scholarly journals Role of Histone-Like Protein H-NS in Multidrug Resistance of Escherichia coli

2004 ◽  
Vol 186 (5) ◽  
pp. 1423-1429 ◽  
Author(s):  
Kunihiko Nishino ◽  
Akihito Yamaguchi
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Multidrug Resistance ◽  
Enteric Bacteria ◽  
Resistance Pattern ◽  
Pcr Analysis ◽  
Reverse Transcription Pcr ◽  
Double Deletion ◽  
Outer Membrane Channel

ABSTRACT The histone-like protein H-NS is a major component of the bacterial nucleoid and plays a crucial role in global gene regulation of enteric bacteria. It is known that the expression of a variety of genes is repressed by H-NS, and mutations in hns result in various phenotypes, but the role of H-NS in the drug resistance of Escherichia coli has not been known. Here we present data showing that H-NS contributes to multidrug resistance by regulating the expression of multidrug exporter genes. Deletion of the hns gene from the ΔacrAB mutant increased levels of resistance against antibiotics, antiseptics, dyes, and detergents. Decreased accumulation of ethidium bromide and rhodamine 6G in the hns mutant compared to that in the parental strain was observed, suggesting the increased expression of some drug exporter(s) in this mutant. The increased drug resistance and decreased drug accumulation caused by the hns deletion were completely suppressed by deletion of the multifunctional outer membrane channel gene tolC. At least eight drug exporter systems require TolC for their functions. Among these, increased expression of acrEF, mdtEF, and emrKY was observed in the Δhns strain by quantitative real-time reverse transcription-PCR analysis. The Δhns-mediated multidrug resistance pattern is quite similar to that caused by overproduction of the AcrEF exporter. Deletion of the acrEF gene greatly suppressed the level of Δhns-mediated multidrug resistance. However, this strain still retained resistance to some compounds. The remainder of the multidrug resistance pattern was similar to that conferred by overproduction of the MdtEF exporter. Double deletion of the mdtEF and acrEF genes completely suppressed Δhns-mediated multidrug resistance, indicating that Δhns-mediated multidrug resistance is due to derepression of the acrEF and mdtEF drug exporter genes.

scholarly journals Antimicrobial resistance in fecal Escherichia coli and Salmonella enterica isolates: a two-year prospective study of small poultry flocks in Ontario, Canada

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Csaba Varga ◽  
Michele T. Guerin ◽  
Marina L. Brash ◽  
Durda Slavic ◽  
Patrick Boerlin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Bacterial Infections ◽  
Animal Health ◽  
Enteric Bacteria ◽  
Positive Sample ◽  
Resistance Pattern ◽  
Resistant Bacteria ◽  
E Coli ◽  
Game Bird

Abstract Background Although keeping small poultry flocks is increasingly popular in Ontario, information on the antimicrobial susceptibility of enteric bacteria of such flocks is lacking. The current study was conducted on small poultry flocks in Ontario between October 2015 and September 2017, and samples were submitted on a voluntary basis to Ontario’s Animal Health Laboratory. From each submission, a pooled cecal sample was obtained from all the birds of the same species from the same flock and tested for the presence of two common enteric pathogens, E. coli and Salmonella. Three different isolates from each E. coli-positive sample and one isolate from each Salmonella-positive sample were selected and tested for susceptibility to 14 antimicrobials using a broth microdilution technique. Results A total of 433 fecal E. coli isolates (358 chicken, 27 turkey, 24 duck, and 24 game bird) and 5 Salmonella isolates (3 chicken, 1 turkey, and 1 duck) were recovered. One hundred and sixty-seven chicken, 5 turkey, 14 duck, and 15 game bird E. coli isolates were pan-susceptible. For E. coli, a moderate to high proportion of isolates were resistant to tetracycline (43% chicken, 81% turkey, 42% duck, and 38% game bird isolates), streptomycin (29% chicken, 37% turkey, and 33% game bird isolates), sulfonamides (17% chicken, 37% turkey, and 21% duck isolates), and ampicillin (16% chicken and 41% turkey isolates). Multidrug resistance was found in 37% of turkey, 20% of chicken, 13% of duck, and 8% of game bird E. coli isolates. Salmonella isolates were most frequently resistant to streptomycin, tetracycline, and sulfonamides. Resistance to cephalosporins, carbapenems, macrolides, and quinolones was infrequent in both E. coli and Salmonella isolates. Cluster and correlation analyses identified streptomycin-tetracycline-sulfisoxazole-trimethoprim-sulfamethoxazole as the most common resistance pattern in chicken E. coli isolates. Turkey E. coli isolates compared to all the other poultry species had higher odds of resistance to tetracycline and ampicillin, and a higher multidrug resistance rate. Conclusions Escherichia coli isolates were frequently resistant to antimicrobials commonly used to treat poultry bacterial infections, which highlights the necessity of judicious antimicrobial use to limit the emergence of multidrug resistant bacteria.

scholarly journals Growth Phase-Dependent Expression of Drug Exporters in Escherichia coli and Its Contribution to Drug Tolerance

2006 ◽  
Vol 188 (16) ◽  
pp. 5693-5703 ◽  
Author(s):  
Asuka Kobayashi ◽  
Hidetada Hirakawa ◽  
Takahiro Hirata ◽  
Kunihiko Nishino ◽  
Akihito Yamaguchi
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Stationary Phase ◽  
Growth Phase ◽  
Maximum Level ◽  
Pcr Analysis ◽  
Reverse Transcription Pcr ◽  
Σ Factor ◽  
Intrinsic Drug Resistance ◽  
Dependent Signaling Pathway

ABSTRACT Drug exporters contribute to the intrinsic drug resistance in many organisms. Although there are at least 20 exporter genes in Escherichia coli, most of them apparently do not confer drug resistance in complex laboratory media except for the AcrAB, EmrE, and MdfA efflux systems. In this study, we comprehensively investigated the growth phase-dependent expression of drug exporter genes. The expression of acrAB, emrAB, emrD, emrE, emrKY, mdfA, and ydgFE is stable at moderate levels during any growth phase, whereas mdtEF promoter activity greatly increased with cell growth and reached the maximum level at the late stationary phase. The growth phase-dependent increase in mdtEF expression was also observed on quantitative reverse transcription-PCR analysis. As expected from the transporter expression, the stationary-phase cells actually showed MdtEF-dependent tolerance to drugs and toxic dyes. Growth phase-dependent elevation of mdtEF expression was found to be mediated by the stationary-phase σ factor rpoS and the RpoS-dependent signaling pathway, Hfq, GadY, and GadX. The induction level was decreased by tnaAB deletion, suggesting that indole sensing stimulates this process.

miR-369-3p serves as prognostic factor and regulates cancer progression of hepatocellular carcinoma

2021 ◽  
Author(s):  
Can Chen ◽  
Yi Zong ◽  
Jiaojiao Tang ◽  
Ruisheng Ke ◽  
Lizhi Lv ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
Cancer Progression ◽  
Cell Counting ◽  
Migration And Invasion ◽  
Pcr Analysis ◽  
Reverse Transcription Pcr ◽  
Huh7 Cells

Background: The aim of this study was to investigate the role of miR-369-3p in hepatocellular carcinoma (HCC). Materials & methods: The expression levels of miR-369-3p were detected using the quantitative real-time reverse transcription-PCR analysis. The cell counting kit-8 and transwell assays were used to explore the effects of miR-369-3p on cell proliferation, migration and invasion of HCC cells. Results: The miR-369-3p expression was downregulated in HCC tissues and cell lines, in comparison to the normal controls, respectively. In vitro, overexpression of miR-369-3p in Hep 3B and Huh7 cells inhibited cell proliferation, migration and invasion. SOX4 was a direct target of miR-369-3p. Conclusion: Our results suggested that miR-369-3p may be a tumor suppressor in HCC by targeting SOX4.

scholarly journals The Emerging Role of Extracellular Vesicle-Mediated Drug Resistance in Cancers: Implications in Advanced Prostate Cancer

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Carolina Soekmadji ◽  
Colleen C. Nelson
Keyword(s):  
Prostate Cancer ◽  
Drug Resistance ◽  
Multidrug Resistance ◽  
Advanced Prostate Cancer ◽  
Control Cell ◽  
Extracellular Vesicle ◽  
Multidrug Resistance Proteins ◽  
Acquired Drug Resistance ◽  
Resistance Proteins

Emerging evidence has shown that the extracellular vesicles (EVs) regulate various biological processes and can control cell proliferation and survival, as well as being involved in normal cell development and diseases such as cancers. In cancer treatment, development of acquired drug resistance phenotype is a serious issue. Recently it has been shown that the presence of multidrug resistance proteins such as Pgp-1 and enrichment of the lipid ceramide in EVs could have a role in mediating drug resistance. EVs could also mediate multidrug resistance through uptake of drugs in vesicles and thus limit the bioavailability of drugs to treat cancer cells. In this review, we discussed the emerging evidence of the role EVs play in mediating drug resistance in cancers and in particular the role of EVs mediating drug resistance in advanced prostate cancer. The role of EV-associated multidrug resistance proteins, miRNA, mRNA, and lipid as well as the potential interaction(s) among these factors was probed. Lastly, we provide an overview of the current available treatments for advanced prostate cancer, considering where EVs may mediate the development of resistance against these drugs.

scholarly journals Multidrug resistance in Shiga toxin-producing Escherichia coli (STEC) isolated from broiler chickens at slaughter

2021 ◽  
Vol 42 (6supl2) ◽  
pp. 3813-3824
Author(s):  
Rodrigo Pacheco Ornellas ◽  
◽  
Hugo Peralva Lopes ◽  
Daniela de Queiroz Baptista ◽  
Thomas Salles Dias ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Shiga Toxin ◽  
Broiler Chickens ◽  
Treatment Success ◽  
Multidrug Resistant ◽  
Resistance Pattern ◽  
Public Health Issue ◽  
Resistant Bacteria ◽  
Systemic Complications

Broiler chickens and derived products are a key source of Shiga toxin-producing Escherichia coli (STEC) in humans. This pathotype is responsible for causing severe episodes of diarrhea, which can progress to systemic complications. A rapid and accurate diagnosis of the disease, and early treatment of the infection with antimicrobials, can prevent it worsening. However, multidrug-resistant strains have potentially negative implications for treatment success. In this context, the aim of the present study was to isolate and identify multidrug-resistant STEC strains from broiler chickens and carcasses. Of 171 E. coli strains, isolated by conventional microbiological techniques and submitted to Polymerase Chain Reaction (PCR), for detection of stx1 and stx2 genes, 21.05% (36/171) were STEC pathotype, and most of them (66.67% - 24/36) carried both stx1 and eae genes. The multidrug resistance pattern was observed in 75% (27/36) of STEC strains. The presence of STEC in broiler chickens and carcasses reinforces that these sources may act as reservoirs for this pathotype. Multidrug-resistant bacteria contaminating animal products represent a public health issue because of the possibility of spread of multidrug-resistant determinants in the food chain and a higher risk of failure in human treatment when antimicrobials are needed.

scholarly journals Prevalence and Drug Resistance Pattern of Escherichia coli Strains Isolated from Milk and Milk Products

2019 ◽  
Vol 8 (10) ◽  
pp. 1338-1346
Author(s):  
Monika Soni ◽  
Abhishek Gaurav ◽  
Bincy Joseph ◽  
S. S. Shekhawat ◽  
Subhash Chand Meena
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Resistance Pattern ◽  
Milk Products ◽  
Drug Resistance Pattern

The role of microvesicles in cancer progression and drug resistance

2013 ◽  
Vol 41 (1) ◽  
pp. 293-298 ◽  
Author(s):  
Samireh Jorfi ◽  
Jameel M. Inal
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Cancer Progression ◽  
Chemotherapeutic Agents ◽  
Malignant Cells ◽  
Intercellular Transport ◽  
Wide Range ◽  
Anti Cancer ◽  
Mdr Multidrug Resistance

Microvesicles are shed constitutively, or upon activation, from both normal and malignant cells. The process is dependent on an increase in cytosolic Ca2+, which activates different enzymes, resulting in depolymerization of the actin cytoskeleton and release of the vesicles. Drug resistance can be defined as the ability of cancer cells to survive exposure to a wide range of anti-cancer drugs, and anti-tumour chemotherapeutic treatments are often impaired by innate or acquired MDR (multidrug resistance). Microvesicles released upon chemotherapeutic agents prevent the drugs from reaching their targets and also mediate intercellular transport of MDR proteins.

scholarly journals Differential regulation of the mcb and emr operons of Escherichia coli: role of mcb in multidrug resistance.

1996 ◽  
Vol 40 (4) ◽  
pp. 1050-1052 ◽  
Author(s):  
O Lomovskaya ◽  
F Kawai ◽  
A Matin
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Differential Regulation ◽  
Negative Regulator ◽  
Toxic Compounds ◽  
Microcin B17

The mcb operon (which is responsible for microcin B17 production) and the emr operon (which encodes a multidrug resistance pump) share a common negative regulator, EmrR. Nevertheless, compounds that induce the emr operon repress the mcb operon. The pump dedicated to microcin B17 extrusion can also protect the calls against sparfloxacin and other toxic compounds.

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