scholarly journals Differential Chromosome- and Plasmid-Borne Resistance of Escherichia coli hfq Mutants to High Concentrations of Various Antibiotics

2021 ◽  
Vol 22 (16) ◽  
pp. 8886
Author(s):  
Lidia Gaffke ◽  
Krzysztof Kubiak ◽  
Zuzanna Cyske ◽  
Grzegorz Węgrzyn
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Terminal Region ◽  
Bacterial Survival ◽  
Null Mutant ◽  
Resistance Marker ◽  
Plasmid Copy ◽  
Rna Chaperone ◽  
High Concentrations ◽  
High Doses

The Hfq protein is a bacterial RNA chaperone, involved in many molecular interactions, including control of actions of various small RNA regulatory molecules. We found that the presence of Hfq was required for survival of plasmid-containing Escherichia coli cells against high concentrations of chloramphenicol (plasmid p27cmr), tetracycline (pSC101, pBR322) and ampicillin (pBR322), as hfq+ strains were more resistant to these antibiotics than the hfq-null mutant. In striking contrast, production of Hfq resulted in low resistance to high concentrations of kanamycin when the antibiotic-resistance marker was chromosome-borne, with deletion of hfq resulting in increasing bacterial survival. These results were observed both in solid and liquid medium, suggesting that antibiotic resistance is an intrinsic feature of these strains rather than a consequence of adaptation. Despite its major role as RNA chaperone, which also affects mRNA stability, Hfq was not found to significantly affect kan and tet mRNAs turnover. Nevertheless, kan mRNA steady-state levels were higher in the hfq-null mutant compared to the hfq+ strain, suggesting that Hfq can act as a repressor of kan expression.This observation does correlate with the enhanced resistance to high levels of kanamycin observed in the hfq-null mutant. Furthermore, dependency on Hfq for resistance to high doses of tetracycline was found to depend on plasmid copy number, which was only observed when the resistance marker was expressed from a low copy plasmid (pSC101) but not from a medium copy plasmid (pBR322). This suggests that Hfq may influence survival against high doses of antibiotics through mechanisms that remain to be determined. Studies with pBR322Δrom may also suggest an interplay between Hfq and Rom in the regulation of ColE1-like plasmid replication. Results of experiments with a mutant devoid of the part of the hfq gene coding for the C-terminal region of Hfq suggested that this region, as well as the N-terminal region, may be involved in the regulation of expression of antibiotic resistance in E. coli independently.

scholarly journals Fate of Escherichia coli during Ensiling of Wheat and Corn

2005 ◽  
Vol 71 (9) ◽  
pp. 5163-5170 ◽  
Author(s):  
Y. Chen ◽  
S. Sela ◽  
M. Gamburg ◽  
R. Pinto ◽  
Z. G. Weinberg
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Dry Matter ◽  
Fluorescent Protein ◽  
Rapid Decrease ◽  
Resistance Marker ◽  
Antibiotic Resistance Marker ◽  
E Coli ◽  
Aerobic Stability ◽  
Green Fluorescent

ABSTRACT A recombinant Escherichia coli strain carrying a plasmid with an antibiotic resistance marker and expressing the green fluorescent protein was inoculated at a concentration of 3.8 × 108 CFU/g into direct-cut wheat (348 g of dry matter kg−1), wilted wheat (450 g of dry matter kg−1), and corn (375 g of dry matter kg−1). The forages were ensiled in mini-silos. The treatments included control (no E. coli added), application of tagged E. coli, and delayed sealing of the inoculated wheat. Three silos per treatment were sampled on predetermined dates, and the numbers of E. coli were determined on Chromocult TBX medium with or without kanamycin. Colonies presumptively identified as E. coli were also tested for fluorescence activity. Addition of E. coli at the time of ensiling resulted in a more rapid decrease in the pH but had almost no effect on the chemical composition of the final silages or their aerobic stability. E. coli disappeared from the silages when the pH decreased below 5.0. It persisted longer in silages of wilted wheat, in which the pH declined more slowly. Control silages of all crops also contained bacteria, presumptively identified as E. coli, that were resistant to the antibiotic, which suggests that some epiphytic strains are naturally resistant to antibiotics.

Structural and dynamic properties of the C-terminal region of the Escherichia coli RNA chaperone Hfq: integrative experimental and computational studies

2017 ◽  
Vol 19 (31) ◽  
pp. 21152-21164 ◽  
Author(s):  
Bin Wen ◽  
Weiwei Wang ◽  
Jiahai Zhang ◽  
Qingguo Gong ◽  
Yunyu Shi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Structural Dynamics ◽  
Functional Role ◽  
Dynamic Properties ◽  
Terminal Region ◽  
Computational Studies ◽  
Rna Chaperone

The structural dynamics of the C-terminal region of Hfq and its functional role were investigated by integrative experimental and computational studies.

scholarly journals Plasmid-Mediated Antibiotic Resistant Escherichia coli in Sarawak Rivers and Aquaculture Farms, Northwest of Borneo

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 776
Author(s):  
Samuel Lihan ◽  
Sai Y. Lee ◽  
Seng C. Toh ◽  
Sui S. Leong
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Molecular Weight ◽  
Antibiotic Resistance ◽  
Plasmid Copy Number ◽  
Resistance Rate ◽  
Climatic Conditions ◽  
Plasmid Copy ◽  
Antibiotic Resistant ◽  
E Coli

Background: The emergence of plasmid-mediated antibiotic resistance in Escherichia coli in water resources could pose a serious threat to public health. The study aims to investigate the dispersion of plasmid-mediated antibiotic-resistant E. coli from six rivers in Sarawak and two aquaculture farms in Borneo. Methods: A total of 74 water samples were collected for the determination of their bacteria colony count. An IMViC test identified 31 E. coli isolates and tested their susceptibility against twelve clinically important antibiotics. The extraction of plasmid DNA was done using alkali lysis SDS procedures. Characteristics, including plasmid copy number, molecular weight size, resistance rate and multiple antibiotic resistance (MAR), were assessed. Results: Our findings revealed that bacterial counts in rivers and aquaculture farms ranged from log 2.00 to 3.68 CFU/mL and log 1.70 to 5.48 cfu/mL, respectively. Resistance to piperacillin (100%) was observed in all E. coli; resistance to amoxicillin (100%) and ampicillin (100%) was observed in E. coli found in aquaculture farms; resistance to streptomycin (93%) was observed in E. coli found in rivers. All E. coli were resistant to ≥2 antibiotics and formed 26 MAR profiles, ranging from an index of 0.17 to 0.83, indicating that there are high risks of contamination. Some (48.4%) of the E. coli were detected with plasmids (1.2 to >10 kb), whereas 51.6% of the E. coli did not harbor any plasmids. The plasmid copy numbers reported were one plasmid (n = 7), two plasmids (n = 4), ≥ two plasmids (4). E. coli isolated from the Muara Tuang River showed the highest-molecular-weight plasmids. A statistical analysis revealed that there is no significant correlation (r = 0.21, p = 0.253) between the number of plasmids and the MAR index of the tested isolates. Conclusion: The distribution of MAR in E. coli from rivers is higher compared to the aquaculture environment. Our study suggests that MAR in isolates could be chromosome-mediated. Our results suggest that riverbed sediments could serve as reservoirs for MAR bacteria, including pathogens, under different climatic conditions, and their analysis could provide information for public health concerns.

scholarly journals Bacteria primed by antimicrobial peptides develop tolerance and persist

2019 ◽  
Author(s):  
Alexandro Rodríguez-Rojas ◽  
Desiree Y. Baeder ◽  
Paul Johnston ◽  
Roland R. Regoes ◽  
Jens Rolff
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptides ◽  
Adaptive Response ◽  
Innate Immune ◽  
New Drugs ◽  
Bacterial Survival ◽  
Population Dynamic Model ◽  
Evolution Of Resistance ◽  
Sublethal Doses ◽  
High Concentrations

SUMMARYAntimicrobial peptides (AMPs) are key components of innate immune defenses. Because of the antibiotic crisis, AMPs have also come into focus as new drugs. Here, we explore whether prior exposure to sublethal doses of AMPs increases bacterial survival and abets the evolution of resistance. We show that Escherichia coli primed by sublethal doses of AMPs develop tolerance and increase persistence by producing curli or colanic acid. We develop a population dynamic model that predicts that priming delays the clearance of infections and fuels the evolution of resistance. The effects we describe should apply to many AMPs and other drugs that target the cell surface. The optimal strategy to tackle tolerant or persistent cells requires high concentrations of AMPs and fast and long-lasting expression. Our findings also offer a new understanding of non-inherited drug resistance as an adaptive response and could lead to measures that slow the evolution of resistance.

scholarly journals Multiple antibiotic resistance (mar) locus protects Escherichia coli from rapid cell killing by fluoroquinolones.

1996 ◽  
Vol 40 (5) ◽  
pp. 1266-1269 ◽  
Author(s):  
J D Goldman ◽  
D G White ◽  
S B Levy
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Bactericidal Activity ◽  
Cell Killing ◽  
Deletion Mutants ◽  
Multiple Antibiotic Resistance ◽  
Wild Type ◽  
E Coli ◽  
High Concentrations

The multiple antibiotic resistance (mar) locus in Escherichia coli consists of two divergently expressed operons (marC and marRAB), both of which contribute to the Mar phenotype. Overexpression of the marRAB operon protected E. coli against rapid cell killing by fluoroquinolones. Inactivation of the operon in mar mutants restored a wild-type bactericidal susceptibility. Both operons of the locus were required for protection from the quinolone-mediated bactericidal activity in mar locus deletion mutants. The effect was lost at high concentrations of fluoroquinolones, unlike the case for the previously described genes hipA and hipQ. The inducible mar locus appears to specify a novel antibactericidal mechanism which may play a role in the emergence of fluoroquinolone-resistant clinical E. coli isolates.

scholarly journals Tracking antibiotic resistance genes and class 1 integrons in Escherichia coli isolates from wastewater and agricultural fields

2021 ◽  
Author(s):  
Zahra Shamsizadeh ◽  
Mohammad Hassan Ehrampoush ◽  
Mahnaz Nikaeen ◽  
Mehdi Mokhtari ◽  
Mahsa Rahimi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Treated Wastewater ◽  
E Coli ◽  
Class 1 Integrons ◽  
Class 1 ◽  
High Concentrations

Abstract Considering high concentrations of multidrug-resistant (MDR) bacteria and antibiotic resistance genes (ARGs) in wastewater, agricultural reuse of treated wastewater may be a public health threat due to ARGs dissemination in different environmental compartments, including soil and edible parts of crops. We investigated the presence of antibiotic-resistant Escherichia coli as an indicator bacterium from secondary treated wastewater (STWW), water- or wastewater-irrigated soil and crop samples. ARGs including blaCTX-m-32, blaOXA-23, tet-W, sul1, cml-A, erm-B, along with intI1 gene in E. coli isolates were detected via molecular methods. The most prevalent ARGs in 78 E. coli isolates were sul1 (42%), followed by blaCTX-m-32 (19%), and erm-B (17%). IntI1 as a class 1 integrons gene was detected in 46% of the isolates. Cml-A was detected in STWW isolates but no E. coli isolate from wastewater-irrigated soil and crop samples contain this gene. The results also showed no detection of E. coli in water-irrigated soil and crop samples. Statistical analysis showed a correlation between sul1 and cml-A with intI1. The results suggest that agricultural reuse of wastewater may contribute to the transmission of ARB to soil and crop. Further research is needed to determine the potential risk of ARB associated with the consumption of wastewater-irrigated crops.

scholarly journals The Periplasmic Murein Peptide-Binding Protein MppA Is a Negative Regulator of Multiple Antibiotic Resistance in Escherichia coli

1999 ◽  
Vol 181 (16) ◽  
pp. 4842-4847 ◽  
Author(s):  
HongShan Li ◽  
James T. Park
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Binding Protein ◽  
Wide Spectrum ◽  
Negative Regulator ◽  
Null Mutant ◽  
Multiple Antibiotic Resistance ◽  
Resistance Phenotype ◽  
E Coli ◽  
K 12

ABSTRACT MppA is a periplasmic binding protein in Escherichia coli essential for uptake of the cell wall murein tripeptidel-alanyl-γ-d-glutamyl-meso-diaminopimelate. We have found serendipitously that E. coli K-12 strains carrying a null mutation in mppA exhibit increased resistance to a wide spectrum of antibiotics and to cyclohexane. Normal sensitivity of the mppA mutant to these agents is restored by mppA expressed from a plasmid. As is observed in the multiple antibiotic resistance phenotype in E. coli cells, the mppA null mutant overproduces the transcriptional activator, MarA, resulting in expression of the membrane-bound AcrAB proteins that function as a drug efflux pump. Reduced production of OmpF similar to that observed in the multiple antibiotic resistance phenotype is also seen in the mppA mutant. These and other data reported herein indicate that MppA functions upstream of MarA in a signal transduction pathway to negatively regulate the expression ofmarA and hence of the MarA-driven multiple antibiotic resistance. Overproduction of cytoplasmic GadA and GadB and of several unidentified cytoplasmic membrane proteins as well as reduction in the amount of the outer membrane protein, OmpP, in the mppAnull mutant indicate that MppA regulates a number of genes in addition to those already known to be controlled by MarA.

scholarly journals Colonization resistance of the digestive tract and the spread of bacteria to the lymphatic organs in mice

1972 ◽  
Vol 70 (2) ◽  
pp. 335-342 ◽  
Author(s):  
D. van der Waaij ◽  
J. M. Berghuis-de Vries ◽  
J. E. C. Lekkerkerk-van der Wees
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Colonization Resistance ◽  
Mesenteric Lymph Nodes ◽  
Entire Observation Period ◽  
Mesenteric Lymph ◽  
High Concentrations ◽  
High Doses ◽  
Lymphatic Organs ◽  
Observation Period

SUMMARYAfter oral contamination of conventional mice with high doses ofEscherichia coli, Klebsiella pneumoniaeorPseudomonas aeruginosathe contaminant was recovered in abnormally high concentrations from the duodenum and caecum during the first few days. In this initial colonization phase, evidence of spread was obtained by culturing the cervical and mesenteric lymph nodes and spleen. Longer after contamination the intestinal concentration decreased to normal and spread stopped. In orally antibiotic-treated mice, the situation seen during the initial colonization phase in conventional mice occurred after a much lower oral contamination dose and persisted during the entire observation period of 2 weeks.

scholarly journals Identification of Escherichia coli Genes Essential for High-Level, Clinically Relevant, Resistance to Antibiotics

2021 ◽  
Author(s):  
Esmeralda Z Reyes Fernandez ◽  
Noemie Alon Cudkowicz ◽  
Sonia Steiner Mordoch ◽  
Shimon Schuldiner
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Molecular Mechanisms ◽  
E Coli ◽  
Novel Approach ◽  
Public Health Challenges ◽  
High Concentrations ◽  
New Perspective ◽  
High Level ◽  
Very High

Antibiotic resistance is one of the biggest public health challenges of our time. Here we present a novel approach to recognizing molecular mechanisms essential for maintaining high-level clinically relevant antibiotic resistance. To identify essential genes in this context, we subjected Escherichia coli EV18, a strain highly resistant to quinolones, to random transposon mutagenesis. This strain's unique advantage is that the screen is performed at very high concentrations of the antibiotic, non-permissive for most strains. The transposon's insertion affected the transcription of five genes required for the maintenance of resistance in EV18. Three of these genes (YihO, YhdP, and WaaY) have not been previously identified as essential for high-level antimicrobial resistance (AMR). Our work provides a new perspective to identify and characterize novel players crucial for maintaining AMR in E. coli.

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