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Diarrheagenic Escherichia coli is one of the most prevalent foodborne pathogens and poses significant clinical challenges due to increasing rates of antibiotic resistance. In this study, 9,068 diarrheagenic E. coli isolates from sporadic diarrhea cases across 20 provinces of China from 2016 to 2022 were systematically analyzed to determine the prevalence and distribution of resistance. A total of 14 antibiotics were included in the antimicrobial resistance surveillance. Antimicrobial susceptibility testing indicated that the majority of the isolates (89.3%) were resistant to at least one antimicrobial agent, with a significant proportion (60.3%) demonstrating multidrug resistance. Isolates showed high levels of resistance to ampicillin (68.2%) and high sensitivity to imipenem (97.0%). Over the 7 years, an increasing trend in resistance to cefoxitin and chloramphenicol among the isolates was found. Enteroaggregative E. coli was identified as the predominant pathotype. Furthermore, antimicrobial resistance rates were higher among the isolates from infants under 1 year of age compared to other populations and resistance levels differed among pathotypes. In summary, our findings revealed the detailed resistance characteristics of diarrheagenic E. coli strains isolated from human sporadic diarrhea cases in China, offering valuable insights that can inform clinical antibiotic treatment strategies and priorities. [ABSTRACT FROM AUTHOR]

The diarrheagenic Escherichia coli (DEC) is the major cause of diarrheal diseases in Africa, including Ethiopia. However, the genetic diversity of E. coli pathotypes found in Ethiopia has not been studied well. This study aimed to characterize potential DEC belonging to enteropathogenic (EPEC), Shiga toxin-producing (STEC), enteroaggregative (EAEC), enterotoxigenic (ETEC), and enteroinvasive (EIEC) E. coli pathotypes from stool specimens of patients attending primary healthcare units (n = 260) in Addis Ababa and Hossana using whole-genome sequencing. Real-time PCR assays were used to identify DEC isolates belonging to EPEC, STEC, EAEC, ETEC, and EIEC pathotypes, which were then subjected to whole-genome sequencing on the Illumina platform. Twenty-four whole-genome nucleotide sequences of DEC strains with good enough quality were analyzed for virulence-associated genes (VAGs), antibiotic resistance genes (ARGs), phylogenetic groups, serogroups, and sequence types. The majority (62.5%) of DEC isolates belonged to the phylogenetic group B1. The identified DEC isolates belonged to 21 different serogroups and 17 different sequence types. All tested DEC isolates carried multiple VAGs and ARGs. The findings highlight the high diversity in the population structure of the studied DEC isolates, which is important for designing targeted interventions to reduce the diarrheal burden in Ethiopia. [ABSTRACT FROM AUTHOR]

ObjectiveTo investigate the contamination characteristics of common foodborne pathogens in raw livestock meat in the Chinese mainland market.MethodsIn 2021， a total of 4 734 samples of raw livestock meat were collected from 31 provinces （autonomous regions/municipalities） and Xinjiang Construction Corps， and qualitative tests were conducted for Salmonella， Listeria monocytogenes （L. monocytogenes）， diarrheagenic Escherichia coli （DEC） and Yersinia enterocolitica according to the national standard method of food safety.ResultsSalmonella had the highest detection rate with 12.10% （573/4 734）， followed by L. monocytogenes， which is 9.51% （450/4 734）， the detection ratio of DEC and Yersinia enterocolitica was 6.36% （301/4 734） and 2.18% （103/4 734） respectively. The detection rates of Salmonella and DEC in pork were 19.86% and 8.37%， respectively， higher than those of beef and mutton （about 4%）. There were differences in the detection of pathogenic bacteria in raw livestock meat under different preservation conditions. The detection rates of L. monocytogenes and Yersinia enterocolitis in chilled and frozen meat were higher than those in fresh meat. Salmonella and DEC had the highest detection rates in fresh meat. The positive rates of Salmonella and DEC in fresh meat in the second and third quarters were higher than those in the first and fourth quarters. The detection rates of Salmonella and DEC in bulk raw livestock meat were higher than those in pre-packaged products. The detection rates of Salmonella and L. monocytogenes were higher in the south China than those in the north China. The detection rate of DEC in the north was higher than that in the south. A total of 573 strains of Salmonella were isolated from raw livestock meat. The top 5 serotypes and their proportions in descending order were S. typhimurium 19.90%， S. derby 12.57%， S. london 12.22%， S. rissen 10.12% and S. enteritidis 2.97%.ConclusionThe detection rate of pathogenic bacteria in raw livestock meat is high， especially the contamination of L. monocytogenes in frozen and chilled livestock meat and Salmonella in fresh livestock meat in the second and third quarters are serious， which should be taken as the focus of monitoring in the future. Enterprises and consumers should pay attention to preventing the possible risk of disease caused by incomplete heating and cross-contamination of raw and cooked animals.

ObjectiveTo comprehend the epidemiological and molecular characteristics of diarrheagenic Escherichia coli （DEC） in a specific district of Beijing City from 2018 to 2022， aiming to provide evidence for the prevention and control of related diseases.MethodsStool specimens of 1 600 diarrhea cases were collected from 3 surveillance sentinel hospitals in one district of Beijing from 2018 to 2022， and DEC strains were isolated from the specimens. The virulence genes were detected by multiplex PCR， and the pathogenic types were obtained. The epidemiological and clinical data were analyzed. Simultaneously， pulsed-field gel electrophoresis （PFGE） was used to ascertain the molecular types of the strains. Cluster analysis was performed on the fingerprints of ETEC， EPEC， and EAEC strains.ResultsDEC strains were isolated in 144 of 1 600 specimens from one district of Beijing from 2018 to 2022， with a detection rate of 9.00% （144/1 600）. The primary pathogenic type was ETEC， followed by EPEC， EAEC， and EHEC， no EIEC cases were detected. The male-to-female ratio of DEC infection cases was 1.48∶1， with the highest detection rate occurring in the 31~45 age group （11.15%， 59/529）. The year 2019 exhibited the highest positive detection rate of DEC， with the highest rates consistently observed during the summer months. Significant differences in the positive detection rate of DEC were observed among different age groups and years. Most of the DEC-positive patients suffered diarrhea， dehydration， abdominal pain and watery stool. The 144 DEC strains yielded 111 bands， with homology ranging from 13.07% to 100.00%. Isolates of the same type ranged from 2 to 7 strains， and their separation intervals varied from the same day to several years.ConclusionETEC and EPEC were the predominant pathogenic types of DEC in this area， while EHEC infections persisted. DEC exhibited a high incidence during the summer and was more frequently detected in young adults. The PFGE bands exhibited a highly polymorphic distribution.

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Diarrheagenic Escherichia coli (DEC) is a kind of foodborne pathogen that poses a significant threat to both food safety and human health. To address the current challenges of high prevalence and difficult subtyping of DEC, this study developed a method that combined multiplex PCR with high-resolution melting (HRM) analysis for subtyping 5 kinds of DEC. The target genes are amplified by multiplex PCR in a single well, and HRM curve analysis was applied for distinct amplicons based on different melting temperature (Tm) values. The method enables discrimination of different DEC types based on characteristic peaks and distinct Tm values in the thermal melting curve. The assay exhibited 100% sensitivity and 100% specificity with a detection limit of 0.5 to 1 ng/μL. The results showed that different DNA concentrations did not influence the subtyping results, demonstrating this method owed high reliability and stability. In addition, the method was also used for the detection and subtyping of DEC in milk. This method streamlines operational procedures, shorts the detection time, and offers a novel tool for subtyping DEC. [ABSTRACT FROM AUTHOR]

ObjectiveTo analyze Salmonella， Listeria monocytogenes and diarrheagenic Escherichia coli in vegetables in Yunnan Province， the antibiotic susceptibilities and whole genome sequencing （WGS） were determined to characterize the antimicrobial resistance and virulence genotypes of these isolates.MethodsSalmonella， Listeria monocytogenes and diarrheagenic Escherichia coli of 180 samples of vegetables that can be eaten raw were isolated and identified by National food safety standard Food GB 4789.4—2016， GB 4789.30—2016， GB 4789.6—2016. The susceptibilities of isolates were determined by broth microdilution. The whole genome of isolates was then sequenced. The corresponding genomes were assembled and further analysis was carried out using appropriate bioinformatics pipelines.ResultsTwelve of 180 samples of vegetables that can be eaten raw had isolates of pathogenic bacteria from Lactuca sativa， cilantro and Houttuynia cordata Thunb and so on. A total of 13 isolates were detected， including 7 strains of Salmonella which contain 7 serotypes， 4 strains of multi-drug resistance （drug resistance phenotype and drug resistance genes were well correlated）， 5 strains carrying IncHI and IncF plasmids related to multi-drug resistance， 4 strains of Listeria monocytogenes which contain 1 strain of multi-drug resistance and 2 strains carrying the virulence island LIPI-3. 2 strains of enteroaggregative Escherichia coli in which 1 strain of multi-drug resistance.ConclusionMore attention should be paid to vegetables that can be eaten raw with regional characteristics， such as Houttuynia cordata Thunb. Some strains of Listeria monocytogenes can be a potential public health risk due to high harboring rate of virulence genes. It is serious that of multidrug resistance of Salmonella and diarrheagenic Escherichia coli isolated from raw vegetables.

ObjectiveWe conducted a drug resistance and homology analysis of diarrheagenic Escherichia coli （DEC） in Fengxian District of Shanghai in order to provide a basis for clinical rational drug use， risk monitoring and early warning.MethodsDEC were isolated from diarrheal patients in Fengxian District， Shanghai from 2019 to 2022. The minimum inhibitory concentrations （MIC） of 21 drugs to the DEC were determined. Genotyping and homology analysis were conducted with pulsed-field gel electrophoresis （PFGE）.ResultsThe DEC detection rate of diarrhea cases was 18.99% （131/690）， including enteroaggregative E.coli （EAEC） 64.89% （85/131）， enterotoxigenic E.coli （ETEC） 22.14% （29/131）， enteropathogenic E.coli （EPEC） 12.21% （16/131）， and enterohemorrhagic E.coli （EHEC） 0.76%（1/131）. The DEC detection showed obvious seasonal characteristics with a high incidence in summer. The DEC multidrug resistance rate was 66.41% with a total of 65 drug resistance profiles. The five antimicrobial drugs with the highest resistance rate were ampicillin （60.31%）， nalidixic acid （51.91%）， cefazolin （50.38%）， tetracycline （44.27%）， and cotrimoxazole （35.11%）. The rate of DEC resistance to levofloxacin was significantly increased from 2019 to 2022. Cluster analysis showed that the similarity of 85 EAEC cluster was 58.4%‒100.0%， and 69 band patterns were obtained. The similarity of 29 ETEC cluster was 58.5%‒100.0%， and 13 band patterns were obtained， including 2 dominant band types. The similarity of 16 EAEC clusters was 53.9%‒100.0%， and 15 band patterns were obtained. Five groups of homologous strains were found， consistent with the resistance phenotypes.ConclusionAmong the diarrhea cases， the DEC epidemic intensity is high， the drug resistance situation is severe， and the risk of outbreak infection is high in Fengxian District， Shanghai. Therefore， health monitoring and prevention need to be strengthened.

Diarrheagenic Escherichia coli (DEC) is the main cause of diarrhea in children under five years old. The virulence of DEC is tightly regulated by environmental signals influenced by the gut microbiota and its metabolites. Short-chain fatty acids (SCFAs) are the main metabolic product of anaerobic fermentation in the gut, but their role in DEC diarrhea has not yet been established. In this study, we determine the levels of acetate, propionate, and butyrate in stool samples from children with diarrhea caused by DEC, and we identify bacteria from the fecal gut microbiota associated with the production of SCFAs. The microbiota and SCFAs levels in stool samples obtained from 40 children with diarrhea and 43 healthy children were determined by 16S rRNA gene sequencing and HPLC, respectively. Additionally, shotgun metagenomics was used to identify metagenome-assembled genomes (MAGs) in a subgroup of samples. The results showed significantly higher levels of all SCFAs tested in diarrheal samples than in healthy controls. The abundance of Streptococcus sp., Limosilactobacillus, Blautia, Escherichia, Bacteroides, Megamonas, and Roseburia was higher in the DEC group than in healthy individuals. Functional analysis of bacteria and their main metabolic pathways made it possible to identify species MAGs that could be responsible for the detected SCFAs levels in DEC-positive diarrhea. In conclusion, based on our results and published data, we suggest that SCFAs may be important in the crosstalk between the microbiota and DEC pathogens in the gut.

Diarrheagenic Escherichia coli serotypes are associated with various clinical syndromes, yet the precise correlation between serotype and pathotype remains unclear. A major barrier to such studies is the reliance on antisera-based serotyping, which is culture-dependent, low-throughput, and cost-ineffective. We have established a highly multiplex PCR-based serotyping assay, termed the MeltArray E. coli serotyping (EST) assay, capable of identifying 163 O-antigen-encoding genes and 53 H-antigen-encoding genes of E. coli. The assay successfully identified serotypes directly from both simulated and real fecal samples, as demonstrated through spike-in validation experiments and a retrospective study. In a multi-province study involving 637 E. coli strains, it revealed that the five major diarrheagenic pathotypes have distinct serotype compositions. Notably, it differentiated 257 Shigella isolates into four major Shigella species, distinguishing them from enteroinvasive E. coli based on their distinct serotype profiles. The assay’s universality was further corroborated by in silico analysis of whole-genome sequences from the EnteroBase. We conclude that the MeltArray EST assay represents a paradigm-shifting tool for molecular serotyping of E. coli, with potential routine applications for comprehensive serotype analysis, disease diagnosis, and outbreak detection.

Background: Diarrheagenic Escherichia coli (DEC) infections constitute the leading causes of morbidity and mortality among children in Sub-Saharan Africa. However, little has so far been done to properly reveal the pathogenic endowments of DEC in these populations. Aims and Objectives: We evaluated 4 DEC strains among children under 5 years. Materials and Methods: A cross-sectional study design was employed among 384 positive cases. Results: There was a significant decline in infections associated with DEC as the children grew older (χ²[12] = 87.366: P = [0.000]. A total of 56 (14.6%) cases were 0-12 months, 168 (43.8%) were 13-24 months, 88 (22.9%) were 25-36 months, 40 (10.4%) were 37-48 months, and 32 (8.3%) were 49-60 months. A total of 248 (64.6%) male subjects exhibited more susceptibility to DEC infections than their female counterparts (n = 136 [35.4%]) (χ² [3] =13.313: P = [0.004]. Subjects from urban areas (n = 248 [64.6%]), significantly bored the brunt of infections than those from rural areas (n = 136 [35.4%]) (χ² [3] = 35.147: P = [0.000]. The prevalence of DEC appeared significantly higher during rainy seasons (n = 269 [70.1%]). Conclusion: Young age, male gender, crowding, and rainy season play a central role in the transmission of DEC pathotypes. [ABSTRACT FROM AUTHOR]

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The diarrheagenic Escherichia coli (DEC) is the major cause of diarrheal diseases in Africa, including Ethiopia. However, the genetic diversity of E. coli pathotypes found in Ethiopia has not been studied well. This study aimed to characterize potential DEC belonging to enteropathogenic (EPEC), Shiga toxin-producing (STEC), enteroaggregative (EAEC), enterotoxigenic (ETEC), and enteroinvasive (EIEC) E. coli pathotypes from stool specimens of patients attending primary healthcare units (n = 260) in Addis Ababa and Hossana using whole-genome sequencing. Real-time PCR assays were used to identify DEC isolates belonging to EPEC, STEC, EAEC, ETEC, and EIEC pathotypes, which were then subjected to whole-genome sequencing on the Illumina platform. Twenty-four whole-genome nucleotide sequences of DEC strains with good enough quality were analyzed for virulence-associated genes (VAGs), antibiotic resistance genes (ARGs), phylogenetic groups, serogroups, and sequence types. The majority (62.5%) of DEC isolates belonged to the phylogenetic group B1. The identified DEC isolates belonged to 21 different serogroups and 17 different sequence types. All tested DEC isolates carried multiple VAGs and ARGs. The findings highlight the high diversity in the population structure of the studied DEC isolates, which is important for designing targeted interventions to reduce the diarrheal burden in Ethiopia.

Antimicrobial-resistant Escherichia coli strains have been circulating in various sectors and can be cross-transferred between them. Among pathogenic E. coli strains, Shiga toxin-producing E. coli (STEC) and hybrid pathogenic E. coli (HyPEC) emerged as responsible for outbreaks worldwide. As bovine are reservoir of STEC strains, these pathogens primarily spread to food products, exposing humans to risk. Therefore, this study aimed to characterize antimicrobial-resistant and potentially pathogenic E. coli strains from fecal samples of dairy cattle. In this regard, most E. coli strains (phylogenetic groups A, B1, B2, and E) were resistant to β-lactams and non-β-lactams and were classified as multidrug-resistant (MDR). Antimicrobial resistance genes (ARGs) related to multidrug resistance profiles were detected. Furthermore, mutations in fluoroquinolone and colistin resistance determinants were also identified, highlighting the deleterious mutation His152Gln in PmrB that may have contributed to the high level (> 64 mg/L) of colistin resistance. Virulence genes of diarrheagenic and extraintestinal pathogenic E. coli (ExPEC) pathotypes were shared among strains and even within the same strain, evidencing the presence of HyPEC (i.e., ExPEC/STEC), which were assigned as unusual B2-ST126-H3 and B1-ST3695-H31. These findings provide phenotypic and molecular data of MDR, ARGs-producing, and potentially pathogenic E. coli strains in dairy cattle, contributing to the monitoring of antimicrobial resistance and pathogens in healthy animals and alerting to potential bovine-associated zoonotic infections. [ABSTRACT FROM AUTHOR]

ObjectiveThis study aimed to understand the epidemic characteristics of Diarrheagenic Escherichia coli （DEC） in domestic meat products.MethodsThe molecular characteristics of 86 strains of DEC were analyzed by whole genome sequencing technology， and the dominant pathological types， STs， and serotypes were identified. The phylogenetic relationship between DEC strains derived from meat products in China was determined through whole genome single nucleotide polymorphism.ResultsThe results showed that the pathological types of DEC in meat products were mainly EAEC. Eighty-six DEC strains were divided into eight virulence genotypes， including 48 ST types （including six new ST types）， and 55 O：H serotypes. ST11 and CC10 were the predominant ST and clonal complex， respectively. O157， O15， and O6 were the predominant serogroups. DEC strains exhibited high genetic heterogeneity， the same pathological type had low homology， and they were in different evolutionary branches.ConclusionThere is no correspondence between DEC pathological types and ST types and serotypes. The pathological types cannot be directly judged by monitoring ST types and serotypes， but the most numerous ST types and serotypes reveal the main hazard characteristics and prevention of DEC. The determination method of DEC can be supplemented and optimized according to the results of whole genome sequencing， which can provide data support for the traceability and epidemiological investigation of DEC in the future.

Acute intestinal infections caused by Escherichia coli affect the gastrointestinal tract, leading to development of diarrheal syndrome, intoxication, and, in some cases, generalization of the pathological process. Diarrheagenic E. coli (DEC) strains differ from non-pathogenic (commensal) strains by the presence of specific virulence genes, pathogenesis characteristics, clinical and epidemiological manifestations of the diseases they cause. Based on the virulence determinants, 6 pathogenic DEC groups are distinguished: enteropathogenic, enterotoxigenic, enteroinvasive, shiga toxin-producing, enteroaggregative, diffusely adherent E. coli strains. The strains of each pathogenic group have distinct pathogenic mechanisms responsible for inflammatory processes in different compartments of the human intestine, which are clinically manifested as diarrheal syndrome. This paper presents a review of current scientific publications on epidemiology, pathogenesis, genetic properties, and antigenic characteristics of pathogenic E. coli. Although DEC biological properties have been extensively studied, many aspects require deeper insights to develop effective laboratory-based diagnostic techniques, treatment methods, epidemic control measures, and prevention strategies against E. coli infections.

ObjectiveThis study aimed to investigate the distribution of virulence genes， antibiotic resistance， and molecular types of diarrheagenic Escherichia coli （DEC） in Wuhan， Hubei Province， China.MethodsDEC strains identified through biochemical means and a time-of-flight mass spectrometer were routinely collected from five medical institutions. Multiple polymerase chain reactions and drug sensitivity tests were carried out. The molecular characteristics of DEC strains were determined using pulsed field gel electrophoresis （PFGE） and multi-locus sequence typing. Homology analysis was carried out based on clustering analogy and the minimum spanning tree.ResultsA total of 59 DEC strains were collected， including 29 strains of enterotoxigenic Escherichia coli （ETEC， 49.15%）， 15 strains of enteroaggregative Escherichia coli （EAEC， 25.42%）， and 15 strains of enteropathogenic Escherichia coli （EPEC， 25.42%）. The resistance rates of DECs to the 11 antibiotics （except polymyxin E） varied， and were especially high for the following： ampicillin （67.80%）， nalidixic acid （61.02%）， tetracycline （45.76%）， cotrimoxazole （37.29%）， cefotaxime （30.51%）， and chloramphenicol （13.56%）. As determined by PFGE， both EAEC and EPEC had 14 different bands， belonging to 11 different sequence types （STs）； whereas ETEC had 28 different bands belonging to 10 different STs. In addition， more than 50% of STs from ETEC were classified as clonal complexes （CC）-10.ConclusionThe contamination of DECs persists in Wuhan， and antimicrobial resistance is at a critical level. The genotypes from EAEC and EPEC are relatively scattered based on molecular detection and typing of DECs. CC-10， the dominant clone complex of ETEC， is widely distributed in Wuhan.

Escherichia coli is a key indicator of food hygiene, and its monitoring in meat samples points to the potential presence of antimicrobial-resistant strains capable of causing infections in humans, encompassing resistance profiles categorized as serious threats by the Centers for Disease Control and Prevention (CDC), such as Extended-Spectrum Beta-Lactamase (ESBL)—a problem with consequences for animal, human, and environmental health. The objective of the present work was to isolate and characterize ESBL-producing E. coli strains from poultry, pork, and beef meat samples, with a characterization of their virulence and antimicrobial resistance profiles. A total of 450 meat samples (150 chicken, 150 beef, and 150 pork) were obtained from supermarkets and subsequently cultured in medium supplemented with cefotaxime. The isolated colonies were characterized biochemically, followed by antibiogram testing using the disk diffusion technique. Further classification involved biofilm formation and the presence of antimicrobial resistance genes (blaCTX-M, AmpC-type, mcr-1, and fosA3), and virulence genes (eaeA, st, bfpA, lt, stx1, stx2, aggR, iss, ompT, hlyF, iutA, iroN, fyuA, cvaC, and hylA). Statistical analysis was performed via the likelihood-ratio test. In total, 168 strains were obtained, with 73% originating from chicken, 22% from pork, and 17% from beef samples. Notably, strains exhibited greater resistance to tetracycline (51%), ciprofloxacin (46%), and fosfomycin (38%), apart from β-lactams. The detection of antimicrobial resistance in food-isolated strains is noteworthy, underscoring the significance of antimicrobial resistance as a global concern. More than 90% of the strains were biofilm producers, and strains carrying many ExPEC genes were more likely to be biofilm formers (OR 2.42), which increases the problem since the microorganisms have a greater chance of environment persistence and genetic exchange. Regarding molecular characterization, bovine samples showed a higher prevalence of blaCTX-M-1 (OR 6.52), while chicken strains were more likely to carry the fosA3 gene (OR 2.43, CI 1.17–5.05) and presented between 6 to 8 ExPEC genes (OR 2.5, CI 1.33–5.01) compared to other meat samples. Concerning diarrheagenic E. coli genes, two strains harbored eae. It is important to highlight these strains, as they exhibited both biofilm-forming capacities and multidrug resistance (MDR), potentially enabling colonization in diverse environments and causing infections. In conclusion, this study underscores the presence of β-lactamase-producing E. coli strains, mainly in poultry samples, compared to beef and pork samples. Furthermore, all meat sample strains exhibited many virulence-associated extraintestinal genes, with some strains harboring diarrheagenic E. coli (DEC) genes. [ABSTRACT FROM AUTHOR]

This study aimed to determine the cause of growth inhibition of diarrheagenic Escherichia coli (DEC) in modified EC (mEC) broth containing other bacteria. The growth of DEC in mEC broth with non-DEC bacteria was evaluated by lactose fermentation, growth rate, and the ratio of DEC to non-DEC bacteria before enrichment culturing. The results showed that non-lactose fermenting bacteria did not compete with DEC because lactose contributes considerably to the growth of bacteria in mEC broth. In the mEC broth, all the bacteria stopped growing after the total number of bacteria reached approximately 9.0 log CFU/mL, primarily because of lactose depletion. Moreover, the growth of DEC in mEC broth with coliform bacteria depends on the ratio of DEC to coliform bacteria in the specimen and the growth rate of coliform bacteria. However, DEC isolation cannot exclude the influence of non-pathogenic E. coli in the specimen because most DEC possess drug susceptibility and biochemical characteristics similar to non-pathogenic E. coli. Estimation of the DEC population in mEC broth after enrichment culturing by quantitative PCR is useful to predict the result of DEC isolation. Moreover, the use of isolation media other than those identified by lactose fermentation can improve the detection rate of DEC. [ABSTRACT FROM AUTHOR]

The safety of fecal microbiota transplantation (FMT) has been highlighted by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli bacteremia transmitted from donors and acquisition of diarrheagenic E. coli (Shiga toxin-producing E. coli (STEC) and enteropathogenic E. coli (EPEC)) via FMT. The use of donor screening criteria to lower the risk of pathogen transmission via FMT is essential. This study aimed to demonstrate the outcomes of our strict donor screening program. This study was conducted at our FMT center between January 2019 and June 2022. Our donor screening program included an initial questionnaire and subsequent blood and stool testing. We further used selective culture for third-generation cephalosporin-resistant (3GCR) Enterobacterales and multiplex PCR to detect diarrheagenic E. coli in stools. The resistance mechanisms and sequence type of 3GCR Enterobacterales were determined. A total of 742 individuals were assessed, and 583 participants (78.6%) were excluded after questionnaire. Of the remaining 159 participants undergoing stool and blood tests, 37 participants were finally qualified (5.0%, 37/742). A high fecal carriage rate of ESBL-producing Enterobacterales (35.2%, 56/159), including E. coli (n=53) and Klebsiella pneumoniae (n=5), and diarrheagenic E. coli (31.4%, 50/159), including EPEC (n=41), enteroaggregative E. coli (n=11), enterotoxigenic E. coli (n=4), and STEC (n=1), was noted. CTX-M-79 and CTX-M-15 were dominant in E. coli and K. pneumoniae, respectively. The sequence types of the ESBL-producing strains were diverse. The screening for 3GCR Enterobacterales and diarrheagenic E. coli in stool is necessary. Our findings also support the effectiveness of multiplex PCR panels in FMT donor screening programs. [ABSTRACT FROM AUTHOR]

Diarrheagenic Escherichia coli (DEC) are the leading cause of infectious diarrhea and pose a significant global, regional, and national burden of disease. This study aimed to investigate the prevalence of six DEC pathotypes in children with diarrhea and determine their antibiotic resistance patterns. Samples from 107 diarrheagenic children were collected and processed for Escherichia coli (E. coli). Single-plex PCR was used to detect target virulence genes as well as characterize and categorize DEC pathotypes. Antibiotic resistance patterns were determined by the Kirby–Bauer disk diffusion method. E. coli was detected in 79 diarrheal stool samples, accounting for 73.8% of the samples collected. Additionally, 49.4% (39 out of 79) of the isolates harbored various typical virulence factors. Results revealed six pathotypes of virulence: enterotoxigenic E. coli (ETEC) (53.8%), enteropathogenic E. coli (EPEC) (12.8%), enteroaggregative E. coli (EAEC) (10.3%), Heteropathotypes (7.8%), Shiga toxin-producing E. coli (STEC), and enterohemorrhagic E. coli (EHEC) (7.7% each). The isolates exhibited high antibiotic resistance against trimethoprim/sulfamethoxazole (82.1%), amoxicillin (79.5%), ampicillin (74.4%), gentamicin (69.2%), and streptomycin (64.1%). An overall occurrence of 84.6% of multiple-drug resistance was observed in the isolates, with resistance ranging from three to four antibiotic classes. Our findings revealed a high level of pathogenic E. coli that were highly resistant to multiple categories of antibiotics among children in the Awi zone. These findings highlight the potential role of pathogenic E. coli in childhood diarrhea in tropical low-resource settings and underscore the need for continued research on the characteristics of pathogenic and antibiotic-resistant strains.

Sheep represent one of the main reservoirs of diarrheagenic Escherichia coli; this microorganism is an etiological agent of food-borne diseases; therefore, this work aimed to identify and characterize the principal pathotypes of diarrheagenic E. coli (DEC) obtained through rectal swabs and carcasses samples from sheep slaughtered in an abattoir at the central region of Mexico. The isolates were subjected to bacteriological identification, serotyping; phylogenetic classification; detection for virulence factors, and antimicrobial sensibility. A total of 90 E. coli isolates were obtained. It was observed through 49 E. coli isolates (54%), 8 of them from carcasses, and 43 from feces was DEC. DEC serotypes with health public relevance were found: O76:H19 (n = 5), O146:H21 (n = 3), O91:H10 (n = 1), O6:NM (n = 1), and O8:NM (n = 1). Regarding the presence of Shiga toxin-producing E.coli (STEC), 43/90 (47.7%) isolates have the stx1 w/o stx2 genes, and therefore were assigned as STEC non-O157; only one isolate expressed stx1 and eae genes and was classified as t-STEC (typical STEC). Additionally, 3/90 (3.3%) harbored only the eae gene and were classified as enteropathogenic E. coli (EPEC), the stp gene was found in 2/90 isolates (2.2%) and were classified as enterotoxigenic E. coli (ETEC); 1/90 (1.1%) isolates harboring the ipaH were classified as enteroinvasive E. coli EIEC. Regarding stx1 genes subtypes, stx1c only was found in 60.5% (26/43), followed by stx1a-stx1c 20.9% (9/43) and stx1a-stx1d 2.3% (1/43). The presence of both, stx1 and stx2 genes was found in 7/43 isolates (16.3%) from rectal swabs; the combination stx1c-stx2g was detected in 3/43 isolates (6.9%), while 4 (9.4%) isolates showed different patterns (stx1a-stx1c-stx2g; stx1c-stx2b-stx2g; stx1c-stx2b and stx1a-stx1c-stx2b-stx2g). STEC isolates showed the major diversity of phylogenetic groups, although phylogroup B1 was predominant in 90.6% (39/43) while there was only one isolate (2.3%) in each remaining phylogroup (A, B2, C, and F). All EPEC, ETEC, and EIEC isolates were clustered in phylogroup B1. We observed that 27.9% (12/43) of STEC isolates carried at least one antibiotic resistance: nine isolates expressed the tetB gene, one isolate the tetA gene, two isolates the sul2 gene, one isolate the sul1 and one isolate the sul1-tetB genes. These results highlight the importance of diarrheagenic E. coli as a potential risk for public health during the slaughtering process. [ABSTRACT FROM AUTHOR]

ObjectiveTo provide scientific basis for preventing foodborne outbreaks and carrying out targeted prevention and control measures， the seasonal characteristics of foodborne diarrheagenic Escherichia coli outbreaks in China’s Mainland from 2010 to 2020 was analyzed.MethodsCircular distribution method was used to analyze the data about diarrheagenic Escherichia coli outbreaks which was collected by Foodborne Disease Outbreaks Surveillance System from 2010 to 2020.ResultsFrom 2010 to 2020， a total of 349 foodborne diarrheagenic Escherichia coli outbreaks were reported in China’s Mainland. Generally， the peak of Escherichia coli outbreaks was from May to September （74.50%， 260/349）， and there was a significant centralized trend in event distribution， with the peak day on July 10. The epidemic peak period was from April 24 to September 25.ConclusionThere is an obvious seasonal trend in foodborne diarrheagenic Escherichia coli outbreaks in China’s Mainland， and the peak period is in summer and autumn. Effective prevention and control measures should be taken in time before the peak period.

Introduction Diarrheal illness such as diarrheagenic Escherichia coli (DEC), apart from rotavirus, is a common etiological agent known to cause moderate-to-severe diarrhea in low-income countries where unregulated use of antibiotics is rampant, giving rise to multidrug resistant (MDR) strains. This study is an earnest effort in reflecting the resistance pattern in such isolates. Materials and Methods It is a hospital-based cross-sectional study conducted over a period of 1 year (January to December, 2015). Children aged less than 18 years presenting with (n = 170) and without (n = 47) diarrhea were included as cases and controls, respectively. Fresh stool sample from eligible participants was collected and inoculated on MacConkey agar. Based on the colony morphology and biochemical identification followed by polymerase chain reaction (PCR), different pathotypes of DEC were identified. All such isolates were subjected to antimicrobial susceptibility testing employing VITEK 2 identification system. The result of the tested antibiotics was evaluated as per Clinical and Laboratory Standards Institute 2015 guidelines. Results DEC with specific virulence genes were detected by multiplex real-time PCR in 39 and 3 children with or without diarrhea, respectively. Most common DEC pathotypes found were enteroaggregative E. coli (38%) followed by enteropathogenic E. coli (28.5%). MDR isolates comprised 35 of 42 DEC pathotypes (83.3%). Resistance among DEC pathotypes to ampicillin, amoxicillin–clavulanate, ciprofloxacin, cephalosporin, nalidixic acid, imipenem, and cotrimoxazole was found to be statistically significant in comparison to non-DEC isolates. Conclusion This study has highlighted the increased prevalence of MDR strains among DEC pathotypes. Looking for these isolates will help detect dreadful DEC pathotypes like enterohemorrhagic E. coli where early administration of a sensitive antibiotic will go a long way in preventing complication like hemorrhagic colitis and hemolytic uremic syndrome.

Background: In developing countries including Iran, there are limited data on diarrheagenic Escherichia coli (DEC) contamination in milk and unpasteurized buttermilks. This study aimed to determine the occurrence of DEC pathotypes by culture and multiplex polymerase chain reaction (M-PCR) in some dairy products from southwest Iran. Methods and results: In this cross-sectional study (September to October 2021), 197 samples (87 unpasteurized buttermilk and 110 raw cow milk) were collected from dairy stores of Ahvaz, southwest Iran. The presumptive E. coli isolates were primarily identified using biochemical tests and then confirmed by PCR of uidA gene. The occurrence of 5 DEC pathotypes: enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), and enteroinvasive E. coli (EIEC) were investigated using M-PCR. Overall, 76 (76/197, 38.6%) presumptive E. coli isolates were identified by biochemical tests. Using uidA gene, only 50 isolates (50/76, 65.8%) were confirmed as E. coli. DEC pathotypes were detected in 27 of 50 (54.0%) E. coli isolates (74.1%, 20/27 from raw cow milk and 25.9%, 7/27 from unpasteurized buttermilk). The frequency of DEC pathotypes was as follows: 1 (3.7%) EAEC, 2 (7.4%) EHEC, 4 (14.8%) EPEC, 6 (22.2%) ETEC, and 14 (51.9%) EIEC. However, 23 (46.0%) E. coli isolates had only the uidA gene and were not considered DEC pathotypes. Conclusion: Possible health risks for Iranian consumers can be attributed to the presence of DEC pathotypes in dairy products. Hence, serious control and prevention efforts are needed to stop the spread of these pathogens. [ABSTRACT FROM AUTHOR]

Background: Enteroaggregative Escherichia coli (EAEC) is increasingly associated with domestically acquired diarrheal episodes in high-income countries, particularly among children. However, its specific role in endemic diarrhea in this setting remains under-recognized and information on molecular characteristics of such EAEC strains is limited. We aimed to investigate the occurrence of EAEC in patients with non-travel related diarrhea in Spain and molecularly characterize EAEC strains associated with illness acquired in this high-income setting. Methods: In a prospective multicenter study, stool samples from diarrheal patients with no history of recent travel abroad (n = 1,769) were collected and processed for detection of EAEC and other diarrheagenic E. coli (DEC) pathotypes by PCR. An additional case-control study was conducted among children =5 years old. Whole-genome sequences (WGS) of the resulting EAEC isolates were obtained. Results: Detection of DEC in the study population. DEC was detected in 23.2% of patients aged from 0 to 102 years, with EAEC being one of the most prevalent pathotypes (7.8%) and found in significantly more patients =5 years old (9.8% vs. 3.4%, p < 0.001). Although not statistically significant, EAEC was more frequent in cases than in controls. WGS-derived characterization of EAEC isolates. Sequence type (ST) 34, ST200, ST40, and ST10 were the predominant STs. O126:H27, O111:H21, and O92:H33 were the predominant serogenotypes. Evidence of a known variant of aggregative adherence fimbriae (AAF) was found in 89.2% of isolates, with AAF/V being the most frequent. Ten percent of isolates were additionally classified as presumptive extraintestinal pathogenic E. coli (ExPEC), uropathogenic E. coli (UPEC), or both, and belonged to clonal lineages that could be specifically associated with extraintestinal infections. Conclusion: EAEC was the only bacterial enteric pathogen detected in a significant proportion of cases of endemic diarrhea in Spain, especially in children =5 years old. In particular, O126:H27-ST200, O111:H21-ST40, and O92:H33-ST34 were the most important subtypes, with all of them infecting both patients and asymptomatic individuals. Apart from this role as an enteric pathogen, a subset of these domestically acquired EAEC strains revealed an additional urinary/systemic pathogenic potential. [ABSTRACT FROM AUTHOR]

ObjectiveTo provide the scientific basis for the prevention and control of diarrheagenic Escherichia coli （DEC） infection， the epidemiological characteristics of DEC infection in Shanghai was identified.MethodsThe epidemiological information of the collected diarrhea cases and the DEC test results from 30 foodborne disease surveillance sentinel hospitals in Shanghai from 2018 to 2020 were analyzed by the descriptive epidemiological methods.ResultsAccording to the result of 13 672 infectious diarrhea cases and specimens， the positive rate of DEC was 5.71% （781/13 672）， mainly ETEC and EAEC. The highest positive rate of DEC was often associated with child below the age of 7 and the farmers， and the highest positive rate of DEC was occurred between July and September. Compared with other patients， the positive rate of DEC in patients with fever and no vomiting or diarrhea 3-9 times/d was significantly higher. The positive rate of DEC was relatively high in cases with suspected food category of fruit and its products.ConclusionETEC and EAEC were the main virulence genotyping of DEC in Shanghai， and the peak of DEC infection occurred in summer. Specific clinical symptoms could play as indications for clinical diagnosis and treatment. The supervision and management of catering service industry and street food should be improved， and the publicity and training of public food safety awareness and good food safety habits should be strengthened.

BackgroundEnteroaggregative Escherichia coli (EAEC) is increasingly associated with domestically acquired diarrheal episodes in high-income countries, particularly among children. However, its specific role in endemic diarrhea in this setting remains under-recognized and information on molecular characteristics of such EAEC strains is limited. We aimed to investigate the occurrence of EAEC in patients with non-travel related diarrhea in Spain and molecularly characterize EAEC strains associated with illness acquired in this high-income setting.MethodsIn a prospective multicenter study, stool samples from diarrheal patients with no history of recent travel abroad (n = 1,769) were collected and processed for detection of EAEC and other diarrheagenic E. coli (DEC) pathotypes by PCR. An additional case–control study was conducted among children ≤5 years old. Whole-genome sequences (WGS) of the resulting EAEC isolates were obtained.ResultsDetection of DEC in the study population. DEC was detected in 23.2% of patients aged from 0 to 102 years, with EAEC being one of the most prevalent pathotypes (7.8%) and found in significantly more patients ≤5 years old (9.8% vs. 3.4%, p

Introduction: Diarrheal diseases are common with worldwide distribution, and diarrheagenic Escherichia coli (DEC) strains are the main causative agents. The present study aimed to define the association of various pathotypes of E. coli from diarrheal patients in Mongolia. Methodology: A total of 341 E. coli strains were isolated from the stool of diarrheal patients. Bacterial susceptibility to antimicrobial agents was determined by the Kirby Bauer disk diffusion method. DEC isolates were identified by HEp-2 cell adherence assay and multiplex polymerase chain reaction (PCR). Results: DEC pathogens were detected in 53.7% of 341 E. coli isolates. Enteroaggregative E. coli (EAEC) was the most common DEC pathotype identified by HEp-2 adherence assay and multiplex PCR methods in 97 samples (28.4%), followed by atypical enteropathogenic E. coli (EPEC) in 50 samples (14.7%), diffusely adherent E. coli (DAEC) in 25 samples (7.3%), enterohaemorrhagic E. coli (EHEC) in 6 samples (1.8%), enterotoxigenic E. coli (ETEC) in 4 samples (1.2%), and enteroinvasive E. coli (EIEC) in 1 sample (0.3%). DEC strains had > 50% antibiotic resistance against cephalothin, ampicillin, and trimethoprim/sulfamethoxazole. All tested DEC strains were susceptible to imipenem. Among the 183 DEC strains, 27 (14.8%) were extended spectrum beta-lactamase producing isolates, and 125 (68.3%) isolates were multiple drug resistant. Conclusions: We have identified six pathotypes of DEC from the clinical isolates tested and concluded that a high prevalence of antimicrobial resistance was observed in these pathotypes. EAEC was the most common pathotype identified and this is the first report of EHEC identification in Mongolia. [ABSTRACT FROM AUTHOR]

The current study aimed to detect virulence, hetero-pathogenicity, and hybridization genes in Escherichia coli strains, previously isolated from cloacal swabs in commercial breeding psittacines and zoological collections, via multiplex PCR. A total of 68 strains of E. coli , previously isolated from psittacines in zoos and commercial breeding facilities in Ceará, Brazil, were assessed for the presence of the following genes and/or probes: eae , bfpA (EPEC - Enteropathogenic E. coli), CVD432 (EAEC - Enteroaggregative E. coli); LT gene and ST gene (ETEC - Enterotoxigenic E. coli); ipaH (EIEC - Enteroinvasive E. coli); stx1 and stx2 (STEC - Shiga toxin-producing E. coli); iroN , ompT , hlyF , iss , and iutA (APEC - Avian pathogenic E. coli). Of the 68 E. coli strains analyzed, 61 (98.7 %) were positive for the following genes and/or probes: Stx1 (61/98.7 %), ST gene (54/79.4 %), CVD432 (49/72 %), bfpA (44/64.7 %), eae (42/61.8 %), Stx2 (41/60.3 %), ipaH (34/50 %), LT gene (33/48.5 %), iroN (21/30.9 %), hlyF (11/6.2 %), iss (06/8.8 %) and iutA (06/8.8 %). The following diarrheagenic pathotypes were identified: 66 (97 %) from STEC, 49 (72 %) from EAEC, 35 (52 %) from EIEC, 25 (37 %) from ETEC, and one (1.5 %) from EPEC. Regarding hetero-pathogenicity, 50 (74 %) heterogeneous strains were identified. Positivity for APEC was seen in four (6 %) strains, all characterized as pathogenic hybrids. This study describes significant associations of virulence factors in E. coli strains DEC/DEC and DEC/APEC, which were isolated from psittacines and may be potentially harmful to One Health. • Psittacines under human care can carry potentially zoonotic pathogens. • Diarrheagenic and avian pathogenic Escherichia coli can share genes and vice versa. • Virulence factors in E. coli highlight the importance of effective sanitary control. [ABSTRACT FROM AUTHOR]

Escherichia coli is a key indicator of food hygiene, and its monitoring in meat samples points to the potential presence of antimicrobial-resistant strains capable of causing infections in humans, encompassing resistance profiles categorized as serious threats by the Centers for Disease Control and Prevention (CDC), such as Extended-Spectrum Beta-Lactamase (ESBL)—a problem with consequences for animal, human, and environmental health. The objective of the present work was to isolate and characterize ESBL-producing E. coli strains from poultry, pork, and beef meat samples, with a characterization of their virulence and antimicrobial resistance profiles. A total of 450 meat samples (150 chicken, 150 beef, and 150 pork) were obtained from supermarkets and subsequently cultured in medium supplemented with cefotaxime. The isolated colonies were characterized biochemically, followed by antibiogram testing using the disk diffusion technique. Further classification involved biofilm formation and the presence of antimicrobial resistance genes (blaCTX-M, AmpC-type, mcr-1, and fosA3), and virulence genes (eaeA, st, bfpA, lt, stx1, stx2, aggR, iss, ompT, hlyF, iutA, iroN, fyuA, cvaC, and hylA). Statistical analysis was performed via the likelihood-ratio test. In total, 168 strains were obtained, with 73% originating from chicken, 22% from pork, and 17% from beef samples. Notably, strains exhibited greater resistance to tetracycline (51%), ciprofloxacin (46%), and fosfomycin (38%), apart from β-lactams. The detection of antimicrobial resistance in food-isolated strains is noteworthy, underscoring the significance of antimicrobial resistance as a global concern. More than 90% of the strains were biofilm producers, and strains carrying many ExPEC genes were more likely to be biofilm formers (OR 2.42), which increases the problem since the microorganisms have a greater chance of environment persistence and genetic exchange. Regarding molecular characterization, bovine samples showed a higher prevalence of blaCTX-M-1 (OR 6.52), while chicken strains were more likely to carry the fosA3 gene (OR 2.43, CI 1.17–5.05) and presented between 6 to 8 ExPEC genes (OR 2.5, CI 1.33–5.01) compared to other meat samples. Concerning diarrheagenic E. coli genes, two strains harbored eae. It is important to highlight these strains, as they exhibited both biofilm-forming capacities and multidrug resistance (MDR), potentially enabling colonization in diverse environments and causing infections. In conclusion, this study underscores the presence of β-lactamase-producing E. coli strains, mainly in poultry samples, compared to beef and pork samples. Furthermore, all meat sample strains exhibited many virulence-associated extraintestinal genes, with some strains harboring diarrheagenic E. coli (DEC) genes.

Bo-Wen Jiang,1,2,* Xue Ji,1,2,* Zhong-Qing Lyu,3 Bing Liang,1,2 Jian-Hang Li,3 Ling-Wei Zhu,1,2 Xue-Jun Guo,1,2 Jun Liu,1,2 Yang Sun,1,2 Yan-Jing Liu3 1Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, Jilin, People’s Republic of China; 2Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun, Jilin, People’s Republic of China; 3Third Affiliated Clinical Hospital to Changchun University of Chinese Medicine, Changchun, Jilin, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yang Sun; Yan-Jing Liu, Tel +86 431-86986933, Email sunyang10@hotmail.com; 214953156@qq.comPurpose: To elucidate the contribution of a transferable plasmid harboring the blaNDM-1 gene in an Escherichia coli clinical isolate to the spread of resistance determinants.Methods: Nine extended-spectrum β-lactamase-producing E. coli were collected from diarrhea samples from a pediatric patient and genetic linkage was investigated through enterobacteriaceae repetitive intragenic consensus polymerase chain reaction (PCR). Bacterial species were identified by 16s rRNA sequencing, susceptibility testing with the use of a BD PhoenixTM-100 Automated Microbiology System, and assessment of virulence genes by PCR. The transferability of blaNDM-1 in E. coli strain TCM3e1 was confirmed by conjugation experiments. Complete sequencing of E. coli strain TCM3e1 was determined with the PacBio and Illumina NovaSeq platforms and the characteristics were analyzed with bioinformatics software.Results: The results showed that all nine E. coli strains were the same clone. E. coli strain TCM3e1 was resistant to 12 antimicrobial agents and carried the virulence gene EAST-1. Conjugation transfer analysis showed that blaNDM-1 was carried on a self-transmissible plasmid. Two copies of the blaNDM-1 gene were present on an IncC plasmid and some resistance genes with two or three copies were located downstream of the blaNDM-1 gene and formed a tandem repeat fragment (blaDNM-1-bleo-sul1- aadA17- dfrA12).Conclusion: A transmissible plasmid harboring two copies of the blaNDM-1 gene, including clonal dispersions of the blaNDM-1 gene, was identified in clinical isolates. These findings emphasized the necessity of surveillance of the plasmid-borne blaNDM-1 to prevent dissemination.Keywords: diarrheagenic Escherichia coli, multi-drug-resistant, New Delhi metallo-β-lactamase, blaDNM-1 gene

ObjectiveTo satisfy the demands of laboratory quality control and proficiency testing for the detection of enteroinvasive Escherichia coli (EIEC), a stable EIEC reference material was developed with independent intellectual property rights, good stability and clear background genomic information.MethodsNGS Technique was used to sequence the whole genome of enteroinvasive Escherichia coli (CMCC 44840), bioinformatics analysis was performed to identify the species, serotype, MLST type and virulence genes; EIEC lyophilized samples with 103 CFU were prepared by freeze-drying method ; The homogeneity test was performed according to CNAS-GL017, and the result were statistically analyzed by one-way ANOVA; The samples were stored at -20, 4, 25 and 37 ℃, respectively, and their storage stability and transport stability were evaluated; Five kinds of food matrix samples were used to verify the applicability of reference materials, and three laboratories were organized for collaborative calibration.ResultsThe genome size of CMCC 44840 was 4.96 Mb, the GC content was 50.7%, and the genome contained 5424 coding genes. This strain was identified as the species of Escherichia coli, and the serotype and the MLST type were predicted to be O28ac: H7 and ST311, respectively, and it carried ipaH, virB, virF and other virulence genes. The homogeneity test result of the EIEC lyophilized sample was F=1.79, which met the homogeneity requirements of reference materials. The EIEC samples were still 103 CFU when storing at -20 ℃ and 4 ℃ for 60 d and storing at 25 ℃ and 4 ℃ for 7 d, and decreased on the third day at 37 ℃. EIEC were detected in 20 different food matrix samples with EIEC lyophilized samples after enrichment. The samples were 103 CFU determined by three collaborative calibration laboratories, and there were no significant differences among these laboratories (F=0.59).ConclusionThe EIEC reference material prepared in this study has clear genome sequence information. The homogeneity and stability meet the requirements and have good applicability, which can meet the requirements of quality control and capability verification in food testing laboratory.

Sheep represent one of the main reservoirs of diarrheagenic Escherichia coli; this microorganism is an etiological agent of food-borne diseases; therefore, this work aimed to identify and characterize the principal pathotypes of diarrheagenic E. coli (DEC) obtained through rectal swabs and carcasses samples from sheep slaughtered in an abattoir at the central region of Mexico. The isolates were subjected to bacteriological identification, serotyping; phylogenetic classification; detection for virulence factors, and antimicrobial sensibility. A total of 90 E. coli isolates were obtained. It was observed through 49 E. coli isolates (54%), 8 of them from carcasses, and 43 from feces was DEC. DEC serotypes with health public relevance were found: O76:H19 (n = 5), O146:H21 (n = 3), O91:H10 (n = 1), O6:NM (n = 1), and O8:NM (n = 1). Regarding the presence of Shiga toxin-producing E.coli (STEC), 43/90 (47.7%) isolates have the stx1 w/o stx2 genes, and therefore were assigned as STEC non-O157; only one isolate expressed stx1 and eae genes and was classified as t-STEC (typical STEC). Additionally, 3/90 (3.3%) harbored only the eae gene and were classified as enteropathogenic E. coli (EPEC), the stp gene was found in 2/90 isolates (2.2%) and were classified as enterotoxigenic E. coli (ETEC); 1/90 (1.1%) isolates harboring the ipaH were classified as enteroinvasive E. coli EIEC. Regarding stx1 genes subtypes, stx1c only was found in 60.5% (26/43), followed by stx1a-stx1c 20.9% (9/43) and stx1a-stx1d 2.3% (1/43). The presence of both, stx1 and stx2 genes was found in 7/43 isolates (16.3%) from rectal swabs; the combination stx1c-stx2g was detected in 3/43 isolates (6.9%), while 4 (9.4%) isolates showed different patterns (stx1a-stx1c-stx2g; stx1c-stx2b-stx2g; stx1c-stx2b and stx1a-stx1c-stx2b-stx2g). STEC isolates showed the major diversity of phylogenetic groups, although phylogroup B1 was predominant in 90.6% (39/43) while there was only one isolate (2.3%) in each remaining phylogroup (A, B2, C, and F). All EPEC, ETEC, and EIEC isolates were clustered in phylogroup B1. We observed that 27.9% (12/43) of STEC isolates carried at least one antibiotic resistance: nine isolates expressed the tetB gene, one isolate the tetA gene, two isolates the sul2 gene, one isolate the sul1 and one isolate the sul1-tetB genes. These results highlight the importance of diarrheagenic E. coli as a potential risk for public health during the slaughtering process.

Introduction Diarrheal illness such as diarrheagenic Escherichia coli (DEC), apart from rotavirus, is a common etiological agent known to cause moderate-to-severe diarrhea in low-income countries where unregulated use of antibiotics is rampant, giving rise to multidrug resistant (MDR) strains. This study is an earnest effort in reflecting the resistance pattern in such isolates. Materials and Methods It is a hospital-based cross-sectional study conducted over a period of 1 year (January to December, 2015). Children aged less than 18 years presenting with (n = 170) and without (n = 47) diarrhea were included as cases and controls, respectively. Fresh stool sample from eligible participants was collected and inoculated on MacConkey agar. Based on the colony morphology and biochemical identification followed by polymerase chain reaction (PCR), different pathotypes of DEC were identified. All such isolates were subjected to antimicrobial susceptibility testing employing VITEK 2 identification system. The result of the tested antibiotics was evaluated as per Clinical and Laboratory Standards Institute 2015 guidelines. Results DEC with specific virulence genes were detected by multiplex real-time PCR in 39 and 3 children with or without diarrhea, respectively. Most common DEC pathotypes found were enteroaggregative E. coli (38%) followed by enteropathogenic E. coli (28.5%). MDR isolates comprised 35 of 42 DEC pathotypes (83.3%). Resistance among DEC pathotypes to ampicillin, amoxicillin–clavulanate, ciprofloxacin, cephalosporin, nalidixic acid, imipenem, and cotrimoxazole was found to be statistically significant in comparison to non-DEC isolates. Conclusion This study has highlighted the increased prevalence of MDR strains among DEC pathotypes. Looking for these isolates will help detect dreadful DEC pathotypes like enterohemorrhagic E. coli where early administration of a sensitive antibiotic will go a long way in preventing complication like hemorrhagic colitis and hemolytic uremic syndrome. [ABSTRACT FROM AUTHOR]

Human diarrhea-causing strains of Escherichia coli are referred to as diarrheagenic E. coli (DEC). DEC can be divided into five main categories based on distinct epidemiological and clinical features, specific virulence determinants, and association with certain serotypes. In the present study, a simple and rapid one-step single reaction multiplex PCR (mPCR) assay was developed for the simultaneous identification and differentiation of five currently established DEC pathotypes causing gastrointestinal diseases. The mPCR incorporated 10 primer pairs to amplify 10 virulence genes specific to the different pathotypes (i.e., stx1 and stx2 for EHEC, elt and sth for ETEC, eaeA and bfpA for EPEC, aggR and astA for EAEC, and ipaH and invE for EIEC) and to generate DNA fragments of sufficiently different sizes to be unequivocally resolved. All strains were detected at concentrations ranging from 104 to 107 CFU/mL. To demonstrate the utility of the mPCR assay, 236 clinically isolated strains of DEC from two hospitals were successfully categorized. One-step mPCR technique reduced the cost and effort involved in the identification of various virulence factors in DEC. Thus, we demonstrated that the newly developed mPCR assay has the potential to be introduced as a diagnostic tool that can be utilized for the detection of DEC as an additional check in clinical laboratories and for confirmation in health and environment institutes, health centers, and reference laboratories.

ObjectiveTo investigate the infection status, main virulence genes and drug resistance of diarrheagenic Escherichia coli (DEC) in the diarrhea population in Huzhou, Zhejiang Province.MethodsDECs were isolated from fecal specimens from patients with diarrhea in three sentinel hospitals from 2018 to 2020. All clinical isolates were then further identified using multiplex real-time fluorescence quantitative polymerase chain reaction (PCR). The microbroth dilution method was used for drug sensitivity testing.ResultsA total of 293 DEC positive cases were detected, and 294 strains were isolated. Enteroaggregative Escherichia coli (EAEC) accounted for 55.4% (163/294), and Enterotoxigenic Escherichia coli (EPEC) accounted for 29.6% (87/294). Enteropathogenic Escherichia coli (EPEC) accounted for 11.2% (33/294), Enteroinvasive Escherichia coli (EIEC) accounted for 3.4% (10/294) and Enterohemorrhagic Escherechia coli (EHEC)accounted for 0.3%(1/294). The antimicrobial resistance rates of 117 randomly selected strains to ampicillin, nalidixic acid, ampicillin-Sulbactam and tetracyclin were 70.9%, 60.7%, 53.8% and 51.3%, respectively. The multidrug resistance rate reached 55.6%. The sensitivity rates to imipenem, ceftazidime, amoxicillin clavulanic acid and cefoxitin were 99.1%, 92.3%, 92.3% and 91.5%. DEC cases had a peak in July to August, and the main infected population was between 20 and 39 years old.ConclusionThe DEC genotypes of the patients with diarrhea in Huzhou, Zhejiang Province were mainly EAEC and ETEC, with multiple antibiotic resistance. The distribution of cases was obviously seasonal, and the infected population was mainly young adults.

ObjectiveTo understand the drug resistance and homology of diarrheagenic Escherichia coli (E. coli), from food in Jiamusi, and to provide basis for effective control of food borne diseases and clinical treatment.MethodsMultiple polymerase chain reaction (PCR) was used to detect diarrheagenic E. coli in food. Drug resistance of diarrheagenic E. coli isolated from food in Jiamusi was analyzed by Sensitire microbial sensitivity analysis system, and the homology of isolates was analyzed by pulsed-field gel electrophoresis (PFGE).ResultsFifty one strains of diarrheagenic E. coli were isolated from 1 320 samples with a total positive rate of 3.86%. Twenty one strains of them were resistant to drugs (41.18%), among which 3 were single drug-resistant and other 18 were multi drug-resistant. A total of 49 different PFGE fingerprints were obtained from 51 strains of diarrheagenic E. coli, and the homology was 38.6%~100%.ConclusionThe multi drug-resistant of diarrheagenic E. coli from food in Jiamusi is obvious. The homology is polymorphic.

Diarrheagenic Escherichia coli (DEC) can cause epidemic diarrhea worldwide. The pathogenic potential of different strains is diverse and the continuous emergence of pathogenic strains has brought serious harm to public health. Accurately distinguishing and identifying DEC with different virulence is necessary for epidemiological surveillance and investigation. Clustered regularly interspaced short palindromic repeats (CRISPR) typing is a new molecular method that can distinguish pathogenic bacteria excellently and has shown great promise in DEC typing. The purpose of this study was to investigate the discrimination of CRISPR typing method for DEC and explore the pathogenicity potential of DEC based on CRISPR types (CT). The whole genome sequences of 789 DEC strains downloaded from the database were applied CRISPR typing and serotyping. The D value (Simpson's index) with 0.9709 determined that CRISPR typing had a higher discrimination. Moreover, the same H antigen strains with different O seemed to share more identical spacers. Further analyzing the strains CRISPR types and the number of virulence genes, it was found that there was a significant correlation between the CRISPR types and the number of virulence genes (p < 0.01). The strains with the largest number of virulence genes concentrated in CT25 and CT56 and the number of virulence genes in CT264 was the least, indicating that the pathway potential of different CRISPR types was variable. Combined with the Caco-2 cell assay of the laboratory strains, the invasion capacity of STEC strains of different CRISPR types was different and there was no significant difference in the invasion rate between different CRISPR type strains (p > 0.05). In the future, with the increase of the number of strains that can be studied experimentally, the relationship between CRISPR types and adhesion and invasion capacities will be further clarified. [ABSTRACT FROM AUTHOR]

Objective. Determine the frequency of diarrheagenic Escherichia coli pathotypes colonizing swine. Materials and Methods. E. coli strains isolated of fecal samples from 280 swine, produced for local consumption, in a semi-technical farm of Morelos state, (central Mexico) were tested to identify the diarrheagenic E. coli pathotypes by multiplex PCR. Results. Of the 521-diarrheagenic E. coli isolates examined, 50 (9.6%) were positive for at least one virulence gene in 42 different animals. Thus, 15% (42/280) of the swine in this farm were colonized with pathogenic E. coli. Among the E. coli isolates, the pathotype EPEC (6.5%) was the most frequently, followed by EHEC (2.3%), ETEC and EIEC (0.4%). Conclusions. In this study, four different E. coli pathotypes were found among swine colonized by E. coli in this farm. Thus, these swine are reservoirs for these virulent bacteria and there is potential risk of causing diarrhea in swine and in the population consuming the meat.

Diarrheagenic Escherichia coli (DEC) can cause epidemic diarrhea worldwide. The pathogenic potential of different strains is diverse and the continuous emergence of pathogenic strains has brought serious harm to public health. Accurately distinguishing and identifying DEC with different virulence is necessary for epidemiological surveillance and investigation. Clustered regularly interspaced short palindromic repeats (CRISPR) typing is a new molecular method that can distinguish pathogenic bacteria excellently and has shown great promise in DEC typing. The purpose of this study was to investigate the discrimination of CRISPR typing method for DEC and explore the pathogenicity potential of DEC based on CRISPR types (CT). The whole genome sequences of 789 DEC strains downloaded from the database were applied CRISPR typing and serotyping. The D value (Simpson’s index) with 0.9709 determined that CRISPR typing had a higher discrimination. Moreover, the same H antigen strains with different O seemed to share more identical spacers. Further analyzing the strains CRISPR types and the number of virulence genes, it was found that there was a significant correlation between the CRISPR types and the number of virulence genes (p < 0.01). The strains with the largest number of virulence genes concentrated in CT25 and CT56 and the number of virulence genes in CT264 was the least, indicating that the pathway potential of different CRISPR types was variable. Combined with the Caco-2 cell assay of the laboratory strains, the invasion capacity of STEC strains of different CRISPR types was different and there was no significant difference in the invasion rate between different CRISPR type strains (p > 0.05). In the future, with the increase of the number of strains that can be studied experimentally, the relationship between CRISPR types and adhesion and invasion capacities will be further clarified.

Background and Objectives: Pathogenic diseases resulting from microbial contamination of food have been widely distributed in many parts of the world. Among these, Escherichia coli is one of the most important foodborne pathogenic bacteria. Diarrhea is one of the major causes of children's death in developing countries, with approximately 2 million deaths annually. The current study aimed to determine the frequency of diarrheagenic E. coli pathotypes such as Enteropathogenic E. coli (EPEC), Enterotoxigenic E. coli (ETEC), Enteroaggregative E. coli (EAEC), and Shiga toxin-producing E. coli (STEC) in Brassica oleracea cultivars in order to provide information on the assessment of diarrheagenic E. coli pathogenesis risk. Materials and Methods: 100 samples of vegetables were collected in Tehran, including cabbage, cauliflower, broccoli and Brussels sprouts. After homogenizing samples, enrichment was done in the EC broth medium. Five colonies of pure culture were used for DNA extraction. Pathotypes were identified by PCR using virulence genes. Results: The results showed that the prevalence of diarrheagenic E. coli strains was 7%. The EPEC prevalence was 3%, All EPEC isolates were atypical. The ETEC frequency was 3%, And the EAEC prevalence was 1%. Conclusion: These findingsindicated that Brassica oleracea cultivars could be consideredas a source of contamination with diarrhea-causing E. coli strains. [ABSTRACT FROM AUTHOR]

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Purpose: To elucidate the contribution of a transferable plasmid harboring the blaNDM-1 gene in an Escherichia coli clinical isolate to the spread of resistance determinants. Methods: Nine extended-spectrum β-lactamase-producing E. coli were collected from diarrhea samples from a pediatric patient and genetic linkage was investigated through enterobacteriaceae repetitive intragenic consensus polymerase chain reaction (PCR). Bacterial species were identified by 16s rRNA sequencing, susceptibility testing with the use of a BD PhoenixTM-100 Automated Microbiology System, and assessment of virulence genes by PCR. The transferability of blaNDM-1 in E. coli strain TCM3e1 was confirmed by conjugation experiments. Complete sequencing of E. coli strain TCM3e1 was determined with the PacBio and Illumina NovaSeq platforms and the characteristics were analyzed with bioinformatics software. Results: The results showed that all nine E. coli strains were the same clone. E. coli strain TCM3e1 was resistant to 12 antimicrobial agents and carried the virulence gene EAST-1. Conjugation transfer analysis showed that blaNDM-1 was carried on a self-transmissible plasmid. Two copies of the blaNDM-1 gene were present on an IncC plasmid and some resistance genes with two or three copies were located downstream of the blaNDM-1 gene and formed a tandem repeat fragment (blaDNM-1-bleo-sul1- aadA17- dfrA12). Conclusion: A transmissible plasmid harboring two copies of the blaNDM-1 gene, including clonal dispersions of the blaNDM-1 gene, was identified in clinical isolates. These findings emphasized the necessity of surveillance of the plasmid-borne blaNDM-1 to prevent dissemination. [ABSTRACT FROM AUTHOR]

Aim: This study was aimed to determine the virulent genes and antibiotic resistance patterns among circulating diarrheagenic Escherichia coli (DEC) pathotypes in a tertiary care health center in east of Nigeria. Materials and Methods: Diarrheal stool samples were obtained from 80 children under 5 years and E. coli was isolated and identified using standard biochemical and molecular methods. Multiplex polymerase chain reaction (PCR) was used to detect eight virulent genes of DEC. Disk diffusion method was used to determine the antibiotic susceptibility of DEC. Results: DEC infection was observed in 54 (68%) children among which ial gene for enteroinvasive E. coli (EIEC) (40% [n=22]) was commonly detected followed by eltA/eltB for enterotoxigenic E. coli (ETEC) (30% [n=16]), pCVD for enteroaggregative E. coli (EAEC) (20% [n=11]), and eaeA/bfpA for typical enteropathogenic E. coli (EPEC) (10% [n=5]). The DEC isolates phenotypically exhibited resistance for ampicillin (AMP) (44 [81%]), followed by ciprofloxacin (CIP)/ levofloxacin (LEV) (28 [52%]), cefoxitin (FOX) (11 [20%]), and amoxicillin-clavulanic acid (AMC) (6 [11%]). About 60% isolates of stable toxins-ETEC were resistant to AMC, CIP, and LEV while all the labile toxin-ETEC exhibited resistance to AMP. About 60% (n=6) resistance were seen in EAEC against ampicillin, AMC, FOX, CIP, and LEV. In EIEC, all the isolates (n=22) were resistant to AMP while 50% (n=11) were resistant to both CIP and LEV. All EPEC (n=5) were resistant to AMP, FOX, CIP, and LEV. Conclusion: High frequency of virulent ial and eltA/eltB genes for EIEC and ETEC, respectively, suggests that they are the primary etiological agents of diarrhea in children among DEC pathotypes. Resistance of DEC to more than two classes of antibiotics indicate possible emergence of multidrug resistance.

Objective To study the epidemiologic and etiologic characteristics of Salmonella, Shigella, Vibrio parahemolyticus, diarrheagenic Escherichia coli (DEC) from foodborne diarrhea patients in Baiyin. Methods Stool samples were collected from foodborne disease patients in Baiyin during 2016-2018 and pathogenic bacteria strains were isolated and identified by biochemical characteristics, serotyping, drug resistance test and pulsed-field gel electrophoresis (PFGE). Results A total of 300 strains were isolated from 1 003 stool samples, the overall positive rate was 29.9% and the positive rate of DEC was the highest (29.1%, 292/1 003), followed by that of Salmonella and Shigella, and Vibrio parahemolyticus were not detected. Totally 1 003 foodborne disease cases were reported and the ratio of male and female was 1.3:1, the detection rate of pathogenic bacteria in female patients (31.8%, 136/428) was higher than male patients (28.5%, 164/575), the patients were mainly adults aged 19-59 years and young children under 5 years old, and the positive rate was 31.5% (76/241) and 30.6% (188/615). Pathogenic bacteria strains were isolated mainly in the second and third quarter of the year. PFGE result indicated that 7 isolates belonged to 6 types, and there was one aggregation phenomenon. Salmonella had high resistant rate to tetracycline (85.7%, 6/7), it was found that 6 strains were multi-drug resistant. Shigella flexneri 2a subtype was resistant to 7 drug.292 strains of DEC were sensitive to imipenem, and the drug sensitive rates of ceftazidime, cefoxitin, chloramphenicol and ciprofloxacin were greater than 80%, the resistance rate to ampicillin was the highest (80.8%, 236/292), the multi-resistance to three or more antibiotics was 75.3% (220/292). Conclusion In the active etiological surveillance for foodborne diseases in Baiyin during 2016-2018, the detection rate of DEC was the highest. Pathogenic bacteria strains were isolated mainly in adults aged 19-59 years. The season specific characteristics of pathogenic bacteria was observed, and the infections mainly occurred in the second and third season. Multidrug resistance of pathogenic bacteria strains was serious with broad-spectrum.

Background and Objectives: Pathogenic diseases resulting from microbial contamination of food have been widely distributed in many parts of the world. Among these, Escherichia coli is one of the most important foodborne pathogenic bacteria. Diarrhea is one of the major causes of children’s death in developing countries, with approximately 2 million deaths annually. The current study aimed to determine the frequency of diarrheagenic E. coli pathotypes such as Enteropathogenic E. coli (EPEC), Enterotoxigenic E. coli (ETEC), Enteroaggregative E. coli (EAEC), and Shiga toxin-producing E. coli (STEC) in Brassica oleracea cultivars in order to provide information on the assessment of diarrheagenic E. coli pathogenesis risk. Materials and Methods: 100 samples of vegetables were collected in Tehran, including cabbage, cauliflower, broccoli and Brussels sprouts. After homogenizing samples, enrichment was done in the EC broth medium. Five colonies of pure culture were used for DNA extraction. Pathotypes were identified by PCR using virulence genes. Results: The results showed that the prevalence of diarrheagenic E. coli strains was 7%. The EPEC prevalence was 3%, All EPEC isolates were atypical. The ETEC frequency was 3%, And the EAEC prevalence was 1%. Conclusion: These findings indicated that Brassica oleracea cultivars could be consideredas a source of contamination with diarrhea-causing E. coli strains.

Copyright of Journal of Modern Laboratory Medicine is the property of Journal of Modern Laboratory Medicine Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives To investigate the epidemiological features of diarrheagenic Escherichia coli (DEC) in patients with acute diarrhea in China. Methods An active sentinel surveillance was performed in all-age patients with acute diarrhea in China, 2009‒2018. DEC was isolated and identified by serological assay and PCR from stool samples. Results DEC was determined in 6.68% (6,119/91,651) of the patients, with higher positive rates among females than among males (6.97% vs. 6.46%) and among 18‒59 years patients (7.88%) than among other age groups. Five pathotypes were identified, the most prevalent was enteroaggregative E. coli (EAEC), followed by enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC). Pediatric patients <5 years had higher positive rate of EAEC (2.07%), followed by EPEC (1.81%), and enterohemorrhagic E. coli (EHEC) (0.31%), while the 18‒59 years patients had higher infection of ETEC (2.36%). ETEC and EPEC were more frequently identified in urban than rural areas, with age and gender adjusted positive rate of 1.68% vs. 1.14% respectively, and 1.77% vs. 1.55%, while EIEC and EHEC were more frequently identified in rural areas. Conclusions These findings highlight the epidemiology features of DEC and underscores the need for conducting DEC surveillance. [ABSTRACT FROM AUTHOR]