Epidemiology and genetic screening of diarrheagenic Escherichia coli among symptomatic and asymptomatic children

Donor screening for fecal microbiota transplantation with a direct stool testing-based strategy: a prospective cohort study

Fecal microbiota transplantation (FMT) is effective against recurrent Clostridioides difficile infection (rCDI), but its safety is jeopardized by the potential transmission of pathogens, so international guidelines recommend either a quarantine or a direct stool testing. Whereas reports of the quarantine-based approach are emerging, data on the direct testing-based approach are not available. Our aim is to report outcomes of a donor screening framework for FMT including direct stool testing. In this prospective cohort study, all donor candidates recruited at our FMT centre underwent a four-step screening process to be enrolled as actual donors. Each collected stool donation was then evaluated with a direct stool testing including a molecular assay for gut pathogens and a culture assay for multi-drug resistant organisms (MDRO). From January 2019 to June 2023, 72 of 227 candidates (32%) were considered eligible and provided 277 stool donations. Ninety-nine donations (36%) were discarded for positivity to intestinal pathogens, most commonly enteropathogenic Escherichia coli (n = 37) and Blastocystis hominis (n = 20). Overall, 337 stool aliquots were obtained from 165 approved donations. All suspensions were used for patients with rCDI, and no serious adverse events or clinically evident infections were observed at 12 weeks after procedures. In our study, screening of donor faeces including direct stool testing led to the discard of a considerable rate of stool donations but was also extremely safe. This approach may represent a reliable strategy to guarantee the safety of FMT programs, especially in countries with high prevalence of MDRO.

Analysis on Foodborne Pathogen Contamination of Food Samples in Longnan City from 2013 to 2022

The objective was to determine the prevalence of foodborne pathogens in food in Longnan City, Gansu Province, China. In this research, we conducted tests on baked foods, catering foods, meat, and fruits and vegetables sold in supermarkets, farmers' markets, restaurants, retail stores, street stalls, and school canteens from 2013 to 2022. We analyzed the variety of foodborne pathogens (Salmonella, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and diarrheagenic Escherichia coli) in different sites and food types. Once foodborne pathogens were detected in the sample, it was deemed unqualified. The total detection rates of foodborne pathogens were 1.559%, 3.349%, 1.980%, 1.040%, 3.383%, and 1.303% in food from supermarkets, farmers' markets, restaurants, retail stores, street stalls, and school canteens, respectively. No pathogenic bacteria were detected in baked foods. Salmonella, S. aureus, L. monocytogenes, B. cereus, and diarrheagenic E. coli were detected in catering foods, among which B. cereus had the highest detection rate. Salmonella was the most common pathogenic bacteria detected in meat, while the detection rate of pathogenic bacteria in fruits and vegetables was low, with only one positive sample for diarrheagenic E. coli. Among the six sites, street stalls (3.382%) and farmers' markets (3.349%) had higher detection rates of pathogens. In general, the detection rate of pathogens from 2013 to 2022 was not high, but there were also some hidden dangers. Catering food is vulnerable to pathogen contamination, and street stalls and farmers' markets are the main sites of pollution. According to the above findings, the regulatory authorities should continue to strengthen supervision, guarantee food safety through early warning, and reduce the risk of food contamination.

Summer diarrhea in children: a monocentric French epidemiological observational study

Pediatric diarrhea is a major public health problem worldwide. In France, continuous surveillance shows a winter epidemic peak and a more modest summer recrudescence. Few studies describe the infectious agents responsible for pediatric summer diarrhea in France. The objectives were to estimate the prevalence of infectious diarrhea and describe the pathogens responsible for summer diarrhea in children; and to describe common factors that can be used as guidance on the etiology of these diarrheas. A cross-sectional, single-center, epidemiological observational study was conducted in the pediatric emergency department of a French hospital between June and September in 2019 and 2020. Multiplex gastrointestinal pathogen panels were used for diagnostics. A multiple correspondence analysis was used to determine profiles of patients. A total of 95 children were included, of whom 82.1% (78/95) were under five years old. The prevalence of infectious summer diarrhea was 81.1% (77/95, 95%CI 71.7-88.4%). A total of 126 infectious agents were detected (50.0% bacteria, 38.1% viruses, 11.9% parasites). The main enteric pathogens were enteropathogen Escherichia coli (24/126), rotavirus (17/126) and Salmonella (16/126). A co-detection was found in 51.9% (40/77) of cases. Four patient profiles, considering the severity and the pathogen involved, were highlighted.

Prevalence of Enteropathogens and Virulence Traits in Brazilian Children With and Without Diarrhea

The use of molecular diagnostics for pathogen detection in epidemiological studies have allowed us to get a wider view of the pathogens associated with diarrhea, but the presence of enteropathogens in asymptomatic individuals has raised several challenges in understanding the etiology of diarrhea, and the use of these platforms in clinical diagnosis as well. To characterize the presence of the most relevant bacterial enteropathogens in diarrheal episodes, we evaluated here the prevalence of diarrheagenic E. coli pathotypes, Salmonella spp., and Yersinia enterocolitica in stool samples of children with and without diarrhea using real-time quantitative PCR (qPCR). We found that the presence of genetic markers associated with bacterial pathogens was significantly higher in stool samples from the diarrhea group compared to the control (P < 0.001). Bacterial loads in samples positive for eae and aggR markers were also determined. Compared to samples from asymptomatic children, a significantly higher number of copies of the eae gene were found in diarrhea samples. Also, the presence of genetic markers associated with STEC strains with clinical significance was evaluated in eae-positive samples by high-throughput real-time PCR. The data presented herein demonstrated that asymptomatic children of an urban area in Brazil might be enteropathogen reservoirs, especially for STEC.

Molecular and Epidemiologic Analysis of Diarrheal Pathogens in Children With Acute Gastroenteritis in Bangladesh During 2014-2019

BACKGROUND

Diarrheal disease is one of the leading causes of childhood morbidity and mortality in the 21st century in developing countries. Mainly infants and young children develop diarrheal diseases. This study aims to determine the incidence of diarrheal pathogens in children in Bangladesh.

METHODS

During 2014 to 2019, 387 fecal specimens were collected from children with diarrhea in Bangladesh. Bacterial pathogens were detected by conventional bacteriologic, biochemical and molecular sequence analysis methods. DNA virus and RNA virus (diarrheal viruses) were detected using polymerase chain reaction and reverse transcriptase polymerase chain reaction, respectively and confirmed by molecular sequence analysis.

RESULTS

Bacterial infections were detected in 39.27% (152 of 387) of the stool samples. Escherichia coli was the most prevalent (17.3%) followed by Vibrio cholerae (13.5%), Salmonella spp. (4.9%) and Shigella spp. (3.6%). From 387 fecal specimens tested, 42.4% (164 of 387) were positive for viral infections. Rotavirus was the most prevalent (26.3%), followed by adenovirus (5.7%), norovirus (5.4%) and human bocavirus (4.9%). Dual infection between rotavirus and E. coli accounted for the largest portion of coinfection (48%). Diarrhea (77%) and abdominal pain (65%) were most common followed by vomiting (63%), fever (43%) and dehydration (39%). E. coli and V. cholerae were most resistant against ciprofloxacin (62.7%) and tetracycline (88.5%). qnrA and sul4 resistance genes were isolated from these pathogens.

CONCLUSIONS

Data from this study underline the high incidence of diarrheal pathogens and presence of antibiotics resistance genes in a pediatric population in Bangladesh.

Analysis of the Virulence Profile and Phenotypic Features of Typical and Atypical Enteroaggregative Escherichia coli (EAEC) Isolated From Diarrheal Patients in Brazil

Enteroaggregative Escherichia coli (EAEC) is an important agent of acute and persistent diarrhea in children and adults worldwide. Here we report a characterization of 220 EAEC isolates, 88.2% (194/220) of which were typical and 11.8% (26/220) were atypical, obtained from diarrheal patients during seven years (2010-2016) of epidemiological surveillance in Brazil. The majority of the isolates were assigned to phylogroups A (44.1%, 97/220) or B1 (21.4%, 47/220). The aggregative adherence (AA) pattern was detected in 92.7% (204/220) of the isolates, with six of them exhibiting AA concomitantly with a chain-like adherence pattern; and agg5A and agg4A were the most common adhesin-encoding genes, which were equally detected in 14.5% (32/220) of the isolates. Each of 12 virulence factor-encoding genes (agg4A, agg5A, pic, aap, aaiA, aaiC, aaiG, orf3, aar, air, capU, and shf) were statistically associated with typical EAEC (P < 0.05). The genes encoding the newly described aggregate-forming pili (AFP) searched (afpB, afpD, afpP, and afpA2), and/or its regulator (afpR), were exclusively detected in atypical EAEC (57.7%, 15/26), and showed a significant association with this subgroup of EAEC (P < 0.001). In conclusion, we presented an extensive characterization of the EAEC circulating in the Brazilian settings and identified the afp genes as putative markers for increasing the efficiency of atypical EAEC diagnosis.