Genomic diversity of non-diarrheagenic fecal Escherichia coli from children in sub-Saharan Africa and south Asia and their relatedness to diarrheagenic E. coli

Versatile spiky spindle-shaped copper-based nanocomposites: A SERS substrate for discrimination, quantification and inactivation of multiple bacteria

Designing a multi-functional strategy that integrates rapid and sensitive detection of pathogenic bacteria and efficient antibacterial activity is of great significance. Here, we reported a smart triple-functional spindle shape copper-based nanocomposites, obtaining the remarkable surface-enhanced Raman scattering (SERS) enhancement, and its spikes at both ends with physical piercing ability cooperate with Ag+ and Cu2+ releasing capability endowed it with robust antibacterial effectiveness. Originally, gold-core silver-shell nanoparticles (Au@Ag NPs) with excellent SERS performance were loaded onto the spindle shape copper-methylimidazole nanoparticles (Cu-MIM) under electrostatic action, obtaining Au@Ag/Cu-MIM nanocomposites. The SERS sandwich nanostructure bacteria/4-mercaptophenylboronic acid (4-MPBA)/Au@Ag/Cu-MIM was fabricated utilizing the unique bacterial "fingerprints" generated through the introduction of bifunctional 4-MPBA, which served as both a SERS label and internal standard. Two different bacteria (E. coli and S. aureus) were highly sensitively discriminated and quantified in the concentration range spanning from 101 to 107 CFU mL-1, with a limit of detection (LOD) of 10 CFU mL-1. The SERS probe under investigation demonstrated its efficacy in human blood samples, exhibiting sensitive discrimination of various bacteria. Meanwhile, 40 μg/mL Au@Ag/Cu-MIM exhibited extraordinary antibacterial activity, the survival rate of S. aureus was 0.15 %, while E. coli was 0.8 %. Furthermore, Au@Ag/Cu-MIM effectively destroyed biofilm, reducing its content to 30 % of the control group after 3 h of treatment. Our work successfully integrated triple-function, which includes specific discrimination, sensitive quantification, and inactivation of multiple bacteria.

Cardamom essential oil-loaded zinc oxide nanoparticles: A sustainable antimicrobial strategy against multidrug-resistant foodborne pathogens

The globalization of the food trade has escalated challenges in ensuring food safety due to foodborne pathogens, including multidrug-resistant (MDR) strains, which pose significant public health risks and economic burdens. Innovative antimicrobial strategies are urgently required. In this study, cardamom essential oil-loaded zinc oxide nanoparticles (CEO-ZnO-NPs) were synthesized and evaluated for their antimicrobial potential and mechanisms of action against MDR Escherichia coli and Staphylococcus aureus. Dynamic light scattering and the transmission electron microscopy (TEM) micrograph confirmed a spherical nanocomposite with an average size of 141.4 nm with good dispersion and stability over 180 days. Antimicrobial activity assessed via the agar well diffusion method showed dose-dependent inhibition, with zones of 25.75 ± 0.90 mm for E. coli and 31.05 ± 0.46 mm for S. aureus at 400 μg/mL. Minimum inhibitory concentrations (MIC) were 25 μg/mL (E. coli) and 12.5 μg/mL (S. aureus), while minimum bactericidal concentrations (MBC) were 50 μg/mL and 25 μg/mL, respectively. Kill-time analysis revealed a marked reduction in bacterial viability after 120 min of exposure. Mechanistic studies using scanning electron microscopy showed structural damage, including disrupted membranes and cell shrinkage. Also, protein levels significantly decreased, with DNA and ATP levels reduced by 74.51 % and 91.15 % in E. coli and 79.40 % and 90.81 % in S. aureus. Enzymatic activities, including ATPase and alkaline phosphatase, were inhibited by up to 84.63 %. In addition, the low cytotoxicity of CEO-ZnO-NPs against Vero cells supporting their potential biosafety for food safety applications. These findings demonstrate that CEO-ZnO-NPs disrupt bacterial processes such as protein synthesis, membrane integrity, and enzymatic activity, offering a promising approach that aligns with the United Nations Sustainable Development Goals (SDGs), particularly SDGs 2, 3, and 12, while promoting circular economy principles by reducing reliance on synthetic preservatives to address antimicrobial resistance in foodborne pathogens.

The pet café is a neglected site for transmission of antimicrobial-resistant Escherichia coli in urban life

The process of urbanization has brought with it several novel lifestyles, but it remains to be seen whether such lifestyles are the potential driver behind the spread of antimicrobial resistance (AMR) in modern society. Hence, this study employs the pet café as a proof of concept to observe how one pathway of AMR transmission occurs within a megacity. A total of 111 samples were collected from consumers, workers, animals and the surrounding environment from three pet cafés in Guangzhou, and 163 bacterial strains were isolated, with Escherichia coli (n=60) being the most dominant species. The sequence type and genomic diversity of E. coli were observed in all three cafés. Notably, 19 highly related ST328 strains were isolated in a single pet café from both workers (skin and faeces) and animals (faeces), suggesting transmission between distinct hosts. The number of SNPs between ST328 E. coli isolated in this study and strains from other provinces in China was minimal, with the possibility of clonal transmission. In terms of AMR, 90% of the isolates exhibited resistance to at least three distinct classes of antimicrobials (multidrug resistance). Multiple antimicrobial resistance genes (ARGs) such as tet(X4) were detected in this study, and plasmid, especially hybrid plasmid, is the main transmission vector of these ARGs. Our findings highlight that the pet café is a neglected site for the transfer of ARGs among Enterobacteriaceae, with a propensity for continuous contamination through either clonal or horizontal transmission of ARGs.

Etiology and risk factors of hemorrhagic abomasitis in goat kids

Hemorrhagic abomasitis, also known as Salivary Abomasum Disease (SAD), is a largely under-researched condition affecting young lambs and kids, often leading to high mortality rates and significant economic losses. The disease's etiopathogenesis, risk factors, and clinical features remain poorly understood. Existing studies have been limited and fragmented, leading to misdiagnoses and confusion about its true nature. Given the lack of a comprehensive investigation into SAD's incidence, risk factors, and causative agents, this study aims to provide a thorough analysis through clinical, necropsy, histopathological, microbiological, and molecular examinations. This study involved 633 kids, with 323 in the SAD group and 310 in the control group. A multifaceted approach was utilized, encompassing clinical evaluations, necropsies, histopathological assessments, risk factors, and microbiological and molecular analyses, focusing on investigating virulence genes. During the kidding season, 323 deaths were linked to SAD, with a mean disease duration of 1.34 ± 0.54 days. The highest incidence occurred in the 8-14 day age group, accounting for 51.7% of cases (p < 0.05). The dominant clinical symptoms included weakness, lethargy, depression, failure to suckle, reluctance to move, significantly reduced mobility, unsteady gait, and a withdrawn demeanor. Necropsy findings consistently showed dark hemorrhagic content in the abomasum and characteristic "coffee grain" lesions, with no abnormalities in other organs. Escherichia coli was isolated in 63% of sampled kids, significantly more than in controls (p < 0.03), and confirmed through molecular analysis. Examination of virulence genes highlighted the presence of hlyA, stx1, cnf1, stx2, and eaeA in complex combinations linked to severe abomasum damage. Poor bed and bottle hygiene were identified as the primary risk factors for SAD (p < 0.001), with risk escalating in the later stages of the kidding season as farm conditions deteriorated. This study thoroughly re-evaluates hemorrhagic abomasitis in young kids, delivering valuable and reliable insights into this fatal disease. Based on multifaceted analyses, it strongly indicates E. coli as the primary causative agent.

Molecular Epidemiology and AMR Perspective of Diarrhoeagenic Escherichia coli in Africa: A Systematic Review and Meta-analysis

INTRODUCTION

Diarrhoeagenic Escherichia coli (DEC) persistently challenges public health in Africa, contributing substantially to the diarrhoeal disease burden. This systematic review and meta-analysis illuminate the distribution and antimicrobial resistance (AMR) patterns of DEC pathotypes across the continent.

METHODS

The review selectively focused on pathotype-specific studies reporting prevalence and/or AMR of human-derived DEC pathotypes from African nations, excluding data from extra-intestinal, animal, and environmental sources and studies focused on drug and mechanism experiments. Pertinent studies were retrieved from SCOPUS, PubMed, and EBSCOhost, processed with Covidence, and screened in alignment with PRISMA guidelines.

RESULTS

The reviewed studies were predominantly hospital-based (80%) and paediatric-focused (91%), with a meagre 4.4% documenting DEC outbreaks. Seven DEC pathotypes were discerned, with Enteroaggregative E. coli (EAEC) being notably prevalent (43%, 95% CI 30-55%) and Enteroinvasive E. coli (EIEC) least prevalent (24%, 95% CI 17-32%). Identified non-susceptibilities were noted against essential antibiotics including ciprofloxacin, ceftriaxone, and ampicillin, while instances of carbapenem and Extended-Spectrum ß-Lactamase (ESBL) resistance were scarce.

CONCLUSION

Despite sporadic data on DEC prevalence and AMR in Africa, particularly in community settings, a palpable gap remains in real-time outbreak surveillance and comprehensive data documentation. Augmenting surveillance and embracing advancements in molecular/genomic characterisation techniques are crucial to precisely discerning DEC's actual impact and resistance continuum in Africa.

Comparative Genomic Analyses of E. coli ST2178 Strains Originated from Wild Birds in Pakistan

The emergence and spread of multidrug-resistance (MDR) pathogenic Escherichia coli due to horizontal gene transfer of antibiotic resistance genes (ARGs) and virulence factors (VFs) is a global health concern, particularly in developing countries. While numerous studies have focused on major sequence types (STs), the implication of minor STs in ARG dissemination and their pathogenicity remains crucial. In this study, two E. coli strains (PEC1011 and PEC1012) were isolated from wild bird feces in Pakistan and identified as ST2178 based on their complete genome sequences. To understand this minor ST, 204 genome assemblies of ST2178 were comparatively analyzed with the isolates' genomes. The phylogenetic analyses revealed five subclades of ST2178. Subclade E strains were predominantly isolated from human specimens, whereas subclades A and B strains including strains PEC1011 and PEC1012, respectively, were frequently isolated from animal. Mobile genetic elements (MGEs) exhibited the positive correlation with ARGs but not with VFs in this ST. Plasmid-borne ARGs exhibited higher correlation with plasmid-borne MGEs, indicating the role of diverse mobile plasmid structures in ARG transmission. Subclade E exhibited diverse plasmid-borne ARG repertoires correlated with MGEs, marking it as a critical surveillance target. In the case of VFs, they exhibited phylogeny-dependent profiles. Strain PEC1012 harbored various plasmid-borne ARGs, which are similar with conserved ARG repertoires in subclade A. The presence of unique ARG insertion in pPEC1012 highlights the importance of subclade A in ARG dissemination. This study comprehensively elucidates the landscape of ST2178, identifying critical phylogenetic subclades and their characteristics in ARG and VF occurrence.

Multifunctional SERS Substrate for Simultaneous Detection of Multiple Contaminants and Photothermal Removal of Pathogenic Bacteria

In this work, a boric-acid-modified Fe3O4@Au@BA-MOF composite material as a multifunctional SERS substrate was ingeniously constructed for detecting both pathogens and antibiotics as well as photothermally inactivating the pathogens. Through improving the dispersity and stability of gold nanoparticles (Au NPs), leveraging the specificity of boric acid (BA) groups in recognizing cis-diol structures, and the ability of SERS technology to provide unique fingerprint spectra of targets, the sensitive and stable detection of pathogens and antibiotics was achieved. Compared with Au NPs and Fe3O4@Au, the SERS enhancement factor of Fe3O4@Au@BA-MOF was 4.31 × 106, which was about 400 times and 16 times higher than the former two, respectively. Among the existing work, the limit of detection for pathogens was lower or comparable, and it exhibited good stability, maintaining consistent performance for 23 days. Additionally, this substrate achieved efficient photothermal inactivation of pathogens under both near-infrared light and natural light excitation. Within 8 min of near-infrared light irradiation, the bactericidal rates for Staphylococcus aureus and Escherichia coli reach 100% and 99.3%, respectively.

Biofilm-producing Escherichia coli O104:H4 overcomes bile salts toxicity by expressing virulence and resistance proteins

We investigated bile salts' ability to induce phenotypic changes in biofilm production and protein expression of pathogenic Escherichia coli strains. For this purpose, 82 pathogenic E. coli strains isolated from humans (n = 70), and animals (n = 12), were examined for their ability to form biofilms in the presence or absence of bile salts. We also identified bacterial proteins expressed in response to bile salts using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-electrophoresis) and liquid chromatography-mass spectrometry (LC-MS/MS). Lastly, we evaluated the ability of these strains to adhere to Caco-2 epithelial cells in the presence of bile salts. Regarding biofilm formation, two strains isolated from an outbreak in Republic of Georgia in 2009 were the only ones that showed a high and moderate capacity to form biofilm in the presence of bile salts. Further, we observed that those isolates, when in the presence of bile salts, expressed different proteins identified as outer membrane proteins (i.e. OmpC), and resistance to adverse growth conditions (i.e. F0F1, HN-S, and L7/L12). We also found that these isolates exhibited high adhesion to epithelial cells in the presence of bile salts. Together, these results contribute to the phenotypic characterization of E. coli O104: H4 strains.

Molecular and Genomic Analysis of the Virulence Factors and Potential Transmission of Hybrid Enteropathogenic and Enterotoxigenic Escherichia coli (EPEC/ETEC) Strains Isolated in South Korea

Hybrid strains Escherichia coli acquires genetic characteristics from multiple pathotypes and is speculated to be more virulent; however, understanding their pathogenicity is elusive. Here, we performed genome-based characterization of the hybrid of enteropathogenic (EPEC) and enterotoxigenic E. coli (ETEC), the strains that cause diarrhea and mortality in children. The virulence genes in the strains isolated from different sources in the South Korea were identified, and their phylogenetic positions were analyzed. The EPEC/ETEC hybrid strains harbored eae and est encoding E. coli attaching and effacing lesions and heat-stable enterotoxins of EPEC and ETEC, respectively. Genome-wide phylogeny revealed that all hybrids (n = 6) were closely related to EPEC strains, implying the potential acquisition of ETEC virulence genes during ETEC/EPEC hybrid emergence. The hybrids represented diverse serotypes (O153:H19 (n = 3), O49:H10 (n = 2), and O71:H19 (n = 1)) and sequence types (ST546, n = 4; ST785, n = 2). Furthermore, heat-stable toxin-encoding plasmids possessing estA and various other virulence genes and transporters, including nleH2, hlyA, hlyB, hlyC, hlyD, espC, espP, phage endopeptidase Rz, and phage holin, were identified. These findings provide insights into understanding the pathogenicity of EPEC/ETEC hybrid strains and may aid in comparative studies, virulence characterization, and understanding evolutionary biology.