Eau et développement

Antibiotic resistance is a leading cause of hospitalization and death worldwide. Heavy metals such as arsenic have been shown to drive co-selection of antibiotic resistance, suggesting arsenic-contaminated drinking water is a risk factor for antibiotic resistance carriage. This study aimed to determine the prevalence and abundance of antibiotic-resistant Escherichia coli (AR-Ec) among people and drinking water in high (Hajiganj, >100 μg/L) and low arsenic-contaminated (Matlab, <20 μg/L) areas in Bangladesh. Drinking water and stool from mothers and their children (<1 year) were collected from 50 households per area. AR-Ec was detected via selective culture plating and isolates were tested for antibiotic resistance, arsenic resistance, and diarrheagenic genes by PCR. Whole-genome sequencing (WGS) analysis was done for 30 E. coli isolates from 10 households. Prevalence of AR-Ec was significantly higher in water in Hajiganj (48%) compared to water in Matlab (22%, p <0.05) and among children in Hajiganj (94%) compared to children in Matlab (76%, p <0.05), but not among mothers. A significantly higher proportion of E. coli isolates from Hajiganj were multidrug-resistant (83%) compared to isolates from Matlab (71%, p <0.05). Co-resistance to arsenic and multiple antibiotics (MAR index >0.2) was observed in a higher proportion of water (78%) and child stool (100%) isolates in Hajiganj than in water (57%) and children (89%) in Matlab (p <0.05). The odds of arsenic-resistant bacteria being resistant to third-generation cephalosporin antibiotics were higher compared to arsenic-sensitive bacteria (odds ratios, OR 1.2–7.0, p <0.01). WGS-based phylogenetic analysis of E. coli isolates did not reveal any clustering based on arsenic exposure and no significant difference in resistome was found among the isolates between the two areas. The positive association detected between arsenic exposure and antibiotic resistance carriage among children in arsenic-affected areas in Bangladesh is an important public health concern that warrants redoubling efforts to reduce arsenic exposure.

The larvae of the black soldier fly (BSFL, Hermetia illucens) efficiently close resource cycles. Next to the nutrient-rich insect biomass used as animal feed, the residues from the process are promising plant fertilizers. Besides a high nutrient content, the residues contain a diverse microbial community and application to soil can potentially promote soil fertility and agricultural production through the introduction of beneficial microbes. This research assessed the application of the residues on plant-associated bacterial and fungal communities in the rhizosphere of a grass-clover mix in a 42-day greenhouse pot study. Potted soil was amended with BSFL residues (BR+) or conventional compost (CC+) produced by Rwandan waste management companies in parallel to residues and compost sterilized (BR-, CC-) by high-energy electron beam (HEEB) as abiotic controls. The fertilizers were applied at a rate of 150  kg N  ha⁻¹. Soil bacterial and fungal communities in both fertilizer and soil were assessed by high-throughput sequencing of ribosomal markers at different times after fertilizer application. Additionally, indicators for soil fertility such as basal respiration, plant yield and soil physicochemical properties were analyzed. Results showed that the application of BSFL residues influenced the soil microbial communities, and especially fungi, stronger than CC fertilizers. These effects on the microbial community structure could partly be attributed to a potential introduction of microbes to the soil by BSFL residues (e.g., members of genus Bacillus) since untreated and sterilized BSFL residues promoted different microbial communities. With respect to the abiotic effects, we emphasize a potential driving role of particular classes of organic matter like fiber and chitin. Indeed, especially taxa associated with decomposition of organic matter (e.g., members of the fungal genus Mortierella) were promoted by the application of BSFL residues. Soil fertility with respect to plant yield (+17% increase compared to unamended control) and basal respiration (+16% increase compared to unamended control) tended to be improved with the addition of BSFL residues. Findings underline the versatile opportunities for soil fertility arising from the application of BSFL residues in plant production and point to further research on quantification of the described effects.

Background The COVID-19 pandemic drew hygiene to the center of disease prevention. The provision of adequate water, sanitation, and hygiene (WASH) services is crucial to protect public health during a pandemic. Yet, access to levels of water supply that support adequate hygiene measures are deficient in many areas in Nepal. We examined WASH practices and their impact on child health and nutritional status in two districts before and during the COVID-19 pandemic.
Methods A longitudinal and mixed method study was conducted in March-May 2018 and November–December 2021. In total, 715 children aged 0-10 years were surveyed at baseline. Of these, 490 children were assessed at endline. Data collection methods included observations, a questionnaire, stool analysis, anthropometric measurements, water quality analysis, and an assessment of clinical signs of nutritional deficiencies. We conducted 10 in-depth interviews to understand major problems related to COVID-19.
Results Most respondents (94.2%) had heard about COVID-19; however, they did not wear face masks or comply with any social distancing protocols. Almost 94.2% of the households self-reported handwashing with soap 5-10 times per day at endline, especially after defecation, compared to 19.6% at baseline. Water quality was better at endline than at baseline with median 12 to 29 CFU Escherichia coli/100 mL (interquartile range at baseline [IQR] = 4-101) at the point of collection and 34 to 51.5 CFU Escherichia coli/100 mL (IQR = 8–194) at the point of consumption. Fever (41.1-16.8%; p = 0.01), respiratory illness (14.3-4.3%; p = 0.002), diarrhea (19.6–9.5%; p = 0.01), and Giardia lamblia infections (34.2-6.5%, p = 0.01) decreased at endline. In contrast, nutritional deficiencies such as bitot’s spots (26.7-40.2%; p = 0.01), pale conjunctiva (47.0-63.3%; p = 0.01), and dermatitis (64.8-81.4%; p = 0.01) increased at endline. The inadequacy of the harvest and the lack of household income to meet households' nutritional needs increased drastically (35.0-94.2%; p = 0.01).
Conclusion We found that improved water quality and handwashing practices were associated with a decrease in infectious diseases. However, food security also decreased resulting in a high prevalence of nutritional deficiencies. Our findings underline that disaster preparedness should consider access to adequate WASH, nutrition, and health supplies.