Enteropathogenic Escherichia coli—A Summary of the Literature

Estimated global and regional causes of deaths from diarrhoea in children younger than 5 years during 2000-21: a systematic review and Bayesian multinomial analysis

BACKGROUND

Information on the causes of deaths from diarrhoea in children younger than 5 years is needed to design improved preventive and therapeutic approaches. We aimed to conduct a systematic analysis of studies to report estimates of the causes of deaths from diarrhoea in children younger than 5 years at global and regional levels during 2000-21.

METHODS

For this systematic review and Bayesian multinomial analysis, we included 12 pathogens with the highest attributable incidence in the Global Enteric Multicenter Study. We searched PubMed, Scopus, Embase, Web of Science, Global Health Index Medicus, Global Health OVID, IndMed, Health Information Platform for the Americas (PLISA), Africa-Wide Information, and Cochrane Collaboration for articles published between Jan 1, 2000, and Dec 31, 2020, using the search terms "child", "hospital", "diarrhea", "diarrhoea", "dysentery", "rotavirus", "Escherichia coli", "salmonella", "shigella", "campylobacter", "Vibrio cholerae", "cryptosporidium", "norovirus", "astrovirus", "sapovirus", and "adenovirus". To be included, studies had to have a patient population of children younger than 5 years who were hospitalised for diarrhoea (at least 90% of study participants), at least a 12-month duration, reported prevalence in diarrhoeal stools of at least two of the 12 pathogens, all patients with diarrhoea being included at the study site or a systematic sample, at least 100 patients with diarrhoea, laboratory tests done on rectal swabs or stool samples, and standard laboratory methods (ie, quantitative PCR [qPCR] or non-qPCR). Studies published in any language were included. Studies were excluded if they were limited to nosocomial, chronic, antibiotic-associated, or outbreak diarrhoea or to a specific population (eg, only children with HIV or AIDS). Each article was independently reviewed by two researchers; a third arbitrated in case of disagreement. If both reviewers identified an exclusion criterion, the study was excluded. Data sought were summary estimates. Data on causes from published studies were adjusted when necessary to account for the poor sensitivity of non-qPCR methods and for attributable fraction based on quantification of pathogens in children who are ill or non-ill. The causes of deaths from diarrhoea were modelled on the causes of hospitalisations for diarrhoea. We separately modelled studies reporting causes of diarrhoea in children who were hospitalised in low-income and middle-income countries (LMICs) and in high-income countries (HICs).

FINDINGS

Of 74 282 papers identified in the initial database search, we included 138 studies (91 included data from LMICs and 47 included data from HICs) from 73 countries. We modelled estimates for 194 WHO member states (hereafter referred to as countries), including 42 HICs and 152 LMICs. We could attribute a cause to 1 003 448 (83·8%) of the estimated 1 197 044 global deaths from diarrhoea in children younger than 5 years in 2000 and 360 730 (81·3%) of the estimated 443 833 global deaths from diarrhoea in children younger than 5 years in 2021. The cause with the largest estimated global attribution was rotavirus; in LMICs, the proportion of deaths from diarrhoea due to rotavirus in children younger than 5 years appeared lower in 2021 (108 322 [24·4%] of 443 342, 95% uncertainty interval 21·6-29·5) than in 2000 (316 382 [26·5%] of 1 196 134, 25·7-28·5), but the 95% CIs overlapped. In 2000, the second largest estimated attribution was norovirus GII (95 817 [8·0%] of 1 196 134 in LMICs and 225 [24·7%] of 910 in HICs); in 2021, Shigella sp had the second largest estimated attribution in LMICs (36 082 [8·1%] of 443 342), but norovirus remained with the second largest estimated attribution in HICs (84 [17·1%] of 490).

INTERPRETATION

Our results indicate progress in the reduction of deaths from diarrhoea caused by 12 pathogens in children younger than 5 years in the past two decades. There is a need to increase efforts for prevention, including with rotavirus vaccine, and treatment to eliminate further deaths.

FUNDING

Bill & Melinda Gates Foundation via Johns Hopkins University and the University of Virginia.

The presence of virulence factor genes downregulates uterine AQP3 and alters glutathione peroxidase activity and uterine histopathology in canine pyometra

Present study was designed to evaluate the role of virulence factor genes (papG, cnf1 and hylA) in the pathogenesis of canine pyometra. Antimicrobial susceptibility test and detection of virulence genes were performed Escherichia coli (E. coli) detected in uterine swab samples. Animals were divided into two groups based on the presence (VF+, n:14) or absence (VF-, n:7) of the virulence factor genes papG, cnf1 and hylA. Blood and tissue glutathione peroxidase activity, uterine histopathologic analysis and AQP3, ESR1, PGR, OXTR gene expressions were determined in both groups. Statistical analyses were performed using Stata version 15.1. All E. coli isolates were susceptible to amikacin, whereas resistant to ampicillin, amoxicillin/clavulanic acid and lincomycin. None of the isolates were susceptible to cefotaxime. E. coli isolates had at least one virulence gene. The most prevalent gene was fimH (100%), followed by fyuA (95.8%), usp (83.3%), sfa (75%), cnf1 and hlyA (70.8%) genes. Blood GPx activity was greater in VF+ animals. On the other hand, uterine tissue GPx activity was lower in VF+ group compared to the control group. Expression levels of AQP3 were upregulated more than fivefold in VF-dogs compared to the control group. In addition, AQP3 expression levels were found approximately threefold higher in VF (-) than VF (+) group (p < .05). Varying degree of inflammation noted for all animals with pyometra, but the presence of bacteria noted only in VF+ animals. In conclusion, the presence of virulence factor genes does not play a role in the histopathological degree of inflammation, the presence of bacteria was found to vary. Serum GPx activity increased in VF+ animals. While the hormone receptor expressions were similar, AQP expression was upregulated in the absence of virulence factor genes.

Modulating Liquid-Liquid Phase Separation of Nck Adaptor Protein against Enteropathogenic Escherichia coli Infection

Signaling proteins often form biomolecular condensates through liquid-liquid phase separation (LLPS) during intracellular signal transduction. Modulating the LLPS property of intracellular protein condensates will redirect intracellular signals and provide a potential way to regulate cellular physiology. Phosphorylation of multiple tyrosine residues of the transmembrane receptor nephrin is known to drive the LLPS of the adaptor protein Nck and neuronal Wiskott-Aldrich Syndrome protein (N-WASP) and form the Nck signaling complex. Phosphorylation of the translocated intimin receptor (Tir) in the host cell may recruit this enteropathogenic Escherichia coli (EPEC) virulence factor to the Nck signaling complex and lead to the entry of EPEC into the intestine cell. In this work, we first identified a phosphotyrosine (pY)-containing peptide 3pY based on the sequence similarity of nephrin and Tir; 3pY promoted the LLPS of Nck and N-WASP, mimicking the role of phosphorylated nephrin. Next, we designed a covalent blocker of Nck, peptide p1 based on the selected pY peptides, which site-selectively reacted with the SH2 domain of Nck (Nck-SH2) at Lys331 through a proximity-induced reaction. The covalent reaction of p1 with Nck blocked the protein binding site of Nck-SH2 and disintegrated the 3pY/Nck/N-WASP condensates. In the presence of membrane-translocating peptide L17E, p1 entered Caco-2 cells in the cytosol, reduced the number of Nck puncta, and rendered Caco-2 cells resistant to EPEC infection. Site-selective covalent blockage of Nck thereby disintegrates intracellular Nck condensates, inhibits actin reorganization, and shuts down the entrance pathway of EPEC. This work showcases the promotion or inhibition of protein phase separation by synthetic peptides and the use of reactive peptides as LLPS disruptors and signal modulators.

Occurrence of multidrug resistance associated with extended-spectrum β‑lactamase and the biofilm forming ability of Escherichia coli in environmental swine husbandry

Extended-spectrum beta-lactamase (ESBL) production and biofilm formation are mechanisms employed by Escherichia coli to resist beta-lactam antibiotics. Thus, we aimed to examine antibiotic resistance associated with ESBL production and biofilm formation in E. coli isolates from swine farms in Southern Thailand. In total, 159 E. coli isolates were obtained, with 44 isolates identified as ESBL producers, originating from feces (18.87 %) and wastewater (8.80 %) samples. All ESBL-producing strains exhibited resistance to ampicillin (100 %), followed by the cephalosporin group (97.73 %) and tetracycline (84.09 %). Multidrug resistance was observed in 17 isolates (38.63 %). Among the isolates from feces samples, the blaGES gene was the most prevalent, detected in 90 % of the samples, followed by blaCTX-M9 (86.67 %) and blaCTX-M1 (66.67 %), respectively. In the bacteria isolated from wastewater, both blaGES and blaCTX-M9 genes were the predominant resistance genes, detected in 100 % of the isolates, followed by blaCTX-M1 (64.29 %) and blaTEM (50 %), respectively. Strong biofilm formation was observed in 11 isolates (36.67 %) from feces and 4 isolates (25.57 %) from wastewater samples. Notably, nearly 100 % of ESBL-producing strains isolated from feces tested positive for both pgaA and pgaC genes, which play a role in intracellular adhesion and biofilm production. These findings contribute to the understanding and potential control of ESBL-producing E. coli, and the dissemination of antibiotic resistance and biofilm-related genes in swine farms.

Genetic Diversity and Expression of Intimin in Escherichia albertii Isolated from Humans, Animals, and Food

Escherichia albertii (E. albertii) is an emerging diarrheagenic pathogen associated with sporadic infections and human gastroenteric outbreaks. The eae gene, which encodes intimin in the locus of enterocyte effacement (LEE) operon, contributes to the establishment of the attaching and effacing (A/E) lesion. Increasing collection of E. albertii strains from various sources has resulted in a rapid increase in the number of eae subtypes. This study systematically investigated the prevalence and genetic diversity of eae among E. albertii strains isolated from humans, animals, and food. The eae gene was present in 452/459 (98.5%) strains and 23 subtypes were identified including two novel subtypes, named eae-α11 and η3. The eae-σ subtype was the most predominant among humans, animals, and food-derived strains, while eae-γ3, τ, and α11 were unique in human-derived strains. Additionally, the LEE island was also analyzed at genomic, transcriptional, and functional levels through genomic analysis, quantitative reverse transcription PCR, and HEp-2 cell adherence assays, respectively. The eae transcript levels were variable and associated with eae subtypes. Three different adherence patterns, including localized adherence-like (LAL), diffuse adherence (DA), and detachment (DE), were observed among E. albertii strains. This study demonstrated a high diversity of functional intimin in E. albertii strains isolated from humans, animals, and food. Further in vivo and in vitro studies are warranted to better elucidate the role of intimin or LEE in different genetic backgrounds.

Resistance and Virulence Surveillance in Escherichia coli Isolated from Commercial Meat Samples: A One Health Approach

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.

The Diversity of Escherichia coli Pathotypes and Vaccination Strategies against This Versatile Bacterial Pathogen

Escherichia coli (E. coli) is a gram-negative bacillus and resident of the normal intestinal microbiota. However, some E. coli strains can cause diseases in humans, other mammals and birds ranging from intestinal infections, for example, diarrhea and dysentery, to extraintestinal infections, such as urinary tract infections, respiratory tract infections, meningitis, and sepsis. In terms of morbidity and mortality, pathogenic E. coli has a great impact on public health, with an economic cost of several billion dollars annually worldwide. Antibiotics are not usually used as first-line treatment for diarrheal illness caused by E. coli and in the case of bloody diarrhea, antibiotics are avoided due to the increased risk of hemolytic uremic syndrome. On the other hand, extraintestinal infections are treated with various antibiotics depending on the site of infection and susceptibility testing. Several alarming papers concerning the rising antibiotic resistance rates in E. coli strains have been published. The silent pandemic of multidrug-resistant bacteria including pathogenic E. coli that have become more difficult to treat favored prophylactic approaches such as E. coli vaccines. This review provides an overview of the pathogenesis of different pathotypes of E. coli, the virulence factors involved and updates on the major aspects of vaccine development against different E. coli pathotypes.

Pathophysiology of Enteropathogenic Escherichia coli-induced Diarrhea

Enteropathogenic Escherichia coli (EPEC) are important diarrheal pathogens of infants and young children. Since the availability of molecular diagnosis methods, we now have new insights into the incidence and prevalence of these infections. Recent epidemiological studies indicate that atypical EPEC (aEPEC) are seen more frequently than typical EPEC (tEPEC) worldwide, including in both endemic diarrhea and diarrhea outbreaks. Therefore, it is important to further characterize the pathogenicity of these emerging strains. The virulence mechanisms and pathophysiology of the attaching and effacing lesion (A/E) and the type-three-secretion-system (T3SS) are complex but well-studied. A/E strains use their pool of locus of enterocyte effacement (LEE)-encoded and non-LEE-encoded effector proteins to subvert and modulate cellular and barrier properties of the host. However, the exact mechanisms of diarrhea in EPEC infection are not completely understood. From the clinical perspective, there is a need for fast, easy, and inexpensive diagnostic methods to define optimal treatment and prevention for children in endemic areas. In this article, we present a review of the classification of EPEC, epidemiology, pathogenesis of the disease caused by these bacteria, determinants of virulence, alterations in signaling, determinants of colonization vs. those of disease, and the limited information we have on the pathophysiology of EPEC-induced diarrhea. This article combines peer-reviewed evidence from our own studies and the results of an extensive literature search in the databases PubMed, EMBASE, and Scopus.

Plant-derived nanoparticles as alternative therapy against Diarrheal pathogens in the era of antimicrobial resistance: A review

Diarrhea is a condition in which feces is discharged from the bowels frequently and in a liquid form. It is one of the frequent causes of morbidity and mortality in developing countries. The impact of Diarrhea is worsened by the increasing incidence of antimicrobial resistance among the causative agents, and this is now categorized as a global healthcare challenge. Antimicrobial resistance among Diarrheal pathogens also contributes to extended infection durations, and huge economic loss even in countries with advanced public health policies. The ever-increasing incidence of antimicrobial resistance including the contraindications arising from the administration of antibiotics in some Diarrheal cases highlights a crucial need for the development of novel non-antibiotic alternative agents for therapeutic and biocontrol applications. One such intervention includes the application of plant-derived nanoparticles (PDNPs) with novel antimicrobial properties. Given their small size and large surface area to volume ratio, PDNPs can attack target bacterial cell walls to generate reactive oxygen species that may simultaneously disrupt bacteria cell components such as DNA and proteins leading to cell damage or death. This potential can make it very difficult for pathogenic organisms to develop resistance against these antibacterial agents. In this review, we provide a critical overview on the antimicrobial resistance crisis among Diarrheagenic bacteria. We also discuss the evidence from the existing literature to support the potential associated with the use of PDNPs as alternative therapeutic agents for multidrug resistant and antibiotics administer contraindicated bacteria that are associated with Diarrhea.

Clinical Manifestations and Stool Load of Atypical Enteropathogenic Escherichia coli Infections in United States Children and Adults

BACKGROUND & AIMS

There is debate whether atypical enteropathogenic Escherichia coli (aEPEC) causes disease in adults. aEPEC is commonly detected in symptomatic and asymptomatic individuals. aEPEC, in contrast to typical EPEC, lacks bundle-forming pili, altering its pathogenicity. Here, we define for the first time the clinical manifestations of sporadic aEPEC infection in United States children and adults and determine whether EPEC load correlates with disease.

METHODS

This is a retrospective case-control study of 380 inpatients/outpatients of all ages. EPEC load in stools was determined by quantitative polymerase chain reaction.

RESULTS

Diarrhea, vomiting, abdominal pain, and fever were more prevalent in EPEC-positive cases than in EPEC-negative controls. aEPEC infection caused mostly acute, mild diarrhea lasting for 6 to 13 days. However, some had severe diarrhea with 10 to 40 bowel movements per day or had persistent/chronic diarrhea. Fever, vomiting, and abnormal serum sodium levels were more common in children. Adults more often reported abdominal pain and longer duration of diarrhea. Symptomatic aEPEC infection was associated with leukocytosis in 24% of patients. EPEC load >0.1% was associated with symptomatic infection; however, loads varied greatly. Co-infecting pathogens did not alter diarrhea severity or EPEC load. Longitudinal data reveal that some are colonized for months to years or are repeatedly infected.

CONCLUSIONS

aEPEC is associated with a wide array of symptoms in adults, ranging from asymptomatic carriage to severe diarrhea. Higher EPEC loads are associated with presence of symptoms, but bacterial load does not predict disease or severity. Future studies are needed to understand bacterial and host factors that contribute to aEPEC pathogenicity to improve diagnostic tools and clinical care.

Sangyod rice bran extract enhances Lacticaseibacillus paracasei growth during the exponential phase and antibacterial activity of L. paracasei supernatant against zoonotic and foodborne pathogens

Background and Aim: Prebiotics are a group of nutrients or compounds that are degraded by the gut microbiota, including Lacticaseibacillus paracasei. The probiotic plays an important role in adhesion to the gut and is able to produce antimicrobial substances to inhibit pathogens. This study aimed to investigate the effects of Sangyod rice bran extract on the growth promotion of L. paracasei. Furthermore, antibacterial activity of the extract and L. paracasei supernatants cultured in De Man, Rogosa and Sharpe (MRS) medium plus the extract against zoonotic and foodborne pathogens was investigated. Materials and Methods: Antibacterial activity of the crude extract and the oil from Sangyod rice bran against the pathogens, including Bacillus cereus, Staphylococcus aureus, Escherichia coli, Avian pathogenic E. coli, and Pseudomonas aeruginosa was investigated using broth microdilution assay. The effects of the crude extract and the oil on the growth and adhesion of L. paracasei were further determined. The antibacterial activity of L. paracasei supernatant cultured in the medium supplemented with the extract and the oil against the pathogens was determined by agar well diffusion assay, followed by the broth microdilution assay. Finally, the chemical constituents and antioxidant activity of the crude extract and the oil from Sangyod rice bran were investigated. Results: The crude extract and the oil from Sangyod rice bran enhanced L. paracasei growth during the exponential phase. Furthermore, the crude extract at 0.25 mg/mL significantly enhanced the adhesion of L. paracasei to the surface compared with the control. Both minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of the crude extract against B. cereus and S. aureus were 0.5 and 1.0 mg/mL, respectively. All pathogens were sensitive to the supernatant of L. paracasei with similar MIC and MBC ranging from 12.5% v/v to 50% v/v. However, the MIC and MBC values of L. paracasei supernatant grown in MRS medium plus the crude extract and oil were not significantly different compared to the supernatant obtained from MRS alone. The crude extract had free radical scavenging activities with IC50 values at 0.61 mg/mL. Conclusion: The results suggested the potential benefits of the crude extract from Sangyod rice bran for inducing the growth and the adhesion of L. paracasei and inhibiting zoonotic and foodborne pathogens.

Discovery of a Novel Inner Membrane-Associated Bacterial Structure Related to the Flagellar Type III Secretion System

The bacterial flagellar type III secretion system (fT3SS) is a suite of membrane-embedded and cytoplasmic proteins responsible for building the flagellar motility machinery. Homologous nonflagellar (NF-T3SS) proteins form the injectisome machinery that bacteria use to deliver effector proteins into eukaryotic cells, and other family members were recently reported to be involved in the formation of membrane nanotubes. Here, we describe a novel, evolutionarily widespread, hat-shaped structure embedded in the inner membranes of bacteria, of yet-unidentified function, that is present in species containing fT3SS. Mutant analysis suggests a relationship between this novel structure and the fT3SS, but not the NF-T3SS. While the function of this novel structure remains unknown, we hypothesize that either some of the fT3SS proteins assemble within the hat-like structure, perhaps including the fT3SS core complex, or that fT3SS components regulate other proteins that form part of this novel structure.

IMPORTANCE The type III secretion system (T3SS) is a fascinating suite of proteins involved in building diverse macromolecular systems, including the bacterial flagellar motility machine, the injectisome machinery that bacteria use to inject effector proteins into host cells, and probably membrane nanotubes which connect bacterial cells. Here, we accidentally discovered a novel inner membrane-associated complex related to the flagellar T3SS. Examining our lab database, which is comprised of more than 40,000 cryo-tomograms of dozens of species, we discovered that this novel structure is both ubiquitous and ancient, being present in highly divergent classes of bacteria. Discovering a novel, widespread structure related to what are among the best-studied molecular machines in bacteria will open new venues for research aiming at understanding the function and evolution of T3SS proteins.

Antimicrobial Susceptibility and Molecular Characterization of Escherichia coli Recovered from Milk and Related Samples

There is a rising concern about illnesses resulting from milk consumption due to contamination by pathogenic microorganisms including Escherichia coli. This study examined the occurrence and antimicrobial susceptibility of E. coli isolated from cow milk and related samples. Furthermore, partial sequencing was done to ascertain the genetic relatedness and possible cross contamination among the samples. In all, 250 samples, that is, 50 each of raw milk, cow teat, milkers’ hands, milking utensils, and fecal matter of cows, were cultured for the identification of E. coli. E. coli was detected in 101/250 samples (40.4%). Milk and fecal samples recorded the highest percentages of 68.0% and 66.0%, respectively. Forty-two (42) E. coli strains examined for antimicrobial resistance showed an overall 25.5% resistance, 15.0% intermediate resistance, and 59.5% susceptibility. The isolates had a high level of resistance to teicoplanin (100.0%), but were susceptible to chloramphenicol (95.2%) and azithromycin (92.9%). The Multiple Antibiotic Resistance (MAR) index pattern ranged from 0.1 to 0.5, and 40.5% exhibited multiple drug resistance. The E. coli strains formed 11 haplotypes, and a phylogenic tree analysis showed relatedness among the isolates in other African countries. This observation is an indication of cross contamination among the milk and its related samples.

Sulforaphane Ameliorates the Intestinal Injury in Necrotizing Enterocolitis by Regulating the PI3K/Akt/GSK-3β Signaling Pathway

Objective

Necrotizing enterocolitis (NEC) is a serious neonatal disease; this study aims to investigate the role of sulforaphane (SFN) in NEC-induced intestinal injury.

Methods

An animal model of NEC was established in newborn mice and intragastrically administrated with SFN; then, the general status and survival of the mice were observed. H&E staining was used to observe the pathological changes of intestinal tissues. ELISA, immunohistochemical staining, and flow cytometry assays were used to detect the levels of inflammatory factors, including TNF-α, IL-6, and IL-17, the expression of Bax, Bcl-2, TLR4, and NF-κB, and the percentages of the Th17 and Treg cells, respectively. GSK-3β expression levels were measured by immunofluorescence. IEC-6 and FHC cells were induced with LPS to mimic NEC in vitro and coincubated with SFN; then, the inflammatory factor levels and cell apoptosis rate were detected. Finally, Western blot was used to assess the expression of PI3K/Akt/GSK-3β pathway-related proteins in vitro and in vivo.

Results

SFN improved the survival rate of NEC mice during modeling, alleviated the severity of the intestinal injury, and reduced the proportion of Th17/Treg cells. SFN could inhibit TLR4 and NF-κB levels, decrease the release of inflammatory factors TNF-α and IL-6, suppress Bax expression, increase Bcl-2 expression, and inhibit apoptosis both in in vitro and in vivo models of NEC. Meanwhile, SFN regulated the expression of PI3K/Akt/GSK-3β pathway-related proteins in vitro and in vivo.

Conclusion

SFN relieved the inflammatory response and apoptosis by regulating the PI3K/Akt/GSK-3β signaling pathway, thereby alleviating NEC in model mice and cells.

Hieracium waldsteinii (Asteraceae) and Onosma stellulata (Boraginaceae) as a Source of Antioxidant and Antimicrobial Agents

The current study aimed to phytochemically characterize (including a detailed phenolic profile) two endemic Balkan's species (Hieracium waldsteinii and Onosma stellulata) and determine their possible application as a source of natural antioxidant and antimicrobial agents. The main phenolic compound in both species (in all examined parts) was chlorogenic acid. Eriodictyol, genistein and naringenin were quantified only in H. waldsteinii while isorhamnetin-3-O-rutinoside and sinapic acid were characteristic for O. stellulata. The highest antioxidant activity (98 mg AAE/g dry weight for TAC assay) was ascribed to the flower extract of H. waldsteinii while the lowest results (∼4.3 mg AAE/g dry weight for FRP assay) were exhibited by the extracts obtained from the plant's stem. Antimicrobial assays showed moderate antibacterial, i. e., moderate/strong activity against several tested fungi (in particular Trichoderma viride). Correlation analysis revealed strong positive connection between phenolic compounds and reducing power of extracts as well as between total phenolic and flavonoid content and the obtained minimal inhibitory concentration recorded in antibacterial assays.

Antimicrobial Resistance, Pathogenic, and Molecular Characterization of Escherichia coli from Diarrheal Patients in South Korea

Diarrheal diseases due to foodborne Escherichia coli are the leading cause of illness in humans. Here, we performed pathogenic typing, molecular typing, and antimicrobial susceptibility tests on seventy-five isolates of E. coli isolated from stool samples of patients suffering from foodborne diseases in Busan, South Korea. All the isolates were identified as E. coli by both biochemical analysis (API 20E system) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The bacteria displayed entero-pathogenic E. coli (EPEC) (47.0%), entero-aggregative E. coli (EAEC) (33.3%), entero-toxigenic E. coli (ETEC) (6.6%), ETEC and EPEC (6.6%), EPEC and EAEC (4%), and ETEC and EAEC (2.7%) characteristics. The E. coli isolates were highly resistant to nalidixic acid (44.0%), tetracycline (41.3%), ampicillin (40%), ticarcillin (38.7%), and trimethoprim/sulfamethoxazole (34.7%); however, they were highly susceptible to imipenem (98.6%), cefotetan (98.6%), cefepime (94.6%), and chloramphenicol (94.6%). Although 52 strains (69.3%) showed resistance against at least 1 of the 16 antibiotics tested, 23 strains (30.7%) were susceptible to all the antibiotics. Nine different serotypes (O166, O8, O20, O25, O119, O159, O28ac, O127a, and O18), five genotypes (I to V, random-amplified polymorphic DNA), and four phenotypes (A to D, MALDI-TOF MS) were identified, showing the high level of heterogeneity between the E. coli isolates recovered from diarrheal patients in South Korea.

Epitheliocystis in Greater Amberjack: Evidence of a Novel Causative Agent, Pathology, Immune Response and Epidemiological Findings

Epitheliocystis is a fish gill disease caused by a broad range of intracellular bacteria infecting freshwater and marine fish worldwide. Here we report the occurrence and progression of epitheliocystis in greater amberjack reared in Crete (Greece). The disease appears to be caused mainly by a novel Betaproteobacteria belonging to the Candidatus Ichthyocystis genus with a second agent genetically similar to Ca. Parilichlamydia carangidicola coinfecting the gills in some cases. After a first detection of the disease in 2017, we investigated epitheliocystis in the following year's cohort of greater amberjack juveniles (cohort 2018) transferred from inland tanks to the same cage farm in the open sea where the first outbreak was detected. This cohort was monitored for over a year together with stocks of gilthead seabream and meagre co-farmed in the same area. Our observations showed that epitheliocystis could be detected in greater amberjack gills as early as a month following the transfer to sea cages, with ionocytes at the base of the gill lamellae being initially infected. Cyst formation appears to trigger a proliferative response, leading to the fusion of lamellae, impairment of gill functions and subsequently to mortality. Lesions are characterized by infiltration of immune cells, indicating activation of the innate immune response. At later stages of the outbreak, cysts were no longer found in ionocytes but were observed in mucocytes at the trailing edge of the filament. Whole cysts appeared finally to be expelled from infected mucocytes directly into the water, which might constitute a novel means of dispersion of the infectious agents. Molecular screening indicates that meagre is not affected by this disease and confirms the presence of previously described epitheliocystis agents, Ca. Ichthyocystis sparus, Ca. Ichthyocystis hellenicum and Ca. Similichlamydia spp., in gilthead seabream. Prevalence data show that the bacteria persist in both gilthead seabream and greater amberjack cohorts after first infection.

Bacteriophages: A possible solution to combat enteropathogenic Escherichia coli infections in neonatal goats

Due to awareness and benefits of goat rearing in developing economies, goats' significance is increasing. Unfortunately, these ruminants are threatened via multiple bacterial pathogens such as Enteropathogenic Escherichia coli (EPEC). In goat kids and lambs, EPEC causes gastrointestinal disease leading to substantial economic losses for farmers and may also pose a threat to public health via the spread of zoonotic diseases. Management of infection is primarily based on antibiotics, but the need for new therapeutic measures as an alternative to antibiotics is becoming vital because of the advent of antimicrobial resistance (AMR). The prevalence of EPEC was established using bfpA gene, uspA gene, and Stx1 gene, followed by phylogenetic analysis using Stx1 gene. The lytic activity of the isolated putative coliphages was tested on multi-drug resistant strains of EPEC. It was observed that a PCR based approach is more effective and rapid as compared to phenotypic tests of Escherichia coli virulence. It was also established that the isolated bacteriophages exhibited potent antibacterial efficacy in-vitro, with some of the isolates (16%) detected as T4 and T4-like phages based on gp23 gene. Hence, bacteriophages as therapeutic agents may be explored as an alternative to antibiotics in managing public, livestock and environmental health in this era of AMR.