The presence of enteropathy in HIV infected children on antiretroviral therapy in Malawi

BACKGROUND

Undernutrition and malnutrition in children in low- and middle-income countries contribute to high mortality rates. Stunting, a prevalent form of malnutrition, is associated with educational and productivity losses. Environmental enteric dysfunction (EED) and human immunodeficiency virus (HIV) infection worsen these conditions. This study seeks to investigate the presence of enteropathy using EED fecal biomarkers in HIV-infected children who are stable on antiretroviral therapy (ART) across various nutritional statuses. By understanding the interplay between EED, HIV, and nutritional status, this study aims to provide insights that can inform targeted interventions to optimize nutritional outcomes in HIV infected children.

METHODS/PRINCIPAL FINDINGS

This study evaluated the levels of alpha-1-antitrypsin, calprotectin and myeloperoxidase in frozen fecal samples from 61 HIV infected (mean age 9.16 ±3.08 years) and 31 HIV uninfected (6.65 ±3.41 years) children in Malawi. Anthropometric measurements and clinical data were collected. The height-for-age z-score (-1.66 vs -1.27, p = 0.040) and BMI-for-age z-score (-0.36 vs 0.01, p = 0.037) were lower in HIV infected children. Enzyme-linked immunosorbent assays were used to measure biomarker concentrations. Statistical tests were applied to compare biomarker levels based on HIV status and anthropometric parameters. Myeloperoxidase, alpha-1-antitrypsin, and calprotectin concentrations did not differ between HIV infected and HIV uninfected children of different age groups. In HIV infected children from 5-15 years, there is no difference in biomarker concentration between the stunted and non-stunted groups.

CONCLUSION/SIGNIFICANCE

Our study found a higher prevalence of stunting in HIV infected children compared to uninfected children, but no significant differences in biomarker concentrations. This suggests no causal relationship between enteropathy and stunting in HIV infected children. These results contribute to the understanding of growth impairment in HIV infected children and emphasize the need for further research, particularly a longitudinal, biopsy-controlled study.

Characterizing the evolving SARS-CoV-2 seroprevalence in urban and rural Malawi between February 2021 and April 2022: A population-based cohort study

OBJECTIVES

This study aimed to investigate the changing SARS-CoV-2 seroprevalence and associated health and sociodemographic factors in Malawi between February 2021 and April 2022.

METHODS

In total, four 3-monthly serosurveys were conducted within a longitudinal population-based cohort in rural Karonga District and urban Lilongwe, testing for SARS-CoV-2 S1 immunoglobulin (Ig)G antibodies using an enzyme-linked immunosorbent assay. Population seroprevalence was estimated in all and unvaccinated participants. Bayesian mixed-effects logistic models estimated the odds of seropositivity in the first survey, and of seroconversion between surveys, adjusting for age, sex, occupation, location, and assay sensitivity/specificity.

RESULTS

Of the 2005 participants (Karonga, n = 1005; Lilongwe, n = 1000), 55.8% were female and median age was 22.7 years. Between Surveys (SVY) 1 and 4, population-weighted SARS-CoV-2 seroprevalence increased from 26.3% to 89.2% and 46.4% to 93.9% in Karonga and Lilongwe, respectively. At SVY4, seroprevalence did not differ by COVID-19 vaccination status in adults, except for those aged 30+ years in Karonga (unvaccinated: 87.4%, 95% credible interval 79.3-93.0%; two doses: 98.1%, 94.8-99.5%). Location and age were associated with seroconversion risk. Individuals with hybrid immunity had higher SARS-CoV-2 seropositivity and antibody titers, than those infected.

CONCLUSION

High SARS-CoV-2 seroprevalence combined with low morbidity and mortality indicate that universal vaccination is unnecessary at this stage of the pandemic, supporting change in national policy to target at-risk groups.

Draft genomes of Aeromonas caviae from patients with cholera-like illness during the 2022-2023 cholera outbreak in Malawi

Aeromonas caviae is an increasingly recognized etiological agent of acute gastroenteritis. Here, we report five draft genomes of A. caviae isolated from suspected cholera cases during the 2022-2023 cholera outbreak in Malawi.

Effect of dietary intervention on the prevalence of asymptomatic malaria among 6-18-month-old children in rural Malawi

BACKGROUND

The complex interaction between malaria and undernutrition leads to increased mortality and morbidity rate among young children in malaria-endemic regions. Results from previous interventions suggest that improving nutritional status of young children may reduce the burden of malaria. This study tested a hypothesis that provision of lipid-based nutrient supplements (LNS) or corn-soy blend (CSB) supplementation to 6-18-month-old children in Malawi would reduce the prevalence of asymptomatic malaria among them.

METHODS

A total of 840 6-month-old children were enrolled in a randomized trial. The participants received 12-month supplementation with three different daily dietary supplementations: CSB, soy-LNS, or milk-LNS, and one control group without supplementation. The prevalence rate of asymptomatic Plasmodium falciparum was determined by real-time PCR from the participant's dried blood spots (DBS) collected at the baseline and every 3 months. The global null hypothesis was tested using modified Poisson regression to estimate the prevalence ratio (PR) between the control group and three intervention groups at all ages combined. All the models were adjusted for malaria at baseline, season of DBS sample collection, site of enrolment, and household asset Z-score.

RESULTS

All children combined, the prevalence of P. falciparum was 14.1% at enrollment, 8.7% at 9 months, 11.2% at 12 months, 13.0% at 15 months and 22.4% at 18 months of age. Among all samples that were taken after enrolment, the prevalence was 12.1% in control group, 12.2% in milk-LNS, 14.0% in soy-LNS, and 17.2% in CSB group. Compared to children in the control group the prevalence ratio of positive malaria tests was 1.19 (95% CI 0.81-1.74; P = 0.372) in the milk-LNS group, 1.32 (95% CI 0.88-1.96; P = 0.177) in the soy-LNS group and 1.72 (95% CI 1.19-2.49; P = 0.004) in the CSB group.

CONCLUSION

The study findings do not support a hypothesis that LNS or CSB supplementation would reduce the prevalence of asymptomatic malaria among Malawian children. In contrast, there was a signal of a possible increase in malaria prevalence among children supplemented with CSB.

Child Aflatoxin Exposure is Associated with Poor Child Growth Outcomes: A Prospective Cohort Study in Rural Malawi

Background

Aflatoxin (AF) exposure is associated with child growth faltering in cross-sectional studies, with limited findings from longitudinal studies.

Objectives

To evaluate the relationship between maternal AF B₁-lysine adduct concentration, child AF B₁-lysine adduct concentration, and child growth in the first 30 mo of life.

Methods

AF B₁-lysine adduct was measured in mother-child dyad plasma samples using isotope dilution mass spectrometry. Using linear regression, we assessed the relationship between AF B₁-lysine adduct concentration and child weight, height, and head and mid-upper arm circumferences at 1 wk, 6, 12, 18, 24, and 30 mo of age.

Results

In adjusted models, maternal prenatal AF B₁-lysine adduct (pg/μL) was positively associated with newborn anthropometric outcomes; largest beta coefficients for associations between standardized values were for newborn weight-for-age z-score [β = 0.13; 95% confidence interval (CI): 0.02, 0.24; P < 0.05 and β = 0.11; 95% CI: 0.00, 0.22; P < 0.05 for second and third trimester AF, respectively]. Child AF B₁-lysine adduct (pg/μL) at 6 mo was negatively associated with head circumference-for-age z-score at 6, 18, 24, and 30 mo, with beta coefficients ranging from β = -0.15; 95% CI: -0.28, -0.02 to β = -0.17; 95% CI: -0.31, -0.03; P < 0.05); 18-mo AF was negatively associated with anthropometric outcomes at 18, 24, and 30 mo, most consistently with length-for-age z-score (β = -0.18; 95% CI: -0.32, -0.04, β = -0.21; 95% CI: -0.35, -0.07, β = -0.18; 95% CI: -0.32, -0.03 at 18, 24 and 30 mo, respectively).

Conclusions

Child AF exposure was associated with impaired child growth, but maternal AF exposure was not. Exposure during infancy was linked to persistent deficit in head circumference, implying reduced brain size lasting beyond the age of 2 years. Exposure at 18 mo was linked to persistent linear growth deficit. Further research should elucidate mechanisms through which AF affects child growth.

Lack of Associations between Environmental Exposures and Environmental Enteric Dysfunction among 18-Month-Old Children in Rural Malawi

Environmental enteric dysfunction (EED) is common and contributes to linear growth faltering (stunting) and mortality among children in low-resource settings. A few studies on the environmental causes of EED have been conducted but the exact exposures that cause or predispose children to EED are context-specific and not clear. This study aimed to assess associations between selected environmental exposures and EED markers among 620 18-month-old children. This was a secondary analysis of data from Malawian children who participated in a randomized controlled trial (iLiNS-DYAD, registered at clinicaltrials.gov as NCT01239693) from birth to 18 months of age. Data on environmental exposures, including drinking water source, sanitation, exposure to animals, housing materials, season, residential area, and food insecurity were collected at enrolment. Biomarkers of EED included concentrations of calprotectin, regenerating 1B protein (REG1B), and alpha-1-antitrypsin from stool samples to assess intestinal inflammation, repair, and permeability, respectively. We performed bivariate and multivariable analyses to assess associations between environmental exposures and EED biomarkers. Adjusting for possible confounders, we did not find associations between the selected environmental exposures and the three biomarkers. These results do not provide support for our hypothesis that the studied adverse environmental exposures are associated with increased concentrations of children's EED markers in rural Malawi.

Association between intestinal bacterial carriage, biomarkers of environmental enteric dysfunction, and stunting in rural Malawian children

Background. Available data from murine studies suggest that intestinal bacteria may have a role in modulating growth phenotypes in the host. We investigated the prevalence of four gut bacteria known in murine models to impair growth (Bifidobacterium longum, Faecalibacterium prausnitzii, Dorea formicigenerans, and Akkermansia muciniphila), the level of fecal biomarkers of environmental enteric dysfunction (EED) and stunting in rural Malawian children. Methods. DNA and protein were extracted from fecal samples of rural Malawian children (aged 1-59 months) at a baseline cross-sectional survey in the Mangochi district of Malawi conducted within the framework of the Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial. Intestinal carriage of bacteria was measured by PCR. Neopterin (NEO), myeloperoxidase (MPO), and alpha-1 antitrypsin (AAT), biomarkers of EED, were measured by an enzyme-linked immunosorbent assay (ELISA) test. Height-for-age Z (HAZ) score <-2 defined stunting. Tests of proportions and regression models were used to explore the relationship between bacterial carriage, EED, and stunting. Results. Fecal samples from 613 children were available for laboratory analyses. F. prausnitzii and D. formicigenerans were prevalent in over 70% of children while B. longum was the least prevalent. B. longum carriage in younger children was associated with elevated EED biomarkers. Two thirds of children had elevated NEO, 33% had elevated MPO, and 16% had elevated AAT. Stunting was found in 38%. No significant associations were found between EED biomarkers or intestinal bacteria carriage and stunting. Conclusion. Intestinal carriage of these four bacteria was not associated with stunting in Malawian children. Carriage was also not associated with EED, nor EED biomarker levels associated with stunting. Further factors acting in concert are necessary to impact EED, perturb growth, and alter gut bacterial carriage.

A fast extraction-free isothermal LAMP assay for detection of SARS-CoV-2 with potential use in resource-limited settings

Background

To retain the spread of SARS-CoV-2, fast, sensitive and cost-effective testing is essential, particularly in resource limited settings (RLS). Current standard nucleic acid-based RT-PCR assays, although highly sensitive and specific, require transportation of samples to specialised laboratories, trained staff and expensive reagents. The latter are often not readily available in low- and middle-income countries and this may significantly impact on the successful disease management in these settings. Various studies have suggested a SARS-CoV-2 loop mediated isothermal amplification (LAMP) assay as an alternative method to RT-PCR.

Methods

Four previously published primer pairs were used for detection of SARS-CoV-2 in the LAMP assay. To determine optimal conditions, different temperatures, sample input and incubation times were tested. Ninety-three extracted RNA samples from St. George's Hospital, London, 10 non-extracted nasopharyngeal swab samples from Great Ormond Street Hospital for Children, London, and 92 non-extracted samples from Queen Elisabeth Central Hospital (QECH), Malawi, which have previously been tested for SARS-Cov-2 by quantitative reverse-transcription RealTime PCR (qRT-PCR), were analysed in the LAMP assay.

Results

In this study we report the optimisation of an extraction-free colourimetric SARS-CoV-2 LAMP assay and demonstrated that a lower limit of detection (LOD) between 10 and 100 copies/µL of SARS-CoV-2 could be readily detected by a colour change of the reaction within as little as 30 min. We further show that this assay could be quickly established in Malawi, as no expensive equipment is necessary. We tested 92 clinical samples from QECH and showed the sensitivity and specificity of the assay to be 86.7% and 98.4%, respectively. Some viral transport media, used routinely to stabilise RNA in clinical samples during transportation, caused a non-specific colour-change in the LAMP reaction and therefore we suggest collecting samples in phosphate buffered saline (which did not affect the colour) as the assay allows immediate sample analysis on-site.

Conclusion

SARS-CoV-2 LAMP is a cheap and reliable assay that can be readily employed in RLS to improve disease monitoring and management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-022-01800-7.

Biannual Administrations of Azithromycin and the Gastrointestinal Microbiome of Malawian Children: A Nested Cohort Study Within a Randomized Controlled Trial

Community-level mass treatment with azithromycin has been associated with a mortality benefit in children. However, antibiotic exposures result in disruption of the gut microbiota and repeated exposures may reduce recovery of the gut flora. We conducted a nested cohort study within the framework of a randomized controlled trial to examine associations between mass drug administration (MDA) with azithromycin and the gut microbiota of rural Malawian children aged between 1 and 59 months. Fecal samples were collected from the children at baseline and 6 months after two or four biannual rounds of azithromycin treatment. DNA was extracted from fecal samples and V4-16S rRNA sequencing used to characterize the gut microbiota. Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria were the dominant phyla while Faecalibacterium and Bifidobacterium were the most prevalent genera. There were no associations between azithromycin treatment and changes in alpha diversity, however, four biannual rounds of treatment were associated with increased abundance of Prevotella. The lack of significant changes in gut microbiota after four biannual treatments supports the use of mass azithromycin treatment to reduce mortality in children living in low- and middle-income settings.

Associations between Gut Microbiota and Intestinal Inflammation, Permeability and Damage in Young Malawian Children

BACKGROUND

Environmental enteric dysfunction (EED) is common in low- and middle-income countries and associated with childhood undernutrition. The composition of gut microbiota has been implicated in the pathogenesis of EED. Our aim was to assess the associations between gut microbiota and EED biomarkers in rural Malawian children. We hypothesized that there would be an inverse association between microbiota maturity and diversity and fecal concentrations of EED biomarkers.

METHODS

We used data from fecal samples collected at 6, 18 and 30 months from 611 children who were followed up during a nutrition intervention trial. The primary time point for analysis was 18 months. Microbiota data were obtained through 16S rRNA sequencing and variables included microbiota maturity and diversity, phylogenetic dissimilarity and relative abundances of individual taxa. EED biomarkers included calprotectin (marker of inflammation), alpha-1 antitrypsin (intestinal permeability) and REG1B (intestinal damage).

RESULTS

There was an inverse association between microbiota maturity and diversity and fecal concentrations of all 3 EED biomarkers at 18 months (p≤0.001). The results were similar at 30 months, while at 6 months inverse associations were found only with calprotectin and alpha-1 antitrypsin concentrations. At 18 months, EED biomarkers were not associated with phylogenetic dissimilarity, but at 6 and 30 months several associations were observed. Individual taxa predicting EED biomarker concentrations at 18 months included several Bifidobacterium and Enterobacteriaceae taxa as well as potentially displaced oral taxa.

CONCLUSIONS

Our findings support the hypothesis of an inverse association between microbiota maturity and diversity and EED in rural Malawian children.

Fecal biomarkers of environmental enteric dysfunction and the gut microbiota of rural Malawian children: An observational study

Environmental enteric dysfunction (EED) is a subclinical condition of the gut characterized by changes in morphology and function with underlying chronic inflammatory responses. This study characterized composition and diversity of the gut microbiota in rural Malawian children with and without signs of EED. Fecal samples were collected from children aged 1-59 months. Neopterin, myeloperoxidase and alpha-1 antitrypsin concentrations were quantified by ELISA and combined to form a composite EED score using principal component analysis. DNA was extracted from fecal samples and V4-16S rRNA gene sequencing was used to characterize the gut microbiota. The concentrations of all three biomarkers decreased with increasing age, which is consistent with other studies of children living in similar low-income settings. Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria were the dominant phyla while Faecalibacterium and Bifidobacterium were the most prevalent genera. Increased alpha diversity was associated with a reduction in neopterin concentration. Microbiota composition was different between fecal samples with low and high composite EED scores; increased abundance of Succinivibrio was associated with reduced composite EED scores.

Validation of a direct-to-PCR COVID-19 detection protocol utilizing mechanical homogenization: A model for reducing resources needed for accurate testing

Efficient and effective viral detection methodologies are a critical piece in the global response to COVID-19, with PCR-based nasopharyngeal and oropharyngeal swab testing serving as the current gold standard. With over 100 million confirmed cases globally, the supply chains supporting these PCR testing efforts are under a tremendous amount of stress, driving the need for innovative and accurate diagnostic solutions. Herein, the utility of a direct-to-PCR method of SARS-CoV-2 detection grounded in mechanical homogenization is examined for reducing resources needed for testing while maintaining a comparable sensitivity to the current gold standard workflow of nasopharyngeal and oropharyngeal swab testing. In a head-to-head comparison of 30 patient samples, this initial clinical validation study of the proposed homogenization-based workflow demonstrated significant agreeability with the current extraction-based method utilized while cutting the total resources needed in half.

Associations of Human Milk Oligosaccharides and Bioactive Proteins with Infant Morbidity and Inflammation in Malawian Mother-Infant Dyads

BACKGROUND

Human milk oligosaccharides (HMOs) and bioactive proteins likely benefit infant health, but information on these relations is sparse.

OBJECTIVES

We aimed to examine associations of milk content of HMOs and bioactive proteins with incidence and longitudinal prevalence of infant morbidity (any illness, fever, diarrhea, acute respiratory infection, and loss of appetite) and markers of inflammation [C-reactive protein (CRP) and α-1-acid glycoprotein (AGP)]. These are secondary analyses of a randomized controlled trial.

METHODS

Breast milk samples at 6 mo postpartum (n  = 659) were analyzed to quantify absolute abundance of HMOs, relative abundance of fucosylated HMOs, sialylated HMOs, and 51 individual HMOs, and concentrations of 6 bioactive proteins (lactalbumin, lactoferrin, lysozyme, antitrypsin, IgA, and osteopontin). We examined associations of these constituents with infant morbidity from 6 to 7 and 6 to 12 mo, and CRP and AGP at 6 and 18 mo, considering maternal secretor status [presence or absence of the functional enzyme encoded by the fucosyltransferase 2 gene (FUT2) ] and adjusting for covariates and multiple hypothesis testing.

RESULTS

In secretors there were positive associations between total HMOs and longitudinal prevalence of fever (P = 0.032), between fucosylated HMOs and incidence of diarrhea (P = 0.026), and between lactoferrin and elevated CRP at 18 mo (P = 0.011). In nonsecretors, there were inverse associations between lactoferrin and incidence of fever (P  = 0.007), between osteopontin and longitudinal prevalence of lost appetite (P  = 0.038), and between fucosylated HMOs and incidence of diarrhea (P = 0.025), lost appetite (P = 0.019), and concentrations of AGP and CRP at 6 mo (P = 0.001 and 0.010); and positive associations between total HMOs and incidence of lost appetite (P = 0.024) and elevated CRP at 18 mo (P  = 0.026), between lactalbumin and incidence of diarrhea (P = 0.006), and between lactoferrin and elevated CRP at 18 mo (P = 0.015).

CONCLUSIONS

Certain HMOs and bioactive proteins were associated with infant morbidity and inflammation, particularly in nonsecretors. Further research is needed to elucidate the causality of these relations.This trial was registered at clinicaltrials.gov as NCT01239693.

Associations of human milk oligosaccharides and bioactive proteins with infant growth and development among Malawian mother-infant dyads

BACKGROUND

Human milk oligosaccharides (HMOs) and bioactive breast milk proteins have many beneficial properties. Information is sparse regarding associations between these milk constituents and infant growth and development in lower-income countries.

OBJECTIVES

We aimed to examine associations of milk content of HMOs and bioactive proteins at 6 mo postpartum with infant growth and motor and cognitive development. These are secondary analyses of a randomized controlled trial in rural Malawi.

METHODS

Breast milk samples were analyzed at 6 mo (n = 659) for general categories of HMOs (total HMOs, fucosylated HMOs, and sialylated HMOs), 51 individual HMOs, and 6 bioactive proteins (lactalbumin, lactoferrin, lysozyme, antitrypsin, IgA, and osteopontin). We examined associations of the relative abundances of HMOs and concentrations of bioactive proteins with infant growth from 6 to 12 mo [change in length-for-age (ΔLAZ), weight-for-age, weight-for-length, and head circumference z-scores] as well as ability to stand or walk alone at 12 mo, and motor and language skills, socioemotional development, executive function, and working memory at 18 mo. Analyses were adjusted for covariates and multiple hypothesis testing.

RESULTS

Among all participants, there were inverse associations of IgA and lactoferrin concentrations with motor skills (P = 0.018 and P = 0.044), and a positive association of lactalbumin concentration with motor skills (P = 0.038). Among secretors only [fucosyltransferase 2 gene (FUT2) positive], there were positive associations of absolute abundance of HMOs with ΔLAZ (P = 0.035), and relative abundance of fucosylated and sialylated HMOs with language at 18 mo (P < 0.001 and P = 0.033, respectively), and inverse associations of osteopontin with standing and walking at 12 mo (P = 0.007 and 0.002, respectively). Relative abundances of several individual HMOs were associated with growth and development, mostly among secretors.

CONCLUSIONS

Certain bioactive breast milk proteins and HMOs are associated with infant growth and motor and cognitive development. Further studies are needed to determine if a causal relation exists.This trial was registered at clinicaltrials.gov as NCT01239693.

Infant gut microbiota characteristics generally do not modify effects of lipid-based nutrient supplementation on growth or inflammation: secondary analysis of a randomized controlled trial in Malawi

An unhealthy gut microbial community may act as a barrier to improvement in growth and health outcomes in response to nutritional interventions. The objective of this analysis was to determine whether the infant microbiota modified the effects of a randomized controlled trial of lipid-based nutrient supplements (LNS) in Malawi on growth and inflammation at 12 and 18 months, respectively. We characterized baseline microbiota composition of fecal samples at 6 months of age (n = 506, prior to infant supplementation, which extended to 18 months) using 16S rRNA gene sequencing of the V4 region. Features of the gut microbiota previously identified as being involved in fatty acid or micronutrient metabolism or in outcomes relating to growth and inflammation, especially in children, were investigated. Prior to correction for multiple hypothesis testing, the effects of LNS on growth appeared to be modified by Clostridium (p-for-interaction = 0.02), Ruminococcus (p-for-interaction = 0.007), and Firmicutes (p-for-interaction = 0.04) and effects on inflammation appeared to be modified by Faecalibacterium (p-for-interaction = 0.03) and Streptococcus (p-for-interaction = 0.004). However, after correction for multiple hypothesis testing these findings were not statistically significant, suggesting that the gut microbiota did not alter the effect of LNS on infant growth and inflammation in this cohort.

Provision of Lipid-Based Nutrient Supplements to Mothers During Pregnancy and 6 Months Postpartum and to Their Infants from 6 to 18 Months Promotes Infant Gut Microbiota Diversity at 18 Months of Age but Not Microbiota Maturation in a Rural Malawian Setting: Secondary Outcomes of a Randomized Trial

BACKGROUND

Diet may alter the configuration of gut microbiota, but the impact of prenatal and postnatal nutritional interventions on infant gut microbiota has not been investigated.

OBJECTIVE

We evaluated whether providing lipid-based nutrient supplements (LNSs) to mother-infant dyads promotes a more diverse and mature infant gut microbiota, compared to maternal supplementation with multiple micronutrients (MMN) or iron and folic acid (IFA).

METHODS

We enrolled 869 pregnant women in a randomized trial in Malawi. There were 3 study groups, with women receiving 1 MMN capsule daily during pregnancy and 6 mo postpartum, or 1 LNS sachet (20 g) daily during pregnancy and 6 mo postpartum, or 1 IFA capsule daily (during pregnancy) then a placebo daily (postpartum). Infants in the LNS group received LNS from 6 to 18 mo; infants in the other groups did not receive supplements. The infants' fecal microbiota were characterized by PCR amplification and sequencing of the bacterial 16S rRNA gene (variable region 4). The primary outcomes were microbiota α diversity and maturation [as microbiota-for-age z score (MAZ)]. Specific associations of taxa with intervention were established with indicator species analysis (ISA).

RESULTS

Primary outcomes did not differ between IFA and MMN groups, so these groups were combined (IFA + MMN). Mean ± SD α diversity was higher in the LNS group at 18 mo for Shannon index [3.01 ± 0.57 (LNS) compared with 2.91 ± 0.60 (IFA + MMN), P = 0.032] and Pielou's evenness index [0.61 ± 0.08 (LNS) compared with 0.60 ± 0.09 (IFA + MMN), P = 0.043]; no significant differences were observed at 1, 6, 12, or 30 mo. MAZ and β diversity did not differ at any age. We found 10 and 3 operational taxonomic units (OTUs) positively associated with LNS and IFA + MMN, respectively; however, these associations became nonsignificant following false discovery rate correction at 10%.

CONCLUSIONS

Prenatal and postnatal LNS intake promoted infant gut microbiota diversity at 18 mo, after 12 mo of child supplementation, but did not alter microbiota maturation. This trial was registered at clinicaltrials.gov as NCT01239693.

Pgp3 seroprevalence and associations with active trachoma and ocular Chlamydia trachomatis infection in Malawi: cross-sectional surveys in six evaluation units

BACKGROUND

Following one to five years of antibiotic mass drug administration (MDA) for the elimination of trachoma as a public health problem, programmes must conduct impact surveys to inform decisions on whether MDA is still needed. These decisions are currently based on the prevalence of trachomatous inflammation-follicular (TF), which, after MDA, correlates poorly with prevalence of ocular Chlamydia trachomatis infection.

METHODOLOGY/PRINCIPAL FINDINGS

Impact surveys in six evaluation units (EUs) of Malawi were used as a platform to explore associations between the prevalence of TF, ocular C. trachomatis infection and anti-Pgp3 antibodies one year after the third annual round of MDA. Participants were examined for trachoma using the World Health Organization simplified grading system. Ocular swabs and dried blood spots (DBS) were collected from children aged 1-9 years. Swabs were tested for C. trachomatis DNA using GeneXpert. DBS were assayed for anti-Pgp3 antibodies using ELISA. EU-level prevalence of TF in children aged 1-9 years ranged from 4.7% (95% CI 3.4-6.3) to 7.2% (95% CI 5.8-8.9). Prevalence of C. trachomatis infection in children ranged from 0.1% (95% CI 0.0-0.6) to 0.7% (95% CI 0.3-1.3) while Pgp3 seroprevalence ranged from 6.9% (95% CI 5.4-8.6) to 12.0% (95% CI 10.1-14.0) and increased with age.

CONCLUSIONS/SIGNIFICANCE

Based on current global policy, the prevalence of TF indicates that a further year of antibiotic MDA is warranted in four of six EUs yet the very low levels of infection cast doubt on the universal applicability of TF-based cut-offs for antibiotic MDA. Pgp3 seroprevalence was similar to that reported following MDA in other settings that have reached the elimination target however the predictive value of any particular level of seropositivity with respect to risk of subsequent infection recrudescence is, as yet, unknown.

The association of gut microbiota characteristics in Malawian infants with growth and inflammation

We tested the hypotheses that a more mature or diverse gut microbiota will be positively associated with infant growth and inversely associated with inflammation. We characterized gut microbiota from the stool samples of Malawian infants at 6 mo (n = 527), 12 mo (n = 632) and 18 mo (n = 629) of age. Microbiota diversity and maturity measurements were based on Shannon diversity index and microbiota for age Z-score (MAZ), respectively. Growth was calculated as change in Z-scores for weight-for-age (WAZ), length-for-age (LAZ) and head circumference-for-age (HCZ) from 6 to 12 mo and 12 to 18 mo. Biomarkers of inflammation (alpha-1-acid glycoprotein (AGP) and C-reactive protein (CRP)) were measured at 6 and 18 mo. Multivariable models were used to assess the association of each independent variable with each outcome. Microbiota diversity and maturity were related to growth in weight from 6 to 12 mo, but not to growth in length or head circumference or to growth from 12 to 18 mo. Microbiota diversity and maturity may also be linked to inflammation, but findings were inconsistent.

Lipid-Based Nutrient Supplements During Pregnancy and Lactation Did Not Affect Human Milk Oligosaccharides and Bioactive Proteins in a Randomized Trial

BACKGROUND

Human milk oligosaccharides (HMOs) and bioactive proteins are beneficial to infant health. Recent evidence suggests that maternal nutrition may affect the amount of HMOs and proteins in breast milk; however, the effect of nutrient supplementation on HMOs and bioactive proteins has not yet been well studied.

OBJECTIVE

We aimed to determine whether lipid-based nutrient supplements (LNSs) affect milk bioactive protein and HMO concentrations at 6 mo postpartum in women in rural Malawi. These are secondary outcomes of a previously published randomized controlled trial.

METHODS

Women were randomly assigned to consume either an iron and folic acid capsule (IFA) daily from ≤20 wk gestation until delivery, followed by placebo daily from delivery to 6 mo postpartum, or a multiple micronutrient (MMN) capsule or LNS daily from ≤20 wk gestation to 6 mo postpartum. Breast milk concentrations of total HMOs, sialylated HMOs, fucosylated HMOs, lactoferrin, lactalbumin, lysozymes, antitrypsin, immunoglobulin A, and osteopontin were analyzed at 6 mo postpartum (n = 647). Between-group differences in concentrations and in proportions of women classified as having low concentrations were tested.

RESULTS

HMO and bioactive protein concentrations did not differ between groups (P > 0.10 for all comparisons). At 6 mo postpartum, the proportions of women with low HMOs or bioactive proteins were not different between groups except for osteopontin. A lower proportion of women in the IFA group had low osteopontin compared with the LNS group after adjusting for covariates (OR: 0.5; 95% CI: 0.3, 0.9; P = 0.016).

CONCLUSION

The study findings do not support the hypothesis that supplementation with an LNS or MMN capsule during pregnancy and postpartum would increase HMO or bioactive milk proteins at 6 mo postpartum among Malawian women. This trial was registered at clinicaltrials.gov as NCT01239693.

Analysis of breast milk fatty acid composition using dried milk samples

Background

The effect of breast milk fatty acid (FA) composition, particularly levels of docosahexaenoic acid (DHA), on infant health outcomes is unclear. Part of the reason for this is difficulties in collecting, storing and shipping milk samples to the laboratory. Here we report the validation of a dried milk spot (DMS) system to measure FA composition to help overcome these obstacles.

Milk FA were measured by gas chromatography and reported as percent of total FA; the FA of primary interest in this study were DHA and industrially produced trans FA (iTFA). Experiments were carried out using pooled milk samples from US (n = 5) and Malawian women (n = 50). Experiments compared liquid vs. DMS samples (n = 55), assessed stability of FA composition under different storage conditions (n = 5), and compared the results from two different labs using the same methods (n = 5).

Results

Both % DHA and % iTFA levels in liquid and DMS samples were strongly correlated (R² = 0.99 and 0.99, respectively, P < 0.0001). The % DHA in DMS samples was stable for up to four weeks at room temperature and up to three years at -80 °C; only slight deviations from the acceptable range of variability (±15 %) occurred in the 4 °C and -20 °C conditions for % DHA. The % iTFA was stable under all conditions. All % DHA and % iTFA were within 15 % of the referent when analyzed in two laboratories.

Conclusions

Valid FA composition values can be obtained from DMS samples using this robust collection and transport system which should facilitate studies of the role of milk FA composition in infant development.

Electronic supplementary material

The online version of this article (doi:10.1186/s13006-016-0060-2) contains supplementary material, which is available to authorized users.

Maternal cortisol and stress are associated with birth outcomes, but are not affected by lipid-based nutrient supplements during pregnancy: an analysis of data from a randomized controlled trial in rural Malawi

BACKGROUND

Prenatal micronutrient supplements have been found to increase birth weight, but mechanisms for increased growth are poorly understood. Our hypotheses were that 1) women who receive lipid-based nutrient supplements (LNS) during pregnancy would have lower mean salivary cortisol concentration at 28 wk and 36 wk gestation compared to the multiple micronutrient (MMN) and iron-folic acid (IFA) supplement groups and 2) both salivary cortisol and perceived stress during pregnancy would be associated with shorter duration of gestation and smaller size at birth.

METHODS

Women were enrolled in the trial in early pregnancy and randomized to receive LNS, MMN, or iron-folic acid (IFA) supplements daily throughout pregnancy. At enrollment, 28 wk and 36 wk gestation, saliva samples were collected and their cortisol concentration was measured. Self-report of perceived stress was measured using questionnaires. Gestation duration was indicated by ultrasound dating and newborn anthropometric measurements (weight, length, head circumference) provided indicators of intrauterine growth.

RESULTS

Of the 1391 women enrolled in the trial, 1372, 906 and 1049 saliva samples were collected from women at baseline, 28 wk and 36 wk, respectively. There were no significant differences in mean cortisol concentrations by intervention group at 28 wk or 36 wk gestation. Cortisol concentrations were negatively associated with duration of gestation (Baseline: β = -0.05, p = 0.039; 36 wk: β = -0.04, p = 0.037) and birth weight (28 wk: β = -0.08, p = 0.035; 36 wk: β = -0.11, p = 0.003) but not associated with length-for-age or head circumference-for-age z-scores. Perceived stress at 36 wk was significantly associated with shorter newborn LAZ (p = 0.001). There were no significant associations with the risk of small for gestational age, preterm birth, or low birth weight.

CONCLUSIONS

Maternal salivary cortisol concentration was strongly associated with birth weight and duration of gestation in rural Malawi, but these data do not support the hypothesis that LNS provision to pregnant women would influence their salivary cortisol concentrations.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT01239693.