SciELO databases from inception to 10 July 2022.

STUDY ELIGIBILITY CRITERIA

We included cross-sectional, cohort, and case-control studies that reported the prevalence of gonorrhoea in pregnant women. In addition, we included baseline data for randomized controlled trials.

PARTICIPANTS

Pregnant women who were tested for gonorrhoea.

METHODS

Pooled prevalence estimates at 95% CIs were calculated using a random-effects meta-analysis model. We stratified countries according to WHO-defined regions and socio-economic factors. Moreover, sub-group-, meta-regression, and sensitivity analyses were conducted to investigate the effects of pre-determined factors on prevalence estimates and heterogeneity.

RESULTS

We identified 235 studies (249 datasets) on 19 104 175 pregnant women from 71 countries. The worldwide pooled prevalence of gonorrhoea in pregnant women was estimated at 1.85% (95% CI 1.73-1.97%), with the highest rate in the African region (3.53%) (2.84-4.29%) and the lowest rate in the European region (0.52%) (0.27-0.84%). Overall, the prevalence estimates were high among low-income countries (3.03%), pregnant women with HIV (2.81%), and pregnant women <20 years old (8.06%). A significant decreasing trend in prevalence was observed over time (β = -0.0008, 95% CI -0.0012 to -0.0004, p 0.001).

DISCUSSION

Our findings indicate that a substantial number of pregnant women have been infected with gonorrhoea globally, which calls for immediate public health measures to reduce the potential risk of infection. The study highlights the inadequacy or lack of data for many countries, emphasizing the need to expand systematic data collection efforts at national and regional levels.

Prevalence of Chlamydia trachomatis infection in pregnant women from Durban, South Africa

INTRODUCTION

The Sub-Saharan African region has some of the world's highest prevalence of sexually transmitted infections (STIs). These infections are considered a major public health concern. Previous studies on the prevalence of C. trachomatis infection in Sub-Saharan Africa have reported rates ranging from 3.1% to 36.8% in pregnant women. This study investigated the prevalence and risk factors associated with C. trachomatis infection in pregnant women.

METHODS

This study included 735 stored clinical samples that were collected from pregnant women attending the antenatal clinic at King Edward VIII Hospital in Durban from 2018 -2021. C. trachomatis was detected using the Applied Biosystems^TM TaqMan^® Assays from stored DNA samples.

RESULTS

A total of 81/735 (11%) samples tested positive for C. trachomatis infection. The overall median (Q1-Q3) age of the women was 29.0 years (24.0-35.0). The majority of the women who tested positive for C. trachomatis were younger, median (Q1-Q3) age 26.0 years (23.0-32.0) vs 30.0 years (25.0-35.0) for the negative women (p < .001). Of the positive women, 96.3% were unmarried (p=0.014). Older women were less likely to test positive for C. trachomatis infection (OR: 0.93; 95% CI 0.89-0.96 p = .001). Women who were married (OR: 0.25; 95% CI 0.06-0.70; p = .022), co-habiting with their partner (OR: 0.60; 95% CI 0.36-0.98; p = .048) and started having sex at older than 15 years (OR:0.26; 95% CI 0.09-0.87; p = .018) were less likely to test positive for C. trachomatis compared to their counterparts.

CONCLUSION

This study showed that behavioural and clinical factors were associated with prevalent infections. In order to reduce prevalent infections, stronger risk reduction counselling messages need to be provided from the educational and public health sector.

Bridging the Gap Between Pilot and Scale-Up: A Model of Antenatal Testing for Curable Sexually Transmitted Infections From Botswana

BACKGROUND

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are common sexually transmitted infections (STIs) associated with adverse outcomes, yet most countries do not test and conduct syndromic management, which lacks sensitivity and specificity. Innovations allow for expanded STI testing; however, cost is a barrier.

METHODS

Using inputs from a pilot program in Botswana, we developed a model among a hypothetical population of 50,000 pregnant women to compare 1-year costs and outcomes associated with 3 antenatal STI testing strategies: (1) point-of-care, (2) centralized laboratory, and (3) a mixed approach (point of care at high-volume sites, and hubs elsewhere), and syndromic management.

RESULTS

Syndromic management had the lowest delivery cost but was associated with the most infections at delivery, uninfected women treated, CT/NG-related low-birth-weight infants, disability-adjusted life years, and low birth weight hospitalization costs. Point-of-care CT/NG testing would treat and cure the most infections but had the highest delivery cost. Among the testing scenarios, the mixed scenario had the most favorable cost per woman treated and cured ($534/cure). Compared with syndromic management, the mixed approach resulted in a mean incremental cost-effectiveness ratio of $953 per disability-adjusted life years averted, which is cost-effective under World Health Organization's one-time per-capita gross domestic product willingness-to-pay threshold.

CONCLUSIONS

As countries consider new technologies to strengthen health services, there is an opportunity to determine how to best deploy resources. Compared with point-of-care, centralized laboratory, and syndromic management, the mixed approach offered the lowest cost per infection averted and is cost-effective if policy makers' willingness to pay is informed by the World Health Organization's gross domestic product/capita threshold.

Comprehensive characterization of purine and pyrimidine transport activities in Trichomonas vaginalis and functional cloning of a trichomonad nucleoside transporter

Trichomoniasis is a common and widespread sexually-transmitted infection, caused by the protozoan parasite Trichomonas vaginalis. T. vaginalis lacks the biosynthetic pathways for purines and pyrimidines, making nucleoside metabolism a drug target. Here we report the first comprehensive investigation into purine and pyrimidine uptake by T. vaginalis. Multiple carriers were identified and characterized with regard to substrate selectivity and affinity. For nucleobases, a high-affinity adenine transporter, a possible guanine transporter and a low affinity uracil transporter were found. Nucleoside transporters included two high affinity adenosine/guanosine/uridine/cytidine transporters distinguished by different affinities to inosine, a lower affinity adenosine transporter, and a thymidine transporter. Nine Equilibrative Nucleoside Transporter (ENT) genes were identified in the T. vaginalis genome. All were expressed equally in metronidazole-resistant and -sensitive strains. Only TvagENT2 was significantly upregulated in the presence of extracellular purines; expression was not affected by co-culture with human cervical epithelial cells. All TvagENTs were cloned and separately expressed in Trypanosoma brucei. We identified the main broad specificity nucleoside carrier, with high affinity for uridine and cytidine as well as purine nucleosides including inosine, as TvagENT3. The in-depth characterization of purine and pyrimidine transporters provides a critical foundation for the development of new anti-trichomonal nucleoside analogues.