Scherichia Coli Research Articles

THE POTENCY OF CINNAMON (Cinnamomum burmanni Blume) LEAF EXTRACT AS A BIOPRESERVATIVE AGENT FOR FOOD SAFETY OF SATE LILIT

ARTICLE HIGLIGHTS- Cinnamon leaf extract combats E. coli in traditional Balinese food.- Natural preservative reduces harmful pathogens in sate lilit.- Cinnamon extract offers a safer alternative to synthetic preservatives.- Active compounds in cinnamon leaves inhibit bacterial growth.- Effective biopreservative for enhancing food safety and quality. ABSTRACTEscherichia coli O157:H7 contamination of the meat used in preparing sate lilit, a favorite traditional food in Bali, Indonesia, has been a great concern for both local people and foreigners. Although C. burmanni has been included in its spice ingredients, active compounds that play a significant role in this pathogen have limitedly been elucidated. The main objectives of this research were to investigate the potency of this plant to control contaminants and elucidate possible compounds that prevent such contaminants by applying the disk diffusion method and LCMS analysis, respectively. The results showed that the leaf extract of this plant inhibited the in vitro growth of E. coli O157:7, with minimal inhibitory concentration (MIC) and LC50 values of 4% and 2.59%, respectively. The LCMS analysis chromatogram showed that the plant extract's most active fraction produced nine peaks, representing nine possible active compounds. Among those, three compounds (Azoxystrobin, Stigmatellin Y, and 2-arachidonoyl glycerol) were suspected of contributing to control contamination, especially by E. coli O157:H7.

Escherichia coli strains with precise domain deletions in the ribonuclease RNase E can achieve greatly enhanced levels of membrane protein production.

Escherichia coli is one of the most widely utilized hosts for production of recombinant membrane proteins (MPs). Bacterial MP production, however, is usually accompanied by severe toxicity and low-level volumetric accumulation. In previous work, we had discovered that co-expression of RraA, an inhibitor of the RNA-degrading activity of RNase E, can efficiently suppress the cytotoxicity associated with the MP overexpression process and, simultaneously, enhance significantly the cellular accumulation of membrane-incorporated recombinant MPs in bacteria. Based on this, we constructed the specialized MP-producing E. coli strain SuptoxR, which can achieve dramatically enhanced volumetric yields of well-folded recombinant MPs. Ιn the present work, we have investigated whether domain deletions in the E. coli RNase E, which exhibit reduced ribonucleolytic activity, can result in suppressed MP-induced toxicity and enhanced recombinant MP production, in a manner resembling the conditions of rraA overexpression in E. coli SuptoxR. We have found that some strains encoding specific RNase E truncation variants can achieve significantly enhanced levels of recombinant MP production. Among these, we have found a single RNase E variant strain, which can efficiently suppress MP-induced toxicity and achieve greatly enhanced levels of recombinant MP production for proteins of both prokaryotic and eukaryotic origin. Based on its properties, and in analogy to the original SuptoxR strain, we have termed this strain SuptoxRNE22. E. coli SuptoxRNE22 can perform better than commercially available bacterial strains, which are frequently utilized for recombinant MP production. We anticipate that SuptoxRNE22 will become a widely utilized host for recombinant MP production in bacteria.

Genomic analyses of an Escherichia coli and Klebsiella pneumoniae urinary tract co‐infection using long‐read nanopore sequencing

AbstractEscherichia coli and Klebsiella pneumoniae isolates presenting with the same antimicrobial susceptibility profile were recovered from the same catheter sample of urine (CSU). Both strains were recovered from a patient with a long‐standing indwelling urinary catheter. Each isolate had its DNA extracted following culture. Nanopore long‐read sequencing was used to build the plasmids and chromosomes from each strain to closure to discern the potential horizontal propagation of resistance‐encoding plasmids and the relationship between resistance genes and insertion sequences. Plasmids derived from resistance strains in the urinary microbiota remain poorly characterized. The same 11 antimicrobial resistance (AMR) genes were found in plasmids from each strain. The 185,239‐bp FIB(K) pKBM1, from the K. pneumoniae strain, additionally encoded the five AMR genes: sul2, strA, strB, blaTEM‐1B, and blaCTX‐M‐15. A multimeric array of AMR genes and IS26 insertion sequences were found in the plasmids from both isolates. Both plasmids from each isolate were similar. Horizontal transfer of plasmids, followed by subsequent plasmid rearrangement, is likely to have occurred during infection. Furthermore, the resistance region in the plasmids shared similarity against the internationally prevalent plasmid, pKPN3‐307_typeA, commonly identified in K. pneumoniae ST307. Biofilm formation in catheterized patients may allow close cell contact between strains. Horizontal propagation of resistance genes may occur, leading to polymicrobial infections.

Antibacterial Activity, TLC-Bioautography Analysis, and Determination of Bioactive Components in Ethyl Acetate Extract of Robusta Coffee Leaf (Coffea canephora L.) From Aceh, Indonesia

Infectious diseases affect many people in the world, including Indonesia. One of the causes of infection is bacteria, including scherichia coli and Staphylococcus aureus. Robusta coffee (Coffea canephora L.) is one of the plants that is widely encountered on Indonesian plantations. The leaves are usually discarded after being trimmed to maximize the growth of coffee beans. The results of several studies show that robusta coffee leaves demonstrate antibacterial and antioxidant activity due to the presence of flavonoids, alkaloids, tannins, saponins, polyphenols, and chlorogenic acids. The aim of this research to investigate antibacterial activities, total flavonoid content and inspect the phytochemicals of the bioactive compounds as antibacterial with TLC Bioautography in the ethyl acetate extract of robusta coffee leaves. The identification of secondary metabolites was conducted by using the TLC-Bioautography method against Escherichia coli and Staphylococcus aureus. The determination of total flavonoid levels was carried out by using Spectrophotometry UV-Vis. Phytochemical testing showed that the extract contained alkaloids, steroids, phenolics, tannins, and flavonoids. The ethyl acetate extract inhibits the growth of Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 (P=0.00) with 100% extract as the most potent. The results of TLC-Bioautography showed the presence of polyphenolic compounds (Rf 0.36) which was confirmed by a clear zone in the disc diffusion test. The total flavonoid content in robusta coffee leaves was 57.255±0.0348 mg QE/g extract. Ethyl acetate extract from coffee leaves (Coffea canephora L). inhibits the growth of S. aureus and E. coli due to the presence of polyphenolic compounds

Approaches for the Detection of Escherichia coli in Wastewater: A Short Review

AbstractEscherichia coli is a harmful pathogenic bacterial species causing serious intestinal sickness in humans. This bacterium has been linked to contaminated epidemics that have led to significant mortality and morbidity across the world. E. coli, like most other waterborne infections, is tricky to discover effectively in the water supply. Therefore, there is a demand for advanced E. coli detection methods that can sensitively and rapidly detect these pathogens. This review reveals several approaches used for the detection of E. coli bacteria using conventional methods such as multiple tube fermentation and membrane filtration techniques. The emerging approaches give quite accurate and speedy identification despite the necessity for culturing; nevertheless, they lack precision and necessitate extra lab testing. Because analytical techniques such as GC‐DMS lack specificity, the invention of a sensing device that is simple to use, compact, extremely sensitive, and specific has proven essential in identifying incredibly low concentrations of harmful E. coli in drinking water.

Allosteric effects of E. coli SSB and RecR proteins on RecO protein binding to DNA.

Escherichia coli single stranded (ss) DNA binding protein (SSB) plays essential roles in DNA maintenance. It binds ssDNA with high affinity through its N-terminal DNA binding core and recruits at least 17 different SSB interacting proteins (SIPs) that are involved in DNA replication, recombination, and repair via its nine amino acid acidic tip (SSB-Ct). E. coli RecO, a SIP, is an essential recombination mediator protein in the RecF pathway of DNA repair that binds ssDNA and forms a complex with E. coli RecR protein. Here, we report ssDNA binding studies of RecO and the effects of a 15 amino acid peptide containing the SSB-Ct monitored by light scattering, confocal microscope imaging, and analytical ultracentrifugation (AUC). We find that one RecO monomer can bind the oligodeoxythymidylate, (dT)15, while two RecO monomers can bind (dT)35 in the presence of the SSB-Ct peptide. When RecO is in molar excess over ssDNA, large RecO-ssDNA aggregates occur that form with higher propensity on ssDNA of increasing length. Binding of RecO to the SSB-Ct peptide inhibits RecO-ssDNA aggregation. RecOR complexes can bind ssDNA via RecO, but aggregation is suppressed even in the absence of the SSB-Ct peptide, demonstrating an allosteric effect of RecR on RecO binding to ssDNA. Under conditions where RecO binds ssDNA but does not form aggregates, SSB-Ct binding enhances the affinity of RecO for ssDNA. For RecOR complexes bound to ssDNA, we also observe a shift in RecOR complex equilibrium towards a RecR4O complex upon binding SSB-Ct. These results suggest a mechanism by which SSB recruits RecOR to facilitate loading of RecA onto ssDNA gaps.

Optimizing Escherichia coli O157:H7 inactivation in goat's milk by thermosonication

AbstractEscherichia coli O157:H7 (STEC) is one of the hazardous foodborne pathogens in milk. Although traditional preservation methods reduce contamination, they are time‐consuming or cause physicochemical changes. Therefore, we optimize STEC inactivation in goat's milk by thermosonication, an alternative to traditional treatments. Different times (1–35 min) and temperatures (45.9–74.1°C) were applied, using a Central Composite Rotatable Design (CCRD). Lipid oxidation was adopted as an optimization limiting factor. Mathematical models described STEC inactivation and lipid oxidation with high performance, considering the high R2adj (0.942 and 0.731), and low mean square error (0.065 and <0.0001) and lack‐of‐fit (0.133 and 0.183). Validation was verified by the accuracy (1.141 and 1.017) and bias (0.992 and 1.006) factors, and the relative error of prediction (0.910 and 1.000). Both variables affected STEC inactivation linearly, enhancing decontamination. Lipid oxidation was affected by time, increasing oxidation products formation. Optimization was achieved around 1–20 min/62–74°C, improving STEC inactivation (6.6 log CFU/ml) with minimal lipid oxidation (0.06 mg MDA/L). Therefore, thermosonication represents a promising technology facing to traditional methods, ensuring bacteriological safety and minimal alterations.Practical ApplicationsDespite traditional methods for milk decontamination still being considered effective, there are some reports on pasteurized milk and dairy products‐related outbreaks. High‐intensity ultrasound is an emerging non‐thermal technology recently explored as a pathogen reduction method, used individually or combined. However, due to cavitation mechanism and free radicals realizing, some oxidative alterations could occur during processing. The present research paper contributes to provide a better understanding on the combined application of ultrasound and heat (thermosonication) to inactivate Escherichia coli in caprine milk. The findings herein are promising to the industrial utilization of thermosonication to obtaining safety products with minimal oxidative changes.

Genome Sequences of 16 Escherichia coli Bacteriophages Isolated from Wastewater, Pond Water, Cow Manure, and Bird Feces.

ABSTRACTEscherichia coli is a highly diverse bacterial species comprising both commensal and pathogenic strains. Here, we report complete genome sequences of 16 E. coli bacteriophages isolated from various environmental samples using the ECOR collection as isolation hosts.

Prevalence, Incidence, and Risk Factors for Intestinal Colonization Due to Fluoroquinolone-Resistant ST131 Escherichia coli: a Longitudinal Study in Highly Dependent, Long-Term Care Facility Residents.

ABSTRACTEscherichia coli ST131 clade C is an important driver for fluoroquinolone resistance (FQ-R). We conducted a prospective observational study in residents from two long-term care facilities (LTCFs) in Seville, Spain, in 2018. Fecal swabs and environmental samples were obtained. E. coli isolates were screened for clade C, FQ-R ST131 by PCR, and molecular typing by PFGE; representatives from pulsotypes were studied by whole-genome-sequencing (WGS) and assigned to lineages (cgSTs). Prevalence of colonization at each time point, incidence density, and risk factors for acquisition were studied. Seventy-six FQ-R ST131 E. coli isolates belonging to 34 cgSTs were obtained; 24 belonging to subclade C1 (116 isolates, 65.9%) and 10 to C2 (60, 34.1%). C1 lineages showed lower virulence scores than C2 (median [IQR], 19 [18 to 20] versus 21 [20 to 21.5], P = 0.001) and higher number of plasmids (4 [3 to 5] versus 2 [2 to 3], P = 0.01). aac(6’)-Ib-cr and blaOXA-1 were less frequent in C1 than C2 (2 [8.3%] versus 6 [60%], P = 0.003 for both); ESBL genes were detected in eight (33.3%) C1 (5 blaCTX-M-27) and three (30%) C2 (all blaCTX-M-15). Of the 82 residents studied, 49 were colonized at some point (59.7%), with a pooled prevalence of 38.6%. Incidence density of new lineage acquisition was 2.22 per 100 resident weeks (1.28 and 0.93 C1 and C2 subclades, respectively). Independent risk factors for acquisitions were having a colonized roommate (HR = 4.21; 95% CI = 1.71 to 10.36; P = 0.002) and urinary or fecal incontinence (HR = 2.82; 95% CI = 1.21 to 6.56; P = 0.01). LTCFs are important reservoirs of clade C ST131 E. coli. The risk factors found suggest that cross-transmission is the most relevant transmission mechanisms.IMPORTANCE We aimed at investigating the microbiological and epidemiological features of clade C fluoroquinolone-resistant ST131 E. coli isolates colonizing highly dependent residents in long-term care facilities (LTCFs) during 40 weeks and the risk factors of acquisition. Isolates from C1 and C2 subclades were characterized in this environment. The clonality of the isolates was characterized and they were assigned to lineages (cgSTs), Resistance genes, virulence factors, and plasmids were also described. This study suggests that cross-transmission is the most relevant transmission mechanisms; however, environmental colonization might also play a role. We believe the data provide useful information to depict the epidemiology of these bacteria by merging detailed microbiological and epidemiological information.

Genomics and pathotypes of the many faces of Escherichia coli.

Escherichia coli is the most researched microbial organism in the world. Its varied impact on human health, consisting of commensalism, gastrointestinal disease, or extraintestinal pathologies, has generated a separation of the species into at least eleven pathotypes (also known as pathovars). These are broadly split into two groups, intestinal pathogenic E. coli (InPEC) and extraintestinal pathogenic E. coli (ExPEC). However, components of E. coli's infinite open accessory genome are horizontally transferred with substantial frequency, creating pathogenic hybrid strains that defy a clear pathotype designation. Here, we take a birds-eye view of the E. coli species, characterizing it from historical, clinical, and genetic perspectives. We examine the wide spectrum of human disease caused by E. coli, the genome content of the bacterium, and its propensity to acquire, exchange, and maintain antibiotic resistance genes and virulence traits. Our portrayal of the species also discusses elements that have shaped its overall population structure and summarizes the current state of vaccine development targeted at the most frequent E. coli pathovars. In our conclusions, we advocate streamlining efforts for clinical reporting of ExPEC, and emphasize the pathogenic potential that exists throughout the entire species.

Parallel Evolution towards Increased Motility in Long-Term Cultures of Escherichia coli, Even Though Motility was Not Required for Long-Term Survival.

ABSTRACTEscherichia coli can survive for long periods in batch culture in the laboratory, where they experience a stressful and heterogeneous environment. During this incubation, E. coli acquires mutations that are selected in response to this environment, ultimately leading to evolved populations that are better adapted to these complex conditions, which can lead to a better understanding of evolutionary mechanisms. Mutations in regulatory genes often play a role in adapting to heterogeneous environments. To identify such mutations, we examined transcriptional differences during log phase growth in unaged cells compared to those that had been aged for 10 days and regrown. We identified expression changes in genes involved in motility and chemotaxis after adaptation to long-term cultures. We hypothesized that aged populations would also have phenotypic changes in motility and that motility may play a role in survival and adaptation to long-term cultures. While aged populations did show an increase in motility, this increase was not essential for survival in long-term cultures. We identified mutations in the regulatory gene sspA and other genes that may contribute to the observed differences in motility. Taken together, these data provide an overall picture of the role of mutations in regulatory genes for adaptation while underscoring that all changes that occur during evolution in stressful environments are not necessarily adaptive.IMPORTANCE Understanding how bacteria adapt in long-term cultures aids in both better treatment options for bacterial infections and gives insight into the mechanisms involved in bacterial evolution. In the past, it has been difficult to study these organisms in their natural environments. By using experimental evolution in heterogeneous and stressful laboratory conditions, we can more closely mimic natural environments and examine evolutionary mechanisms. One way to observe these mechanisms is to look at transcriptomic and genomic data from cells adapted to these complex conditions. Here, we found that although aged cells increase motility, this increase is not essential for survival in these conditions. These data emphasize that not all changes that occur due to evolutionary processes are adaptive, but these observations could still lead to hypotheses about the causative mutations. The information gained here allow us to make inferences about general mechanisms underlying phenotypic changes due to evolution.

Novel Multiplex PCR Method and Genome Sequence-Based Analog for High-Resolution Subclonal Assignment and Characterization of Escherichia coli Sequence Type 131 Isolates.

ABSTRACTEscherichia coli sequence type 131 (ST131) is a pandemic, multidrug-resistant extraintestinal pathogen. The multiple distinctive ST131 subclones differ for rfb and fliC alleles (O and H antigens), fimH allele (type-1 fimbriae adhesin), resistance phenotype and genotype, clinical correlates, and host predilection. Current PCR assays for detecting ST131 and its main subclones offer limited sub-ST characterization. Here we combined 22 novel and 14 published primers for a multiplex PCR assay to detect and extensively characterize ST131 isolates. The primers target mdh36, gyrB47, trpA72, sbmA, plsB, nupC, rmuC, kefC, ybbW, the O16 and O25b rfb variants, five fimH alleles (fimH22, fimH27, fimH30, fimH35, and fimH41), two fliC alleles (H4 and H5), a (subclone-specific) fluoroquinolone resistance-associated parC allele, and a (subclone-specific) prophage marker. The resulting amplicons resolve 15 molecular subsets within ST131, including 3 within clade A (H41 subclone), 5 within clade B (H22 subclone), and 7 within clade C (H30 subclone), which includes subclones C0 (H30S: 2 subsets), C1 and C1-M27 (H30R1: 2 subsets), and C2 (H30Rx: 3 subsets). Validation in three laboratories showed that this assay provides a rapid, accurate, and portable method for rapidly detecting and characterizing E. coli ST131 and its key subsets. Additionally, for users with whole genome sequencing (WGS) capability, we developed a command-line executable called ST131Typer, an in silico version of the extended multiplex PCR assay. Its accuracy was 87.8%, with most issues due to incomplete or fragmented input genome assemblies. These two novel assays should facilitate detailed ST131 subtyping using either endpoint PCR or WGS.IMPORTANCE These novel assays provide greater subclonal resolution and characterization of E. coli ST131 isolates than do the available comparable PCR assays, plus offer a novel sequence-based alternative to PCR. They may prove useful for molecular epidemiological studies, surveillance, and, potentially, clinical management.

Marine plant mediated green synthesis of silver nanoparticles using mangrove Rhizophora stylosa: Effect of variable process and their antibacterial activity.

Background:Most natural plants used in the synthesis of silver nanoparticles are limited to marine plants. To carry out applications, colloidal silver nanoparticles (AgNps) should have appropriate properties such as homogeneous shapes, small and narrow particle size distribution, and long time stability. This study aims to determine the effects of a variable process of AgNps mediated mangrove Rhizophora stylosa (RS) leaf extract, and antibacterial activity. Methods: Synthesis of AgNps was carried out by stirring silver nitrate solution with aqueous extract. The characterization of AgNps was carried out using UV-Vis spectrophotometry, X-ray diffraction (XRD), Dynamic Light Scattering (DLS) zetasizer and Transmission Electron Microscopy (TEM). Evaluation of antibacterial activity was carried out on E scherichia coli and Staphylococcus aureus. Reaction conditions such as the concentration of metal ions (0.001 M, 0.005 M, and 0.01 M), extracts (1%, 3%, and 5% v/v), and the reaction time on the size and stability of nanoparticles were also explored. Results: The UV-Vis spectroscopy showed an absorption of colloidal AgNps in a wavelength range of 403-443 nm. TEM analysis showed that as-synthesized AgNps were spherical in shape with a size range of 5-87 nm. The use of 0.001 M and 0.005 M of Ag + resulted in a smaller diameter than the synthesized AgNps, using 0.01 M Ag +, in the same extract concentration. The range of zeta potential was -24.9 mV to -27.7 mV. The as-synthesized AgNps were stable for more than one month. The XRD analysis showed four peaks, which were attributed to the face centered cubic crystal structure of metallic silver. The results of the silver nanoparticles synthesis showed good activity on E scherichia coli and Staphylococcus aureus, with an inhibition zone between 4.1-7.2 mm. Conclusions: The AgNps synthesized with RS leaf extract, which is a reducing agent, showed good potential as an antibacterial component.

Environmental injustice and Escherichia coli in urban streams: Potential for community‐led response

AbstractEscherichia coli are fecal indicator bacteria that reach waterbodies through aging and failing infrastructure in cities. Exposure to pathogens in untreated sewage can result in gastrointestinal disease, which frequently goes unreported. In the United States, the Clean Water Act regulates point source discharges of sewage and treated wastewater, but fecal indicator bacteria remain the second leading cause of river impairment. The burden of this contamination is not equitably distributed, with Black, Indigenous, and communities of color suffering from a disproportionate burden of untreated and overflowing waste and subsequent health impacts. Regulatory failures, and even abandonment, along with the exclusion of people of color from the mainstream environmental movement, mean that new approaches are needed to help communities empower themselves to address contamination. Community‐led groups that engage residents in addressing issues within and beyond regulatory frameworks have used approaches including trash traps, riparian planting and restoration, and community‐led monitoring. Mycofiltration, or the use of fungi to filter pollutants from water, is an emerging and understudied method of remediating E. coli. The low cost of mycofilter installation and maintenance may give agency to communities that have been unduly burdened with sewage contamination to diminish harmful exposures in the near term, even as they continue working toward longer‐term regulatory fixes. Continued research is needed to fully understand how different species of mycelium work under varying hydrologic conditions, including in‐field installations, along with long‐term monitoring and community acceptance to understand the efficacy and the potential impact of this strategy.

Genome Informatics and Machine Learning-Based Identification of Antimicrobial Resistance-Encoding Features and Virulence Attributes in Escherichia coli Genomes Representing Globally Prevalent Lineages, Including High-Risk Clonal Complexes.

ABSTRACTEscherichia coli, a ubiquitous commensal/pathogenic member from the Enterobacteriaceae family, accounts for high infection burden, morbidity, and mortality throughout the world. With emerging multidrug resistance (MDR) on a massive scale, E. coli has been listed as one of the Global Antimicrobial Resistance and Use Surveillance System (GLASS) priority pathogens. Understanding the resistance mechanisms and underlying genomic features appears to be of utmost importance to tackle further spread of these multidrug-resistant superbugs. While a few of the globally prevalent sequence types (STs) of E. coli, such as ST131, ST69, ST405, and ST648, have been previously reported to be highly virulent and harboring MDR, there is no clarity if certain ST lineages have a greater propensity to acquire MDR. In this study, large-scale comparative genomics of a total of 5,653 E. coli genomes from 19 ST lineages revealed ST-wide prevalence patterns of genomic features, such as antimicrobial resistance (AMR)-encoding genes/mutations, virulence genes, integrons, and transposons. Interpretation of the importance of these features using a Random Forest Classifier trained with 11,988 genomic features from whole-genome sequence data identified ST-specific or phylogroup-specific signature proteins mostly belonging to different protein superfamilies, including the toxin-antitoxin systems. Our study provides a comprehensive understanding of a myriad of genomic features, ST-specific proteins, and resistance mechanisms entailing different lineages of E. coli at the level of genomes; this could be of significant downstream importance in understanding the mechanisms of AMR, in clinical discovery, in epidemiology, and in devising control strategies.

F Plasmid Lineages in Escherichia coli ST95: Implications for Host Range, Antibiotic Resistance, and Zoonoses.

ABSTRACTEscherichia coli sequence type 95 (ST95) is an extraintestinal pathogenic E. coli (ExPEC) renowned for its ability to cause significant morbidity and mortality in humans and poultry. A core genome analysis of 668 ST95 isolates generated 10 clades (A to J), 5 of which are reported here for the first time. F plasmid replicon sequence typing showed that almost a third (178/668 [27%]) of the collection carry pUTI89 (F29:B10) and were restricted to clade A and a sublineage of clade B. In contrast, almost half (328/668 [49%]) of the collection across multiple clades harbor ColV plasmids (multiple F types). Strikingly, ST95 lineages with pUTI89 were almost exclusively from humans, while ColV+ ST95 lineages were sourced from poultry and humans. Clade I was notable because it comprises temporally and geographically matched ColV+ isolates sourced from human and retail poultry meat, suggesting interspecies transmission via food. Clade F contained ST95 isolates of bovine origin, none of which carried ColV or pUTI89 plasmids. Remarkably, an analysis of a cohort of 34,176 E. coli isolates comprising 2,570 sequence types mirrored what was observed in ST95: (i) pUTI89 was overwhelmingly linked to E. coli sourced from humans but almost entirely absent from 13,027 E. coli isolates recovered from poultry, pigs, and cattle, and (ii) E. coli isolates harboring ColV plasmids were from multiple sources, including humans, poultry, and swine. Overall, our data suggest that F plasmids influence E. coli host range, clade structure, and zoonotic potential in ST95 and ExPEC more broadly.IMPORTANCE E. coli ST95 is one of five dominant ExPEC lineages globally and noted for causing urinary tract and bloodstream infections and neonatal meningitis in humans and colibacillosis in poultry. Using high-resolution phylogenomics, we show that F replicon sequence type is linked to ST95 clade structure and zoonotic potential. Specifically, human centric ST95 clades overwhelmingly harbor F29:B10 (pUTI89) plasmids, while clades carrying both human- and poultry-sourced isolates are typically ColV+ with multiple replicon types. Importantly, several clades identified clonal ColV+ ST95 isolates from human and poultry sources, but clade I, which housed temporally and spatially matched isolates, provided the most robust evidence. Notably, patterns of association of F replicon types with E. coli host were mirrored within a diverse collection of 34,176 E. coli genomes. Our studies indicate that the role of food animals as a source of human ExPEC disease is complex and warrants further investigation.

Genome Sequence of Escherichia coli Stbl4, a Versatile Genetic Tool for Heterologous Expression.

ABSTRACTEscherichia coli Stbl4 is widely used as a laboratory strain for heterologous expression of large gene clusters. Since no genome sequence has been publicly available, we here report the draft sequence of Stbl4, including its F-plasmid. It should serve as a useful reference for researchers working with Stbl4.

Conjugation of a phenanthrene‐imidazole fluorophore with the chondroitin sulfate generated from Escherichia coliK4 polysaccharide

AbstractEscherichia coli K4 expressed a fructosylated chondroitin (K4), which had a chondroitin structure after the defructosylation treatment. Polysaccharide K4 as a preferred precursor was modified to produce chondroitin sulfate A (CSA). Here, glycosaminoglycans including K4, defructosylated K4, and CSA were conjugated with fluorophore A, which were optimized under three reaction conditions to give the maximum DS of 2.9, 6.5, and 8.5%, respectively. All of conjugates displayed luminescence response linearly to concentration. And they exhibited good storage stability in luminescence and dispersion within 24 h. The conjugate CSA‐A with substituted degree of 6.4% was chosen for the bioimaging study in vitro. CSA‐A showed nontoxic to astrocytes with concentrations lower than 100 μg/ml. It was internalized effectively by astrocytes after incubation for 24 h.

Complete Genome Sequence of Escherichia coli Sequence Type 1193 Isolate AVS0096, Recovered from River Water in Switzerland.

ABSTRACTEscherichia coli sequence type 1193 (ST1193) is an important cause of multidrug-resistant extraintestinal infections. Here, we report the complete genome sequence of strain AVS0096, isolated from river water in Switzerland in 2020. The genome consists of a chromosome (4.9 Mbp), a multidrug resistance plasmid (101 kb), and two small plasmids.

Construction of an Escherichia coli Strain Lacking Fimbriae by Deleting 64 Genes and Its Application for Efficient Production of Poly(3-Hydroxybutyrate) and l-Threonine.

ABSTRACTEscherichia coli contains 12 chaperone-usher operons for biosynthesis and assembly of various fimbriae. In this study, each of the 12 operons was deleted in E. coli MG1655, and the resulting 12 deletion mutants all grew better than the wild type, especially in the nutrient-deficient M9 medium. When the plasmid pBHR68 containing the key genes for polyhydroxyalkanoate production was introduced into these 12 mutants, each mutant synthesized more polyhydroxyalkanoate than the wild-type control. These results indicate that the fimbria removal in E. coli benefits cell growth and polyhydroxyalkanoate production. Therefore, all 12 chaperone-usher operons, including 64 genes, were deleted in MG1655, resulting in the fimbria-lacking strain WQM026. WQM026 grew better than MG1655, and no fimbria structures were observed on the surface of WQM026 cells. Transcriptomic analysis showed that in WQM026 cells, the genes related to glucose consumption, glycolysis, flagellar synthesis, and biosynthetic pathways of some key amino acids were upregulated, while the tricarboxylic acid cycle-related genes were downregulated. When pBHR68 was introduced into WQM026, huge amounts of poly-3-hydroxybutyrate were produced; when the plasmid pFW01-thrA*BC-rhtC, containing the key genes for l-threonine biosynthesis and transport, was transferred into WQM026, more l-threonine was synthesized than with the control. These results suggest that this fimbria-lacking E. coli WQM026 is a good host for efficient production of polyhydroxyalkanoate and l-threonine and has the potential to be developed into a valuable chassis microorganism.IMPORTANCE In this study, we investigated the interaction between the biosynthesis and assembly of fimbriae and intracellular metabolic networks in E. coli. We found that eliminating fimbriae could effectively improve the production of polyhydroxyalkanoate and l-threonine in E. coli MG1655. These results contribute to understanding the necessity of fimbriae and the advantages of fimbria removal for industrial microorganisms. The knowledge gathered from this study may be applied to the development of superior chassis microorganisms.