Enteric infections, diarrhea, and their impact on function and development

Protopine-Type Alkaloids Alleviate Lipopolysaccharide-Induced Intestinal Inflammation and Modulate the Gut Microbiota in Mice

In this study, we assessed the therapeutic effects of Macleaya cordata (Willd). R. Br.-derived protopine-type alkaloids (MPTAs) in a mouse model of lipopolysaccharide (LPS)-induced intestinal inflammation. The experimental design involved the allocation of mice into distinct groups, including a control group, a model group treated with 6 mg/kg LPS, a berberine group treated with 50 mg/kg berberine hydrochloride and low-, medium- and high-dose MPTA groups treated with 6, 12 and 24 mg/kg MPTAs, respectively. Histological analysis of the ileum, jejunum and duodenum was performed using Hematoxylin and Eosin (H&E) staining. Moreover, the quantification of intestinal goblet cells (GCs) was performed based on PAS staining. The serum levels of IL-1β, IL-6, IL-8 and TNF-α were quantified using an enzyme-linked immunosorbent assay (ELISA), while the mRNA levels of TLR4, NF-κB p65, NLRP3, IL-6 and IL-1β were assessed using quantitative PCR (qPCR). The protein levels of TLR4, Md-2, MyD88, NF-κB p65 and NLRP3 were determined using Western blotting. Furthermore, the 16S rDNA sequences of bacterial taxa were amplified and analysed to determine alterations in the gut microbiota of the mice following MPTA treatment. Different doses of MPTAs were found to elicit distinct therapeutic effects, leading to enhanced intestinal morphology and an increased abundance of intestinal GCs. A significant decrease was noted in the levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8 and TNF-α). Additionally, the protein levels of TLR4, MyD88, NLRP3 and p-p65/p65 were markedly reduced by MPTA treatment. Furthermore, 16S rDNA sequencing analysis revealed that the administration of 24 mg/kg MPTAs facilitated the restoration of microbial composition.

Convergent synthesis of the pentasaccharide repeating unit corresponding to the cell wall O-polysaccharide of Salmonella milwaukee (group U) O:43 strain

Synthesis of the pentasaccharide repeating unit of the cell O-polysaccharide produced by Salmonella milwaukee O:43 strain (group U) has been achieved in very good yield adopting a convergent stereoselective [3 + 2] block glycosylation strategy. Thioglycosides and glycosyl trichloroacetimidate derivative were used as glycosyl donors in the presence of a combination of N-iodosuccinimide (NIS) and trimethylsilyl trifluoromethanesulfonate (TMSOTf) as thiophilic activator and TMSOTf as trichloroacetimidate activator respectively. The stereochemical outcome of all glycosylation reactions was excellent.

LncRNA Nostrill promotes interferon-γ-stimulated gene transcription and facilitates intestinal epithelial cell-intrinsic anti-Cryptosporidium defense

Intestinal epithelial cells possess the requisite molecular machinery to initiate cell-intrinsic defensive responses against intracellular pathogens, including intracellular parasites. Interferons(IFNs) have been identified as cornerstones of epithelial cell-intrinsic defense against such pathogens in the gastrointestinal tract. Long non-coding RNAs (lncRNAs) are RNA transcripts (>200 nt) not translated into protein and represent a critical regulatory component of mucosal defense. We report here that lncRNA Nostrill facilitates IFN-γ-stimulated intestinal epithelial cell-intrinsic defense against infection by Cryptosporidium, an important opportunistic pathogen in AIDS patients and a common cause of diarrhea in young children. Nostrill promotes transcription of a panel of genes controlled by IFN-γ through facilitating Stat1 chromatin recruitment and thus, enhances expression of several genes associated with cell-intrinsic defense in intestinal epithelial cells in response to IFN-γ stimulation, including Igtp, iNos, and Gadd45g. Induction of Nostrill enhances IFN-γ-stimulated intestinal epithelial defense against Cryptosporidium infection, which is associated with an enhanced autophagy in intestinal epithelial cells. Our findings reveal that Nostrill enhances the transcription of a set of genes regulated by IFN-γ in intestinal epithelial cells. Moreover, induction of Nostrill facilitates the IFN-γ-mediated epithelial cell-intrinsic defense against cryptosporidial infections.

Open Defecation, Livestock Ownership, and Child Nutritional Status in India

South Asian children are among the most severely malnourished worldwide. One prominent hypothesis is that open defecation in the local area exposes children to human fecal pathogens that can cause diarrhea and malnutrition. Much of the existing research uses district-level measures of open defecation, which could mask important local-area variation. A second hypothesis is that animal fecal matter is a major source of exposure. This analysis tested these dual hypotheses using census data collected from 949 villages in Tamil Nadu, India, and a survey conducted in a random sample of 5,000 households in the same area. The final analytic sample consisted of 2,561 children aged 0-10 years. We estimated the association between the measures of village- and household-level open defecation, household livestock ownership, and child height-for-age Z-scores in a regression framework, controlling for potential confounders. Results revealed that village- and household-level open defecations are negatively associated with child height. There was an estimated difference of approximately 0.5 height-for-age Z-score between children living in villages with no open defecation and children in villages where all households practiced open defecation (P = 0.001) and a 0.2 Z-score difference between children living in households that practiced open defecation and those living in households that did not (P = 0.001). Livestock ownership was not associated with child height. Overall, the findings provide evidence on the centrality of open defecation in explaining persistent child malnutrition in India and the higher risk of exposure to human fecal pathogens compared with animal feces in the south Indian context.

Epidemiology of Rotavirus in Humans, Animals, and the Environment in Africa: A Systematic Review and Meta-analysis

BACKGROUND

Globally, rotavirus infections are the most common cause of diarrhea-related deaths, especially among children under 5 years of age. This virus can be transmitted through the fecal-oral route, although zoonotic and environmental contributions to transmission are poorly defined. The purpose of this study is to determine the epidemiology of rotavirus in humans, animals, and the environment in Africa, as well as the impact of vaccination.

METHODS

We searched PubMed, Web of Science, Africa Index Medicus, and African Journal Online, identifying 240 prevalence data points from 224 articles between 2009 and 2022.

RESULTS

Human rotavirus prevalence among patients with gastroenteritis was 29.8% (95% confidence interval [CI], 28.1%-31.5%; 238 710 participants), with similar estimates in children under 5 years of age, and an estimated case fatality rate of 1.2% (95% CI, .7%-2.0%; 10 440 participants). Prevalence was estimated to be 15.4% and 6.1% in patients with nongastroenteritis illnesses and apparently healthy individuals, respectively. Among animals, prevalence was 9.3% (95% CI, 5.7%-13.7%; 6115 animals), and in the environmental water sources, prevalence was 31.4% (95% CI, 17.7%-46.9%; 2530 samples).

DISCUSSION

Our findings highlight the significant burden of rotavirus infection in Africa, and underscore the need for a One Health approach to limiting the spread of this disease.

Risk factors for food contamination among children discharged from community management of acute malnutrition programmes in South Sudan: A cross-sectional study and hazard analysis critical control point approach

Children under-5 years of age are particularly vulnerable to severe acute malnutrition (SAM), and the risk factors associated with relapse to SAM are poorly understood. Possible causes are asymptomatic or symptomatic infection with enteric pathogens, with contaminated food as a critical transmission route. This cross-sectional study comprised a household survey with samples of child food (n = 382) and structured observations of food preparation (n = 197) among children aged 6-59 months that were discharged from treatment in community management of acute malnutrition (CMAM) programmes in South Sudan. We quantified Escherichia coli and total coliforms (TCs), measured in colony forming units per g of food (CFU/g), as indicators of microbial contamination of child food. A modified hazard analysis critical control point (HACCP) approach was utilised to determine critical control points (CCPs) followed by multivariate logistic regression analysis to understand the risk factors associated with contamination. Over 40% (n = 164) of samples were contaminated with E. coli (43% >0 E. coli CFU/g, 95% CI 38%-48%), and 90% (n = 343) had >10 TCs (CFU/g) (>10 TC CFU/g, 95% CI 87%-93%). Risk factors associated (p < 0.05) with child food contamination included if the child fed themselves (9.05 RR, 95% CI [3.18, 31.16]) and exposure to animals (2.63 RR, 95% CI [1.33, 5.34]). This study highlights the risk factors and potential control strategies that can support interventions that reduce food contamination exposure in young children and help further protect those that are highly vulnerable to recurrent exposure to enteric pathogens.

Extracellular vesicles derived from Lactobacillus johnsonii promote gut barrier homeostasis by enhancing M2 macrophage polarization

INTRODUCTION

Diarrheic disease is a common intestinal health problem worldwide, causing great suffering to humans and animals. Precise manipulation strategies based on probiotics to combat diarrheic diseases have not been fully developed.

OBJECTIVES

The aim of this study was to investigate the molecular mechanisms by which probiotics manipulate macrophage against diarrheic disease.

METHODS

Metagenome reveals gut microbiome profiles of healthy and diarrheic piglets. Fecal microbial transplantation (FMT) was employed to explore the causal relationship between gut microbes and diarrhea. The protective role of probiotics and their derived extracellular vesicles (EVs) was investigated in ETEC K88-infected mice. Macrophage depletion was performed to assess the role of macrophages in EVs against diarrhea. Execution of in vitro cell co-culture and transcriptome analyses elucidated the molecular mechanisms by which EVs modulate the macrophage and intestinal epithelial barrier.

RESULTS

Escherichia coli was enriched in weaned diarrheic piglets, while Lactobacillus johnsonii (L. john) showed a negative correlation with Escherichia coli. The transmission of diarrheic illness symptoms was achieved by transferring fecal microbiota, but not metabolites, from diarrheic pigs to germ-free (GF) mice. L. john's intervention prevented the transmission of disease phenotypes from diarrheic piglets to GF mice. L. john also reduces the gut inflammation induced by ETEC K88. The EVs secreted by L. john demonstrated enhanced efficacy in mitigating the adverse impacts induced by ETEC K88 through the modulation of macrophage phenotype. In vitro experiments have revealed that EVs activate M2 macrophages in a manner that shuts down ERK, thereby inhibiting NLRP3 activation in intestinal epithelial cells.

CONCLUSION

Our results reveal that intestinal microbiota drives the onset of diarrheic disease and that probiotic-derived EVs ameliorate diarrheic disease symptoms by modulating macrophage phenotypes. These findings can enhance the advancement of innovative therapeutic approaches for diarrheic conditions based on probiotic-derived EVs.

Multicenter evaluation of BioCode GPP for syndromic molecular detection of gastrointestinal pathogens from stool specimens

Acute gastroenteritis (AGE) is a leading cause of morbidity and mortality worldwide across all age groups that disproportionally affects young children in low- and middle-income countries and immunocompromised patients in high-income countries. Regional outbreaks of AGE are typically detected by traditional microbiological detection methods that target limited organisms and are associated with low sensitivity and lengthy time-to-results. Combined, these may result in repeat testing, imprecise or delayed treatment, and delayed recognition of outbreaks. We conducted a multi-site prospective study comparing the BioCode Gastrointestinal Pathogen Panel (BioCode GPP) for the detection of 17 common bacterial, viral, and protozoan causes of gastroenteritis with reference methods, including stool culture, enzyme immunoassays, pathogen-specific PCR assays, and sequencing. One thousand five hundred fifty-eight residual, de-identified stool samples (unpreserved stool and stool in Cary-Blair transport medium) were enrolled and tested for 11 bacterial, 3 viral, and 3 protozoan pathogens. BioCode GPP and reference methods were positive for 392 (25.2%) and 283 (18.2%) samples, respectively (P < 0.0001). In this study, the BioCode GPP and reference methods detected 69 and 65 specimens positive for Clostridioides difficile, 51 and 48 for enteroaggregative Escherichia coli, 33 and 27 for enterotoxigenic E. coli, 50 and 47 for norovirus GI/GII, and 30 and 22 for rotavirus A, respectively. The BioCode GPP showed good positive and negative agreements for each pathogen ranging from 89.5% to 100%, with overall sensitivity and specificity of 96.1% and 99.7%, post adjudication. The BioCode GPP detected >1 pathogens in 49 samples, representing 12.5% of the total 392 positive specimens.

IMPORTANCE

This study highlights performance of a novel technology for timely and accurate detection and differentiation of 17 common bacterial, viral, and protozoan causes of gastroenteritis. Utilizing molecular tests such as the BioCode Gastrointestinal Pathogen Panel may improve the detection of gastrointestinal pathogens and provide actionable results, particularly for patient populations at most risk.

A pilot study using hospital surveillance and a birth cohort to investigate enteric pathogens and malnutrition in children, Dili, Timor-Leste

In low-to-middle-income countries (LMICs), enteric pathogens contribute to child malnutrition, affecting nutrient absorption, inducing inflammation, and causing diarrhoea. This is a substantial problem in LMICs due to high disease burden, poor sanitation and nutritional status, and the cyclical nature of pathogen infection and malnutrition. This relationship remains understudied in Timor-Leste. In our pilot study of enteric pathogens and malnutrition in Dili, Timor-Leste (July 2019-October 2020), we recruited 60 infants in a birth cohort from Hospital Nacional Guido Valadares (HNGV) with up to four home visits. We collected faecal samples and details of demographics, anthropometrics, diet and food practices, and animal husbandry. Additionally, we collected faecal samples, diagnostics, and anthropometrics from 160 children admitted to HNGV with a clinical diagnosis of severe diarrhoea or severe acute malnutrition (SAM). We tested faeces using the BioFire® FilmArray® Gastrointestinal Panel. We detected high prevalence of enteric pathogens in 68.8% (95%CI 60.4-76.2%) of infants at home, 88.6% of SAM cases (95%CI 81.7-93.3%) and 93.8% of severe diarrhoea cases (95%CI 67.7-99.7%). Diarrhoeagenic Escherichia coli and Campylobacter spp. were most frequently detected. Pathogen presence did not significantly differ in birth cohort diarrhoeal stool, but hospital data indicated associations between Salmonella and Shigella and diarrhoea. We observed wasting in 18.4% (95%CI 9.2-32.5%) to 30.8% (95%CI 17.5-47.7%) of infants across home visits, 57.9% (95%CI 34.0-78.9%) of severe diarrhoea cases, and 92.5% (95%CI 86.4-96.2%) of SAM cases. We associated bottle feeding with increased odds of pathogen detection when compared with exclusive breastfeeding at home (OR 8.3, 95%CI 1.1-62.7). We detected high prevalence of enteric pathogens and signs of malnutrition in children in Dili. Our pilot is proof of concept for a study to fully explore the risk factors and associations between enteric pathogens and malnutrition in Timor-Leste.

Effect of hot-melt extruded Morus alba leaves on intestinal microflora and epithelial cells

Although rutin and isoquercitrin have many effects, they are insoluble substances, making it difficult to obtain pure substances. This study was to investigate whether Morus alba leaves containing rutin and isoquercitrin could improve intestinal health by making a sustained-release formulation through a hot-melt extrusion (HME) process with improved stability and solubility and determine whether it could upregulate the balance of intestinal microorganisms and intestinal epithelial cells. A sustained-release formulation was prepared by the HME process using Morus alba leaves and a hydrophilic polymer matrix. Antibacterial activities of pathogenic microorganisms (Escherichia coli, Streptococcus aureus, Enterococcus faecalis) and proliferative effect of probiotics (Lactobacillus rhamnosus, Pediococcus pentosaceus) were tested against intestinal microorganisms. Regarding intestinal epithelial cells, a co-culture model of Caco-2 cells and RAW 264.7 cells was used. It was confirmed that the extrudate exhibited high antibacterial activities against pathogenic microorganisms and affected the proliferation of probiotics. Furthermore, after inducing inflammation through LPS, it recovered transepithelial electrical resistance-increased levels of tight junction proteins and decreased expression levels of pro-inflammatory cytokines. HME of Morus alba leaves containing rutin and isoquercitrin can upregulate intestinal microbial balance and intestinal epithelial cells.

IL-18-induced HIF-1α in ILC3s ameliorates the inflammation of C. rodentium-induced colitis

Group 3 innate lymphoid cells (ILC3s) are vital for defending tissue barriers from invading pathogens. Hypoxia influences the production of intestinal ILC3-derived cytokines by activating HIF. Yet, the mechanisms governing HIF-1α in ILC3s and other innate RORγt+ cells during in vivo infections are poorly understood. In our study, transgenic mice with specific Hif-1a gene inactivation in innate RORγt+ cells (RAG1KO HIF-1α▵Rorc) exhibit more severe colitis following Citrobacter rodentium infection, primarily due to the inability to upregulate IL-22. We find that HIF-1α▵Rorc mice have impaired IL-22 production in ILC3s, while non-ILC3 innate RORγt+ cells, also capable of producing IL-22, remain unaffected. Furthermore, we show that IL-18, induced by Toll-like receptor 2, selectively triggers IL-22 in ILC3s by transcriptionally upregulating HIF-1α, revealing an oxygen-independent regulatory pathway. Our results highlight that, during late-stage C. rodentium infection, IL-18 induction in the colon promotes IL-22 through HIF-1α in ILC3s, which is crucial for protection against this pathogen.

Detection of enteric viruses and SARS-CoV-2 in beach sand

Beach sand harbors a diverse group of microbial organisms that may be of public health concern. Nonetheless, little is known about the presence and distribution of viruses in beach sand. In this study, the first objective was to evaluate the presence of seven viruses (Aichi virus, enterovirus, hepatitis A virus, human adenovirus, norovirus, rotavirus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)) in sands collected at public beaches. The second objective was to assess the spatial distribution of enteric viruses in beach sand. To that end, 27 beach sand samples from different beaches in Portugal were collected between November 2018 and August 2020 and analyzed for the presence of viruses. At seven beaches, samples were collected in the supratidal and intertidal zones. Results show that viruses were detected in 89 % (24/27) of the sand samples. Aichi virus was the most prevalent (74 %). Noroviruses were present in 19 % of the samples (norovirus GI - 15 %, norovirus GII - 4 %). Human adenovirus and enterovirus were detected in 48 % and 22 % of the samples, respectively. Hepatitis A virus and rotavirus were not detected. Similarly, SARS-CoV-2 in beach sand collected during the initial stages of the pandemic was also not detected. The detection of three or more viruses occurred in 15 % of the samples. Concentrations of viruses were as high as 7.2 log copies (cp)/g of sand. Enteric viruses were found in higher prevalence in sand collected from the supratidal zone compared to the intertidal zone. Human adenovirus was detected in 43 % of the supratidal and 14 % in the intertidal samples and Aichi virus in 57 % and 86 % of the intertidal and supratidal areas, respectively. Our findings suggest that beach sand can be a reservoir of enteric viruses, suggesting that it might be a vehicle for disease transmission, particularly for children, the elderly, and immunocompromised users.

Protocol for the PATHOME study: a cohort study on urban societal development and the ecology of enteric disease transmission among infants, domestic animals and the environment

INTRODUCTION

Global morbidity from enteric infections and diarrhoea remains high in children in low-income and middle-income countries, despite significant investment over recent decades in health systems and water and sanitation infrastructure. Other types of societal development may be required to reduce disease burden. Ecological research on the influence of household and neighbourhood societal development on pathogen transmission dynamics between humans, animals and the environment could identify more effective strategies for preventing enteric infections.

METHODS AND ANALYSIS

The 'enteric pathome'-that is, the communities of viral, bacterial and parasitic pathogens transmitted from human and animal faeces through the environment is taxonomically complex in high burden settings. This integrated cohort-exposure assessment study leverages natural socioeconomic spectrums of development to study how pathome complexity is influenced by household and neighbourhood infrastructure and hygiene conditions. We are enrolling under 12-month-old children in low-income and middle-income neighbourhoods of two Kenyan cities (Nairobi and Kisumu) into a 'short-cohort' study involving repeat testing of child faeces for enteric pathogens. A mid-study exposure assessment documenting infrastructural, behavioural, spatial, climate, environmental and zoonotic factors characterises pathogen exposure pathways in household and neighbourhood settings. These data will be used to inform and validate statistical and agent-based models (ABM) that identify individual or combined intervention strategies for reducing multipathogen transmission between humans, animals and environment in urban Kenya.

ETHICS AND DISSEMINATION

The protocols for human subjects' research were approved by Institutional Review Boards at the University of Iowa (ID-202004606) and AMREF Health Africa (ID-ESRC P887/2020), and a national permit was obtained from the Kenya National Commission for Science Technology and Innovation (ID# P/21/8441). The study was registered on Clinicaltrials.gov (Identifier: NCT05322655) and is in pre-results stage. Protocols for research on animals were approved by the University of Iowa Animal Care and Use Committee (ID 0042302).

Experimental measurements and numerical simulations of the transport and retention of nanocrystal CdSe/ZnS quantum dots in saturated porous media: Effects of electrolytes, organic ligand, and natural organic matter

This study explores the transport and retention of CdSe/ZnS quantum dot (QD) nanoparticles in water-saturated sand columns as a function of electrolytes (Na+ and Ca2+), ionic strength, organic ligand citrate, and Suwannee River natural organic matter (SRNOM). Numerical simulations were carried out to understand the mechanisms that govern the transport and interactions of QDs in porous media and to assess how environmental parameters impact these mechanisms. An increase in the ionic strength of NaCl and CaCl2 increased QDs retention in porous media. The reduction of the electrostatic interactions screened by dissolved electrolyte ions and the increase of divalent bridging effect are the causes for this enhanced retention behavior. Citrate or SRNOM enhanced QDs transport in NaCl and CaCl2 systems by either increasing the repulsion energy barrier or inducing the steric interactions between QDs and the quartz sand collectors. A non-exponential decay characterized the retention profiles of QDs along the distance to the inlet. The modeling results indicated the four models containing the attachment, detachment, and straining terms - Model 1: M1-attachment, Model 2: M2-attachment and detachment, Model 3: M3-straining, and Model 4: M4-attachment, detachment, and straining - closely simulated the observed breakthrough curves (BTCs) but inadequately described the retention profiles.

Rutin from Begonia roxburghii modulates iNOS and Sep A activity in treatment of Shigella flexneri induced diarrhoea in rats: An in vitro, in vivo and computational analysis

In developing countries, diarrhoea is a major issue of concern, where consistent use of antibiotics has resulted in several side effects along with development of resistance among pathogens against these antibiotics. Since natural products are becoming the treatment of choice, therefore present investigation involves mechanistic evaluation of antidiarrhoeal potential of Begonia roxburghii and its marker rutin against Shigella flexneri (SF) induced diarrhoea in rats following in vitro, in vivo and in silico protocols. The roots of the plant are used as vegetable in the North East India and are also used traditionally in treating diarrhoea. Phytochemically standardized ethanolic extract of B. roxburghii (EBR) roots and its marker rutin were first subjected to in vitro antibacterial evaluation against SF. Diarrhoea was induced in rats using suspension of SF and various diarrhoeagenic parameters were examined after first, third and fifth day of treatment at 100, 200 and 300 mg/kg, p.o. with EBR and 50 mg/kg, p.o. with rutin respectively. Additionally, density of SF in stools, stool water content, haematological and biochemical parameters, cytokine profiling, ion concentration, histopathology and Na+/K+-ATPase activity were also performed. Molecular docking and dynamics simulation studies of ligand rutin was studied against secreted extracellular protein A (Sep A, PDB: 5J44) from SF and Inducible nitric oxide synthase (iNOS, PDB: 1DD7) followed by network pharmacology. EBR and rutin demonstrated a potent antibacterial activity against SF and also showed significant recovery from diarrhoea (EBR: 81.29 ± 0.91% and rutin: 75.27 ± 0.89%) in rats after five days of treatment. EBR and rutin also showed significant decline in SF density in stools, decreased cytokine expression, potential antioxidant activity, cellular proliferative nature and recovered ion loss due to enhanced Na+/K+-ATPase activity, which was also supported by histopathology. Rutin showed a very high docking score of -11.61 and -9.98 kcal/mol against iNOS and Sep A respectively and their stable complex was also confirmed through dynamics, while network pharmacology suggested that, rutin is quite capable of modulating the pathways of iNOS and Sep A. Thus, we may presume that rutin played a key role in the observed antidiarrhoeal activity of B. roxburghii against SF induced diarrhoea.

Associations between early infections and childhood cognition in the Newcastle Thousand Families Study birth cohort

Childhood infections have been shown to stunt growth, contribute to malnutrition and reduce cognition in early adulthood. This study aimed to assess relationships between early life infections and childhood cognition at age 11 years in the Newcastle Thousand Families Study (NTFS). The analysis included 741 members from the NTFS who had complete data for infections between birth and 5 years, and the 11-plus examinations. School records from the 11-plus examinations showed cognitive (IQ), English (EQ) and arithmetic (AQ) abilities. Housing conditions, overcrowding, birth order and social class were recorded at birth. Helicobacter pylori seropositivity was measured at age 49-51 years. Multivariable linear regression was used to examine relationships between infections and cognition. The total number of infections in the first 5 years of life was not significantly associated with IQ, EQ or AQ, nor were there significant relationships between cognitive outcomes and most infections. Tonsillitis did display a positive, significant association with IQ after adjustment for confounders (b = 6.43, 95% CI 0.92, 11.94, p = 0.022). Lower respiratory tract infections (LRTIs) showed significant negative relationships with all cognitive outcomes. H. pylori seropositivity at age 50 exhibited negative, significant relationships with EQ (p = 0.014) and AQ (p = 0.024) after adjustment for confounders. Although no significant relationship between overall infections and cognition were found, there were indications that LRTIs and gastrointestinal system infections may limit cognitive development. Given these infections remain prevalent, further research regarding severity and recurrence of infections and how they affect childhood cognition is needed.

de Souza P, Costa H, Houpt ER, Bessong PO, Mduma E, Lima AAM, Guerrant RL. Early-Life Enteric Pathogen Exposure, Socioeconomic Status, and School-Age Cognitive Outcomes

Early-life experiences of enteric infections and diarrheal illness are common in low-resource settings and are hypothesized to affect child development. However, longer-term associations of enteric infections with school-age cognitive outcomes are difficult to estimate due to lack of long-term studies. The objective of this study was to examine the relationship between enteropathogen exposure in the first 2 years of life with school-age cognitive skills in a cohort of children followed from birth until 6 to 8 years in low-resource settings in Brazil, Tanzania, and South Africa. The study included participants from three sites from the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health Study who were enrolled just after birth and followed for enteric infections, diarrheal illness, and cognitive development until 2 years of age. When the children were school-age, further data were collected on reasoning skills and semantic/phonemic fluency. We estimated associations between the burden of specific enteric pathogens and etiology-specific diarrhea from 0 to 2 years with cognitive test scores at 6 to 8 years using linear regression and adjusting for confounding variables. In this study, children who carried more enteric pathogens in the first 2 years of life showed overall decreases in school-age cognitive abilities, particularly children who carried protozoa, although this was not statistically significant in this sample. Socioeconomic factors such as maternal education and income were more closely associated with school-age cognitive abilities. Early-life enteric pathogens may have a small, lasting influence on school-age cognitive outcomes, although other socioeconomic factors likely contribute more significantly.

Intelligent Biological Networks: Improving Anti-Microbial Resistance Resilience through Nutritional Interventions to Understand Protozoal Gut Infections

Enteric protozoan pathogenic infections significantly contribute to the global burden of gastrointestinal illnesses. Their occurrence is considerable within remote and indigenous communities and regions due to reduced access to clean water and adequate sanitation. The robustness of these pathogens leads to a requirement of harsh treatment methods, such as medicinal drugs or antibiotics. However, in addition to protozoal infection itself, these treatments impact the gut microbiome and create dysbiosis. This often leads to opportunistic pathogen invasion, anti-microbial resistance, or functional gastrointestinal disorders, such as irritable bowel syndrome. Moreover, these impacts do not remain confined to the gut and are reflected across the gut-brain, gut-liver, and gut-lung axes, among others. Therefore, apart from medicinal treatment, nutritional supplementation is also a key aspect of providing recovery from this dysbiosis. Future proteins, prebiotics, probiotics, synbiotics, and food formulations offer a good solution to remedy this dysbiosis. Furthermore, nutritional supplementation also helps to build resilience against opportunistic pathogens and potential future infections and disorders that may arise due to the dysbiosis. Systems biology techniques have shown to be highly effective tools to understand the biochemistry of these processes. Systems biology techniques characterize the fundamental host-pathogen interaction biochemical pathways at various infection and recovery stages. This same mechanism also allows the impact of the abovementioned treatment methods of gut microbiome remediation to be tracked. This manuscript discusses system biology approaches, analytical techniques, and interaction and association networks, to understand (1) infection mechanisms and current global status; (2) cross-organ impacts of dysbiosis, particularly within the gut-liver and gut-lung axes; and (3) nutritional interventions. This study highlights the impact of anti-microbial resistance and multi-drug resistance from the perspective of protozoal infections. It also highlights the role of nutritional interventions to add resilience against the chronic problems caused by these phenomena.

A prospective study on linking diarrheagenic E. coli with stunted childhood growth in relation to gut microbiome

Stunted growth is an emerging global challenge affecting children under the age of 5 years in low- and middle-income countries. Despite such a high global prevalence of stunting, the mechanism of pathogenesis and the role of associated gut microbiota is poorly understood. The present study was designed to investigate the association of pathogenic strains of E. coli with the residential gut microbiota of stunted growth children. A total of 64 stool sample were collected from children aged ≤ 5 years, and were processed for isolation and molecular characterization of diarrheagenic E. coli. Selected stool samples (n = 39 including three normal controls) were then analysed for microbial community profiling using 16S ribosomal RNA (rRNA) gene sequencing. Furthermore, associations between changes in the microbiota in the presence of different E. coli strains was explored. Pathotyping of the isolated E. coli (n = 64) has shown that 39.68% belonged to one of the five pathotypes of E. coli whilst the remaining ones were non-typeable. Amongst the different pathotypes, EPEC was found to be the most prevalent (52%; n = 13), followed by EAEC (20%; n = 5), EIEC (12%; n = 3), EHEC (8%; n = 2) and ETEC 2 (8%; n = 2). Phylogrouping analysis has shown that majority of the strains belonged to B2 (28.12%). Microbial diversity is shown to be significant and varied when the samples are organized under the recovered phylogroups. Moreover, based on predictive metabolism, the colonization of these strains were found to be significantly associated with energy utilization pathways such as Denovoprine-2 and glyoxylate-by. Differential analysis has shown that Escherichia-Shigella and Enterococcus were altered for the children with stunted growth.

Understanding the relationship between WASH and malnutrition: Analysis of anthropometric data of children attending WASH-supported schools in Ogun State, Nigeria

BACKGROUND

There has been a growing interest in better understanding the association between water, sanitation, and hygiene (WASH) and malnutrition.

AIM

We analysed anthropometric data of children attending WASH intervention schools and those from non-intervention schools in Ogun State, Nigeria.

METHODS

A total of 353 children across six schools (three interventions and three non-interventions) participated in this study. WASH conditions were assessed using WHO standardized tools and anthropometric data of children were analysed in WHO AnthroPlus and R Software.

RESULTS

The prevalence of stunting was 26.2% in the intervention group, and 29.4% in the control group (p = 0.045). Underweight was lower in the intervention group (3.9% vs. 10.1%) (p = 0.45). However, wasting was higher in the intervention group (32.3% vs. 8.2%) (p = 0.001). Of the variables included in our multivariate model (age, gender, and school category, i.e. intervention/control and class grade), only age was selected, and negatively associated with underweight, stunting and wasting (p = 0.000).

CONCLUSION

Regardless of WASH programming status, nutritional outcomes were significantly influenced by age of the children. Children are more likely to have lower z-scores as they grow older.

Modulatory Effects of Heat-Inactivated Streptococcus Thermophilus Strain 7 on the Inflammatory Response: A Study on an Animal Model with TLR3-Induced Intestinal Injury

Rotavirus infections result in severe gastroenteritis with a detrimental inflammatory response in the intestine. Because probiotics have an anti-inflammatory effect and can modulate the gut microbiota profile, they can be used as a biotherapy for inflammatory intestinal diseases. In this study, we isolated Streptococcus thermophilus strain 7 (ST7) from cow milk and examined the effect of heat-inactivated ST7 on the intestinal histopathological score, inflammatory cytokine levels, T-cell activation and effector function, and microbiome profile in a mouse model with intestinal injury induced by polyinosinic-polycytidylic acid (poly I:C), a Toll-like receptor 3 agonist. The results indicated that ST7 treatment prevented weight loss and intestinal injury and prevented the upregulation of serum interleukin-6 (IL-6), tumor necrosis factor-α, and IL-15 levels in intestinal epithelial cells; prevented the upregulation of inflammation-associated Gammaproteobacteria and Alistipes; and increased the levels of Firmicutes in fecal microbiota after poly I:C stimulation. ST7 treatment also increased the serum interferon-γ (IFN-γ) level and promoted the expression of IFN-γ in both CD8 and CD4 T cells. In summary, ST7 prevented the inflammatory response, promoted the T-cell effector function, and modulated the microbiota profile of mice with poly I:C-induced small intestine injury.

Neglected gut microbiome: interactions of the non-bacterial gut microbiota with enteric pathogens

A diverse array of commensal microorganisms inhabits the human intestinal tract. The most abundant and most studied members of this microbial community are undoubtedly bacteria. Their important role in gut physiology, defense against pathogens, and immune system education has been well documented over the last decades. However, the gut microbiome is not restricted to bacteria. It encompasses the entire breadth of microbial life: viruses, archaea, fungi, protists, and parasitic worms can also be found in the gut. While less studied than bacteria, their divergent but important roles during health and disease have become increasingly more appreciated. This review focuses on these understudied members of the gut microbiome. We will detail the composition and development of these microbial communities and will specifically highlight their functional interactions with enteric pathogens, such as species of the family Enterobacteriaceae. The interactions can be direct through physical interactions, or indirect through secreted metabolites or modulation of the immune response. We will present general concepts and specific examples of how non-bacterial gut communities modulate bacterial pathogenesis and present an outlook for future gut microbiome research that includes these communities.

In vitro antibacterial activity of OPS-2071 against Gram-positive and Gram-negative enteropathogenic bacteria

BACKGROUND

Enteric infections are a major public health issue in developing countries. Antimicrobial resistance is also a problem for enteric infection. OPS-2071 is a novel quinolone antibiotic with low oral absorption and potent antibacterial activity against Clostridioides difficile.

OBJECTIVES

This study was conducted to confirm the antimicrobial activity of OPS-2071 against major enteropathogenic bacteria and to evaluate the risk of emergence of drug resistance.

METHODS

The antibacterial activity was evaluated by the agar dilution method. The inhibitory activity against DNA gyrase and topoisomerase IV was determined by supercoiling assay and decatenation assay, respectively. The mutant prevention concentration and frequency of spontaneous resistance were determined by inoculation on drug-containing agar.

RESULTS

Compared with the reference drugs, the antibacterial activity of OPS-2071 was more potent against Gram-positive bacteria and Campylobacter jejuni, including quinolone-resistant strains. Against other Gram-negative bacteria, OPS-2071 was comparable to existing quinolones. The inhibitory activities against DNA gyrase with quinolone-resistant mutations closely correlated with the antibacterial activity. Spontaneous resistance to OPS-2071 was not observed in Staphylococcus aureus and Escherichia coli and was lower than that of existing quinolones and higher than that of azithromycin in C. jejuni. The mutant prevention concentration of OPS-2071 was lower than that of tested compounds in S. aureus and C. jejuni and slightly higher than that of existing quinolones in E. coli.

CONCLUSIONS

The broad and potent in vitro antibacterial activity and lower risk of drug resistance suggested that OPS-2071 may be useful for enteric infections caused by major pathogens including quinolone-resistant Campylobacter.

Stunting among children aged 24-59 months and associations with sanitation, enteric infections, and environmental enteric dysfunction in rural northwest Ethiopia

Stunting is a public health issue of global concern. Despite, poor sanitation, diarrhea, parasitic infections, and environmental enteric dysfunction (EED) are associated with stunting, their link is poorly understood and has not been investigated in Ethiopia. This study was conducted to assess the associations of stunting with sanitation, enteric infections, and EED among children aged 24-59 months in rural northwest Ethiopia. A community-based cross-sectional study was conducted among 224 randomly selected children aged 24-59 months in rural areas of the east Dembiya district. We collected information on household food insecurity and dietary diversity using pre-tested questionnaires adopted from the food and nutrition technical assistance (FANTA) project. We used height-for-age-z score (HAZ) to define stunting. We also used the data collected to measure the environmental exposures of children to intestinal parasitic infections and fecal biomarkers of EED. A multivariable binary logistic regression model was used to assess the association of stunting with sanitation, enteric infections, and EED. Of the 224 children, 33% (95% CI 27, 39%) were stunted. Stunting in children was significantly associated with poor dietary intake (AOR 3.0, 95% CI 1.2, 7.3), open defecation practice (AOR 3.0, 95% CI 1.2, 7.9), presence of animal excreta in the living environment (AOR 3.4, 95% CI 1.2, 9.9), E. coli contamination of drinking water (AOR 4.2, 95% CI 1.1, 15.3), diarrheal disease incidence (AOR 3.4, 95% CI 1.5, 7.7), intestinal parasites in children (AOR 3.3, 95% CI 1.3, 8.8), and higher EED disease activity scores (AOR 2.9, 95% CI 1.2, 6.7). One-third of the children in the study area were stunted and this high prevalence of stunting was associated with poor dietary intake, poor hygiene and sanitation conditions, enteric infections, and EED. Thus, stunting can be prevented by improving sanitation and hygienic conditions to prevent repeated enteric infections in children and by promoting dietary diversity of children.

Antimicrobial peptide human β-defensin-2 improves in vitro cellular viability and reduces pro-inflammatory effects induced by enteroinvasive Escherichia coli in Caco-2 cells by inhibiting invasion and virulence factors’ expression

Escherichia coli is one of the commensal species most represented in the intestinal microbiota. However, there are some strains that can acquire new virulence factors that enable them to adapt to new intestinal niches. These include enteroinvasive E. coli (EIEC) that is responsible for the bacillary dysentery that causes severe diarrheal symptoms in both children and adults. Due to the increasing onset of antibiotic resistance phenomena, scientific research is focused on the study of other therapeutic approaches for the treatment of bacterial infections. A promising alternative could be represented by antimicrobial peptides (AMPs), that have received widespread attention due to their broad antimicrobial spectrum and low incidence of bacterial resistance. AMPs modulate the immune defenses of the host and regulate the composition of microbiota and the renewal of the intestinal epithelium. With the aim to investigate an alternative therapeutic approach, especially in the case of antibiotic resistance, in this work we created a line of intestinal epithelial cells able to express high concentrations of AMP human β-defensin-2 (HBD-2) in order to test its ability to interfere with the pathogenicity mechanisms of EIEC. The results showed that HBD-2 is able to significantly reduce the expression of the proinflammatory cytokines by intestinal epithelial cells, the invasiveness ability of EIEC and the expression of invasion-associated genes.

Prolonged diarrhea among under-five children in Bangladesh: Burden and risk factors

Introduction & background

Prolonged (duration >7 to 13 days) diarrhea (ProD) in under-five children is a universal health problem including Bangladesh. Data on epidemiology and associated or risk factors of ProD are limited, particularly in Bangladesh where a high burden of ProD is reported. This study intended to assess the case load of ProD and its associated or risk factors compared to acute diarrhea (AD, duration ≤7 days).

Methods

We analyzed the data collected between 1996–2014 from a hospital-based Diarrheal-Disease-Surveillance-System (DDSS) in the ‘Dhaka Hospital’ of International Centre for Diarrhoeal Diseases, Bangladesh (icddr,b). The DDSS enrolled a 2% systematic sample, regardless of age, sex, and diarrhea severity. The data included information on socio-demographic factors, environmental history, clinical characteristics, nutritional status, and diarrhea-pathogens. After cleaning of data, relevant information of 21,566 under-five children were available who reported with ≤13 days diarrhea (including AD and ProD), and their data were analyzed. Variables found significantly associated with ProD compared to AD in bi-variate analysis were used in logistic regression model after checking the multicollinearity between independent variables.

Results

The mean±SD age of the children was 14.9±11.7 months and 40.4% were female; 7.6% had ProD and 92.4% had AD. Age <12 months, mucoid- or bloody-stool, warmer months (April-September), drug used at home before seeking care from hospital, and history of diarrhea within last one month were found associated with ProD (p<0.05); however, rotavirus infection was less common in children with ProD (p<0.05). ProD children more often needed inpatient admission than AD children (14.4 vs. 6.3, p<0.001). Case fatality rate of ProD vs. AD was 0.3% (n = 5) vs. 0.1% (n- = 22) respectively (p = 0.051).

Conclusion

A considerable proportion (7.6%) of under-five children reporting to icddr,b hospital suffered from ProD. Understanding the above-mentioned associated or risk factors is likely to help policy makers formulating appropriate strategies for alleviating the burden and effectively managing ProD in under-five children.

The Physiological Function and Potential Role of the Ubiquitous Na+/H+ Exchanger Isoform 8 (NHE8): An Overview Data

The Na⁺/H⁺ exchanger transporters (NHE) play an important role in various biologic processes including Na⁺ absorption, intracellular pH homeostasis, cell volume regulation, proliferation, and apoptosis. The wide expression pattern and cellular localization of NHEs make these proteins pivotal players in virtually all human tissues and organs. In addition, recent studies suggest that NHEs may be one of the primeval transport protein forms in the history of life. Among the different isoforms, the most well-characterized NHEs are the Na⁺/H⁺ exchanger isoform 1 (NHE1) and Na⁺/H⁺ exchanger isoform 3 (NHE3). However, Na⁺/H⁺ exchanger isoform 8 (NHE8) has been receiving attention based on its recent discoveries in the gastrointestinal tract. In this review, we will discuss what is known about the physiological function and potential role of NHE8 in the main organ systems, including useful overviews that could inspire new studies on this multifaceted protein.

Mucin O-glycan-microbiota axis orchestrates gut homeostasis in a diarrheal pig model

BACKGROUND

Post-weaning diarrhea in piglets reduces growth performance and increases mortality, thereby causing serious economic losses. The intestinal epithelial cells and microbiota reciprocally regulate each other in order to maintain intestinal homeostasis and control inflammation. However, a relative paucity of research has been focused on the host-derived regulatory network that controls mucin O-glycans and thereby changes gut microbiota during diarrhea in infancy. At the development stage just after birth, the ontogeny of intestinal epithelium, immune system, and gut microbiota appear similar in piglets and human infants. Here, we investigated the changes of mucin O-glycans associated with gut microbiota using a diarrheal post-weaned piglet model.

RESULTS

We found that diarrhea disrupted the colonic mucus layer and caused aberrant mucin O-glycans, including reduced acidic glycans and truncated glycans, leading to an impaired gut microenvironment. Subsequently, the onset of diarrhea, changes in microbiota and bacterial translocation, resulting in compromised epithelial barrier integrity, enhanced susceptibility to inflammation, and mild growth faltering. Furthermore, we found the activation of NLRP3 inflammasome complexes in the diarrheal piglets when compared to the healthy counterparts, triggered the release of proinflammatory cytokines IL-1β and IL-18, and diminished autophagosome formation, specifically the defective conversion of LC3A/B I into LC3A/B II and the accumulation of p62. Additionally, selective blocking of the autophagy pathway by 3-MA led to the reduction in goblet cell-specific gene transcript levels in vitro.

CONCLUSIONS

We observed that diarrheal piglets exhibited colonic microbiota dysbiosis and mucosal barrier dysfunction. Our data demonstrated that diarrhea resulted in the activation of inflammasomes and autophagy restriction along with aberrant mucin O-glycans including reduced acidic glycans and truncated glycans. The results suggested the mucin O-glycans-microbiota axis is likely associated with diarrheal pathogenesis. Our study provides novel insights into the pathophysiology of early-weaning-induced diarrheal disease in piglets and potentially understanding of disease mechanisms of diarrhea for human infants. Understanding the molecular pathology and pathogenesis of diarrhea is a prerequisite for the development of novel and effective therapies. Our data suggest that facilitating O-glycan elongation, modifying the microbiota, and developing specific inhibitors to some key inflammasomes could be the options for therapy of diarrhea including human infants. Video abstract.

Mucosal Immune Profiles Associated with Diarrheal Disease Severity in Shigella- and Enteropathogenic Escherichia coli-Infected Children Enrolled in the Global Enteric Multicenter Study

Enteropathogenic Escherichia coli (EPEC) and Shigella are etiologic agents of diarrhea in children <5 years old living in resource-poor countries. Repeated bouts of infection lead to lifelong morbidity and even death. The goal of this study was to characterize local mucosal immune responses in Shigella- and EPEC-infected children <5 years of age with moderate to severe diarrhea (MSD) enrolled in the Global Enteric Multicenter Study (GEMS). We hypothesized that infection with each of these pathogens would induce distinct gut mucosal immune profiles indicative of disease etiology and severity. To test this hypothesis, innate and adaptive immune markers were measured in stools from children with diarrhea due to EPEC, Shigella, or other organisms and in children who had no diarrhea. Shigella-positive diarrhea evoked robust proinflammatory and T_H1/T_H2 cytokine responses compared to diarrhea caused by EPEC or other organisms, with the exception of interleukin 5 (IL-5), which was associated with EPEC infection. The presence of IL-1β, IL-4, IL-16, and tumor necrosis factor beta (TNF-β) was associated with the absence of dysentery. EPEC-positive diarrhea evoked high levels of IL-1β, vascular endothelial growth factor (VEGF), and IL-10. Granulocyte-macrophage colony-stimulating factor (GM-CSF) had opposing roles in disease severity, being associated with absence of diarrhea in EPEC-infected children and with dysenteric Shigella infection. High levels of antigen-specific antibodies were detected in the controls and children with Shigella without dysentery, which suggests a protective role against severe disease. In summary, this study identified distinct local immune responses associated with two clinically relevant diarrheagenic pathogens, Shigella and EPEC, in children and identified protective immune phenotypes that can inform the development of preventive measures.

Key Food Hygiene Behaviors to Reduce Microbial Contamination of Complementary Foods in Rural Bangladesh

Microbial contamination of complementary foods puts young children at risk of developing intestinal infections and could be reduced by improved handwashing and food hygiene practices. We aimed to identify which promoted food hygiene practices are associated with reduced complementary food contamination in a rural population in Bangladesh. We collected cross-sectional data on reported and observed maternal food hygiene behaviors and measured Escherichia coli counts as an indicator of microbial contamination in complementary food samples from 342 children of women enrolled in the Food and Agricultural Approaches to Reducing Malnutrition trial in Sylhet, Bangladesh. We used multivariable logistic regression to examine associations of food hygiene behaviors with food contamination. Approximately 46% of complementary food samples had detectable levels of E. coli. Handwashing with soap at critical times and fresh preparation of food before feeding were strongly associated with reduced odds of food sample contamination (odds ratio [OR]: 0.8, 95% confidence interval [CI]: 0.6-0.9 and OR: 0.3, 95% CI: 0.1-0.7, respectively); in contrast, there was no or only weak evidence that reheating of stored food, safe food storage, and cleanliness of feeding utensils reduced contamination. Reduction in food contamination could be more than halved only when several food hygiene behaviors were practiced in combination. In conclusion, single food hygiene practices showed limited potential and a combined practice of multiple food hygiene behaviors may be needed to achieve a substantial reduction of complementary food contamination.

Enteric viruses replicate in salivary glands and infect through saliva

Enteric viruses like norovirus, rotavirus and astrovirus have long been accepted as spreading in the population through fecal-oral transmission: viruses are shed into feces from one host and enter the oral cavity of another, bypassing salivary glands (SGs) and reaching the intestines to replicate, be shed in feces and repeat the transmission cycle1. Yet there are viruses (for example, rabies) that infect the SGs2,3, making the oral cavity one site of replication and saliva one conduit of transmission. Here we report that enteric viruses productively and persistently infect SGs, reaching titres comparable to those in the intestines. We demonstrate that enteric viruses get released into the saliva, identifying a second route of viral transmission. This is particularly significant for infected infants, whose saliva directly transmits enteric viruses to their mothers' mammary glands through backflow during suckling. This sidesteps the conventional gut-mammary axis route4 and leads to a rapid surge in maternal milk secretory IgA antibodies5,6. Lastly, we show that SG-derived spheroids7 and cell lines8 can replicate and propagate enteric viruses, generating a scalable and manageable system of production. Collectively, our research uncovers a new transmission route for enteric viruses with implications for therapeutics, diagnostics and importantly sanitation measures to prevent spread through saliva.

Elucidating the Role of Innate and Adaptive Immune Responses in the Pathogenesis of Canine Chronic Inflammatory Enteropathy-A Search for Potential Biomarkers

Simple Summary

Canine chronic inflammatory enteropathy (CIE) is a chronic disease affecting the small or large intestine and, in some cases, the stomach of dogs. This gastrointestinal disorder is common and is characterized by recurrent vomiting, diarrhea, and weight loss in affected dogs. The pathogenesis of IBD is not completely understood. Similar to human IBD, potential disease factors include genetics, environmental exposures, and dysregulation of the microbiota and the immune response. Some important components of the innate and adaptive immune response involved in CIE pathogenesis have been described. However, the immunopathogenesis of the disease has not been fully elucidated. In this review, we summarized the literature associated with the different cell types and molecules involved in the immunopathogenesis of CIE, with the aim of advancing the search for biomarkers with possible diagnostic, prognostic, or therapeutic utility.

Abstract

Canine chronic inflammatory enteropathy (CIE) is one of the most common chronic gastrointestinal diseases affecting dogs worldwide. Genetic and environmental factors, as well as intestinal microbiota and dysregulated host immune responses, participate in this multifactorial disease. Despite advances explaining the immunological and molecular mechanisms involved in CIE development, the exact pathogenesis is still unknown. This review compiles the latest reports and advances that describe the main molecular and cellular mechanisms of both the innate and adaptive immune responses involved in canine CIE pathogenesis. Future studies should focus research on the characterization of the immunopathogenesis of canine CIE in order to advance the establishment of biomarkers and molecular targets of diagnostic, prognostic, or therapeutic utility.

Multidrug-resistant enteric bacteria in Nigeria and potential use of bacteriophages as biocontrol

Enteric bacterial pathogens have been implicated in many cases of gastroenteritis in Nigeria, a West African country. This situation is worsened by some reports of the high prevalence of multidrug-resistant enteric bacteria. To better prepare for situations in which even antibiotics of last resort would fail to treat infections caused by these pathogens, attention should be paid to alternative antimicrobial strategies. Here, we summarize existing reports of multidrug-resistant enteric bacterial infections in Nigeria, and importantly present the use of bacteriophages (viruses of bacteria) as an attractive antimicrobial alternative to combat these pathogens. It is hoped that this review will encourage research into the use of lytic bacteriophages against multidrug-resistant enteric bacteria in Nigeria.

Association between Pathogenic Variants of Diarrheagenic Escherichia coli and Growth in Children under 5 Years of Age in the Global Enteric Multicenter Study

There is a lack of information highlighting associations between different pathogenic variants of diarrheagenic Escherichia coli and childhood growth. Pathogenic variants of E. coli from stool samples, collected from 22,567 children enrolled in the Global Enteric Multicenter Study from December 2007 to March 2011, were detected by real-time polymerase chain reaction. We estimated the associations of different pathogenic variants of diarrheagenic E. coli with child growth. The association between an explanatory variable and the outcome variable was assessed using multiple linear regression, where the dependent variables were height-for-age, weight-for-age, and weight-for-height z-scores, and the independent variable was the presence of different pathogenic variants of diarrheagenic E. coli. After adjusting for potential covariates, such as age, gender, diarrhea, breastfeeding status, mother’s education, number of under-5 children, handwashing practice, handwashing material, source of drinking water, wealth index, available toilet facility, copathogens, comorbidity, time, and study site, the multivariable model identified a negative association between different pathogenic variants of diarrheagenic E. coli and child growth. Our analyses may provide the cornerstone for prospective epidemiologic investigation for the development of preventive measures for diarrheagenic E. coli and combat childhood undernutrition.

Diarrhoeal outcomes in young children depend on diarrhoeal cases of other household members: a cross-sectional study of 16,025 people in rural Uganda

BACKGROUND

There is a limited understanding of how diarrhoeal cases across other household members influence the likelihood of diarrhoea in young children (aged 1-4 years).

METHODS

We surveyed 16,025 individuals from 3421 households in 17 villages in Uganda. Using logistic regressions with standard errors clustered by household, diarrhoeal cases within households were used to predict diarrhoeal outcomes in young children. Regressions were adjusted for socio-demographic, water, sanitation, and hygiene (WASH), and ecological covariates. Selection bias for households with (1632/3421) and without (1789/3421) young children was examined.

RESULTS

Diarrhoeal prevalence was 13.7% (2118/16,025) across all study participants and 18.5% (439/2368) in young children. Young children in households with any other diarrhoeal cases were 5.71 times more likely to have diarrhoea than young children in households without any other diarrhoeal cases (95% CI: 4.48-7.26), increasing to over 29 times more likely when the other diarrhoeal case was in another young child (95% CI: 16.29-54.80). Diarrhoeal cases in older household members (aged ≥ 5 years) and their influence on the likelihood of diarrhoea in young children attenuated with age. School-aged children (5-14 years) had a greater influence on diarrhoeal cases in young children (Odds Ratio 2.70, 95% CI: 2.03-3.56) than adults of reproductive age (15-49 years; Odds Ratio 1.96, 95% CI: 1.47-2.59). Diarrhoeal cases in individuals aged ≥ 50 years were not significantly associated with diarrhoeal outcomes in young children (P > 0.05). These age-related differences in diarrhoeal exposures were not driven by sex. The magnitude and significance of the odds ratios remained similar when odds ratios were compared by sex within each age group. WASH factors did not influence the likelihood of diarrhoea in young children, despite influencing the likelihood of diarrhoea in school-aged children and adults. Households with young children differed from households without young children by diarrhoeal prevalence, household size, and village WASH infrastructure and ecology.

CONCLUSIONS

Other diarrhoeal cases within households strongly influence the likelihood of diarrhoea in young children, and when controlled, removed the influence of WASH factors. Future research on childhood diarrhoea should consider effects of diarrhoeal cases within households and explore pathogen transmission between household members.

Maternal Underweight and Its Association with Composite Index of Anthropometric Failure among Children under Two Years of Age with Diarrhea in Bangladesh

Malnutrition in women has been a long-standing public health concern, with serious effects on child survival and development. Maternal body mass index (BMI) is an important maternal nutritional indicator. There are few published studies although child anthropometric failures do not occur in isolation and identifying children with single versus several co-occurring failures can better capture cases of growth failure in combination: stunting, wasting, and underweight. In the context of multiple anthropometric failures, traditional markers used to assess children's nutritional status tend to underestimate overall undernutrition. Using the composite index of anthropometric failure (CIAF), we aimed to assess the association between maternal undernutrition and child undernutrition among children with diarrhea under the age of two and to investigate the correlates. Using 1431 mother-child dyads from the Antibiotic for Children with Diarrhea (ABCD) trial, we extracted children's data at enrollment and on day 90 and day 180 follow-ups. ABCD was a randomized, multi-country, multi-site, double-blind, placebo-controlled clinical trial. The Bangladesh site collected data from July 2017 to July 2019. The outcome variable, CIAF, allows combinations of height-for-age, height-for-weight, and weight-for-age to determine the overall prevalence of undernutrition. The generalized estimating equation was used to explore the correlates of CIAF. After adjusting all the potential covariates, maternal undernutrition status was found to be strongly associated with child undernutrition using the CIAF [aOR: 1.4 (95% CI: 1.0, 1.9), p-value = 0.043] among the children with diarrhea under 2 years old. Maternal higher education had a protective effect on CIAF [aOR: 0.7 (95% CI: 0.5, 0.9), p-value = 0.033]. Our study findings highlight the importance of an integrated approach focusing on maternal nutrition and maternal education could affect a reduction in child undernutrition based on CIAF.

β-defensin 118 attenuates inflammation and injury of intestinal epithelial cells upon enterotoxigenic Escherichia coli challenge

Background

Antimicrobial peptides including various defensins have been attracting considerable research interest worldwide, as they have potential to substitute for antibiotics. Moreover, AMPs also have immunomodulatory activity. In this study, we explored the role and its potential mechanisms of β-defensin 118 (DEFB118) in alleviating inflammation and injury of IPEC-J2 cells (porcine jejunum epithelial cell line) upon the enterotoxigenic Escherichia coli (ETEC) challenge.

Results

The porcine jejunum epithelial cell line (IPEC-J2) pretreated with or without DEFB118 (25 μg/mL) were challenged by ETEC (1×10⁶ CFU) or culture medium. We showed that DEFB118 pretreatment significantly increased the cell viability (P<0.05) and decreased the expressions of inflammatory cytokines such as the interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in IPEC-J2 cells exposure to ETEC (P<0.05). Interestingly, DEFB118 pretreatment significantly elevated the abundance of the major tight-junction protein zonula occludens-1 (ZO-1), but decreased the number of apoptotic cells upon ETEC challenge (P<0.05). The expression of caspase 3, caspase 8, and caspase 9 were downregulated by DEFB118 in the IPEC-J2 cells exposure to ETEC (P<0.05). Importantly, DEFB118 suppressed two critical inflammation-associated signaling proteins, nuclear factor-kappa-B inhibitor alpha (IκB-α) and nuclear factor-kappaB (NF-κB) in the ETEC-challenged IPEC-J2 cells.

Conclusions

DEFB118 can alleviate ETEC-induced inflammation in IPEC-J2 cells through inhibition of the NF-κB signaling pathway, resulting in reduced secretion of inflammatory cytokines and decreased cell apoptosis. Therefore, DEFB118 can act as a novel anti-inflammatory agent.

Transcriptional Profiling of the Small Intestine and the Colon Reveals Modulation of Gut Infection with Citrobacter rodentium According to the Vitamin A Status

Vitamin A (VA) deficiency and diarrheal diseases are both serious public health issues worldwide. VA deficiency is associated with impaired intestinal barrier function and increased risk of mucosal infection-related mortality. The bioactive form of VA, retinoic acid, is a well-known regulator of mucosal integrity. Using Citrobacter rodentium-infected mice as a model for diarrheal diseases in humans, previous studies showed that VA-deficient (VAD) mice failed to clear C. rodentium as compared to their VA-sufficient (VAS) counterparts. However, the distinct intestinal gene responses that are dependent on the host’s VA status still need to be discovered. The mRNAs extracted from the small intestine (SI) and the colon were sequenced and analyzed on three levels: differential gene expression, enrichment, and co-expression. C. rodentium infection interacted differentially with VA status to alter colon gene expression. Novel functional categories downregulated by this pathogen were identified, highlighted by genes related to the metabolism of VA, vitamin D, and ion transport, including improper upregulation of Cl⁻ secretion and disrupted HCO₃⁻ metabolism. Our results suggest that derangement of micronutrient metabolism and ion transport, together with the compromised immune responses in VAD hosts, may be responsible for the higher mortality to C. rodentium under conditions of inadequate VA.

Epidemiology of Campylobacter infections among children of 0–24 months of age in South Africa

Background

Campylobacter spp. are one of the most frequent causes of diarrhoeal disease in humans throughout the world. This study aimed at determining the prevalence and the genotypic distribution of Campylobacter spp. and their association with diarrhoea and child growth in children of less than the age of two in the Limpopo Province of South Africa.

Methods

A total of 4280 diarrheal and non-diarrheal stool samples were collected on a monthly basis from children recruited at birth and followed up to 24 months. All stool samples were screened for the presence Campylobacter antigen using ELISA technique after which CAH 16S primer was used on the positive samples to confirm the presence of Campylobacter. Subsequently, the PCR positive samples were further characterised using species specific primers for Campylobacter jejuni and Campylobacter coli.

Results

Campylobacter antigen was detected in 564/4280 (13.2%). Campylobacter was more commonly found in diarrheal stools (20.4%) compared to non-diarrheal stools (12.4%) with a statistically significant difference (χ² = 7.345; p = 0.006). Throughout the year there were two main peaks of Campylobacter infection one in December- January and the second peak in June. The prevalence of Campylobacter increased with the age of the children up to 11 months after which the prevalence decreased. Out of 564 positive ELISA samples, 257 (45.6%) were confirmed to have 16S rRNA gene for Campylobacter spp. Furthermore, C. jejuni was found to be more prevalent (232/257) than C. coli (25/257) with a prevalence of 90.3% and 9.7%, respectively. Both C. jejuni and C. coli were significantly associated with diarrhea with statistical values of (χ² = 22.224; p < 0.001) and (χ² = 81.682; p < 0.001) respectively. Sequences generated from the analysis of hip gene confirmed the PCR positives samples were C. jejuni positive.

Conclusions

This study has delineated a high prevalence of Campylobacter spp. in the study cohort. Moreover, C. jejuni was found to be more prevalent than C. coli both of which were associated with diarrhea. These findings are of clinical and epidemiological significance.

Associations between ambient temperature and enteric infections by pathogen: a systematic review and meta-analysis

BACKGROUND

Numerous studies have quantified the associations between ambient temperature and enteric infections, particularly all-cause enteric infections. However, the temperature sensitivity of enteric infections might be pathogen dependent. Here, we sought to identify pathogen-specific associations between ambient temperature and enteric infections.

METHODS

We did a systematic review and meta-analysis by searching PubMed, Web of Science, and Scopus for peer-reviewed research articles published from Jan 1, 2000, to Dec 31, 2019, and also hand searched reference lists of included articles and excluded reviews. We included studies that quantified the effects of ambient temperature increases on common pathogen-specific enteric infections in humans. We excluded studies that expressed ambient temperature as a categorical or diurnal range, or in a standardised format. Two authors screened the search results, one author extracted data from eligible studies, and four authors verified the data. We obtained the overall risks by pooling the relative risks of enteric infection by pathogen for each 1°C temperature rise using random-effects modelling and robust variance estimation for the correlated effect estimates. Between-study heterogeneity was measured using I², τ², and Q-statistic. Publication bias was determined using funnel plot asymmetry and the trim-and-fill method. Differences among pathogen-specific pooled estimates were determined using subgroup analysis of taxa-specific meta-analysis. The study protocol was not registered but followed the PRISMA guidelines.

FINDINGS

We identified 2981 articles via database searches and 57 articles from scanning reference lists of excluded reviews and included articles, of which 40 were eligible for pathogen-specific meta-analyses. The overall increased risks of incidence per 1°C temperature rise, expressed as relative risks, were 1·05 (95% CI 1·04-1·07; I² 97%) for salmonellosis, 1·07 (1·04-1·10; I² 99%) for shigellosis, 1·02 (1·01-1·04; I² 98%) for campylobacteriosis, 1·05 (1·04-1·07; I² 36%) for cholera, 1·04 (1·01-1·07; I² 98%) for Escherichia coli enteritis, and 1·15 (1·07-1·24; I² 0%) for typhoid. Reduced risks per 1°C temperature increase were 0·96 (95% CI 0·90-1·02; I² 97%) for rotaviral enteritis and 0·89 (0·81-0·99; I² 96%) for noroviral enteritis. There was evidence of between-pathogen differences in risk for bacterial infections but not for viral infections.

INTERPRETATION

Temperature sensitivity of enteric infections can vary according to the enteropathogen causing the infection, particularly for bacteria. Thus, we encourage a pathogen-specific health adaptation approach, such as vaccination, given the possibility of increasingly warm temperatures in the future.

FUNDING

Japan Society for the Promotion of Science (Kakenhi) Grant-in-Aid for Scientific Research.

Projecting Temperature-Attributable Mortality and Hospital Admissions due to Enteric Infections in the Philippines

BACKGROUND

Enteric infections cause significant deaths, and global projection studies suggest that mortality from enteric infections will increase in the future with warmer climate. However, a major limitation of these projection studies is the use of risk estimates derived from nonmortality data to project excess enteric infection mortality associated with temperature because of the lack of studies that used actual deaths.

OBJECTIVE

We quantified the associations of daily temperature with both mortality and hospital admissions due to enteric infections in the Philippines. These associations were applied to projections under various climate and population change scenarios.

METHODS

We modeled nonlinear temperature associations of mortality and hospital admissions due to enteric infections in 17 administrative regions of the Philippines using a two-stage time-series approach. First, we quantified nonlinear temperature associations of enteric infections by fitting generalized linear models with distributed lag nonlinear models. Second, we combined regional estimates using a meta-regression model. We projected the excess future enteric infections due to nonoptimal temperatures using regional temperature-enteric infection associations under various combinations of climate change scenarios according to representative concentration pathways (RCPs) and population change scenarios according to shared socioeconomic pathways (SSPs) for 2010-2099.

RESULTS

Regional estimates for mortality and hospital admissions were significantly heterogeneous and had varying shapes in association with temperature. Generally, mortality risks were greater in high temperatures, whereas hospital admission risks were greater in low temperatures. Temperature-attributable excess deaths in 2090-2099 were projected to increase over 2010-2019 by as little as 1.3% [95% empirical confidence intervals (eCI): -3.1%, 6.5%] under a low greenhouse gas emission scenario (RCP 2.6) or as much as 25.5% (95% eCI: -3.5%, 48.2%) under a high greenhouse gas emission scenario (RCP 8.5). A moderate increase was projected for temperature-attributable excess hospital admissions, from 0.02% (95% eCI: -2.0%, 1.9%) under RCP 2.6 to 5.2% (95% eCI: -12.7%, 21.8%) under RCP 8.5 in the same period. High temperature-attributable deaths and hospital admissions due to enteric infections may occur under scenarios with high population growth in 2090-2099.

DISCUSSION

In the Philippines, futures with hotter temperatures and high population growth may lead to a greater increase in temperature-related excess deaths than hospital admissions due to enteric infections. Our results highlight the need to strengthen existing primary health care interventions for diarrhea and support health adaptation policies to help reduce future enteric infections. https://doi.org/10.1289/EHP9324.

Crosstalk Between the Gut Microbiota and Epithelial Cells Under Physiological and Infectious Conditions

The gastrointestinal tract (GIT) is considered the largest immunological organ, with a diverse gut microbiota, that contributes to combatting pathogens and maintaining human health. Under physiological conditions, the crosstalk between gut microbiota and intestinal epithelial cells (IECs) plays a crucial role in GIT homeostasis. Gut microbiota and derived metabolites can compromise gut barrier integrity by activating some signaling pathways in IECs. Conversely, IECs can separate the gut microbiota from the host immune cells to avoid an excessive immune response and regulate the composition of the gut microbiota by providing an alternative energy source and releasing some molecules, such as hormones and mucus. Infections by various pathogens, such as bacteria, viruses, and parasites, can disturb the diversity of the gut microbiota and influence the structure and metabolism of IECs. However, the interaction between gut microbiota and IECs during infection is still not clear. In this review, we will focus on the existing evidence to elucidate the crosstalk between gut microbiota and IECs during infection and discuss some potential therapeutic methods, including probiotics, fecal microbiota transplantation (FMT), and dietary fiber. Understanding the role of crosstalk during infection may help us to establish novel strategies for prevention and treatment in patients with infectious diseases, such as C. difficile infection, HIV, and COVID-19.

Characterization of Escherichia coli from Water and Food Sold on the Streets of Maputo: Molecular Typing, Virulence Genes, and Antibiotic Resistance

The aim of this study was to investigate the pathogenic potential and antibiotic resistance of 59 Escherichia coli isolates from ready-to-eat (RTE) street food (n = 31) and drinking water (n = 28) sold in the city of Maputo, Mozambique. The isolates were characterized by XbaI subtyping analysis via pulsed field gel electrophoresis. Multiplex PCRs were performed targeting five virulence genes (stx, lt, st, astA, and eae) and three groups of antibiotic-resistant genes, namely ß-lactamases (extended-spectrum ß-lactamase and AmpC), tetracycline (tetA, tetB, and tetM) and sulfamethoxazole/trimethoprim (sul1, sul2, and sul3). The stx virulence gene, encoding the Shiga/Vero (VT) toxin produced by the verotoxin-producing E. coli (VTEC), was identified with similar frequency in isolates from food (5/31) and water (6/28). The highest percentages of resistant isolates from food and water were found for ß-lactams imipenem (35.5 and 39.3%, respectively) and ampicillin (39.3 and 46.4%, respectively). Multidrug resistance was observed in 31.3% of the isolates, being higher in E. coli isolates from water (45.5%) compared to RTE street food isolates (19.2%). Virulence genes were detected in 73% of the multidrug-resistant isolates. Concerning antibiotic-resistant genes, ESBL was the most frequent (57.7%) among β-lactamases while tetA was the most frequent (50%) among non-β-lactamases.

Antidiarrheal and Antibacterial Activities of Monterey Cypress Phytochemicals: In Vivo and In Vitro Approach

Monterey cypress (Cupressus macrocarpa) is a decorative plant; however, it possesses various pharmacological activities. Therefore, we explored the phytochemical profile of C. macrocarpa root methanol extract (CRME) for the first time. Moreover, we investigated its antidiarrheal (in vivo), antibacterial, and antibiofilm (in vitro) activities against Salmonella enterica clinical isolates. The LC-ESI-MS/MS analysis of CRME detected the presence of 39 compounds, besides isolation of 2,3,2″,3″-tetrahydro-4'-O-methyl amentoflavone, amentoflavone, and dihydrokaempferol-3-O-α-l-rhamnoside for the first time. Dihydrokaempferol-3-O-α-l-rhamnoside presented the highest antimicrobial activity and the range of values of MICs against S. enterica isolates was from 64 to 256 µg/mL. The antidiarrheal activity of CRME was investigated by induction of diarrhea using castor oil, and exhibited a significant reduction in diarrhea and defecation frequency at all doses, enteropooling (at 400 mg/kg), and gastrointestinal motility (at 200, 400 mg/kg) in mice. The antidiarrheal index of CRME increased in a dose-dependent manner. The effect of CRME on various membrane characters of S. enterica was studied after typing the isolates by ERIC-PCR. Its impact on efflux and its antibiofilm activity were inspected. The biofilm morphology was observed using light and scanning electron microscopes. The effect on efflux activity and biofilm formation was further elucidated using qRT-PCR. A significant increase in inner and outer membrane permeability and a significant decrease in integrity and depolarization (using flow cytometry) were detected with variable percentages. Furthermore, a significant reduction in efflux and biofilm formation was observed. Therefore, CRME could be a promising source for treatment of gastrointestinal tract diseases.

Bacteroides Microbial Source Tracking Markers Perform Poorly in Predicting Enterobacteriaceae and Enteric Pathogen Contamination of Cow Milk Products and Milk-Containing Infant Food

Consumption of microbiologically contaminated food is one of the leading causes of diarrheal diseases. Understanding the source of enteric pathogens in food is important to guide effective interventions. Enterobacteriaceae bacterial assays typically used to assess food safety do not shed light on the source. Source-specific Bacteroides microbial source tracking (MST) markers have been proposed as alternative indicators for water fecal contamination assessment but have not been evaluated as an alternative fecal indicator in animal-derived foods. This study tested various milk products collected from vendors in urban Kenyan communities and infant foods made with the milk (n = 394 pairs) using conventional culture methods and TaqMan qPCR for enteric pathogens and human and bovine-sourced MST markers. Detection profiles of various enteric pathogens and Bacteroides MST markers in milk products differed from that of milk-containing infant foods. MST markers were more frequently detected in infant food prepared by caregivers, indicating recent contamination events were more likely to occur during food preparation at home. However, Bacteroides MST markers had lower sensitivity in detecting enteric pathogens in food than traditional Enterobacteriaceae indicators. Bacteroides MST markers tested in this study were not associated with the detection of culturable Salmonella enterica and Shigella sonnei in milk products or milk-containing infant food. The findings show that while Bacteroides MST markers could provide valuable information about how foods become contaminated, they may not be suitable for predicting the origin of the enteric pathogen contamination sources.

Water, sanitation and hygiene interventions and the prevention and treatment of childhood acute malnutrition: A systematic review

Undernutrition is more prevalent among children living in unsanitary environments with inadequate water, sanitation and hygiene (WASH). Despite good evidence for the effect of WASH on multiple infectious diseases, evidence for the effect of WASH interventions on childhood undernutrition is less well established, particularly for acute malnutrition. To assess the effectiveness of WASH interventions in preventing and treating acute childhood malnutrition, we performed electronic searches to identify relevant studies published between 1 January 2000 and 13 May 2019. We included studies assessing the effect of WASH on prevention and treatment of acute malnutrition in children under 5 years of age. Data were extracted by two independent reviewers. We included 26 articles of 599 identified references with a total of 43,083 participants. Twenty-five studies reported on the effect of WASH on prevention, and two studies reported its effect on treatment of acute malnutrition. Current evidence does not show consistent associations of WASH conditions and interventions with prevention of acute malnutrition or with the improvement of its treatment outcomes. Only two high-quality randomized controlled trials (RCTs) demonstrated that improved water quality during severe acute malnutrition treatment improved recovery outcomes but did not prevent relapse. Many of the interventions consisted of a package of WASH services, making impossible to attribute the effect to one specific component. This highlights the need for high-quality, rigorous intervention studies assessing the effects of WASH interventions specifically designed to prevent acute malnutrition or improve its treatment.

Independent and joint contribution of inappropriate complementary feeding and poor water, sanitation and hygiene (WASH) practices to stunted child growth

The causes of undernutrition are often linked to inappropriate complementary feeding practices and poor households' access to water, sanitation and hygiene (WASH), but limited evidence exists on the combined effect of poor WASH and inappropriate complementary feeding practices on stunted child growth. We assessed the independent and joint contribution of inappropriate complementary feeding and poor WASH practices to stunted growth among children aged 6-23 months in the Jirapa Municipality of Ghana. A community-based cross-sectional analytical study design was used with a sample of 301 mothers/caregivers having children aged 6-23 months. The results indicate that in a multivariable logistic regression model that adjusted for confounders, children receiving both unimproved water and inappropriate complementary feeding had a higher and significant odd of becoming stunted (adjusted odds ratio = 33. 92; 95 % confidence interval 3⋅04, 37⋅17; P = 0⋅004) compared to households having both improved water sources and appropriate complementary feeding practices. Except for unimproved drinking water sources, poor sanitation and hygiene, which comprised the use of unimproved household toilet facilities, washing hands without soap and improper disposal of child faeces were not associated with the risks of stunting among children aged 6-23 months. The combined effect of unimproved water and inappropriate complementary feeding on stunting was greater than either unimproved water only or inappropriate complementary feeding only.

Site specific incidence rate of virulence related genes of enteroaggregative Escherichia coli and association with enteric inflammation and growth in children

There is a lack of information highlighting the possible association between strain carrying genes of enteroaggregative Escherichia coli (EAEC) and environmental enteric dysfunction (EED) and on linear growth during childhood. Strain carrying genes of EAEC from stool samples collected from 1705 children enrolled in the MAL-ED birth cohort were detected by TaqMan Array Cards. We measured site-specific incidence rate by using Poisson regression models, identified the risk factors and estimated the associations of strain carrying genes of EAEC with the composite EED score and linear growth at 24 months of age. Overall highest incidence rate (43.3%) was found among children having infection with the aggR gene, which was the greatest in Tanzania (56.7%). Low maternal education, lack of improved floor, and ownership of domestic cattle were found to be risk factors for EAEC infection. In the multivariate models, after adjusting the potential covariates, strain carrying genes of EAEC showed strong positive associations with the EED scores and with poor linear growth at 24 months of age. Our analyses may lay the cornerstone for a prospective epidemiologic investigation for a potential vaccine development aimed at reducing the burden of EAEC infections and combat childhood malnutrition.