scholarly journals Disbalancing Envelope Stress Responses as a Strategy for Sensitization of Escherichia coli to Antimicrobial Agents

2021 ◽  
Vol 12 ◽  
Author(s):  
Esther Recacha ◽  
Valeria Fox ◽  
Sara Díaz-Díaz ◽  
Ana García-Duque ◽  
Fernando Docobo-Pérez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stress Responses ◽  
Antimicrobial Agents ◽  
Growth Curves ◽  
Bacterial Survival ◽  
Beta Lactam ◽  
E Coli ◽  
Envelope Stress ◽  
Time Kill ◽  
Isogenic Strains

Disbalancing envelope stress responses was investigated as a strategy for sensitization of Escherichia coli to antimicrobial agents. Seventeen isogenic strains were selected from the KEIO collection with deletions in genes corresponding to the σE, Cpx, Rcs, Bae, and Psp responses. Antimicrobial activity against 20 drugs with different targets was evaluated by disk diffusion and gradient strip tests. Growth curves and time-kill curves were also determined for selected mutant-antimicrobial combinations. An increase in susceptibility to ampicillin, ceftazidime, cefepime, aztreonam, ertapenem, and fosfomycin was detected. Growth curves for Psp response mutants showed a decrease in optical density (OD) using sub-MIC concentrations of ceftazidime and aztreonam (ΔpspA and ΔpspB mutants), cefepime (ΔpspB and ΔpspC mutants) and ertapenem (ΔpspB mutant). Time-kill curves were also performed using 1xMIC concentrations of these antimicrobials. For ceftazidime, 2.9 log10 (ΔpspA mutant) and 0.9 log10 (ΔpspB mutant) decreases were observed at 24 and 8 h, respectively. For aztreonam, a decrease of 3.1 log10 (ΔpspA mutant) and 4 log1010 (ΔpspB mutant) was shown after 4–6 h. For cefepime, 4.2 log10 (ΔpspB mutant) and 2.6 log10 (ΔpspC mutant) decreases were observed at 8 and 4 h, respectively. For ertapenem, a decrease of up to 6 log10 (ΔpspB mutant) was observed at 24 h. A deficient Psp envelope stress response increased E. coli susceptibility to beta-lactam agents such as cefepime, ceftazidime, aztreonam and ertapenem. Its role in repairing extensive inner membrane disruptions makes this pathway essential to bacterial survival, so that disbalancing the Psp response could be an appropriate target for sensitization strategies.

scholarly journals Activation of Toxin-Antitoxin System Toxins Suppresses Lethality Caused by the Loss of σEin Escherichia coli

2015 ◽  
Vol 197 (14) ◽  
pp. 2316-2324 ◽  
Author(s):  
Yasushi Daimon ◽  
Shin-ichiro Narita ◽  
Yoshinori Akiyama
Keyword(s):  
Escherichia Coli ◽  
Stress Responses ◽  
Ectopic Expression ◽  
Growth Media ◽  
Content Type ◽  
E Coli ◽  
Envelope Stress ◽  
Genes Encoding ◽  
Σ Factor ◽  
Mutant Forms

ABSTRACTσE, an alternative σ factor that governs a major signaling pathway in envelope stress responses in Gram-negative bacteria, is essential for growth ofEscherichia colinot only under stressful conditions, such as elevated temperature, but also under normal laboratory conditions. A mutational inactivation of thehicBgene has been reported to suppress the lethality caused by the loss of σE.hicBencodes the antitoxin of the HicA-HicB toxin-antitoxin (TA) system; overexpression of the HicA toxin, which exhibits mRNA interferase activity, causes cleavage of mRNAs and an arrest of cell growth, while simultaneous expression of HicB neutralizes the toxic effects of overproduced HicA. To date, however, how the loss of HicB rescues the cell lethality in the absence of σEand, more specifically, whether HicA is involved in this process remain unknown. Here we showed that simultaneous disruption ofhicAabolished suppression of the σEessentiality in the absence ofhicB, while ectopic expression of wild-type HicA, but not that of its mutant forms without mRNA interferase activity, restored the suppression. Furthermore, HicA and two other mRNA interferase toxins, HigB and YafQ, suppressed the σEessentiality even in the presence of chromosomally encoded cognate antitoxins when these toxins were overexpressed individually. Interestingly, when the growth media were supplemented with low levels of antibiotics that are known to activate toxins,E. colicells with no suppressor mutations grew independently of σE. Taken together, our results indicate that the activation of TA system toxins can suppress the σEessentiality and affect the extracytoplasmic stress responses.IMPORTANCEσEis an alternative σ factor involved in extracytoplasmic stress responses. Unlike other alternative σ factors, σEis indispensable for the survival ofE. colieven under unstressed conditions, although the exact reason for its essentiality remains unknown. Toxin-antitoxin (TA) systems are widely distributed in prokaryotes and are composed of two adjacent genes, encoding a toxin that exerts harmful effects on the toxin-producing bacterium itself and an antitoxin that neutralizes the cognate toxin. Curiously, it is known that inactivation of an antitoxin rescues the σEessentiality, suggesting a connection between TA systems and σEfunction. We demonstrate here that toxin activation is necessary for this rescue and suggest the possible involvement of TA systems in extracytoplasmic stress responses.

scholarly journals Characterization and Comparative Genomics Analysis of lncFII Multi-Resistance Plasmids Carrying blaCTX–M and Type1 Integrons From Escherichia coli

2021 ◽  
Vol 12 ◽  
Author(s):  
Wei Zhou ◽  
Enbao Zhang ◽  
Jinzhi Zhou ◽  
Ze He ◽  
Yuqiao Zhou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Antimicrobial Agents ◽  
Antibiotic Resistance Genes ◽  
Beta Lactam ◽  
Detection Rates ◽  
E Coli ◽  
Extended Spectrum ◽  
Poultry Breeding ◽  
Resistance Plasmids

This research aimed to investigate the presence and transferability of the extended-spectrum β-lactamase resistance genes to identify the genetic context of multi-drug resistant (MDR) loci in two Escherichia coli plasmids from livestock and poultry breeding environment. MICs were determined by broth microdilution. A total of 137 E. coli resistant to extended-spectrum β-lactam antibiotics were screened for the presence of the ESBL genes by PCR. Only two E. coli out of 206 strains produced carbapenemases, including strain 11011 that produced enzyme A, and strain 417957 that produced enzyme B. The genes were blaKPC and blaNDM, respectively. The plasmids containing blaCTX–M were conjugatable, and the plasmids containing carbapenem resistance gene were not conjugatable. Six extended-spectrum β-lactamase resistance genes were detected in this research, including blaTEM, blaCTX–M, blaSHV, blaOAX–1, blaKPC, and blaNDM, and the detection rates were 94.89% (130/137), 92.7% (127/137), 24.81% (34/137), 20.43% (28/137), 0.72% (1/137), and 0.72% (1/137), respectively. Two conjugative lncFII multi-resistance plasmids carrying blaCTX–M, p11011-fosA and p417957-CTXM, were sequenced and analyzed. Both conjugative plasmids were larger than 100 kb and contained three accessory modules, including MDR region. The MDR region of the two plasmids contained many antibiotic resistance genes, including blaCTX–M, mph (A), dfrA17, aadA5, sul1, etc. After transfer, both the transconjugants displayed elevated MICs of the respective antimicrobial agents. A large number of resistance genes clusters in specific regions may contribute to the MDR profile of the strains. The presence of mobile genetic elements at the boundaries can possibly facilitate transfer among Enterobacteriaceae through inter-replicon gene transfer. Our study provides beta-lactam resistance profile of bacteria, reveals the prevalence of β-lactamase resistance genes in livestock and poultry breeding environment in Zhejiang Province, and enriches the research on IncFII plasmids containing blaCTX–M.

scholarly journals Dimercaptosuccinic acid in combination with carbapenems against isogenic strains of Escherichia coli producing or not producing a metallo-β-lactamase in vitro and in murine peritonitis

2020 ◽  
Vol 75 (12) ◽  
pp. 3593-3600 ◽  
Author(s):  
G Cheminet ◽  
V de Lastours ◽  
L Poirel ◽  
F Chau ◽  
K Peoc’h ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Peritoneal Fluid ◽  
Dimercaptosuccinic Acid ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Bacterial Counts ◽  
E Coli ◽  
Time Kill ◽  
Isogenic Strains

Abstract Background Carbapenemase-producing Enterobacterales represent a major therapeutic challenge. MBLs, requiring zinc at their catalytic site, could be inhibited by meso-dimercaptosuccinic acid (DMSA), a heavy metal chelator already widely used for treating lead intoxication. Objectives To evaluate the activity of carbapenems alone or combined with DMSA against MBL-producing Escherichia coli in a severe murine peritonitis model. Methods Isogenic strains of wild-type E. coli CFT073 producing the MBLs NDM-1, VIM-2 and IMP-1, and the control serine carbapenemases OXA-48 and KPC-3 were constructed. MIC determinations and time–kill assays were performed for imipenem, meropenem and ertapenem alone or in combination with DMSA. Infected mice were treated intraperitoneally for 24 h with imipenem, DMSA or their combination. Bacterial counts in peritoneal fluid and spleen were assessed at 24 h. Results DMSA in combination with each carbapenem caused a significant decrease in the MICs for all MBL-producing strains, in a concentration-dependent manner, but did not provide benefit against non-MBL strains. In mice infected with the NDM-1-producing strain, the combination of imipenem and DMSA significantly reduced bacterial counts in peritoneal fluid (P = 0.0006) and spleen (P < 0.0001), as compared with imipenem alone, with no benefit against the KPC-3-producing and CFT073 strains. DMSA concentrations in plasma of mice were comparable to those obtained in humans with a standard oral dose. Conclusions DMSA restores the activity of carbapenems against MBL-producing strains, and its combination with carbapenems appears to be a promising strategy for the treatment of NDM-producing E. coli infections.

scholarly journals Stress Reduction, Bacterial Style

2017 ◽  
Vol 199 (20) ◽  
Author(s):  
Susan Gottesman
Keyword(s):  
Escherichia Coli ◽  
Stress Reduction ◽  
Stress Responses ◽  
Cell Envelope ◽  
Content Type ◽  
E Coli ◽  
Envelope Stress ◽  
Multiple Cell ◽  
As Stress ◽  
Sigma E

ABSTRACT Bacteria have robust responses to a variety of stresses. In particular, bacteria like Escherichia coli have multiple cell envelope stress responses, and generally we evaluate what these responses are doing by the repair systems they induce. However, probably at least as important in interpreting what is being sensed as stress are the genes that these stress systems downregulate, directly or indirectly. This is discussed here for the Cpx and sigma E systems of E. coli.

scholarly journals Genetic Characterization Among Carbapenem-resistant Escherichia coli Strains Using Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) Fingerprinting in South Africa

2020 ◽  
Author(s):  
Kingsley Ehi Ebomah ◽  
Anthony Ifeanyi Okoh
Keyword(s):  
Escherichia Coli ◽  
Polymerase Chain Reaction ◽  
Antimicrobial Agents ◽  
Genetic Relatedness ◽  
Carbapenem Resistance ◽  
Beta Lactam ◽  
Enterobacterial Repetitive Intergenic Consensus ◽  
Chain Reaction ◽  
E Coli ◽  
Polymerase Chain

Abstract Background Carbapenems belong to beta-lactam class of antibiotics usually considered as the last line of defense because they can be effective against severe infections caused by prevalent multidrug-resistant (MDR) pathogens. However, carbapenems can be deactivated by bacteria that produce carbapenemase (beta-lactamase). This study was conducted to screen for carbapenem-resistance genes (CRGs) harbored by pathogenic strains of Escherichia coli recovered from different environmental samples. We also assessed the genetic relatedness among selected E. coli pathotypes using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR).Method: Molecular identification and characterization of the presumptive isolates were performed using PCR and isolates that exhibited antimicrobial resistance (AMR) phenotypically were further screened for some relevant CRGs (blaNDM−1, blaKPC and blaOXA−48−like). Furthermore, ERIC-PCR was used to determine the similarity and diversity of 31 E. coli strains which were randomly selected from the different sources analyzed in this study.Result Our findings revealed a total of 238 presumptive E. coli isolates, out of which 192 were confirmed positive for uidA gene. Further screening revealed 77 (40%) isolates belong to six key E. coli pathotypes and 70 of them exhibited phenotypic AMR. Additionally, twenty-nine (41%) of the 70 MDR pathogenic E. coli strains harbored CRGs; with 24 strains harboring blaNDM−1, 8 harboring blaKPC and 2 harboring blaOXA−48−like genes.Conclusion Findings also suggest that the selected E. coli pathotypes belonged to different genomic clusters, while the cluster analysis showed a possible genetic diversity among aquatic and farm isolates. Proper treatment of final effluents before discharge as well as the development of more effective strategies to control and manage the use of antimicrobial agents were strongly recommended.

scholarly journals Transcriptional Responses of Escherichia coli to a Small-Molecule Inhibitor of LolCDE, an Essential Component of the Lipoprotein Transport Pathway

2016 ◽  
Vol 198 (23) ◽  
pp. 3162-3175 ◽  
Author(s):  
Christian Lorenz ◽  
Thomas J. Dougherty ◽  
Stephen Lory
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Small Molecule ◽  
Stress Responses ◽  
Transport Pathway ◽  
Transcript Levels ◽  
Content Type ◽  
E Coli ◽  
Molecule Inhibitor ◽  
Envelope Stress

ABSTRACTIn Gram-negative bacteria, a dedicated machinery consisting of LolABCDE components targets lipoproteins to the outer membrane. We used a previously identified small-molecule inhibitor of the LolCDE complex ofEscherichia colito assess the global transcriptional consequences of interference with lipoprotein transport. Exposure ofE. colito the LolCDE inhibitor at concentrations leading to minimal and significant growth inhibition, followed by transcriptome sequencing, identified a small group of genes whose transcript levels were decreased and a larger group whose mRNA levels increased 10- to 100-fold compared to those of untreated cells. The majority of the genes whose mRNA concentrations were reduced were part of the flagellar assembly pathway, which contains an essential lipoprotein component. Most of the genes whose transcript levels were elevated encode proteins involved in selected cell stress pathways. Many of these genes are involved with envelope stress responses induced by the mislocalization of outer membrane lipoproteins. Although several of the genes whose RNAs were induced have previously been shown to be associated with the general perturbation of the cell envelope by antibiotics, a small subset was affected only by LolCDE inhibition. Findings from this work suggest that the efficiency of the Lol system function may be coupled to a specific monitoring system, which could be exploited in the development of reporter constructs suitable for use for screening for additional inhibitors of lipoprotein trafficking.IMPORTANCEInhibition of the lipoprotein transport pathway leads toE. colideath and subsequent lysis. Early significant changes in the levels of RNA for a subset of genes identified to be associated with some periplasmic and envelope stress responses were observed. Together these findings suggest that disruption of this key pathway can have a severe impact on balanced outer membrane synthesis sufficient to affect viability.

scholarly journals DNA Sequence and Comparative Genomics of pAPEC-O2-R, an Avian Pathogenic Escherichia coli Transmissible R Plasmid

2005 ◽  
Vol 49 (11) ◽  
pp. 4681-4688 ◽  
Author(s):  
Timothy J. Johnson ◽  
Kylie E. Siek ◽  
Sara J. Johnson ◽  
Lisa K. Nolan
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Open Reading Frames ◽  
Beta Lactam ◽  
Class 1 Integron ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Class 1

ABSTRACT In this study, a 101-kb IncF plasmid from an avian pathogenic Escherichia coli (APEC) strain (APEC O2) was sequenced and analyzed, providing the first completed APEC plasmid sequence. This plasmid, pAPEC-O2-R, has functional transfer and antimicrobial resistance-encoding regions. The resistance-encoding region encodes resistance to eight groups of antimicrobial agents, including silver and other heavy metals, quaternary ammonium compounds, tetracycline, sulfonamides, aminoglycosides, trimethoprim, and beta-lactam antimicrobial agents. This region of the plasmid is unique among previously described IncF plasmids in that it possesses a class 1 integron that harbors three gene cassettes and a heavy metal resistance operon. This region spans 33 kb and is flanked by the RepFII plasmid replicon and an assortment of plasmid maintenance genes. pAPEC-O2-R also contains a 32-kb transfer region that is nearly identical to that found in the E. coli F plasmid, rendering it transferable by conjugation to plasmid-less strains of bacteria, including an APEC strain, a fecal E. coli strain from an apparently healthy bird, a Salmonella enterica serovar Typhimurium strain, and a uropathogenic E. coli strain from humans. Differences in the G+C contents of individual open reading frames suggest that various regions of pAPEC-O2-R had dissimilar origins. The presence of pAPEC-O2-R-like plasmids that encode resistance to multiple antimicrobial agents and that are readily transmissible from APEC to other bacteria suggests the possibility that such plasmids may serve as a reservoir of resistance genes for other bacteria of animal and human health significance.

scholarly journals Detection of Extended-Spectrum Beta-Lactamase-ProducingEscherichia coliin Market-Ready Chickens in Zambia

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
K. Chishimba ◽  
B. M. Hang’ombe ◽  
K. Muzandu ◽  
S. E. Mshana ◽  
M. I. Matee ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Human Consumption ◽  
Antibiotic Administration ◽  
Beta Lactam ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Antimicrobial Sensitivity ◽  
Extended Spectrum ◽  
Potential Reservoir

The frequent administering of antibiotics in the treatment of poultry diseases may contribute to emergence of antimicrobial-resistant strains. The objective of this study was to detect the presence of extended-spectrumβ-lactamase- (ESBL-) producingEscherichia coliin poultry in Zambia. A total of 384 poultry samples were collected and analyzed for ESBL-producingEscherichia coli. The culturedE. coliisolates were subjected to antimicrobial susceptibility tests and the polymerase chain reaction for detection ofblaCTX-M,blaSHV, andblaTEMgenes. Overall 20.1%, 77/384, (95% CI; 43.2–65.5%) of total samples analyzed contained ESBL-producingEscherichia coli. The antimicrobial sensitivity test revealed that 85.7% (66/77; CI: 75.7–92) of ESBL-producingE. coliisolates conferred resistance to beta-lactam and other antimicrobial agents. These results indicate that poultry is a potential reservoir for ESBL-producingEscherichia coli. The presence of ESBL-producingEscherichia coliin poultry destined for human consumption requires strengthening of the antibiotic administering policy. This is important as antibiotic administration in food animals is gaining momentum for improved animal productivity in developing countries such as Zambia.

Antimicrobial Effects of Zataria multiflora and Ocimum basilicum on Escherichia coli O157:H7 During Ripening of Traditional Lighvan Cheese

2020 ◽  
Vol 16 (3) ◽  
pp. 373-380
Author(s):  
Mohammad B. Zendeh ◽  
Vadood Razavilar ◽  
Hamid Mirzaei ◽  
Khosrow Mohammadi
Keyword(s):  
Escherichia Coli ◽  
Essential Oils ◽  
Dairy Products ◽  
Antimicrobial Agents ◽  
Escherichia Coli O157 ◽  
Zataria Multiflora ◽  
Antimicrobial Effects ◽  
E Coli ◽  
Common Causes ◽  
Lighvan Cheese

Background: Escherichia coli O157:H7 is one of the most common causes of contamination in Lighvan cheese processing. Using from natural antimicrobial essential oils is applied method to decrease the rate of microbial contamination of dairy products. The present investigation was done to study the antimicrobial effects of Z. multiflora and O. basilicum essential oils on survival of E. coli O157:H7 during ripening of traditional Lighvan cheese. Methods: Leaves of the Z. multiflora and O. basilicum plants were subjected to the Clevenger apparatus. Concentrations of 0, 100 and 200 ppm of the Z. multiflora and 0, 50 and 100 ppm of O. basilicum essential oils and also 103 and 105 cfu/ml numbers of E. coli O157:H7 were used. The numbers of the E. coli O157:H7 bacteria were analyzed during the days 0, 30, 60 and 90 of the ripening period. Results: Z. multiflora and O. basilicum essential oils had considerable antimicrobial effects against E. coli O157:H7. Using the essential oils caused decrease in the numbers of E. coli O157:H7 bacteria in 90th days of ripening (P <0.05). Using from Z. multiflora at concentration of 200 ppm can reduce the survival of E. coli O157:H7 in Lighvan cheese. Conclusion: Using Z. multiflora and O. basilicum essential oils as good antimicrobial agents can reduce the risk of foodborne bacteria and especially E. coli O157:H7 in food products.

scholarly journals Impact of Feed Supplementation with Antimicrobial Agents on Growth Performance of Broiler Chickens, Clostridium perfringens and Enterococcus Counts, and Antibiotic Resistance Phenotypes and Distribution of Antimicrobial Resistance Determinants in Escherichia coli Isolates

2007 ◽  
Vol 73 (20) ◽  
pp. 6566-6576 ◽  
Author(s):  
Moussa S. Diarra ◽  
Fred G. Silversides ◽  
Fatoumata Diarrassouba ◽  
Jane Pritchard ◽  
Luke Masson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Broiler Chickens ◽  
Antimicrobial Agents ◽  
Growth Promoters ◽  
Feed Supplementation ◽  
E Coli ◽  
Resistance Determinants ◽  
Class 1

ABSTRACT The effects of feed supplementation with the approved antimicrobial agents bambermycin, penicillin, salinomycin, and bacitracin or a combination of salinomycin plus bacitracin were evaluated for the incidence and distribution of antibiotic resistance in 197 commensal Escherichia coli isolates from broiler chickens over 35 days. All isolates showed some degree of multiple antibiotic resistance. Resistance to tetracycline (68.5%), amoxicillin (61.4%), ceftiofur (51.3%), spectinomycin (47.2%), and sulfonamides (42%) was most frequent. The levels of resistance to streptomycin, chloramphenicol, and gentamicin were 33.5, 35.5, and 25.3%, respectively. The overall resistance levels decreased from day 7 to day 35 (P < 0.001). Comparing treatments, the levels of resistance to ceftiofur, spectinomycin, and gentamicin (except for resistance to bacitracin treatment) were significantly higher in isolates from chickens receiving feed supplemented with salinomycin than from the other feeds (P < 0.001). Using a DNA microarray analysis capable of detecting commonly found antimicrobial resistance genes, we characterized 104 tetracycline-resistant E. coli isolates from 7- to 28-day-old chickens fed different growth promoters. Results showed a decrease in the incidence of isolates harboring tet(B), bla TEM, sulI, and aadA and class 1 integron from days 7 to 35 (P < 0.01). Of the 84 tetracycline-ceftiofur-resistant E. coli isolates, 76 (90.5%) were positive for bla CMY-2. The proportions of isolates positive for sulI, aadA, and integron class 1 were significantly higher in salinomycin-treated chickens than in the control or other treatment groups (P < 0.05). These data demonstrate that multiantibiotic-resistant E. coli isolates can be found in broiler chickens regardless of the antimicrobial growth promoters used. However, the phenotype and the distribution of resistance determinants in E. coli can be modulated by feed supplementation with some of the antimicrobial agents used in broiler chicken production.

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