scholarly journals Stress Resistance Development and Genome-Wide Transcriptional Response ofEscherichia coliO157:H7 Adapted to Sublethal Thymol, Carvacrol, andtrans-Cinnamaldehyde

2018 ◽  
Vol 84 (22) ◽  
Author(s):  
Wenqian Yuan ◽  
Zi Jing Seng ◽  
Gurjeet Singh Kohli ◽  
Liang Yang ◽  
Hyun-Gyun Yuk
Keyword(s):  
Escherichia Coli ◽  
Stress Resistance ◽  
Virulence Genes ◽  
Acid Resistance ◽  
Gastric Fluid ◽  
Simulated Gastric Fluid ◽  
Cross Resistance ◽  
Resistance Development ◽  
Content Type ◽  
E Coli

ABSTRACTThymol, carvacrol, andtrans-cinnamaldehyde are essential oil (EO) compounds with broad-spectrum antimicrobial activities against foodborne pathogens, includingEscherichia coliO157:H7. However, little is known regarding direct resistance and cross-resistance development inE. coliO157:H7 after adaptation to sublethal levels of these compounds, and information is scarce on microbial adaptive responses at a molecular level. The present study demonstrated thatE. coliO157:H7 was able to grow in the presence of sublethal thymol (1/2T), carvacrol (1/2C), ortrans-cinnamaldehyde (1/2TC), displaying an extended lag phase duration and a lower maximum growth rate. EO-adapted cells developed direct resistance against lethal EO treatments and cross-resistance against heat (58°C) and oxidative (50 mM H2O2) stresses. However, no induction of acid resistance (simulated gastric fluid, pH 1.5) was observed. RNA sequencing revealed a large number (310 to 338) of differentially expressed (adjustedPvalue [Padj], <0.05; fold change, ≥5) genes in 1/2T and 1/2C cells, while 1/2TC cells only showed 27 genes with altered expression. In accordance with resistance phenotypes, the genes related to membrane, heat, and oxidative stress responses and genes related to iron uptake and metabolism were upregulated. Conversely, virulence genes associated with motility, biofilm formation, and efflux pumps were repressed. This study demonstrated the development of direct resistance and cross-resistance and characterized whole-genome transcriptional responses inE. coliO157:H7 adapted to sublethal thymol, carvacrol, ortrans-cinnamaldehyde. The data suggested that caution should be exercised when using EO compounds as food antimicrobials, due to the potential stress resistance development inE. coliO157:H7.IMPORTANCEThe present study was designed to understand transcriptomic changes and the potential development of direct and cross-resistance in essential oil (EO)-adaptedEscherichia coliO157:H7. The results demonstrated altered growth behaviors ofE. coliO157:H7 during adaptation in sublethal thymol, carvacrol, andtrans-cinnamaldehyde. Generally, EO-adapted bacteria showed enhanced resistance against subsequent lethal EO, heat, and oxidative stresses, with no induction of acid resistance in simulated gastric fluid. A transcriptomic analysis revealed the upregulation of related stress resistance genes and a downregulation of various virulence genes in EO-adapted cells. This study provides new insights into microbial EO adaptation behaviors and highlights the risk of resistance development in adapted bacteria.

scholarly journals Vibrio cholerae Triggers SOS and Mutagenesis in Response to a Wide Range of Antibiotics: a Route towards Multiresistance

2011 ◽  
Vol 55 (5) ◽  
pp. 2438-2441 ◽  
Author(s):  
Zeynep Baharoglu ◽  
Didier Mazel
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Vibrio Cholerae ◽  
Fluorescent Protein ◽  
Resistance Development ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Green Fluorescent ◽  
Regulated Promoters

ABSTRACTAntibiotic resistance development has been linked to the bacterial SOS stress response. InEscherichia coli, fluoroquinolones are known to induce SOS, whereas other antibiotics, such as aminoglycosides, tetracycline, and chloramphenicol, do not. Here we address whether various antibiotics induce SOS inVibrio cholerae. Reporter green fluorescent protein (GFP) fusions were used to measure the response of SOS-regulated promoters to subinhibitory concentrations of antibiotics. We show that unlike the situation withE. coli, all these antibiotics induce SOS inV. cholerae.

scholarly journals Subtilase Cytotoxin-Coding Genes in Verotoxin-Producing Escherichia coli Strains from Sheep and Goats Differ from Those from Cattle

2011 ◽  
Vol 77 (23) ◽  
pp. 8259-8264 ◽  
Author(s):  
José A. Orden ◽  
Pilar Horcajo ◽  
Ricardo de la Fuente ◽  
José A. Ruiz-Santa-Quiteria ◽  
Gustavo Domínguez-Bernal ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Human Disease ◽  
Virulence Genes ◽  
Small Ruminants ◽  
Human Beings ◽  
Content Type ◽  
Sheep And Goats ◽  
E Coli ◽  
Healthy Cattle ◽  
Subtilase Cytotoxin

ABSTRACTSubtilase cytotoxin (SubAB) from verotoxin (VT)-producingEscherichia coli(VTEC) strains was first described in the 98NK2 strain and has been associated with human disease. However, SubAB has recently been found in two VT-negativeE. colistrains (ED 591 and ED 32). SubAB is encoded by two closely linked, cotranscribed genes (subAandsubB). In this study, we investigated the presence ofsubABgenes in 52 VTEC strains isolated from cattle and 209 strains from small ruminants, using PCR. Most (91.9%) VTEC strains from sheep and goats and 25% of the strains from healthy cattle possessedsubABgenes. The presence ofsubABin a high percentage of the VTEC strains from small ruminants might increase the pathogenicity of these strains for human beings. Some differences in the results of PCRs and in the association with some virulence genes suggested the existence of different variants ofsubAB. We therefore sequenced thesubAgene in 12 strains and showed that thesubAgene in most of thesubAB-positive VTEC strains from cattle was almost identical (about 99%) to that in the 98NK2 strain, while thesubAgene in most of thesubAB-positive VTEC strains from small ruminants was almost identical to that in the ED 591 strain. We propose the termssubAB1to describe the SubAB-coding genes resembling that in the 98NK2 strain andsubAB2to describe those resembling that in the ED 591 strain.

scholarly journals Extraintestinal Pathogenic and Antimicrobial-Resistant Escherichia coli, Including Sequence Type 131 (ST131), from Retail Chicken Breasts in the United States in 2013

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
James R. Johnson ◽  
Stephen B. Porter ◽  
Brian Johnston ◽  
Paul Thuras ◽  
Sarah Clock ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Virulence Genes ◽  
Meat Products ◽  
The United States ◽  
Sequence Type ◽  
The Other ◽  
Antibiotic Resistant ◽  
Content Type ◽  
E Coli

ABSTRACT Chicken meat products are hypothesized to be vehicles for transmitting antimicrobial-resistant and extraintestinal pathogenic Escherichia coli (ExPEC) to consumers. To reassess this hypothesis in the current era of heightened concerns about antimicrobial use in food animals, we analyzed 175 chicken-source E. coli isolates from a 2013 Consumer Reports national survey. Isolates were screened by PCR for ExPEC-defining virulence genes. The 25 ExPEC isolates (12% of 175) and a 2:1 randomly selected set of 50 non-ExPEC isolates were assessed for their phylogenetic/clonal backgrounds and virulence genotypes for comparison with their resistance profiles and the claims on the retail packaging label (“organic,” “no antibiotics,” and “natural”). Compared with the findings for non-ExPEC isolates, the group of ExPEC isolates had a higher prevalence of phylogroup B2 isolates (44% versus 4%; P < 0.001) and a lower prevalence of phylogroup A isolates (4% versus 30%; P = 0.001), a higher prevalence of multiple individual virulence genes, higher virulence scores (median, 11 [range, 4 to 16] versus 8 [range, 1 to 14]; P = 0.001), and higher resistance scores (median, 4 [range, 0 to 8] versus 3 [range, 0 to 10]; P < 0.001). All five isolates of sequence type 131 (ST131) were ExPEC (P = 0.003), were as extensively resistant as the other isolates tested, and had higher virulence scores than the other isolates tested (median, 12 [range, 11 to 13] versus 8 [range, 1 to 16]; P = 0.005). Organic labeling predicted lower resistance scores (median, 2 [range, 0 to 3] versus 4 [range, 0 to 10]; P = 0.008) but no difference in ExPEC status or virulence scores. These findings document a persisting reservoir of extensively antimicrobial-resistant ExPEC isolates, including isolates from ST131, in retail chicken products in the United States, suggesting a potential public health threat. IMPORTANCE We found that among Escherichia coli isolates from retail chicken meat products purchased across the United States in 2013 (many of these isolates being extensively antibiotic resistant), a minority had genetic profiles suggesting an ability to cause extraintestinal infections in humans, such as urinary tract infection, implying a risk of foodborne disease. Although isolates from products labeled “organic” were less extensively antibiotic resistant than other isolates, they did not appear to be less virulent. These findings suggest that retail chicken products in the United States, even if they are labeled “organic,” pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent E. coli isolates.

scholarly journals Estimating the Prevalence of Potential Enteropathogenic Escherichia coli and Intimin Gene Diversity in a Human Community by Monitoring Sanitary Sewage

2013 ◽  
Vol 80 (1) ◽  
pp. 119-127 ◽  
Author(s):  
Kun Yang ◽  
Eulyn Pagaling ◽  
Tao Yan
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Content Type ◽  
E Coli ◽  
Enteric Diseases ◽  
Detection Frequency ◽  
Alternative Approach ◽  
Prevalent Subtype ◽  
Qpcr Quantification

ABSTRACTPresently, the understanding of bacterial enteric diseases in the community and their virulence factors relies almost exclusively on clinical disease reporting and examination of clinical pathogen isolates. This study aimed to investigate the feasibility of an alternative approach that monitors potential enteropathogenicEscherichia coli(EPEC) and enterohemorrhagicE. coli(EHEC) prevalence and intimin gene (eae) diversity in a community by directly quantifying and characterizing target virulence genes in the sanitary sewage. The quantitative PCR (qPCR) quantification of theeae,stx1, andstx2genes in sanitary sewage samples collected over a 13-month period detectedeaein all 13 monthly sewage samples at significantly higher abundance (93 to 7,240 calibrator cell equivalents [CCE]/100 ml) thanstx1andstx2, which were detected sporadically. The prevalence level of potential EPEC in the sanitary sewage was estimated by calculating the ratio ofeaetouidA, which averaged 1.0% (σ = 0.4%) over the 13-month period. Cloning and sequencing of theeaegene directly from the sewage samples covered the majority of theeaediversity in the sewage and detected 17 uniqueeaealleles belonging to 14 subtypes. Among them,eae-β2 was identified to be the most prevalent subtype in the sewage, with the highest detection frequency in the clone libraries (41.2%) and within the different sampling months (85.7%). Additionally, sewage and environmentalE. coliisolates were also obtained and used to determine the detection frequencies of the virulence genes as well aseaegenetic diversity for comparison.

scholarly journals Extended-Spectrum-β-Lactamase- and Plasmid AmpC-Producing Escherichia coli Causing Community-Onset Bloodstream Infection: Association of Bacterial Clones and Virulence Genes with Septic Shock, Source of Infection, and Recurrence

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Inga Fröding ◽  
Badrul Hasan ◽  
Isak Sylvin ◽  
Maarten Coorens ◽  
Pontus Nauclér ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Septic Shock ◽  
Prostate Biopsy ◽  
Virulence Genes ◽  
Multivariable Analysis ◽  
Bloodstream Infections ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
Community Onset

ABSTRACT Invasive infections due to extended-spectrum-β-lactamase- and pAmpC-producing Escherichia coli (ESBL/pAmpC-EC) are an important cause of morbidity, often caused by the high-risk clone sequence type (ST131) and isolates classified as extraintestinal pathogenic E. coli (ExPEC). The relative influence of host immunocompetence versus microbiological virulence factors in the acquisition and outcome of bloodstream infections (BSI) is poorly understood. Herein, we used whole-genome sequencing on 278 blood culture isolates of ESBL/pAmpC-EC from 260 patients with community-onset BSI collected from 2012 to 2015 in Stockholm to study the association of virulence genes, sequence types, and antimicrobial resistance with severity of disease, infection source, ESBL/pAmpC-EC BSI low-risk patients, and patients with repeated episodes. ST131 subclade C2 comprised 29% of all patients. Factors associated with septic shock in multivariable analysis were patient host factors (hematologic cancer or transplantation and reduced daily living activity), presence of the E. coli virulence factor iss (increased serum survival), absence of phenotypic multidrug resistance, and absence of the genes pap and hsp. Adhesins, particularly pap, were associated with urinary tract infection (UTI) source, while isolates from post-prostate biopsy sepsis had a low overall number of virulence operons, including adhesins, and commonly belonged to ST131 clades A, B, and subclade C1, ST1193, and ST648. ST131 was associated with recurrent episodes. In conclusion, the most interesting finding is the association of iss with septic shock. Adhesins are important for UTI pathogenesis, while otherwise low-pathogenic isolates from the microbiota can cause post-prostate biopsy sepsis.

scholarly journals Fitness, Stress Resistance, and Extraintestinal Virulence in Escherichia coli

2013 ◽  
Vol 81 (8) ◽  
pp. 2733-2742 ◽  
Author(s):  
Alexandre Bleibtreu ◽  
Pierre-Alexis Gros ◽  
Cédric Laouénan ◽  
Olivier Clermont ◽  
Hervé Le Nagard ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Stress Response ◽  
Mouse Model ◽  
Stress Resistance ◽  
Maximum Growth ◽  
Competitive Fitness ◽  
Content Type ◽  
General Stress Response ◽  
E Coli

ABSTRACTThe extraintestinal virulence ofEscherichia coliis dependent on numerous virulence genes. However, there is growing evidence for a role of the metabolic properties and stress responses of strains in pathogenesis. We assessed the respective roles of these factors in strain virulence by developing phenotypic assays for measuringin vitroindividual and competitive fitness and the general stress response, which we applied to 82 commensal and extraintestinal pathogenicE. colistrains previously tested in a mouse model of sepsis. Individual fitness properties, in terms of maximum growth rates in various media (Luria-Bertani broth with and without iron chelator, minimal medium supplemented with gluconate, and human urine) and competitive fitness properties, estimated as the mean relative growth rate per generation in mixed cultures with a reference fluorescentE. colistrain, were highly diverse between strains. The activity of the main general stress response regulator, RpoS, as determined by iodine staining of the colonies, H2O2resistance, andrpoSsequencing, was also highly variable. No correlation between strain fitness and stress resistance and virulence in the mouse model was found, except that the maximum growth rate in urine was higher for virulent strains. Multivariate analysis showed that the number of virulence factors was the only independent factor explaining the virulence in mice. At the species level, growth capacity and stress resistance are heterogeneous properties that do not contribute significantly to the intrinsic virulence of the strains.

scholarly journals Occurrence of Virulence Genes Associated with Diarrheagenic Pathotypes in Escherichia coli Isolates from Surface Water

2012 ◽  
Vol 79 (1) ◽  
pp. 328-335 ◽  
Author(s):  
Jatinder P. S. Sidhu ◽  
Warish Ahmed ◽  
Leonie Hodgers ◽  
Simon Toze
Keyword(s):  
Escherichia Coli ◽  
Health Risks ◽  
High Frequency ◽  
Aquatic Ecosystems ◽  
Virulence Genes ◽  
Storm Water ◽  
Storm Events ◽  
Widespread Occurrence ◽  
Content Type ◽  
E Coli

ABSTRACTEscherichia coliisolates (n= 300) collected from six sites in subtropical Brisbane, Australia, prior to and after storm events were tested for the presence of 11 virulence genes (VGs) specific to diarrheagenic pathotypes. The presence ofeaeA,stx1,stx2, andehxAgenes specific for the enterohemorrhagicE. coli(EHEC) pathotype was detected in 56%, 6%, 10%, and 13% of isolates, respectively. The VGsastA(69%) andaggR(29%), carried by enteroaggregative (EAEC) pathotypes, were frequently detected inE. coliisolates. The enteropathogenicE. coli(EPEC) genebfpwas detected in 24% of isolates. In addition, enteroinvasiveE. coli(EIEC) VGipaHwas also detected in 14% of isolates. During dry periods, isolates belonging to the EAEC pathotype were most commonly detected (23%), followed by EHEC (11%) and EPEC (11%). Conversely, a more uniform prevalence of pathotypes, EPEC (14%), EAEC (12%), EIEC (10%), EHEC (7%), and ETEC (7%), was observed after the storm events. The results of this study highlight the widespread occurrence of potentially diarrheagenic pathotypes in the urban aquatic ecosystems. While the presence of VGs inE. coliisolates alone is insufficient to determine pathogenicity, the presence of diarrheagenicE. colipathotypes in high frequency after the storm events could lead to increased health risks if untreated storm water were to be used for nonpotable purposes and recreational activities.

scholarly journals Adaptation of Escherichia coli O157:H7 to pH Alters Membrane Lipid Composition, Verotoxin Secretion, and Resistance to Simulated Gastric Fluid Acid

2004 ◽  
Vol 70 (6) ◽  
pp. 3500-3505 ◽  
Author(s):  
Hyun-Gyun Yuk ◽  
Douglas L. Marshall
Keyword(s):  
Escherichia Coli ◽  
Membrane Fluidity ◽  
Lipid Composition ◽  
Vaccenic Acid ◽  
Acid Resistance ◽  
Gastric Fluid ◽  
Membrane Lipid ◽  
Simulated Gastric Fluid ◽  
Acidic Ph ◽  
Membrane Lipid Composition

ABSTRACT The influence of adaptation to pH (from pH 5.0 to 9.0) on membrane lipid composition, verotoxin concentration, and resistance to acidic conditions in simulated gastric fluid (SGF) (pH 1.5, 37�C) was determined for Escherichia coli O157:H7 (HEC, ATCC 43895), an rpoS-deficient mutant of ATCC 43895 (HEC-RM, FRIK 816-3), and nonpathogenic E. coli (NPEC, ATCC 25922). Regardless of the strain, D values (in SGF) of acid-adapted cells were higher than those of non-acid-adapted cells, with HEC adapted at pH 5.0 having the greatest D value, i.e., 25.6 min. Acid adaptation increased the amounts of palmitic acid (C16:0) and decreased cis-vaccenic acid (C18:1ω7c) in the membrane lipids of all strains. The ratio of cis-vaccenic acid to palmitic acid increased at acidic pH, causing a decrease in membrane fluidity. HEC adapted to pH 8.3 and HEC-RM adapted to pH 7.3 exhibited the greatest verotoxin concentrations (2,470 and 1,460 ng/ml, respectively) at approximately 108 CFU/ml. In addition, the ratio of extracellular to intracellular verotoxin concentration decreased at acidic pH, possibly due to the decrease of membrane fluidity. These results suggest that while the rpoS gene does not influence acid resistance in acid-adapted cells it does confer decreased membrane fluidity, which may increase acid resistance and decrease verotoxin secretion.

scholarly journals Pathogenic Potential, Genetic Diversity, and Population Structure of Escherichia coli Strains Isolated from a Forest-Dominated Watershed (Comox Lake) in British Columbia, Canada

2014 ◽  
Vol 81 (5) ◽  
pp. 1788-1798 ◽  
Author(s):  
Abhirosh Chandran ◽  
Asit Mazumder
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Population Structure ◽  
Virulence Genes ◽  
Repetitive Element ◽  
Fingerprint Analysis ◽  
Pathogenic Potential ◽  
Content Type ◽  
E Coli ◽  
Heat Stable

ABSTRACTEscherichia coliisolates (n= 658) obtained from drinking water intakes of Comox Lake (2011 to 2013) were screened for the following virulence genes (VGs):stx1andstx2(Shiga toxin-producingE. coli[STEC]),eaeand the adherence factor (EAF) gene (enteropathogenicE. coli[EPEC]), heat-stable (ST) enterotoxin (variants STh and STp) and heat-labile enterotoxin (LT) genes (enterotoxigenicE. coli[ETEC]), andipaH(enteroinvasiveE. coli[EIEC]). The only genes detected wereeaeandstx2, which were carried by 37.69% (n= 248) of the isolates. Onlyeaewas harbored by 26.74% (n= 176) of the isolates, representing potential atypical EPEC strains, while onlystx2was detected in 10.33% (n= 68) of the isolates, indicating potential STEC strains. Moreover, four isolates were positive for both thestx2andeaegenes, representing potential EHEC strains. The prevalence of VGs (eaeorstx2) was significantly (P< 0.0001) higher in the fall season, and multiple genes (eaeplusstx2) were detected only in fall. Repetitive element palindromic PCR (rep-PCR) fingerprint analysis of 658E. coliisolates identified 335 unique fingerprints, with an overall Shannon diversity (H′) index of 3.653. Diversity varied among seasons over the years, with relatively higher diversity during fall. Multivariate analysis of variance (MANOVA) revealed that the majority of the fingerprints showed a tendency to cluster according to year, season, and month. Taken together, the results indicated that the diversity and population structure ofE. colifluctuate on a temporal scale, reflecting the presence of diverse host sources and their behavior over time in the watershed. Furthermore, the occurrence of potentially pathogenicE. colistrains in the drinking water intakes highlights the risk to human health associated with direct and indirect consumption of untreated surface water.

scholarly journals Evolutionary Silence of the Acid Chaperone Protein HdeB in Enterohemorrhagic Escherichia coli O157:H7

2011 ◽  
Vol 78 (4) ◽  
pp. 1004-1014 ◽  
Author(s):  
Michelle Q. Carter ◽  
Jacqueline W. Louie ◽  
Clifton K. Fagerquist ◽  
Omar Sultan ◽  
William G. Miller ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acid Resistance ◽  
Significant Loss ◽  
Enterohemorrhagic Escherichia Coli ◽  
Survival Strategies ◽  
Start Codon ◽  
Divergent Evolution ◽  
Content Type ◽  
E Coli ◽  
K 12

ABSTRACTThe periplasmic chaperones HdeA and HdeB are known to be important for cell survival at low pH (pH < 3) inEscherichia coliandShigellaspp. Here we investigated the roles of HdeA and HdeB in the survival of various enterohemorrhagicE. coli(EHEC) following exposure to pH 2.0. Similar to K-12 strains, the acid protections conferred by HdeA and HdeB in EHEC O145 were significant: loss of HdeA and HdeB led to over 100- to 1,000-fold reductions in acid survival, depending on the growth condition of prechallenge cells. However, this protection was much less inE. coliO157:H7 strains. Deletion ofhdeBdid not affect the acid survival of cells, and deletion ofhdeAled to less than a 5-fold decrease in survival. Sequence analysis of thehdeABoperon revealed a point mutation at the putative start codon of thehdeBgene in all 26E. coliO157:H7 strains analyzed, which shifted the ATG start codon to ATA. This mutation correlated with the lack of HdeB inE. coliO157:H7; however, the plasmid-borne O157-hdeBwas able to restore partially the acid resistance in anE. coliO145ΔhdeABmutant, suggesting the potential function of O157-HdeB as an acid chaperone. We conclude thatE. coliO157:H7 strains have evolved acid survival strategies independent of the HdeA/B chaperones and are more acid resistant than nonpathogenic K-12 for cells grown under nonfavorable culturing conditions such as in Luria-Bertani no-salt broth at 28°C. These results suggest a divergent evolution of acid resistance mechanisms withinE. coli.

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