A practical approach to screening for carbapenemase-producing Enterobacterales- views of a group of multidisciplinary experts from English hospitals

INTRODUCTION

Carbapenemase-producing Enterobacterales (CPE) are an important public health threat, with costly operational and economic consequences for NHS Integrated Care Systems and NHS Trusts. UK Health Security Agency guidelines recommend that Trusts use locally developed risk assessments to accurately identify high-risk individuals for screening, and implement the most appropriate method of testing, but this presents many challenges.

METHODS

A convenience sample of cross-specialty experts from across England met to discuss the barriers and practical solutions to implementing UK Health Security Agency framework into operational and clinical workflows. The group derived responses to six key questions that are frequently asked about screening for CPE.

KEY FINDINGS

Four patient groups were identified for CPE screening: high-risk unplanned admissions, high-risk elective admissions, patients in high-risk units, and known positive contacts. Rapid molecular testing is a preferred screening method for some of these settings, offering faster turnaround times and more accurate results than culture-based testing. It is important to stimulate action now, as several lessons can be learnt from screening during the COVID-19 pandemic, as well as from CPE outbreaks.

CONCLUSION

Further decisive and instructive information is needed to establish CPE screening protocols based on local epidemiology and risk factors. Local management should continually evaluate local epidemiology, analysing data and undertaking frequent prevalence studies to understand risks, and prepare resources- such as upscaled screening- to prevent increasing prevalence, clusters or outbreaks. Rapid molecular-based methods will be a crucial part of these considerations, as they can reduce unnecessary isolation and opportunity costs.

Impact of Point-of-Care Testing on the Management of Sexually Transmitted Infections in South Africa: Evidence from the HVTN702 Human Immunodeficiency Virus Vaccine Trial

BACKGROUND

Alternative approaches to syndromic management are needed to reduce rates of sexually transmitted infections (STIs) in resource-limited settings. We investigated the impact of point-of-care (POC) versus central laboratory-based testing on STI treatment initiation and STI adverse event (STI-AE) reporting.

METHODS

We used Kaplan-Meier and Cox regression models to compare times to treatment initiation and STI-AE reporting among HVTN702 trial participants in South Africa. Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) were diagnosed POC at eThekwini clinic and in a central laboratory at Verulam/Isipingo clinics. All clinics used POC assays for Trichomonas vaginalis (TV) testing.

RESULTS

Among 959 women (median age, 23 [interquartile range, 21-26] years), median days (95% confidence interval [95%CI]) to NG/CT treatment initiation and NG/CT-AE reporting were 0.20 (.16-.25) and 0.24 (.19-.27) at eThekwini versus 14.22 (14.12-15.09) and 15.12 (13.22-21.24) at Verulam/Isipingo (all P < .001). Median days (95%CI) to TV treatment initiation and TV-AE reporting were 0.17 (.12-.27) and 0.25 (.20-.99) at eThekwini versus 0.18 (.15-.2) and 0.24 (.15-.99) at Verulam/Isipingo (all P > .05). Cox regression analysis revealed that NG/CT treatment initiation (adjusted hazard ratio [aHR], 39.62 [95%CI, 15.13-103.74]) and NG/CT-AE reporting (aHR, 3.38 [95%CI, 2.23-5.13]) occurred faster at eThekwini versus Verulam/Isipingo, while times to TV treatment initiation (aHR, 0.93 [95%CI, .59-1.48]) and TV-AE reporting (aHR, 1.38 [95%CI, .86-2.21]) were similar.

CONCLUSIONS

POC testing led to prompt STI management with potential therapeutic and prevention benefits, highlighting its utility as a diagnostic tool in resource-limited settings.

Ethically acceptable consent approaches to adolescent research in South Africa

Background

Adolescents are a unique population with significant unmet health needs. They are often excluded from research that may benefit them as they are perceived as vulnerable and needing protection from research participation. For Research Ethics Committees, conflicting positions in statutes, regulations and ethical guidelines about who provides informed consent for adolescent involvement in health research can be a significant barrier to approving adolescent research. For researchers, the requirement for parental/guardian proxy consent or prolonged approval processes may potentially result in the exclusion of those adolescents most vulnerable and at risk, particularly if issues such as gender-based violence, gender identity, sexuality and sexual practices are in question.

Objectives

To describe the challenges to adolescent research and suggest strategies to address these.

Method

We consider the legal and ethical framework in South Africa regarding the consenting age for adolescents in research, outline the challenges and, using examples of best practices, suggest strategies to address the current conundrum.

Results

We suggest three principles to guide Research Ethics Committees on their approach to reviewing health research involving adolescents. Strategies to develop ethically acceptable approaches to adolescent research and consent processes are described, which include community involvement. We elaborate on examples of nuanced approaches to adolescent research.

Conclusion

The inclusion of adolescents in research is critical in informing appropriate and effective health services for this vulnerable population, whilst providing an opportunity to link them into care and services where relevant.

Getting to under 1% vertical HIV transmission: lessons from a breastfeeding cohort in South Africa

We report here on the transmission of HIV in a cohort of breastfeeding infants enrolled in a prevention of mother to child HIV transmission (PMTCT) programme at the epicentre of the HIV pandemic. South Africa implemented option B+ for PMTCT in 2015. Between 2013 and 2018, we enrolled 1219 infants born to HIV positive women into a non-inferiority trial assessing the current cotrimoxazole prophylaxis guidelines for HIV-exposed uninfected infants. Breastfeeding mothers and infants were enrolled and followed up at one of two clinics in eThekwini, KwaZulu-Natal, until 12 months of age. During the study period, 8 infants seroconverted (<1% transmission); these were likely four birth transmissions and four breastfeeding transmissions. It is critical in the post option B era to assess the reasons for vertical transmission of HIV to enable healthcare workers and policy makers to provide strategies to mitigate future infections. This report details the possible contributors to vertical transmission in this cohort and highlights the continued strategies that should be employed to further our goal towards reaching the elimination of mother to child HIV transmission

Characterization of Human Immunodeficiency Virus (HIV) Infections in Women Who Received Injectable Cabotegravir or Tenofovir Disoproxil Fumarate/Emtricitabine for HIV Prevention: HPTN 084

BACKGROUND

HIV Prevention Trials Network 084 demonstrated that long-acting injectable cabotegravir (CAB) was superior to daily oral tenofovir (TFV) disoproxil fumarate (TDF)/emtricitabine (FTC) for preventing human immunodeficiency virus (HIV) infection in sub-Saharan African women. This report describes HIV infections that occurred in the trial before unblinding.

METHODS

Testing was performed using HIV diagnostic assays, viral load testing, a single-copy RNA assay, and HIV genotyping. Plasma CAB, plasma TFV, and intraerythrocytic TFV-diphosphate concentrations were determined by liquid chromatography-tandem mass spectrometry.

RESULTS

Forty HIV infections were identified (CAB arm, 1 baseline infection, 3 incident infections; TDF/FTC arm, 36 incident infections). The incident infections in the CAB arm included 2 with no recent drug exposure and no CAB injections and 1 with delayed injections; in 35 of 36 cases in the TDF/FTC arm, drug concentrations indicated low or no adherence. None of the cases had CAB resistance. Nine women in the TDF/FTC arm had nonnucleoside reverse-transcriptase inhibitor resistance; 1 had the nucleoside reverse-transcriptase inhibitor resistance mutation, M184V.

CONCLUSIONS

Almost all incident HIV infections occurred in the setting of unquantifiable or low drug concentrations. CAB resistance was not detected. Transmitted nonnucleoside reverse-transcriptase inhibitor resistance was common; 1 woman may have acquired nucleoside reverse-transcriptase inhibitor resistance from study drug exposure.

Cabotegravir for the prevention of HIV-1 in women: results from HPTN 084, a phase 3, randomised clinical trial

BACKGROUND

Oral pre-exposure prophylaxis has been introduced in more than 70 countries, including many in sub-Saharan Africa, but women experience considerable barriers to daily pill-taking, such as stigma, judgement, and the fear of violence. Safe and effective long-acting agents for HIV prevention are needed for women. We aimed to evaluate the safety and efficacy of injectable cabotegravir compared with daily oral tenofovir diphosphate plus emtricitabine (TDF-FTC) for HIV prevention in HIV-uninfected women.

METHODS

HPTN 084 was a phase 3, randomised, double-blind, double-dummy, active-controlled, superiority trial in 20 clinical research sites in seven countries in sub-Saharan Africa. Participants were eligible for enrolment if they were assigned female sex at birth, were aged 18-45 years, reported at least two episodes of vaginal intercourse in the previous 30 days, were at risk of HIV infection based on an HIV risk score, and agreed to use a long-acting reversible contraceptive method. Participants were randomly assigned (1:1) to either active cabotegravir with TDF-FTC placebo (cabotegravir group) or active TDF-FTC with cabotegravir placebo (TDF-FTC group). Study staff and participants were masked to study group allocation, with the exception of the site pharmacist who was responsible for study product preparation. Participants were prescribed 5 weeks of daily oral product followed by intramuscular injections every 8 weeks after an initial 4-week interval load, alongside daily oral pills. Participants who discontinued injections were offered open-label daily TDF-FTC for 48 weeks. The primary endpoints of the study were incident HIV infection in the intention-to-treat population, and clinical and laboratory events that were grade 2 or higher in all women who had received at least one dose of study product. This study is registered with ClinicalTrials.gov, NCT03164564.

FINDINGS

From Nov 27, 2017, to Nov 4, 2020, we enrolled 3224 participants (1614 in the cabotegravir group and 1610 in the TDF-FTC group). Median age was 25 years (IQR 22-30); 1755 (54·7%) of 3209 had two or more partners in the preceding month. 40 incident infections were observed over 3898 person-years (HIV incidence 1·0% [95% CI 0·73-1·40]); four in the cabotegravir group (HIV incidence 0·2 cases per 100 person-years [0·06-0·52]) and 36 in the TDF-FTC group (1·85 cases per 100 person-years [1·3-2·57]; hazard ratio 0·12 [0·05-0·31]; p<0·0001; risk difference -1·6% [-1·0% to -2·3%]. In a random subset of 405 TDF-FTC participants, 812 (42·1%) of 1929 plasma samples had tenofovir concentrations consistent with daily use. Injection coverage was 93% of the total number of person-years. Adverse event rates were similar across both groups, apart from injection site reactions, which were more frequent in the cabotegravir group than in the TDF-FTC group (577 [38·0%] of 1519 vs 162 [10·7%] of 1516]) but did not result in injection discontinuation. Confirmed pregnancy incidence was 1·3 per 100 person-years (0·9-1·7); no congenital birth anomalies were reported.

INTERPRETATION

Although both products for HIV prevention were generally safe, well tolerated, and effective, cabotegravir was superior to TDF-FTC in preventing HIV infection in women.

FUNDING

National Institute of Allergy and Infectious Diseases, ViiV Healthcare, and the Bill & Melinda Gates Foundation. Additional support was provided through the National Institute of Mental Health, the National Institute on Drug Abuse, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development. ViiV Healthcare and Gilead Sciences provided pharmaceutical support.

TB testing in HIV-positive patients prior to antiretroviral treatment

BACKGROUND: TB diagnosis in patients with HIV is challenging due to the lower sensitivities across tests. Molecular tests are preferred and the Xpert^® MTB/RIF assay has limitations in lower-income settings. We evaluated the performance of loop-mediated isothermal amplification (LAMP) and the lipoarabinomannan (LAM) test in HIV-positive, ART-naïve clinic patients.METHODS: A total of 783 eligible patients were enrolled; three spot sputum samples of 646 patients were tested using TB-LAMP, Xpert, smear microscopy and culture, while 649 patients had TB-LAM testing. Sensitivity, specificity, and negative and positive predictive values were estimated with 95% confidence intervals.RESULTS: Sensitivities for smear microscopy, TB-LAMP and Xpert were respectively 50%, 63% and 74% compared to culture, with specificities of respectively 99.2%, 98.5% and 97.5%. An additional eight were positive on TB-LAM alone. Seventy TB patients (9%) were detected using standard-of-care testing, an additional 27 (3%) were detected using study testing. Treatment was initiated in 57/70 (81%) clinic patients, but only in 56% (57/97) of all those with positive TB tests; 4/8 multidrug-resistant samples were detected using Xpert.CONCLUSION: TB diagnostics continue to miss cases in this high-burden setting. TB-LAMP was more sensitive than smear microscopy, and if followed by culture and drug susceptibility testing as required, can diagnose TB in HIV-positive patients. TB-LAM is a useful add-in test and both tests at the point-of-care would maximise yield.

Point-of-care CD4 testing: Differentiated care for the most vulnerable

Background

South Africa, with the highest burden of HIV infection globally, has made huge strides in its HIV/ART programme, but AIDS deaths have not decreased proportionally to ART uptake. Advanced HIV disease (CD4 < 200 cells/mm³) persists, and CD4 count testing is being overlooked since universal test-and-treat was implemented. Point-of-care CD4 testing could address this gap and assure differentiated care to these vulnerable patients with low CD4 counts.

Methods

A time randomised implementation trial was conducted, enrolling 603 HIV positive non-ART, not pregnant patients at a primary health care clinic in Durban, South Africa. Weeks were randomised to either point-of-care CD4 testing (n = 305 patients) or standard-of-care central laboratory CD4 testing (n = 298 patients) to assess the proportion initiating ART at 3 months. Cox regression, with robust standard errors adjusting for clustering by week, were used to assess the relationship between treatment initiation and arm.

Results

Among the 578 (299 point-of-care and 279 standard-of-care) patients eligible for analysis, there was no significant difference in the number of eligible patients initiating ART within 3 months in the point-of-care (73%) and the standard-of-care (68%) groups (P = 0.112). The time-to-treat analysis was not significantly different in patients with CD4 counts of 201-500 cells/mm³ which could have been due to appointment scheduling to cope with the large burden of cases. However, in patients with advanced HIV disease (CD4 < 200cells/mm³) 65% more patients started ART earlier in the point-of-care group (HR 1.65 (95% confidence interval (CI) = 0.99-2.75; P = 0.052) compared to the standard-of-care group.

Conclusions

Point-of-care testing decreased time-to-treatment in those with advanced HIV disease. With universal test and treat for HIV, rollout of simple point-of-care CD4 testing would ensure early diagnosis of advanced HIV disease and facilitate differentiated care for these vulnerable patients as per the World Health Organisation 2020 target product profile for point-of-care CD4 testing.

Trial registration

ISRCTN14220457.

Assessment of the Impact of Rapid Point-of-Care CD4 Testing in Primary Healthcare Clinic Settings: A Survey Study of Client and Provider Perspectives

BACKGROUND

The high burden of disease in South Africa presents challenges to public health services. Point-of-care (POC) technologies have the potential to address these gaps and improve healthcare systems. This study ascertained the acceptability and impact of POC CD4 testing on patients' health and clinical management.

METHODS

We conducted a qualitative survey study with patients (n = 642) and healthcare providers (n = 13) at the Lancers Road (experienced POC) and Chesterville (non-experienced POC) primary healthcare (PHC) clinics from September 2015 to June 2016.

RESULTS

Patients (99%) at Lancers and Chesterville PHCs were positive about POC CD4 testing, identifying benefits: No loss/delay of test results (6.4%), cost/time saving (19.5%), and no anxiety (5.1%), and 58.2% were ready to initiate treatment. Significantly more patients at Chesterville than Lancers Road PHC felt POC would provide rapid clinical decision making (64.7% vs. 48.1%; p < 0.0001) and better clinic accessibility (40.4% vs. 24.7%; p < 0.0001) respectively. Healthcare providers thought same-day CD4 results would impact: Clinical management (46.2%), patient readiness (46.2%), and adherence (23.0%), and would reduce follow-up visits (7.7%), while 38.5% were concerned that further tests and training (15.4%) were required before antiretroviral therapy (ART) initiation.

CONCLUSION

The high acceptability of POC CD4 testing and the immediate health, structural, and clinical management benefits necessitates POC implementation studies.

Evaluation of a health system intervention to improve virological management in an antiretroviral programme at a municipal clinic in central Durban

BACKGROUND

With the largest antiretroviral therapy (ART) programme globally, demand for effective HIV management is increasing in South Africa. While viral load (VL) testing is conducted, VL follow-up and management are sub-optimal.

OBJECTIVES

The objective of this study was to address gaps in the VL cascade to improve VL testing and management.

METHODS

Antiretroviral therapy records were sampled for an in-depth review. The study team then reviewed individual records, focusing on ART management, virological suppression and retention. Multifaceted interventions focused on virological control, including a clinical summary chart for ART care; streamlining laboratory results receipt and management; monitoring VL suppression, flagging virological failure and missed visits for follow-up; down-referral of stable patients eligible for the chronic club system; and training of personnel and patients.

RESULTS

Pre-intervention, 78% (94/120) of eligible patients had VL tests, versus 92% (145/158) post-intervention (p = 0.0009). Pre-intervention, 59% (71/120) of patients accessed their VL results, versus 86% (136/158) post-intervention (p < 0.0001). Post-intervention, 73% (19/26) of patients eligible for ART change were appropriately managed, versus 11% (4/36) pre-intervention (p < 0.0001). Only 27% had no regimen changes (7/26) post-intervention, versus 81% (29/36) pre-intervention (p < 0.0001).

CONCLUSION

Service delivery was streamlined to facilitate HIV services by focusing on VL test monitoring, protocol training and accessibility of results, thereby improving clinical management.

Point-of-care HIV testing best practice for early infant diagnosis: an implementation study

Background

With Universal Health Coverage and Integrated People-centred Health Care, streamlined health-systems and respectful care are necessary. South Africa has made great strides in prevention of mother-to-child transmission (PMTCT) but with the great burden of HIV, a minimum of birth and 10-week HIV-PCR testing are required for the estimated 360,000 HIV-exposed infants born annually which presents many challenges including delayed results and loss to follow-up. Point-of-care (POC) HIV testing of infants addresses these challenges well and facilitates initiation of HIV-infected infants rapidly after diagnosis for best clinical outcomes.

Methods

Objectives were to determine accuracy, feasibility and acceptability of POC testing compared to standard-of-care (SOC) central-laboratory testing. HIV-exposed infants for birth PCR testing in hospital (n = 323) and follow-up at a primary health care clinic (n = 117) in Durban, South Africa were included. A baseline situational-analysis reviewed registers and phoned mothers of HIV-exposed infants prior to the intervention. An effectiveness-implementation study of the Alere™q HIV-1/2 Detect POC test (heel-prick specimen processed in 50 min) was compared with SOC with questionnaires to mothers and staff. Stata 14 was used for analysis.

Results

At baseline 2% of birth HIV tests were missed; only 40% of mothers could be contacted; 17% did not receive birth test result; 19% did not have a 10-week test; 39% had not received the 10-week results. There were 5(1.5%) HIV-infected and 318(98.5%) HIV-negative infants detected in hospital with all clinic babies negative. All positive infants commenced ART before discharge. Ultimately POC and SOC had perfect concordance but for 10 SOC tests researchers actively tracked-down results or repeated tests. Turn around times for SOC tests were on average 8-days (IQR 6-10  days) and for POC testing was 0-days. The POC error-rate was 9,6% with all giving a result when repeated. The majority of mothers (92%) preferred POC testing with 7% having no preference. No staff preferred SOC testing with 79% preferring POC and 21% having no preference.

Conclusions

Point-of-care HIV testing for EID is accurate, feasible and acceptable, with benefits of early ART for all positive infants at birth facilities. We recommend that it be considered best practice for EID.

Trial registration

ISRCTN38911104 registered 9 January 2018 – retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6990-z) contains supplementary material, which is available to authorized users.

Randomised controlled trial testing the effect of cotrimoxazole prophylaxis on morbidity and mortality outcomes in breastfed HIV-exposed uninfected infants: study protocol

INTRODUCTION

No randomised controlled trial (RCT) has examined the efficacy of cotrimoxazole (CTX) prophylaxis in HIV-exposed uninfected (HEU) infants during the breastfeeding period, in this new era of effective prevention of mother-to-child transmission (PMTCT) prophylaxis. The efficacy of CTX prophylaxis has presently been demonstrated only in HIV-infected children. The absence of proven benefits in HEU breastfed infants associated with infectious diseases justifies an RCT as proposed. Herewith lies the rationale for conducting the proposed study.

METHODS

A partially blinded RCT is proposed to evaluate the efficacy of CTX prophylaxis administered from 6 weeks of age to HEU infants receiving a PMTCT regimen. A non-inferiority design will be used, randomising 1298 infants to receive CTX or not to receive CTX. Participants will be reviewed at the following time points: 6 weeks (enrolment and randomisation), 10 weeks, 14 weeks, 4 months and monthly thereafter until 12 months of age. They will be evaluated for anthropometric growth, interval illness, CTX adherence, signs and symptoms of study drug toxicity, concomitant medication use, breastfeeding status and HIV infection status. The study will compare the incidence of grade 3 and grade 4 common childhood illnesses (focusing on pneumonia and diarrhoea) and all-cause mortality until 12 months of age. In a subset of participants, we will compare grade 3 and grade 4 haemoglobin and alanine aminotransferase results as well as investigate gut integrity.

ETHICS AND DISSEMINATION

The study has ethical approval from the University of KwaZulu-Natal Biomedical Research Ethics Committee (BFC212/13).

TRIAL REGISTRATION NUMBERS

PACTR201311000621110 and DOH-27-0614-4728; Pre-results.

PIMA™ point-of-care testing for CD4 counts in predicting antiretroviral initiation in HIV-infected individuals in KwaZulu-Natal, Durban, South Africa

Introduction

Limited information is available on the usefulness of the PIMA™ analyser in predicting antiretroviral treatment eligibility and outcome in a primary healthcare clinic setting in disadvantaged communities in KwaZulu-Natal, South Africa.

Materials and methods

The study was conducted under the eThekwini Health Unit, Durban, KwaZulu-Natal. Comparison of the enumeration of CD4+ T-cells in 268 patients using the PIMA™ analyser and the predicate National Health Laboratory Services (NHLS) was undertaken during January to July 2013. Bland-Altman analysis to calculate bias and limits of agreement, precision and levels of clinical misclassification at various CD4+ T-cell count thresholds was performed.

Results

There was high precision of the PIMA™ control bead cartridges with low and normal CD4+ T-cell counts using three different PIMA™ analysers (%CV < 5). Under World Health Organization (WHO) guidelines (≤ 500 cells/mm³), the sensitivity of the PIMA™ analyser was 94%, specificity 78% and positive predictive value (PPV) 95%. There were 24 (9%) misclassifications, of which 13 were false-negative in whom the mean bias was 149 CD4+ T-cells/mm³. Most (87%) patients returned for their CD4 test result but only 67% (110/164) of those eligible (≤ 350 cells/mm³) were initiated on antiretroviral therapy (ART) with a time to treatment of 49 days (interquartile range [IQR], 42–64 days).

Conclusion

There was adequate agreement between PIMA™ analyser and predicate NHLS CD4+ T-cell count enumeration (≤ 500 cells/mm³) in adult HIV-positive individuals. The high PPV, sensitivity and acceptable specificity of the PIMA™ analyser technology lend it as a reliable tool in predicting eligibility and rapid linkage to care in ART programmes.

Rictor regulates cell migration by suppressing RhoGDI2

Rictor and its binding partner Sin1 are indispensable components of mTORC2 (mammalian Target of Rapamycin Complex 2). The mTORC2 signaling complex functions as the regulatory kinase of the distinct members of AGC kinase family known to regulate cell proliferation and survival. In the early chemotaxis studies in Dictyostelium, the rictor's ortholog has been identified as a regulator of cell migration. How rictor regulates cell migration is poorly characterized. Here we show that rictor regulates cell migration by controlling a potent inhibitor of Rho proteins known as the Rho-GDP dissociation inhibitor 2 (RhoGDI2). Based on our proteomics study we identified that the rictor-dependent deficiency in cell migration is caused by up-regulation of RhoGDI2 leading to a low activity of Rac and Cdc42. We found that a suppression of RhoGDI2 by rictor is not related to the Sin1 or raptor function that excludes a role of mTORC2 or mTORC1 in regulation of RhoGDI2. Our study reveals that rictor by suppressing RhoGDI2 promotes activity of the Rho proteins and cell migration.

Routinely available cotrimoxazole prophylaxis and occurrence of respiratory and diarrhoeal morbidity in infants born to HIV-infected mothers in South Africa

OBJECTIVES

To examine the influence of cotrimoxazole (CTM) prophylaxis on incidence of lower respiratory tract infections (LRTIs) and diarrhoea.

DESIGN

A prospective observational cohort study. Morbidity and feeding data on infants born to HIV-infected mothers were collected routinely at clinic visits at 1 week, 6 weeks and 3 months, and 3-monthly thereafter, with blood drawn for determining HIV status.

SETTING

Two hospitals in Durban, South Africa. In one hospital (King Edward VIII Hospital), infants born to HIV infected mothers received CTM prophylaxis and in the other (McCord Hospital) infants did not receive CTM prophylaxis.

SUBJECTS

Infants born to HIV-infected mothers. Outcome measures. Incidence of LRTI and diarrhoea.

RESULTS

In multivariate analysis controlling for breast-feeding status, number of clinic visits and HIV infection status, HIV infected infants with access to CTM prophylaxis had a significantly lower incidence of LRTI (82%) than those without access to prophylaxis. However in HIV-uninfected infants, this was not the case. CTM prophylaxis was associated with a non-significant increased risk for diarrhea in both infected (odds ratio (OR) 1.58, p = 0.45) and uninfected infants (OR 1.52, p = 0.10).

CONCLUSIONS

This observational study confirms current thinking that CTM prophylaxis is protective against LRTIs in HIV-infected children. However, because of a possible association between CTM prophylaxis and an increased risk of diarrhoea, HIV status of infants should be determined as early as possible in order to prevent unnecessary exposure of uninfected infants to CTM prophylaxis, while further studies to quantify both beneficial and adverse effects of CTM prophylaxis are undertaken.

Morbidity in children born to women infected with human immunodeficiency virus in South Africa: does mode of feeding matter?

AIM

To examine infant morbidity risks associated with refraining from breastfeeding where it is used in an attempt to prevent mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV).

METHODS

The population consisted of infants born to HIV-infected women in South Africa who were participating in a vitamin A intervention trial to prevent MTCT of HIV. Women chose to breastfeed or formula feed their infants according to UNAIDS guidelines. Actual feeding practices and morbidity were recorded at clinic follow-up visits at I wk, 6 wk, 3 mo and every 3 mo thereafter until 15 mo of age or cessation of breastfeeding. The infant's HIV status was assessed according to a predetermined algorithm.

RESULTS

HIV-infected infants who were never breastfed had a poorer outcome than those who were breastfed; 9 (60%) of those who were never breastfed had 3 or more morbidity episodes compared with 15 (32%) of breastfed children [odds ratio (OR) 4.05, 95% confidence interval (95% CI) 0.91-20.63, p = 0.05]. During the first 2 mo of life, never-breastfed infants (regardless of HIV status) were nearly twice as likely to have had an illness episode than breastfed infants (OR 1.91, 95% CI 1. 17-3.13, p = 0.006).

CONCLUSION

The significant extra morbidity experienced in the first few months by all never-breastfed infants and at all times by HIV-infected infants who are not breastfed needs to be considered in all decisions by mothers, health workers and policy makers so as not to offset any gains achieved by decreasing HIV transmission through avoiding breastfeeding.

Method of feeding and transmission of HIV-1 from mothers to children by 15 months of age: prospective cohort study from Durban, South Africa

OBJECTIVE

To determine the risk of HIV transmission by infant feeding modality.

DESIGN AND SETTING

A prospective study in two hospitals in Durban, South Africa.

PARTICIPANTS

A total of 551 HIV-infected pregnant women enrolled in a randomized trial of vitamin A.

INTERVENTIONS

Women self-selected to breastfeed or formula feed after being counselled. Breastfeeders were encouraged to practice exclusive breastfeeding for 3-6 months.

MAIN OUTCOME MEASURES

Cumulative probabilities of detecting HIV over time were estimated using Kaplan-Meier methods and were compared in three groups: 157 formula-fed (never breastfed); 118 exclusively breastfed for 3 months or more; and 276 mixed breastfed.

RESULTS

The three feeding groups did not differ in any risk factors for transmission, and the probability of detecting HIV at birth was similar. Cumulative probabilities of HIV detection remained similar among never and exclusive breastfeeders up to 6 months: 0.194 (95% CI 0.136-0.260) and 0.194 (95% CI 0.125-0.274), respectively, whereas the probabilities among mixed breastfeeders soon surpassed both groups reaching 0.261 (95% CI 0.205-0.319) by 6 months. By 15 months, the cumulative probability of HIV infection remained lower among those who exclusively breastfed for 3 months or more than among other breastfeeders (0.247 versus 0.359).

CONCLUSION

Infants exclusively breastfed for 3 months or more had no excess risk of HIV infection over 6 months than those never breastfed. These findings, if confirmed elsewhere, can influence public health policies on feeding choices available to HIV-infected mothers in developing countries.

Randomized trial testing the effect of vitamin A supplementation on pregnancy outcomes and early mother-to-child HIV-1 transmission in Durban, South Africa. South African Vitamin A Study Group

OBJECTIVE

Poor vitamin A status has been associated with a higher risk for mother-to-child transmission of HIV-1 and there is contradictory evidence on the impact of vitamin A on perinatal outcome. We therefore assessed the effect of vitamin A supplementation to mothers on birth outcome and mother-to-child transmission of HIV-1.

DESIGN AND METHODS

In Durban, South Africa 728 pregnant HIV infected women received either vitamin A (368) or placebo (360) in a randomized, double-blind trial. The vitamin A treatment consisted of a daily dose of 5000 IU retinyl palmitate and 30 mg beta-carotene during the third trimester of pregnancy and 200000 IU retinyl palmitate at delivery. HIV infection results were available on 632 children who were included in the Kaplan-Meier transmission analysis. Results are reported on mother-to-child transmission rates up to 3 months of age.

RESULTS

There was no difference in the risk of HIV infection by 3 months of age between the vitamin A [20.3%; 95% confidence interval (CI), 15.7-24.9] and placebo groups (22.3%; 95% CI, 17.5-27.1), nor were there differences in foetal or infant mortality rates between the two groups. Women receiving vitamin A supplement were, however, less likely to have a preterm delivery (11.4% in the vitamin A and 17.4% in the placebo group; P = 0.03) and among the 80 preterm deliveries, those assigned to the vitamin A group were less likely to be infected (17.9%; 95% CI, 3.5-32.2) than those assigned to the placebo group (33.8%; 95% CI, 19.8-47.8).

CONCLUSION

Vitamin A supplementation, a low-cost intervention, does not appear to be effective in reducing overall mother-to-child transmission of HIV; however, its potential for reducing the incidence of preterm births, and the risk of mother-to-child transmission of HIV in these infants needs further investigation.

Influence of infant-feeding patterns on early mother-to-child transmission of HIV-1 in Durban, South Africa: a prospective cohort study. South African Vitamin A Study Group

BACKGROUND

The observation that mother-to-child transmission of HIV-1 can occur through breastfeeding has resulted in policies that recommend avoidance of breastfeeding by HIV-1-infected women in the developed world and under specific circumstances in developing countries. We compared transmission rates in exclusively breastfed, mixed-fed, and formula-fed (never breastfed) infants to assess whether the pattern of breastfeeding is a critical determinant of early mother-to-child transmission of HIV-1.

METHODS

We prospectively assessed infant-feeding practices of 549 HIV-1-infected women who were part of a vitamin A intervention trial in Durban, South Africa. The proportions of HIV-1-infected infants at 3 months (estimated by use of Kaplan-Meier life tables) were compared in the three different feeding groups. HIV-1 infection was defined by a positive RNA-PCR test.

FINDINGS

At 3 months, 18.8% (95% CI 12.6-24.9) of 156 never-breastfed children were estimated to be HIV-1 infected compared with 21.3% (17.2-25.5) of 393 breastfed children (p=0.5). The estimated proportion (Kaplan-Meier) of infants HIV-1 infected by 3 months was significantly lower for those exclusively breastfed to 3 months than in those who received mixed feeding before 3 months (14.6% [7.7-21.4] vs 24.1% [19.0-29.2], p=0.03). After adjustment for potential confounders (maternal CD4-cell/CD8-cell ratio, syphilis screening test results, and preterm delivery), exclusive breastfeeding carried a significantly lower risk of HIV-1 transmission than mixed feeding (hazard ratio 0.52 [0.28-0.98]) and a similar risk to no breastfeeding (0.85 [0.51-1.42]).

INTERPRETATIONS

Our findings have important implications for prevention of HIV-1 infection and infant-feeding policies in developing countries and further research is essential. In the meantime, breastfeeding policies for HIV-1-infected women require urgent review. If our findings are confirmed, exclusive breastfeeding may offer HIV-1-infected women in developing countries an affordable, culturally acceptable, and effective means of reducing mother-to-child transmission of HIV-1 while maintaining the overwhelming benefits of breastfeeding.

Cloning of a yeast 8-oxoguanine DNA glycosylase reveals the existence of a base-excision DNA-repair protein superfamily

BACKGROUND

Reactive oxygen species, ionizing radiation, and other free radical generators initiate the conversion of guanine (G) residues in DNA to 8-oxoguanine (OG), which is highly mutagenic as it preferentially mispairs with adenine (A) during replication. Bacteria counter this threat with a multicomponent system that excises the lesion, corrects OG:A mispairs and cleanses the nucleotide precursor pool of dOGTP. Although biochemical evidence has suggested the existence of base-excision DNA repair proteins specific for OG in eukaryotes, little is known about these proteins.

RESULTS

Using substrate-mimetic affinity chromatography followed by a mechanism-based covalent trapping procedure, we have isolated a base-excision DNA repair protein from Saccharomyces cerevisiae that processes OG opposite cytosine (OG:C) but acts only weakly on OG:A. A search of the yeast genome database using peptide sequences from the protein identified a gene, OGG1, encoding a predicted 43 kDa (376 amino acid) protein, identical to one identified independently by complementation cloning. Ogg1 has OG:C-specific base-excision DNA repair activity and also intrinsic beta-lyase activity, which proceeds through a Schiff base intermediate. Targeted disruption of the OGG1 gene in yeast revealed a second OG glycosylase/lyase protein, tentatively named Ogg2, which differs from Ogg1 in that it preferentially acts on OG:G.

CONCLUSIONS

S. cerevisiae has two OG-specific glycosylase/lyases, which differ significantly in their preference for the base opposite the lesion. We suggest that one of these, Ogg1, is closely related in overall three-dimensional structure to Escherichia coli endonuclease III (endo III), a glycosylase/lyase that acts on fragmented and oxidatively damaged pyrimidines. We have recently shown that AlkA, a monofunctional DNA glycosylase that acts on alkylated bases, is structurally homologous to endo III. We have now identified a shared active site motif amongst these three proteins. Using this motif as a protein database searching tool, we find that it is present in a number of other base-excision DNA repair proteins that process diverse lesions. Thus, we propose the existence of a DNA glycosylase superfamily, members of which possess a common fold yet act upon remarkably diverse lesions, ranging from UV photoadducts to mismatches to alkylated or oxidized bases.

Right heart reconstruction following repair of tetralogy of fallot

Ten patients in whom tetralogy of Fallot had been repaired underwent late reconstruction of the outflow tract of the right ventricle because of poor hemodynamic results. The major hemodynamic problems that necessitated right ventricular (RV) outflow tract reconstruction were severe pulmonary insufficiency in 9 patients and pulmonary stenosis in 1. Impaired RV contractility and RV aneurysm were the most important factors prompting valve replacement for severe pulmonary insufficiency. Seven patients received a Hancock prosthesis and 3, an aortic homograft. Among the 7 patients who underwent postoperative cardiac catheterization, the surgical results were hemodynamically excellent in 2, good in 3, and unsatisfactory in 2. The management of pulmonary insufficiency in such patients is discussed.

Ventricular diastolic pressure-volume relations after the intra-atrial baffle operation for transposition of the great arteries

Right and left ventricular diastolic pressure-volume (P-V) relations were assessed in 30 patients approximately 2 years after the Mustard operation. The overall distensibility index (delta V/ delta P), the compliance index at end-diastole (dv/dp), and the modulus of ventricular stiffness (Kp) were calculated in all, as well as the half-time of early diastolic pressure fall (T) in 10 cases. Transducer-tipped catheters were used in 15 patients and biplane cineangiography was employed in all. Values for the above indices equal to 2 standard deviations below the mean, obtained from five postoperative Mustard patients with no residual defects, were used as "normals." Seven patients with pulmonary hypertension (PH) and six with pulmonic stenosis (PS) were found to have impaired P-V relations. The impairment was more profound in the PH group. Delta v/delta p and dv/dp were abnormal in six of seven patients for both ventricles and T was abnormal in two of five. Kp was abnormal for the LV, and the RV ejection fraction was diminished. In the PS group (nine patients) the impairment was milder, affecting more than LV and end-diastole (dv/dp). Compliance studies might be useful in patients with LV afterload problems following the Mustard operation.

Left ventricular function and compliance in pulmonary atresia with intact ventricular septum

Left ventricular systolic function and compliance were assessed in 15 cases of pulmonary atresia with intact ventricular septum. The left ventricular ejection fraction measured from cineangiography was used for the evaluation of the systolic function. The end-diastolic pressure (EDP), left ventricular compliance index at end-diastole (dv/dp), and left ventricular stiffness constant K were used as compliance indices. The mean left ventricular ejection fraction was slightly diminished. The right ventricular end diastolic pressures (RVEDPs) correlated significantly (r = 0.90) with the left ventricular end diastolic pressure (LVEDP). On the basis of left ventricular compliance, two distinctive groups of patients could be identified: Group I consisted of Patients 1 to 7, all with impaired left ventricular compliance. A shunt operation was the basic palliation in this group. None of these patients survived infancy. Group II consisted of Patients 8 to 15, all with normal left ventricular compliance. Pulmonary valvotomy as well as aortopulmonary shunts were the basic palliative procedures in this group. Six of eight patients in this group are long-term survivors. No difference was found in right ventricular size, tricuspid valve size, presence of tricuspid insufficiency, presence of a patent ductus arteriosus, postoperative oxygen saturations, and atrial pressure gradients between the two groups. Evaluation of the left ventricular compliance in patients with pulmonary atresia and intact ventricular septum might be of significant prognostic valve for their early survival.

Late spontaneous disruption of a porcine xenograft mitral valve. Clinical, hemodynamic, echocardiographic, and pathological findings

A case is presented of failure of a Hancock porcine xenograft mitral prosthesis secondary to disruption of the prosthetic leaflets. Clinical, hemodynamic, and echocardiographic evidence of prosthetic dysfunction has been correlated with operative, pathological, and ultrastructural findings. Other instances of dysfunction of this prosthesis have been reviewed. Echocardiography should be routinely employed when the diagnosis of xenograft dysfunction is entertained.

A different approach for the total correction of tricuspid atresia

A new surgical procedure has been used successfully to correct tricuspid atresia in a 9-year-old girl. An external conduit containing a porcine aortic valve was positioned to lead from the right atrium to the underdeveloped right ventricle. The right ventricle was reconstructed with a large Dacron patch, thus providing a large cavity for the small hypoplastic right ventricle. The atrial and ventricular septal defects were closed. The patient made a satisfactory recovery and is doing well four months after the operation.