Fecal Colonization With Multidrug-Resistant E. coli Among Healthy Infants in Rural Bangladesh

Third generation cephalosporins (3GC) are one of the main choices for treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria. Due to their overuse, an increasing trend of resistance to 3GC has been observed in developing countries. Here, we describe fecal colonization of 3GC-resistant (3GCr) Escherichia coli in healthy infants (1–12 months old) living in rural areas of Bangladesh. We found that stool samples of 82% of infants (n = 100) were positive for 3GCr E. coli with a mean ± standard deviation of 6.21 ± 1.32 log10 CFU/g wet weight of stool. 3GCr E. coli encompasses an average one third (33%) of the total E. coli of stool. Almost 77% (n = 63) of these 3GCr E. coli were MDR (or resistant to ≥3 classes of antibiotics). Around 90% (n = 74) of 3GCr E. coli were extended spectrum beta-lactamase (ESBL)-producing in which blaCTX–M–group–1 was the predominant (96%, n = 71) ESBL-gene followed by blaTEM (41%, n = 30) and blaOXA–1 (11%, n = 8). A significant proportion (26.5%, n = 22) of 3GCr E. coli was pathogenic, comprising two types, enteroaggregative (EAEC, n = 19) and enteropathogenic (EPEC, n = 3). Colonization of 3GCr E. coli in infant guts was not associated with demographic characteristics such as age, sex, mode of delivery, maternal and infant antibiotic use, disease morbidity, and feeding practices. The high rate of colonization of 3GCr E. coli in infants’ guts is a serious public health concern which needs immediate attention and warrants further studies to explore the cause

Enteric Pathogens in Stored Drinking Water and on Caregiver's Hands in Tanzanian Households with and without Reported Cases of Child Diarrhea.

Diarrhea is one of the leading causes of mortality in young children. Diarrheal pathogens are transmitted via the fecal-oral route, and for children the majority of this transmission is thought to occur within the home. However, very few studies have documented enteric pathogens within households of low-income countries. The presence of molecular markers for three enteric viruses (enterovirus, adenovirus, and rotavirus), seven Escherichia coli virulence genes (ECVG), and human-specific Bacteroidales was assessed in hand rinses and household stored drinking water in Bagamoyo, Tanzania. Using a matched case-control study design, we examined the relationship between contamination of hands and water with these markers and child diarrhea. We found that the presence of ECVG in household stored water was associated with a significant decrease in the odds of a child within the home having diarrhea (OR = 0.51; 95% confidence interval 0.27-0.93). We also evaluated water management and hygiene behaviors. Recent hand contact with water or food was positively associated with detection of enteric pathogen markers on hands, as was relatively lower volumes of water reportedly used for daily hand washing. Enteropathogen markers in stored drinking water were more likely found among households in which the markers were also detected on hands, as well as in households with unimproved water supply and sanitation infrastructure. The prevalence of enteric pathogen genes and the human-specific Bacteroidales fecal marker in stored water and on hands suggests extensive environmental contamination within homes both with and without reported child diarrhea. Better stored water quality among households with diarrhea indicates caregivers with sick children may be more likely to ensure safe drinking water in the home. Interventions to increase the quantity of water available for hand washing, and to improve food hygiene, may reduce exposure to enteric pathogens in the domestic environment

Hand-to-Mouth Contacts Result in Greater Ingestion of Feces than Dietary Water Consumption in Tanzania: A Quantitative Fecal Exposure Assessment Model

Diarrheal diseases kill 1800 children under the age of five die each day, and nearly half of these deaths occur in sub-Saharan Africa. Contaminated drinking water and hands are two important environmental transmission routes of diarrhea-causing pathogens to young children in low-income countries. The objective of this research is to evaluate the relative contribution of these two major exposure pathways in a low-income country setting. A Monte Carlo simulation was used to model the amount of human feces ingested by children under five years old from exposure via hand-to-mouth contacts and stored drinking water ingestion in Bagamoyo, Tanzania. Child specific exposure data were obtained from the USEPA 2011 Exposure Factors Handbook, and fecal contamination was estimated using hand rinse and stored water fecal indicator bacteria concentrations from over 1200 Tanzanian households. The model outcome is a distribution of a child’s daily dose of feces via each exposure route. The model results show that Tanzanian children ingest a significantly greater amount of feces each day from hand-to-mouth contacts than from drinking water, which may help elucidate why interventions focused on water without also addressing hygiene often see little to no effect on reported incidence of diarrhea

Hands and Water as Vectors of Diarrheal Pathogens in Bagamoyo, Tanzania

Diarrheal disease is a leading cause of under-five childhood mortality worldwide, with at least half of these deaths occurring in sub-Saharan Africa. Transmission of diarrheal pathogens occurs through several exposure routes including drinking water and hands, but the relative importance of each route is not well understood. Using molecular methods, this study examines the relative importance of different exposure routes by measuring enteric bacteria (pathogenic <i>Escherichia coli</i>) and viruses (rotavirus, enterovirus, adenovirus) in hand rinses, stored water, and source waters in Bagamoyo, Tanzania. Viruses were most frequently found on hands, suggesting that hands are important vectors for viral illness. The occurrence of <i>E. coli</i> virulence genes (ECVG) was equivalent across all sample types, indicating that both water and hands are important for bacterial pathogen transmission. Fecal indicator bacteria and turbidity were good predictors of ECVG, whereas turbidity and human-specific <i>Bacteroidales</i> were good predictors of viruses. ECVG were more likely found in unimproved water sources, but both ECVG and viral genes were detected in improved water sources. ECVG were more likely found in stored water of households with unimproved sanitation facilities. The results provide insights into the distribution of pathogens in Tanzanian households and offer evidence that hand-washing and improved water management practices could alleviate viral and bacterial diarrhea

Prevalence of <i>E. coli</i> virulence genes (ECVG), enteric virus genes, human-specific <i>Bacteroidales</i> genes, and FIB detected in household stored drinking water and hand rinse samples of respondents with at least one child younger than five years old that were either sick with diarrhea (cases) versus matched healthy children under five years of age (controls).

<p>The study consisted of 112 unique case households (containing 113 case children) and 111 unique households with only healthy children (containing 113 matched, control children).</p><p>^a At least one of the seven pathogenic <i>E. coli</i> virulence genes (ECVG) measured present.</p><p>^b At least one of the three enteric viruses measured (rotavirus, adenovirus, enterovirus) present.</p><p>^c CI, confidence interval.</p><p>Presence/Absence of CFU per 2 hands; Presence/Absence or within specified range of CFU/100 mL stored drinking water with 0 CFU/100 mL as the reference group.</p><p>Indicates a median unbiased estimate.</p><p>Statistically significant (p≤0.05).</p

Binary logistic regression model of <i>E. coli</i> virulence genes (ECVG), enteric virus genes, and human-specific <i>Bacteroidales</i> genes presence in hand rinse samples as a function of hygiene behaviors.

<p>^a Ln-transformed.</p><p>^b Binary variables with values of 0 and 1.</p><p>^c Refers to the reported activity prior to the respondent having their hand rinse sample taken.</p><p>^d TZS Tanzanian Shillings.</p><p>N <306 because sample was lost or survey response not collected.</p><p>Statistically significant (p≤0.05).</p

Binary logistic regression model of <i>E. coli</i> virulence genes (ECVG), enteric virus genes, and human-specific <i>Bacteroidales</i> gene presence in household stored water as a function of water management behaviors.

<p>^a Ln-transformed.</p><p>^b Binary variables with values of 0 and 1.</p><p>^c Boiling, chlorinating, filtering, or SODIS (versus no treatment including settling).</p><p>^d Cup, mug, or bowl (versus pouring, long handled dipper, or spigot).</p><p>^e Borewell, rainwater, or tap (versus shallow well, cart/tanker, surface water, or vendor).</p><p>^f TZS Tanzanian Shillings.</p><p>N <306 because sample was lost or survey response not collected.</p><p>Statistically significant (p≤0.05).</p

Solar Inactivation of Enterococci and <i>Escherichia coli</i> in Natural Waters: Effects of Water Absorbance and Depth

The decay of sewage-sourced <i>Escherichia coli</i> and enterococci was measured at multiple depths in a freshwater marsh, a brackish water lagoon, and a marine site, all located in California. The marine site had very clear water, while the waters from the marsh and lagoon contained colored dissolved organic matter that not only blocked light but also produced reactive oxygen species. First order decay rate constants of both enterococci and <i>E. coli</i> were between 1 and 2 d^–1 under low light conditions and as high as 6 d^–1 under high light conditions. First order decay rate constants were well correlated to the daily average UVB light intensity corrected for light screening incorporating water absorbance and depth, suggesting endogenous photoinactivation is a major pathway for bacterial decay. Additional laboratory experiments demonstrated the presence of colored dissolved organic matter in marsh water enhanced photoinactivation of a laboratory strain of <i>Enterococcus faecalis</i>, but depressed photoinactivation of sewage-sourced enterococci and <i>E. coli</i> after correcting for UVB light screening, suggesting that although the exogenous indirect photoinactivation mechanism may be active against <i>Ent. faecalis,</i> it is not for the sewage-source organisms. A simple linear regression model based on UVB light intensity appears to be a useful tool for predicting inactivation rate constants in natural waters of any depth and absorbance