Site specific incidence rate of genomic subtypes of enteropathogenic Escherichia coli and association with enteric inflammation and child growth

Molecular identification and antimicrobial resistance profiling of pathogenic E. coli isolates from smallholder livestock households in Central Ethiopia

Escherichia coli of different pathotypes are frequently involved in morbidity and mortality in animals and humans. The study aimed to identify E. coli pathotypes and determine antimicrobial resistance (AMR) profiles in Ethiopian smallholder livestock households. The pathotyping included 198 E. coli isolates identified from human and environmental samples collected from 98 households. AMR profiling was conducted on selected E. coli pathotypes from 89 households, along with known isolates from calf samples obtained from the same households. Morphological and biochemical tests were used to identify presumptive E. coli isolates. DNA was extracted and then singleplex PCR was used to amplify virulence genes. A disc diffusion test was applied for AMR profilings in E. coli pathotypes. Data were evaluated using chi-square tests and logistic regression. Calf (79.8 %) and human (73.7 %) samples were more likely to contain pathotypes (OR 3.2; 95 % CI: 1.7, 5.9; p=0.001 and OR 2.3; 95 % CI: 1.2, 4.1; p=0.008, respectively) than the environmental samples (55.6 %). ETEC (32.3 %) and STEC (15.2 %) were the most common pathotypes detected in the study samples. Out of the 176 isolates selected for AMR profiling, 85 % were resistant to at least one drug and 36 % were multi-drug resistant (MDR). The MDR isolates were found in 44 households, with 11 sharing identical pathotypes and resistance profiles among the different samples. Thus, E. coli strains were likely circulated among humans, animals, and the environment. This in turn calls for a One-health approach to improve antimicrobial usage standards and promote proper waste disposal practices.

Impact of water, sanitation, and hygiene indicators on enteric viral pathogens among under-5 children in low resource settings

Poor water, sanitation, and hygiene (WASH) are the primary risks of exposure to enteric viral infection. Our study aimed to describe the role of WASH conditions and practices as risk factors for enteric viral infections in children under 5. Literature on the risk factors associated with all-cause diarrhea masks the taxa-specific drivers of diarrhea from specific pathogens, limiting the application of relevant control strategies. We analyzed data from children enrolled in the Global Enteric Multicenter Study (GEMS) across seven study sites between December 2007 and March 2011 as cases (moderate-to-severe diarrhea: MSD) and asymptomatic controls. MSD was defined as new and acute diarrhea, with at least one of the following criteria for MSD: dehydration based on the study clinician's assessment, dysentery, or hospitalization with diarrhea or dysentery. Multiple logistic regression was used to examine the role of water quality, sanitation access, and hygiene facilities on the enteric viral pathogens adjusted for potential covariates. Among MSD symptomatic children (cases), longer water retrieval time (≥15 vs <15 min) was associated with increased Norovirus (aOR 1.33, 95 % CI 1.08-1.64) and Astrovirus (aOR 1.43, 95 % CI 1.01-2.02); scooping as drinking water retrieval method was associated with lower Rotavirus (aOR 0.77, 95 % CI 0.62-0.96), but higher Adenovirus (aOR 2.3, 95 % CI 1.32-4.11) infection compared to non-users. Among asymptomatic children (controls), consumption of non-tube well drinking water was associated with higher Norovirus infection (aOR 1.38, 95 % CI 1.01-1.89). Longer drinking water retrieval time (≥15 vs <15 min) increased Norovirus (aOR 1.47, 95 % CI 1.21-1.78) and Rotavirus (aOR 1.51, 95 % CI 1.20-1.89) infections. Pouring (aOR 0.51, 95 % CI 0.32-0.83) or scooping drinking water with a cup (aOR: 0.52; 95 % CI: 0.32, 0.86) lower Astrovirus infection; restricted water access (aOR 1.57, 95 % CI 1.21-2.02) higher Rotavirus infection. Handwashing before cooking was associated with lower Astrovirus (aOR 0.64, 95 % CI 0.47-0.88) infection in asymptomatic children. Our analysis did not find a significant effect of poor sanitation on different enteric viral pathogens examined. Norovirus and Astrovirus were detected more commonly in sub-Saharan Africa while Rotavirus was less prevalent than South Asia. Though we found statistically significant associations, we did not observe any overall pattern between WASH and enteric viral pathogens. Our findings provide insights to guide further research on targeted interventions for enteric viral pathogens, responsible for a major burden of pediatric diarrhea globally.

Designing of immunodiagnostic assay using polyclonal antibodies for detection of Enteropathogenic Escherichia coli strains

Enteropathogenic Escherichia coli (EPEC) is a significant bacterial pathogen that causes infantile diarrhea, particularly in low- and middle-income countries. The lack of a reliable diagnostic method greatly contributes to the increased occurrence and severity of the disease. This study aimed at developing of a cost-effective, rapid, and efficient immunodiagnostic assay for detecting EPEC infection. Lipopolysaccharide (LPS) was extracted from overnight EPEC cultures and combined with alum adjuvant, and then injected into mice for three rounds of immunizations. Subsequently, sera were collected after each immunization and utilized in agglutination assays conducted on glass slides. Both the LPS and colonies of the EPEC isolate used for LPS preparation were employed in these agglutination assays. To evaluate the assay's performance, a total of 34 bacteria, which comprise pathogenic, non-diarrheic E. coli and non-E. coli pathogenic bacteria were used. The developed assay detected EPEC, which yielded positive reactions within 6 minutes on average for both purified LPS and bacterial isolates. The assay exhibited 100% sensitivity and a 95.83% specificity for the detection of EPEC local isolates. Moreover, the assay also detected a low number of bacteria forming units (104X 104 CFU/ml) in spiked fecal samples. This study conclusively confirms that the developed immunodiagnostic assay possesses multiple favorable characteristics, including user-friendliness, high sensitivity, high specificity, cost-effectiveness, and time-efficiency. Hence, this assay can be used as ideal diagnostic assay, which is highly suitable for the detection and screening of EPEC infection in both humans and cattle in one health perspective of resource-limited laboratories.

Gut biomolecules (I-FABP, TFF3 and lipocalin-2) are associated with linear growth and biomarkers of environmental enteric dysfunction (EED) in Bangladeshi children

In the current world, a major challenge to diagnose environmental enteric dysfunction (EED) is the lack of validated non-invasive biomarkers. Intestine derived molecules, including intestinal fatty acid binding protein (I-FABP), trefoil factor-3 (TFF3), lactoferrin, lipocalin-2 (LCN2), and mucin-2, have been reported as indicators of intestinal inflammation and gut health. Therefore, we aimed to investigate the levels of these bio-molecules as biomarkers of EED among under-2 children in Bangladesh. A total of 140 children were recruited in a case-control design. All the biomarkers were measured by ELISA. Spearman's rank correlation was performed to see the correlation between the biomarkers and the EED score. Moreover, multivariable linear regression was performed to investigate the association of biomarkers with length-for-age z-score (LAZ). TFF3 correlates positively with myeloperoxidase (r = 0.26, p < 0.05) and EED score (r = 0.17, p < 0.05). Likewise, LCN2 correlates positively with myeloperoxidase (r = 0.37, p < 0.05), neopterin (r = 0.33, p < 0.05) and EED score (r = 0.31, p < 0.05). Moreover, multivariable linear regression revealed a negative association of I-FABP with LAZ of the study participants. Our results imply that TFF3 and LCN2 might be promising biomarkers to diagnose intestinal inflammation and EED, while I-FABP is negatively associated with linear growth of Bangladeshi children.