The emergence of carbapenem-resistant Escherichia coli (CREC) poses crucial challenges in clinical management, requiring continuous monitoring to inform control and treatment strategies. This study aimed to investigate the genomic and epidemiological characteristics of CREC isolates obtained from a tertiary hospital in China between 2015 and 2022. Next-generation sequencing was used for genomic profiling, and clinical data from patients were integrated into the analysis. ST405 (21.2%), ST167 (20.3%) and ST410 (15.9%) were the most prevalent of the 30 distinct sequence types (STs) identified among the 113 unique CREC isolates. Infections caused by the ST405 CREC clone and severe underlying diseases were associated with higher in-hospital mortality rates, particularly in patients aged ≥65 years. Furthermore, the ST405 clone exhibited a greater number of virulence and resistance genes than non-ST405 CREC clones. The virulence gene eaeX and resistance genes mph(E) and msr(E) were exclusively found in ST405 clones, while other virulence genes (agn43, ipad and malX) and resistance genes (armA, catB3 and arr-3) were more prevalent in this clones. Additionally, ST405 showed higher minimum inhibitory concentrations for both meropenem and imipenem and showed superior growth under the meropenem challenge. Galleria mellonella virulence assays revealed that the ST405 CREC clone was more virulent than other predominant CREC STs. Our findings underscore the clinical threat posed by the ST405 CREC clone, which exhibits both enhanced virulence and extensive drug resistance. These results highlight the urgent need for stringent surveillance and targeted interventions to curb its further dissemination and prevent potential outbreaks.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important intestinal pathogen that causes severe foodborne diseases. We previously demonstrated that the genomic island-encoded regulator LmiA activates the locus of enterocyte effacement (LEE) genes to promote EHEC O157:H7 adherence and colonization in the host intestine. However, whether LmiA is involved in the regulation of any other biological processes in EHEC O157:H7 remains largely unexplored. Here, we compared global gene expression differences between the EHEC O157:H7 wild-type strain and an lmiA mutant strain using RNA-seq technology. Genes whose expression was affected by LmiA were identified and classified using the Cluster of Orthologous Groups (COG) database. Specifically, the expression of acid resistance genes (including gadA, gadB, and gadC) was significantly downregulated, whereas the transcript levels of biofilm-related genes (including Z_RS00105, yadN, Z_RS03020, and fdeC) were increased, in the ΔlmiA mutant compared to the EHEC O157:H7 wild-type strain. Further investigation revealed that LmiA enhanced the acid resistance of EHEC O157:H7 by directly activating the transcription of gadA and gadBC. In contrast, LmiA reduced EHEC O157:H7 biofilm formation by indirectly repressing the expression of biofilm-related genes. Furthermore, LmiA-mediated regulation of acid resistance and biofilm formation is highly conserved and widespread among EHEC and enteropathogenic E. coli (EPEC). Our findings provide essential insight into the regulatory function of LmiA in EHEC O157:H7, particularly its role in regulating acid resistance and biofilm formation.

Pathogenic Escherichia coli are a major cause of infections in both humans and animals, leading to conditions such as severe diarrheal diseases, urinary tract infections, enteritis, and septicemia. To combat bacterial infections, antibiotics are widely utilized. However, the extensive and inappropriate use of antibiotics has fueled the development and spread of antibiotic resistance, posing a significant challenge to the effective treatment of E. coli. There is consequently an urgent need to explore alternative therapies to control such infections. This review provides an overview of the recent findings concerning indole signaling in E. coli. E. coli uses indole as a quorum sensing molecule, and indole signaling has been reported to decrease various virulence factors in pathogenic E. coli, including motility, biofilm formation, adherence to host cells, expression of the LEE pathogenicity island, and formation of attaching and effacing lesions. This makes indole signaling an interesting target for the development of new therapeutics in the framework of antivirulence therapy. Both natural and synthetic indole analogues have been explored as potential virulence inhibitors. This alternative approach could be advantageous, as it will exert less selective pressure for resistance development than conventional antibiotics.

Enteropathogenic E. coli (EPEC) is a significant cause of diarrhea, leading to high infant mortality rates. A key toxin produced by EPEC is the EspC autotransporter, which is regulated alongside genes from the locus of enterocyte effacement (LEE), which collectively result in the characteristic attaching and effacing lesions on the intestinal epithelium. In this study, we present the crystal structure of the EspC passenger domain (αEspC) revealing a toxin comprised a serine protease attached to a large β-helix with additional subdomains. Using various modified EspC expression constructs, alongside type III secretion system-mediated cell internalization assays, we dissect how the αEspC structural features enable toxin entry into the intestinal epithelium to cause cell cytotoxicity.

Aptamer sensors based on surface-enhanced Raman scattering (SERS) technology have demonstrated great potential in the ultrasensitive and rapid detection of Escherichia coli (E. coli). Herein, this paper presents a digital SERS aptamer sensor. This sensor integrates ordered nanoscale array synthesis technology and digital analysis technology, enabling highly sensitive and rapid bacterial quantification. The ordered monolayer gold nanosphere arrays (Au NS) can form uniform and dense "hot spots" on the silicon wafer due to their uniform spherical structures and narrow gaps. Moreover, digital SERS is adopted to further optimize the signal uniformity so as to achieve precise quantification. The sensor modules are combined together through base pairing. The aptamers labeled with Raman tags are detached from the complementary DNA due to the competition of the target substance, thus realizing the detection of E. coli. The digital SERS aptamer sensor has been verified to possess excellent selectivity and reproducibility. It has a wide dynamic linear detection range from 1.0 * 101 to 1.0 * 109 CFU/ml and a detection limit of 0.657 CFU/ml, maintaining excellent specificity even in the presence of mixed bacterial interference. The spiked recoveries in actual samples range from 98.80 % to 99.81 %. Leveraging different aptamers and digital analysis, the sensor holds promise for food safety and environmental monitoring applications.

Floppy kid syndrome (FKS) is a metabolic disorder disease in newborn goats caused by intestinal dysbiosis. In this study, pathogens were isolated from the intestinal contents of FKS-affected goats (8 Escherichia coli isolates and 2 Staphylococcus aureus isoates), and virulence gene detection showed that Escherichia coli predominantly expressed HlyD (62.5 %) and K88 (37.5 %), with 37.5 % of isolates co-expressing HlyD/K88; all Staphylococcus aureus isolates carried the nuc, sea, sed, and FnbA. Antibiotic susceptibility testing revealed that amikacin exhibited the highest sensitivity against both pathogens, with sensitivity rates of 87.5 % in Escherichia coli and 100 % in Staphylococcus aureus. By combining virulence gene detection and antimicrobial susceptibility tests, a comprehensive treatment regimen (amikacin + sodium bicarbonate + glucose) was designed, and clinical trial indicated that the 3-day cure rate in the treatment group reached 100 % (24/24), significantly higher than 14.3 % (2/14) in the control group. This study revealed a synergistic pathogenic mechanism between Escherichia coli HlyD/K88 and Staphylococcus aureus enterotoxins, confirming that an amikacin-based combined treatment regimen can effectively alleviate FKS symptoms, thereby providing a theoretical basis for precision medication in FKS.

This study introduces a novel biosensing platform, Plasmonic Array Nanohole Technology on Metal-Insulator-Metal (PANTOMIM), designed to overcome limitations of traditional plasmonic nanohole array biosensors. PANTOMIM utilizes a metal-insulator-metal structure as a lossy waveguide to dampen metal/substrate peaks, ensuring high extinction coefficients and spectral purity for biosensing. The architecture is optimized for the 800-850 nm wavelength range, with potential for future integration into nanophotonic devices. To demonstrate its clinical utility, we applied PANTOMIM to the detection of uropathogenic Escherichia coli (UPEC) in urine samples. This approach addresses the need for rapid diagnosis of urinary tract infections, providing results in 15 min and requiring minimal sample preparation. The efficacy of the technology was validated in a clinical setting with a cohort of 100 patients, showcasing its potential to revolutionize the detection of UPEC. PANTOMIM combines the advantages of plasmonic nanohole arrays, including tunable periodicity, coupled plasmonic response, and extraordinary optical transmission, while mitigating the challenges associated with thin-film plasmonic metals. This innovation paves the way for integrated nanoplasmonic biosensors for point-of-care diagnostics.

Escherichia coli is a rod-shaped Gram-negative bacterium notorious for provoking diverse human infections. In this study, we report the first total synthesis of tetrasaccharide repeating unit of the cell wall of Gram-negative bacteria Escherichia coli O50 augmented with aminoethyl linker, employing both linear [1+1+1+1] and one-pot [1+1+2] approaches, and later one providing the better yield. As an aminoethyl linker, it can be further utilized for biological purposes; the challenging cis (1 → 4)-β-glycosidic linkage between l-rhamnose and d-glucosamine is addressed here with high stereo control.

Infections caused by invasive intracellular bacteria pose major therapeutic challenges due to pathogen survival and growth inside of host cells as well as the low intracellular accessibility for conventional antibiotics. The limited ability of most antibiotics to enter intracellular compartments underscores the urgent need for innovative antimicrobial agents capable of overcoming these barriers. In this study, the antibacterial peptide Pac525 was synthesized with the RGD domain to facilitate efficient penetration into eukaryotic cells. The efficacy and safety of RGD-Pac525 was evaluated in intracellular infection models, using the macrophage cell line RAW 264.7, chicken intestinal organoids, and chicken embryo tissues via the chorioallantoic membrane (CAM). Our findings from cell line experiments demonstrate that the RGD-Pac525 peptide retained the antimicrobial properties of the original peptide without compromising its efficacy. While RGD-Pac525 reduced the intracellular adherent-invasive pathogen Escherichia coli KV203 by 50% in RAW 264.7 macrophage cells, it did not adversely affect the macrophage viability. Additionally, RGD-Pac525 effectively reduced the intracellular bacterial burden in organoids, without compromising their structural integrity. In ovo bioassays, a substantial reduction in the bacterial load was observed in liver and intestinal tissues, indicating the peptide ability to achieve systemic distribution and to overcome tissue barriers. RGD-Pac525 was effective in infection models by suppressing bacterial growth. Preliminary observations suggest it may also affect host responses, indicating a potential for combined antimicrobial and therapeutic effects that warrant further studies. This study provides a compelling proof of concept for utilizing RGD-modified antimicrobial peptides for treatment of intracellular bacterial infections.

Humans are home to a diverse community of bacteria, many of which form symbiotic relationships with their host. Notably, tumors can also harbor their own unique bacterial populations that can influence tumor growth and progression. These bacteria, which selectively colonize hypoxic and acidic tumor microenvironments, present a novel therapeutic strategy to combat cancer. Advancements in synthetic biology enable us to safely and efficiently program therapeutic drug production in bacteria, further enhancing their potential. This review provides a comprehensive guide to utilizing bacteria for cancer treatment. We discuss key considerations for selecting bacterial strains, emphasizing their colonization efficiency, the delicate balance between safety and anti-tumor efficacy, and the availability of tools for genetic engineering. We also delve into strategies for precise spatiotemporal control of drug delivery to minimize adverse effects and maximize therapeutic impact, exploring recent examples of engineered bacteria designed to combat tumors. Finally, we address the underlying challenges and future prospects of bacterial cancer therapy. This review underscores the versatility of bacterial therapies and outlines strategies to fully harness their potential in the fight against cancer.

Water quality is under threat due to the presence of pathogenic and antibiotic-resistant bacteria. Escherichia coli (E. coli) serves as an indicator of faecal contamination and the potential presence of other harmful pathogens. Understanding E. coli concentrations helps in assessing the overall health risks associated with waterborne diseases and developing effective water management strategies. Therefore, we developed the first large-scale model, GloWPa-Ecoli C1 to simulate E. coli loads and concentrations in rivers and apply this model to China. The model provides the first comprehensive overview of microbial water quality across China's rivers. The model simulates E. coli concentrations in 2020 to range from 10-1.2 to 106.3 CFU/L, with 45.6 %-78.1 % of rivers exhibiting poor microbial water quality. Major hotspots of E. coli pollution are Haihe, Huaihe and Pearl River Basins. Direct discharge of human faecal waste contributes 80.2 % of the total E. coli load, while directly discharged livestock waste accounts for 13.1 %. To mitigate E. coli pollution in rivers in China, we recommend increasing human faecal waste collection rates, expanding wastewater treatment plant (WWTP) coverage, phasing out primary treatment WWTPs and eliminating direct livestock faecal waste discharge, particularly from smallholder farms. The study underscores the urgent need to improve microbial water quality in China's rivers. The findings provide actionable insights to inform policy development aimed at safeguarding water quality and public health. Furthermore, the modelling approach is applicable to other regions and microorganisms, offering a foundation for developing models to address antibiotic-resistant bacteria and other emerging water quality challenges.

Shiga toxin (stx), produced by enterohemorrhagic Escherichia coli (EHEC) or Shigella, causes hemolytic uremic syndrome (HUS) in humans. EHEC-mediated illnesses are recommended to treat by immune supportive strategies, instead of antibiotic therapy. Widely used probiotic Lactobacillus casei produces many bioactive metabolites, i.e., conjugated linoleic acids (CLAs) which have potential to educate host immunity and control EHEC growth and expression of its virulence genes. In this study, it was found that total metabolites of L. casei exerted a protective effect on Gb3 receptor containing mammalian cells against stx exposure.

Emerging evidence suggests a significant role of gut microbiota on neurodevelopmental disorders, including Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD).

Our study aimed to compare gut microbiota composition between these disorders and evaluate the effect of probiotic supplementation.

We conducted a 12-week randomized, double-blind, placebo-controlled trial with 80 children aged 5-14 years (39 with ADHD, 41 with ASD). Baseline and post-intervention fecal samples were analyzed using 16S rRNA gene sequencing to identify changes in gut microbiota composition.

We identified 22 taxa differentiating ADHD and ASD (AUC = 0.939), characterised by increased presence of Clostridia, Ruminococcaceae, and Lachnospiraceae in ADHD, and Bacteroides, Bacilli and Actinobacteria in ASD. These differences remained after accounting for potential confounders. ASD children receiving probiotics had significant increases in Chao 1, Fisher's alpha, and Shannon indices whereas no significant differences in α and β-diversity were found in ADHD. In ADHD, bacteria with potential adverse effects were under-represented. In ASD, the abundance of Eggerthellaceae, and other taxa associated with gastrointestinal problems and anxiety was decreased.

Variations in gut microbiota may influence responses in ADHD and ASD. Probiotic supplementation favorably altered gut microbiota composition, offering insights for future therapeutic strategies targeting the microbiome in neurodevelopmental disorders.

Recent research underscores the role of gut microbiota in ADHD and ASD, indicating that diet can significantly influence microbiota composition and potentially manage these neurodevelopmental disorders. This study reveals distinct differences in gut microbiota composition between children with ADHD and ASD and demonstrates that probiotic supplementation can modulate specific microbial genera in each disorder. These findings pave the way for the development of innovative microbiome-targeted therapies, offering a new avenue for the treatment of neurodevelopmental disorders. Understanding this relationship is crucial for designing future interventions.

The spiking rise in the prevalence of multidrug-resistant (MDR) pathogens necessitates discovering new antimicrobial agents. This study aims to investigate the intrinsic activity of two novel diazabicyclooctane (DBO) β-lactamase inhibitors, zidebactam and nacubactam, against diverse MDR Escherichia coli isolates from the United Arab Emirates. We aimed to correlate their antibacterial efficacy with the genomic characteristics of the strains.

This study investigated 73 E. coli strains and tested them for susceptibility to different antibiotics, including DBOs. PCR screening for carbapenemase and major β-lactamase genes was done. The strains were then grouped according to phenotypic and genotypic profiles. Whole-genome sequencing was employed to characterize the genetic landscape and clonality of selected 32 strains. Additionally, time-kill studies were conducted to confirm the bactericidal activity of DBOs.

Zidebactam demonstrated superior efficacy compared to nacubactam, primarily due to its higher affinity for penicillin-binding protein 2 (PBP2). Notably, zidebactam alone exhibited the most potent in vitro activity, outperforming both traditional β-lactams and novel antibiotics like cefiderocol. DBOs maintained effectiveness against strains harboring various resistance determinants, including NDM-5, OXA-181, CTX-M-15, SHV-12, CMY, and DHA. Genomic analysis revealed multiple mutations in PBP1-3, with PBP2 mutations correlating with DBO susceptibility variations. Importantly, DBOs remained highly effective against isolates with PBP mutations, even those belonging to high-risk clonal lineages (ST167, ST410, ST131). Time-kill studies confirmed the bactericidal activity of DBOs, with only one strain showing reduced susceptibility (MIC: 4 µg/ml).

This study provides compelling evidence for the potential of DBOs, particularly zidebactam, as novel antibacterial agents. Their unique characteristics and broad-spectrum activity position them as promising candidates for future antibiotic development. While the inclusion of DBO therapies in the antibiotic arsenal could significantly impact MDR pathogen treatment, realizing their full potential requires further research, clinical evaluation, and vigilant monitoring of resistance mechanisms through integrated genomic approaches.

Escherichia coli causes >400,000 annual deaths in children aged <5 years worldwide, with morbidity and mortality exacerbated by antimicrobial-resistant strains. A high-throughput multiplexing assay called digital multiplex ligation assay (dMLA) was developed to detect simultaneously 43 priority genes in E. coli related to the following: antibiotic resistance (n = 19), virulence factors (n = 16), and phylogroup markers (n = 6) with controls (uidA, gapdh). Genes are detected via PCR amplification of adjacent probe pairs that ligate in the presence of target gene-specific DNA, followed by sequencing of amplicons on short-read sequencers. The assay was tested in technical replicates on 63 synthetic DNA controls, and applied to 58 E. coli, 2 Staphylococcus aureus, 2 Klebsiella pneumoniae, 1 Klebsiella oxytoca, 1 Vibrio cholera, 1 Pseudomonas lurida, and 1 Salmonella enterica isolates in duplicate. Whole-genome sequencing was used to assess specificity and sensitivity. dMLA showed 100% sensitivity and >99.9% specificity and balanced accuracy on synthetic DNA. Balanced accuracy, calculated as the average of sensitivity and specificity, accounts for imbalanced data sets where negative outcomes are significantly more prevalent than positive ones. dMLA achieved a balanced accuracy of 90% for bacterial isolates. The results underline dMLA's effectiveness in high-throughput characterization of E. coli libraries for antimicrobial resistance genes and virulence factors, leveraging sequencing for massively parallel multiplexing of gene regions on multiple samples simultaneously, and are extendable to targets beyond E. coli.

The successful sustainable cultivation of the well-known medicinal plant sundew on rewetted peatlands not only leads to the preservation of natural populations, but also provides a basis for the sustainable pharmaceutical use of the plant. The bioactive compounds of sundew, flavonoids and naphthoquinones, show biofilm-inhibiting properties against multidrug-resistant, ESBL-producing E. coli strains and open up new therapeutic possibilities. This study investigates the molecular mechanisms of these compounds in biofilm inhibition through proteomic analyses. Specific fractions of flavonoids and naphthoquinones, as well as individual substances like 7-methyljuglone and 2″-O-galloylhyperoside, are analyzed. Results show that naphthoquinones appear to act via central regulatory proteins such as OmpR and alter the stress response while flavonoids likely affect biofilm formation by creating an iron-poor environment through iron complexation and additionally influence polyamine balance, reducing intracellular spermidine levels. Further investigations including assays for iron complexation and analysis of polyamines confirmed the proteomic data. Safety evaluations through cytotoxicity tests in 3D cell cultures and the Galleria mellonella in vivo model confirm the safety of the extracts used. These findings highlight sundew as a promising candidate for new phytopharmaceuticals.

Currently, carbapenemase-producing Enterobacteriaceae (CPE) are becoming a global public health threat. Infections caused by these bacteria limit treatment options and are associated with high morbidity and mortality. This study aimed to assess the prevalence of CPE and identify associated risk factors.

A hospital-based cross-sectional study was conducted from June to August 2023. Clinical samples were cultured, and species identification was performed using standard biochemical tests. Antimicrobial susceptibility testing was done, and a modified carbapenem inactivation method was employed to confirm carbapenemase production. Data were entered using Epi Data and analysed with SPSS.

From a total of 143 isolates, the most commonly identified species were Escherichia coli (62 isolates, 43.4%) and Klebsiella pneumoniae (39 isolates, 27.3%). The highest level of resistance was against ampicillin (138 isolates, 96.5%), whereas the lowest was observed with meropenem (19 isolates, 13.3%). Overall, 123 isolates (86.0%) were classified as MDR. The prevalence of CPE and carbapenem-resistant Enterobacteriaceae (CRE) was 5.7% and 8.1%, respectively. K. pneumoniae and E. coli were the most common carbapenemase producers. Chronic underlying disease, consuming raw vegetables, and lack of regular hand-washing habits before meals showed adjusted odds ratios of 7.9 (95% CI 1.9-31.5), 11 (95% CI 3.4-40) and 8.0 (95% CI 1.7-85), respectively, showing a significant association.

The high prevalence of CPE underscores the need for urgent infection control measures. Implementing antimicrobial stewardship, strengthening infection control measures, and further molecular studies are vital to combating this problem.

Atypical enteropathogenic Escherichia coli (aEPEC) mainly causes sporadic diarrhea and occasional outbreaks. However, the genetic determinant of aEPEC causing large outbreaks is still unknown. In June 2022, 171 of 934 people presented with diarrhea and abdominal pain after eating a lunch box in the Kinki region of Japan. We investigated 44 fecal samples from persons who ate the cuisine and isolated enteropathogenic Escherichia coli (EPEC) serotype O45:H15 from 38 of them. The same pathogen was also isolated from the feces of two employees and a leftover sample (mashed tofu salad with spinach). Pulsed-field gel electrophoresis and whole genome sequencing supported the clonality of the isolates. The isolates were negative for bfpA, encoding the bundle-forming pilus, and were accordingly identified as aEPEC. Whole genome sequencing revealed the presence of a plasmid-encoded type 3 secretion system effector gene, espT, involving the invasive phenotype of EPEC. Finally, we concluded that this was a foodborne outbreak caused by aEPEC O45:H15. Since the food poisoning case caused by aEPEC O45:H15 harboring espT has not been reported previously, the current study broadens our understanding of aEPEC food poisoning and its genetic background.IMPORTANCEaEPEC causes diarrhea in humans, despite the reported asymptomatic carriers of aEPEC worldwide. Several outbreaks caused by aEPEC also support that this pathogen is a diarrheagenic agent; however, the genetic determinant of aEPEC causing large outbreaks is still unclear. In 2022, a large foodborne outbreak by aEPEC O45:H15 affected more than 170 people in the Kinki region of Japan. We sequenced the whole genomes of the etiological agents and identified a potential virulent plasmid carrying espT, which is a virulence factor of aEPEC O111 that caused diarrhea in more than 600 people in Finland. Our data strengthen the importance of espT as a virulence factor of aEPEC outbreaks.

In recent years, rapid fatal hemorrhagic pneumonia (HP) has been increasingly reported in mink. In several studies, the virulence factors of strains isolated from diseased tissues have been identified as extraintestinal pathogenic Escherichia coli (ExPEC). The molecular characteristics of the strains were also analyzed, but whether ExPEC is the etiological agent of HP has not been confirmed in an animal challenge model. In this study, we characterized the antibiotic resistance, virulence characteristics, and pathogenicity of a bacterial strain isolated from a typical case of mink HP, and designated it L1. Our study revealed that isolate L1 has high levels of antibiotic resistance, to multiple antibiotics, including ampicillin, tylosin, kanamycin, and so on. Numerous virulence genes were detected in isolate L1, including those encoding adhesins (focG, afa/draB, mat, crl), invasins (ibeA, einv), and toxin (cnf1). ExPEC isolate L1 belongs to the O121 serogroup and was classified in the B2 phylogroup and sequence type 131 (ST131). Animal experiments showed that L1 is highly pathogenic to mice, and induced fatal HP in mink. A mouse model of isolate L1 infection showed lethargy, depression, and then death. The sick minks showed similar clinical signs and died soon after nasal bleeding and hematemesis, with a large amount of congestion and consolidation in the lungs. Using animal challenge experiments based on Koch's postulates, we demonstrate for the first time that ExPEC is a causative agent of rapid fatal HP in minks. Our research provides important insights into the identification and control of rapid fatal HP in minks and effective antibiotic treatments for infected animals.

The commensal Escherichia coli population may significantly influence the pathogenesis of extraintestinal infections. The assignment to specific sequence type (ST) lineages and the presence of particular combinations of virulence genes are characteristic features of extraintestinal pathogenic E. coli (ExPEC)-although not exclusively. Extraintestinal virulence genes are also identified among commensal E. coli. This study aimed to examine the genotypic and phenotypic characteristics of the extraintestinal virulence potential of two populations of commensal E. coli isolates from adults and young children.

Genotypic traits were detected using polymerase chain reaction (PCR). Appropriate phenotypic assays and real-time PCR were used to analyze the expression of virulence factors. Multilocus sequence typing was performed using the seven-loci Achtman scheme.

Genotypic studies revealed the virulence potential of the commensal isolates, and phenotypic analyses confirmed whether the genes are expressed. E. coli from adults carried pathogenicity islands and virulence genes in significantly higher proportions, resulting from the dominance of phylogroup B2 in this set of isolates. The hemolytic activity and higher levels of siderophore receptor expression were more common in E. coli from adults and were closely related to the dominance of phylogroup B2. Other traits not associated with phylogroup B2, such as adhesion abilities mediated by type 1 and P fimbriae and strong biofilm formation propensities, were detected with similar frequencies in both pools of isolates. E. coli harboring pathogenicity islands were subjected to multilocus sequence typing analysis. Sequence types ST73, ST59, ST131, ST95, ST141, and ST69 were most common in isolates from adults, whereas ST10, ST155, ST59, and ST1823 from children. In our collection of E. coli, the ST73 exhibited the highest potential for extraintestinal virulence.

A significant proportion of E. coli from adults compared to young children exhibited considerable virulence potential, which may enable them to function as endogenous pathogens. Our research highlights the significant accumulation of extraintestinal pathogenicity features in commensal E. coli, indicating the need to monitor genetic and phenotypic profiles in "silent" potential pathogens.

The rise in antimicrobial resistance and the consequent ineffectiveness of conventional antibiotics emphasise the need for novel therapeutic strategies. Antisense nucleic acid mimics (NAMs) are emerging as promising precision therapeutic agents, inhibiting specific genes through hybridisation with selected nucleic acid targets. However, delivering NAMs into bacteria remains a significant challenge. This study explores the use of poly(amidoamine) (PAMAM) amphiphilic dendrimers (ADs) as delivery vehicles for NAMs targeting the essential acpP gene in Escherichia coli. Two ADs bearing primary amine or tertiary amine terminals, 1a and 1b, were tested for their ability to permeabilise the bacterial envelope, facilitate NAM internalisation, and enhance NAM-based antibacterial activity. Physicochemical characterisation studies, flow cytometry measurements, fluorescence and electron microscopy imaging, bacterial viability assays, and an in vivo toxicity assessment using a greater wax moth (Galleria mellonella) model were conducted. Both ADs acted as permeabilisers of the bacterial envelope and assisted in NAM internalisation and antibacterial activity. The most effective formulation, 1b combined with the peptide nucleic acid (PNA)-based NAM, achieved an 8 log10 reduction in viable bacteria, with sustained activity up to 24 h against E. coli. In vivo, the most promising formulations showed no toxicity, with G. mellonella larvae maintaining overall health and no significant mortality detected for up to three days. These findings demonstrate that amphiphilic dendrimers can effectively deliver PNA-based NAMs, highlighting their potential as a novel strategy against antimicrobial-resistant pathogens.

Antimicrobial resistance (AMR) is a growing concern in veterinary and public health, with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli playing a significant role. This study examined 1,000 healthy and sick dogs from a veterinary clinic in northern Germany and identified 85 ESBL-producing E. coli. Whole-genome sequencing of these isolates revealed seven phylogroups. A (38.8%) and B1 (32.9%) were the most common. Multilocus sequence typing identified 42 sequence types (STs), with the globally occurring lineages ST744 and ST10 being predominant. Single nucleotide polymorphism analysis showed the clonal circulation of ST744 among dogs in shared environments, such as households or breeders, whereas ST10 isolates displayed greater genetic diversity. ST131, a pathogenic international high-risk clonal lineage often associated with humans, was assigned to one isolate. Virulence-associated genes (VAGs) were abundant across the isolates, with siderophore systems, biofilm formation, and adherence traits being prominent. All isolates carried enterobactin genes with additional siderophore systems, such as yersiniabactin and aerobactin, present in 36 isolates. The highest number of VAGs (25) was observed in isolates belonging to the pathogenic lineages ST648 and ST405. Sixty-nine percent of the isolates were multidrug-resistant, carrying resistance genes for three or more antibiotic classes, with beta-lactam, aminoglycoside, and tetracycline resistance being the most frequent. This study highlights globally occurring E. coli lineages in companion animals and the role of close contact environments in their dissemination. Although dog-to-human transmission was not investigated in this study, these findings support the need for a One Health approach to address AMR, emphasizing the interconnected health of humans, animals, and the environment.IMPORTANCEThis study demonstrated the presence of globally significant Escherichia coli lineages in dogs and highlighted the impact of close-contact environments, such as households and breeders, on their spread. Many of the isolates exhibited genetic multidrug resistance and virulence features, posing challenges for effective treatment and control. These findings emphasize the interconnected nature of human, animal, and environmental health, underlining the need for a One Health approach to address antimicrobial resistance.

The blood-brain barrier is a physiological protective barrier around blood vessels in the brain. It prevents most bacteria and harmful substances from entering the brain through the blood. However, when bacterial meningitis occurs, bacteria enter the brain either from the circulation or by direct invasion from neighbouring structures, causing an inflammatory response that in severe cases may lead to death. High morbidity and mortality are prominent features of the disease. Many pathogenic bacteria can break through the blood-brain barrier and cause meningitis, such as Streptococcus pneumoniae, Group B Streptococcus, Streptococcus suis, Neisseria meningitidis, meningitis-associated Escherichia coli, etc. This article reviews the mechanisms by which these bacteria cross the blood-brain barrier when causing meningitis and the interactions between bacteria and host cells to help pathogens invade the brain. Clarifying the mechanism by which pathogens cross the blood-brain barrier can provide new ideas for developing effective treatments for bacterial meningitis.

Bacteria employ a wide range of RNA-based regulatory systems to adapt to various environmental stressors. Among these, small non-coding RNAs (sRNAs) have emerged as critical regulators of gene expression. These compact RNA molecules modulate numerous cellular functions, including stress adaptation, biofilm development, and virulence. By acting primarily at the post-transcriptional level, sRNAs enable bacteria to swiftly adjust gene expression in response to external challenges. One key mechanism of sRNA action is translational repression, which includes the regulation of toxin-antitoxin systems pathways essential for bacterial persistence and antibiotic resistance. Additionally, sRNAs orchestrate the expression of genes involved in biofilm formation, enhancing surface adhesion, extracellular matrix production, and resistance to antimicrobial agents. Bacterial outer membrane vesicles (OMVs) also play a significant role in stress adaptation and intercellular communication. These vesicles transport a complex cargo of proteins, lipids, and nucleic acids, including sRNAs. The transfer of sRNAs through OMVs can modulate the physiology of neighboring bacterial cells as well as host cells, highlighting their role in cross-kingdom signaling. sRNAs serve as versatile and potent regulatory elements that support bacterial survival under hostile conditions. Advancing our understanding of sRNA-mediated networks offers promising avenues for uncovering bacterial pathogenesis and developing innovative antimicrobial therapies.

Cationic antiseptics are deployed in a variety of settings, where salinity ranges from almost pure water to hypertonic salt. Here, we examine how dissolved NaCl affects the antimicrobial action of a model antimicrobial, polydiallyldimethylammonium chloride (PDADMAC) to the bacterium Escherichia coli (E. coli). Fluorescence microscopy is used to measure the time course of both the adsorption of PDADMAC to E. coli and the cell viability. NaCl decreases the density of adsorbed PDADMAC and diminishes its efficacy. At NaCl concentrations at or above 0.15 M, PDADMAC no longer kills bacteria but still prevents reproduction by halting the growth in cell length. Reproduction can be restarted if PDADMAC is removed. Fluorescence depolarization measurements show that PDADMAC rigidifies model membranes, but salt reduces the rigidity. We therefore attribute the halt in cell growth to reversible bridging by the polymer on the cell surface that prevents expansion of the cell membrane.

Human health is influenced by the gut microbiota, particularly in aspects of host immune homeostasis and intestinal immune response. Tryptophan (Trp) not only acts as a nutrient enhancer but also plays a critical role in the balance between host immune tolerance and gut microbiota maintenance. Both endogenous and bacterial metabolites of Trp, exert significant effects on gut microbial composition, microbial metabolism, the host immunity and the host-microbiome interface. Trp metabolites regulate host immunity by activating aryl hydrocarbon receptor (AhR), thereby contributing to immune homeostasis. Among Trp metabolites, AhR ligands include endogenous metabolites (such as kynurenine), and bacterial metabolites (such as indole and its derivatives). Here, we present a comprehensive analysis of the relationships between Trp metabolism and 14 key microbiota, encompassing fungi (e.g., Candida albicans, Aspergillus), bacteria (e.g., Ruminococcus gnavus, Bacteroides, Prevotella copri, Clostridium difficile, Escherichia coli, lactobacilli, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus, Helicobacter. Pylori), and viruses (e.g., SARS-CoV-2, influenza virus). This review clarifies how the gut microbiota regulates Trp metabolism and uncovers the underlying mechanisms of these interactions. And increased mechanistic insight into how the microbiota modulate the host immune system through Trp metabolism may allow for the identification of innovative therapies that are specifically designed to target Trp absorption, Trp metabolites, the gut microbiota, or interactions between Trp and gut microbiota to treat both intestinal and extra-intestinal inflammation as well as microbial infections.

The rapid increase in drug resistance in recent years has become a significant global public health concern. Escherichia coli are ubiquitous bacteria, widely distributed in various environments. This study isolated a bacterial strain (HD-593) from diseased Chinese soft-shelled turtles (Pelodiscus sinensis). The bacterium was identified based on morphology, biochemical tests, and 16S rRNA sequencing, confirming it as E. coli. Drug susceptibility tests revealed that the HD-593 strain was highly resistant to ceftriaxone, enrofloxacin, doxycycline, sulfadiazine, gentamicin, neomycin, florfenicol, carbenicillin, cefradine, erythromycin, penicillin, ampicillin, midecamycin, and streptomycin. Resistance gene analysis confirmed the presence of quinolone resistance genes (oqxA and oqxB), aminoglycoside resistance genes (aac(3)-II and aphA1), a β-lactam resistance gene (blaTEM), and an acylaminol resistance gene (floR) in HD-593. The median lethal dose (LD50) of HD-593 for P. sinensis was 6.53 × 105 CFU/g. Biochemical analysis of serum revealed that HD-593 infection caused a significant reduction in total protein, albumin, and globulin levels, while markedly increasing the levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. Histopathological analysis revealed severe intestinal damage characterized by villi detachment and muscle cell necrosis. Additionally, extensive splenocyte necrosis with nuclear marginalization, glomerular swelling, and pronounced hepatic steatosis accompanied by distended sinusoids were observed. This study identified a multidrug-resistant E. coli strain from deceased P. sinensis, suggesting that drug resistance genes may circulate in aquaculture ecosystems, posing potential risks to aquaculture.

The global rise of antimicrobial resistance (AMR), driven by antibiotic use in healthcare and agriculture, poses a major public health threat. While AMR in clinical settings is well studied, there is a gap in understanding the resistance profiles of Escherichia coli from diseased livestock, particularly regarding zoonotic transmission. This study analyzes 114 E. coli isolates from diseased swine over 12 years, revealing that 99.12% were multidrug-resistant. Resistance was highest for ampicillin and amoxicillin/clavulanic acid (100%), followed by ciprofloxacin (96.49%) and tetracycline (94.74%). Furthermore, 21.05% of isolates were resistant to colistin, and 1.75% to tigecycline. A total of 76 antimicrobial resistance genes (ARGs) were identified, with mcr-1 found in 18.42%, mcr-3 in 4.39%, and tet(X4) in 1.75%. Significant co-occurrence of ARGs and plasmids suggests potential for co-selective dissemination. This study is the first to report enterotoxigenic E. coli (ETEC) strains carrying both mcr-1 and mcr-3 genes. After the 2017 colistin ban in China, mcr-1 detection rates significantly decreased, while florfenicol resistance rates increased in 2018-2021 (94.29%) compared to 2010-2017 (79.55%). This work provides valuable insights into the AMR profiles of E. coli from diseased swine and highlights trends that can inform strategies for monitoring and controlling public health risks associated with zoonotic E. coli transmission.IMPORTANCEThis study highlights the critical role of diseased and deceased swine in the spread of antimicrobial resistance (AMR), providing new insights into the transmission of resistance genes in zoonotic contexts. By analyzing E. coli from diseased swine, we identify key resistance genes such as mcr-1, mcr-3, and tet(X4), which pose significant public health risks, especially regarding last-resort antibiotics like colistin. Moreover, the study identifies novel transmission patterns of mcr genes, including ETEC strains carrying the mcr-3 gene and strains harboring both mcr-1 and mcr-3 genes. The role of plasmids in horizontal gene transfer is also revealed, facilitating rapid AMR spread across species. The long-term persistence of resistant strains highlights the challenges in controlling AMR in livestock. These findings underscore the need for enhanced surveillance and a One Health approach to mitigate AMR risks across animal, human, and environmental health.

Foodborne outbreaks are becoming increasingly common and linked to zoonotic diseases caused by microbial spillover from wild or farm animals. Furthermore, agricultural animals could be considered reservoirs of multidrug-resistant (MDR) microorganisms. Escherichia coli O157:H7, a widespread foodborne pathogen, poses a substantial hazard due to its ubiquitous environmental distribution, MDR phenotypes, and life-threatening pathogenicity. This bacterium produces a potent toxin (Shiga toxin, Stx) encoded by prophages (Stx-phage). In addition to antibiotic resistance, E. coli O157:H7 has been shown to express more Stx upon treatment with antibiotics such as trimethoprim-sulfamethoxazole and metronidazole than controls. The combination of MDR and increased pathogenicity upon antibiotic treatment requires the development of alternatives for treating and preventing E. coli O157:H7 and related bacteria. Bacterial viruses (phages) are gaining popularity in clinical and veterinary settings due to their high antibacterial activities and lack of side effects in animals. Phage application in food production can help reduce the spread of E. coli O157:H7 and other Stx-producing E. coli (STEC), thus decreasing the burden of infection and economic loss due to these foodborne zoonoses. The present review will provide an update on phage utilization in the food industry to reduce the STEC load, with particular focus on O157:H7.

Gene therapy refers to the use of vectors to introduce target genes into target cells to exert a therapeutic effect on tumors. As a new type of tumor therapy, gene therapy has the advantage of precision and specificity. Excellent delivery vehicles have a major impact on the efficiency, precision and safety of gene therapy. Unlike traditional vectors, bacteria based on prokaryotes have the advantages of good targeting, large load, and simplicity. In addition, different types of bacteria also have characteristics that can be used in various scenarios.

In this review, we searched the gene therapy-related literature in PubMed, mainly in the last five years, and compared the characteristics of different gene vectors, focusing on the bacterial gene therapy and aiming to explore excellent bacterial gene therapy programs.

Compared with traditional tumor gene therapy vectors, bacteria have many advantages, such as good targeting, large carrying capacity, and simple production. Meanwhile, the combination of artificial intelligence technology, bacterial imaging probe technology and suicide genes will be expected to control the bacterial therapy process, improve the safety of treatment, and promote the translational application of bacterial gene therapy.

Photo-triggered carbon monoxide (CO) release, mediated by reactive oxygen species (ROS), shows a significant potential in therapeutic applications. However, the existing photosensitizers predominantly function as type II ROS generators. When ROS are present in excess, they are always wasted due to their short half-lives, which limit their ability to travel significant distances and effectively achieve therapeutic outcomes. In this study, the biological function of a single-component molecule, PdHF, is investigated. This molecule is formed by covalently conjugating 3-hydroxyflavone (3-HF) to a palladium(II) tetraphenyltetrabenzoporphyrin (PdTPTBP) photosensitizer. Subsequently, PdHF is loaded into the 2-hexamethyleneimino ethyl methacrylate (C7A)-modified PEG-b-PCL block copolymer (PC7A) to form a PdHF@PC7A micellar system capable of co-releasing CO and ROS under red-light irradiation. CO/ROS co-release can be attributed to the generation of singlet oxygen species that not only oxidize 3-HF to release CO but are concurrently reduced by the tertiary amine, C7A, to form cytotoxic superoxide anions and hydrogen peroxide. In vitro studies on these positively charged micelles validate a high biosafety and excellent antibacterial effects with competent elimination of Gram-negative bacteria, Escherichia coli. Furthermore, evidence of micelle uptake by bacterial cells supports synergistic photodynamic and gas therapy through intracellular CO/ROS co-release.

To investigate the correlations among antibiotic resistance, virulence gene, phylogenetic group, and genetic diversity, providing essential data for Escherichia coli (E. coli) infection prevention and control in Tibetan pigs.

A total of 244 E. coli isolates were collected. Antimicrobial susceptibility was assessed using the microdilution method. PCR was used to detect antibiotic resistance genes (ARGs), virulence genes, and phylogenetic groups. Genetic diversity was analyzed using enterobacterial repetitive element sequence-based PCR. Enteroaggregative E. coli (EAEC) 5-12, a representative strain with multidrug resistance and strong biofilm-forming ability, harboring abundant virulence genes, was selected for whole-genome sequencing (WGS) to validate PCR results.

Among the 244 isolates, 84.43% showed multidrug resistance (MDR), with the highest resistance rates for chloramphenicol (99.59%), sulfadiazine (96.31%), and sulfamethoxazole (93.85%). Twenty-five ARGs were detected, with ant(3')-Ia, bla TEM, aac(3')-II, floR, and qnrS exceeding 80% detection rates. Integrase genes intl1 and intl2 were found in 90.16% and 15.16% of isolates, respectively. Seventeen virulence genes were detected; bcsA (98.77%), fimC (89.75%), and agn43 (59.43%) were the most prevalent. A total of 106 virulence patterns were identified, with agn43/bcsA/fimC being predominant (17.92%). Most strains belonged to phylogenetic group A (45.90%), followed by B1 (34.43%), while 29 strains were unclassified. Sixty-four isolates were identified as diarrheagenic E. coli (DEC), predominantly enteroaggregative E. coli (EAEC, 90.63%). Biofilm-forming ability was categorized as strong (4.69%), moderate (21.88%), weak (59.38%), or absent (14.06%). Clustering based on 61.2% similarity grouped the 64 DEC into five clusters, with 84.38% in cluster II, which contained all strong biofilm producers.

Antimicrobial resistance profiles of EAEC 5-12 confirmed that primarily confer resistance through antibiotic efflux, target alteration, and reduced permeability. These findings will contribute to further understanding the positive correlation between antibiotic resistance and pathogenicity in E. coli from Tibetan pig farms, shedding light on the rational use of antimicrobial agents and tackling the antibiotic resistance crisis in Tibetan pig breeding in Garze Tibetan Autonomous Prefecture, Sichuan, China.

This study was undertaken to determine the effect of bird age and administering either Lactococcus lactis ssp. lactis 1 (LL) or Limosilactobacillus fermentum 1 (LF) in the drinking water on the prevalence of antimicrobial resistance by phenotypic test, multilocus sequence typing (MLST) and virulence genes of Escherichia coli (E. coli) isolated from broiler caeca by whole-genome sequencing (WGS) analysis. Male (Ross 308) day-old chicks (240) were reared for 28 days. Water was provided either untreated (CON) or with LL (107/mL) or LF (107/mL) via a nipple drinker on three days each week during the starter phase (days 1, 3, 5, 7, 9 and 11 d) in eight replicate pens per treatment, with initially ten chicks per pen. One chick from each pen was sacrificed when LL or LF was added to the water, and again on d 14 and 28. There was no evidence that LL and LF had any effect on the prevalence of antimicrobial resistance and virulence genes in E. coli isolates. The population density of Lactobacillus sp. and coliforms decreased with age (p < 0.001). The high resistance of E. coli to ampicillin and tetracycline was maintained throughout the life of the broilers. The prevalence of virulence genes was greatest during the starter phase but declined when birds were 28 days of age (p < 0.05). In birds < 14 d of age, E. coli MLST 457, 1640, 1485 and 155 were dominant, and these carried iucD, irp2, astA, iutA and iroN genes. When birds were 28 d of age, MLST 1286, 1112 and 973 predominated, and these carried few virulence genes. This suggests that young birds were more susceptible to putative pathogenic E. coli than older birds. Supporting the development of a healthy microbiome that might control the proliferation of potentially pathogenic E. coli is an area of future research.

The integration of biopolymers with antimicrobial inorganic materials has emerged as a promising strategy for developing eco-friendly and biocompatible functional materials for food packaging and biomedical applications. However, the impact of biopolymer matrix composition on the antimicrobial efficacy of inorganic fillers remains underexplored. This study addresses this critical gap by investigating the effects of chitin or chitosan oligosaccharides (NACOS or COS) on the antimicrobial properties of sodium alginate (SA)/cuprous oxide (Cu2O) composite gels. The composite gels were synthesized through a physical blending of the components, followed by calcium-induced crosslinking of SA. Characterization using UV-vis, FTIR, and EDX confirmed the successful incorporation of Cu2O, while a SEM analysis revealed its uniform dispersion. Antibacterial assays demonstrated that SA-Cu2O exhibited the highest inhibition rates, with a 67.4 ± 11.9% growth suppression of Staphylococcus aureus (MRSA), 33.7 ± 5.1% against Escherichia coli, and 39.1 ± 14.8% against Pseudomonas aeruginosa. However, incorporating NACOS and COS reduced inhibition, as oligosaccharides served as bacterial carbon sources. Swelling and contact angle measurements indicate that antimicrobial effectiveness was independent of surface hydrophilicity. These findings underscore the importance of rational composite design to balance bioactivity and material stability for antimicrobial applications.

The human microbiota, consisting of trillions of bacteria from six main phyla, produces peptide and non-peptide secondary metabolites which have antibacterial properties vital to medicine and biotechnology. These metabolites influence biological processes linked to diseases, yet much remains unknown. This review explores their structures and functions, aiming to spur novel metabolite discovery and advance drug development.

Background: Urinary tract infection (UTI) is predominantly caused by uropathogenic Escherichia coli (UPEC). Previous studies have reported that the fimbriae of UPEC are involved in virulence and antimicrobial resistance. We aimed to analyze the fimbrial gene profiles of UPEC and investigate the specificity of these expressions in symptomatic UTI, urinary device use, and levofloxacin (LVFX) resistance/extended-spectrum beta-lactamase (ESBL) production. Methods: A total of 120 UPEC strains were isolated by urine culture between 2019 and 2023 at our institution. They were subjected to an antimicrobial susceptibility test and polymerase chain reaction (PCR) to identify 14 fimbrial genes and their association with clinical outcomes or antimicrobial resistance. Results: The prevalence of the papG2 gene was significantly higher in the symptomatic UTI group by multivariate analyses (OR 5.850, 95% CI 1.390-24.70, p = 0.016). The prevalence of the c2395 gene tended to be lower in the symptomatic UTI group with urinary devices (all p < 0.05). In LVFX-resistant UPEC strains from both the asymptomatic bacteriuria (ABU) and the symptomatic UTI group, the expression of the papEF, papG3, c2395, and yadN genes tended to be lower (all p < 0.05). Conclusion: The fimbrial genes of UPEC are associated with virulence and LVFX resistance, suggesting that even UPEC with fewer motility factors may be more likely to ascend the urinary tract in the presence of the urinary devices. These findings may enhance not only the understanding of the virulence of UPEC but also the management of UTI.

This study investigated commensal and pathogenic E. coli isolated from pigs at farms and slaughterhouses in Sardinia, focusing on genetic relatedness and antimicrobial resistance (AMR). Samples were collected from six fattening pig farms (A-F) and five slaughterhouses (S1-S5). In the farms, environmental fecal sampling from the fattening pigs' pens was carried out and information regarding farm management and biosecurity measures were collected. Pigs that had been in the sampled pens were selected for sampling at the slaughterhouse. Carcass surface, mesenteric lymph nodes and colon content samples were sampled at the five slaughterhouses (S1-S5), in total 38 samples from 152 animals were collected. At the slaughterhouses, environmental samples were also collected from food-contact surfaces and non-food-contact surfaces (36 samples overall). E. coli was detected in all farms, 97 % of pigs, and all slaughterhouses. Whole genome sequencing and antimicrobial susceptibility testing were performed on 95 isolates, revealing 13.7 % pathogenic isolates, including ExPEC, ETEC, STEC-ETEC hybrids, and UPEC. A total of 40 sequence types (STs) were identified, with ST10 being the most common. High-risk clones (ST88, ST101, ST410, and ST648) were also detected. Over half of the isolates (52.6 %) carried at least one AMR gene, with 43 % harboring multiple AMR genes, particularly tet (37.9 %) and blaTEM (32.6 %). Phenotypic resistance was observed for tetracycline, ampicillin, and sulfamethoxazole-trimethoprim. This study reveals extensive AMR in commensal and environmental E. coli, underscoring their role as resistance gene reservoirs. The presence of AMR genes without direct antimicrobial exposure suggests complex transmission dynamics. Findings support the significance of AMR surveillance also for commensal E. coli, and the importance of combining phenotypical and sequencing methods to assess antimicrobial removal effects in pig farms.

Escherichia coli is a key pathogen causing gastrointestinal and urinary tract infections. Diarrheagenic E. coli (DEC) and uropathogenic E. coli (UPEC) are distinct major pathotypes linked to specific clinical outcomes. Therefore, this study aimed to compare DEC and UPEC isolates regarding distribution, antimicrobial resistance, serotypes, resistance, and virulence gene profiles.

A total of 400 clinical samples (200 stools and 200 urine) were analyzed using phenotypic and genotypic methods. Antimicrobial resistance, serotyping, and detection of resistance and virulence genes were performed. Phylogenetic and correlation analyses were conducted to explore genetic relationships and interactions.

Of 97 E. coli isolates (24.25% prevalence), 56 DEC and 41 UPEC were detected. DEC isolates primarily included serotypes O26, O45, and O55, while UPEC predominantly featured O1 and O25. UPEC showed higher multidrug resistance, while DEC was more virulent. UPEC carried unique markers (ureC, papC), and DEC harbored stx and aggR genes associated with gastrointestinal infections. Phylogenetic analysis showed separate clustering for DEC and UPEC, with limited genetic overlap. Correlation analysis identified strong associations within resistance and virulence genes but a negative correlation between these traits.

This study compared the phenotypic and genetic features of DEC and UPEC, highlighting their distinct pathogenic traits. Limited genetic overlap suggests potential gene transfer, influencing adaptability, and evolution.

In this study, we have designed and developed a cationic bolaform C12-(2,3-dihydroxy-N, N-dimethyl-N-(2-ureidoethyl)propan-1-aminium chloride)2 (C12(DDUPAC)2) that is derived from biocompatible molecules. The bolaform C12(DDUPAC)2 has hydroxyl (OH) functionality at both the cationic head groups. The impact of head group structure on the self-assembly and effectiveness of gene transfection and antimicrobial activity was investigated and compared with that of the hydrochloride salt C12-(N, N-dimethyl-N-(2-ureidoethan-1-aminium chloride)2 (C12(DUAC)2) of its precursor molecule. The formation of spherical as well as rod-like self-assembled structures was found to occur above a relatively low critical aggregation concentration (CAC) by the bolaforms. The results of calorimetric measurements demonstrated thermodynamically favorable aggregation in water. Interaction studies of the cationic bolaforms with the calf thymus DNA revealed stronger binding of C12(DDUPAC)2 in comparison to C12(DUAC)2, which explained higher in vitro gene transfection efficiency of C12(DDUPAC)2 than C12(DUAC)2. Both bolaforms interact weakly with the bovine serum albumin protein. MTT-based in vitro cytotoxicity assay was performed and both bolaforms were found to have marginal cytotoxicity. Further, both bolaforms exhibit advantageous antibacterial activity against E. coli and potent antifungal activity against Fusarium oxysporum at high dosages.