Role of calcium in the efflux system of Escherichia coli

Martins, Ana; Machado, Lisa; Costa, Susana Goulart; Cerca, Pedro; Spengler, Gabriella; Viveiros, Miguel; Amaral, Leonard

doi:10.1016/j.ijantimicag.2011.01.010

Cited by 41 publications

(42 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The effects promoted by TZ are dependent upon calcium [21] and in the current study calcium plays a similar role. This is consistent with the fact that binding of calcium to calcium-dependent processes is inhibited by phenothiazines such as CPZ and TZ [19].…”

Section: Discussionsupporting

confidence: 73%

“…1C). However, as is the case with Escherichia coli [21], the presence of calcium in the assay system prevents the accumulation of EtBr produced by TZ. Previous results demonstrated that at pH 8 the activity of the efflux pump system of the Salmonella NCTC strain was totally dependent upon metabolic energy [20].…”

Section: Resultsmentioning

confidence: 99%

“…These results are interpreted to signify that palmitic acid provides the needed energy for efflux, hence little accumulation of EtBr results. Moreover, because TZ inhibits enzymes that are involved in the generation of energy from metabolic sources such as glucose and their dependence on calcium [21], and because the effects of TZ on the accumulation of EtBr are reduced or even obviated with palmitic acid, it may well be that the enzymes that act on the fatty acid for the generation of energy are either not affected by the phenothiazine or are beyond its reach.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent

Spengler

Rodrigues

Martins

et al. 2012

International Journal of Antimicrobial Agents

Self Cite

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 73%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent

Spengler

Rodrigues

Martins

et al. 2012

International Journal of Antimicrobial Agents

Self Cite

View full text Add to dashboard Cite

“…However, in 2003, Kaatz and others (994) demonstrated that these compounds decrease the MICs of several agents in S. aureus, presumably by inhibiting MFS pumps, although there was a small decrease in membrane potential. A phenothiazine, thioridazine, was found to inhibit the presumably AcrB-catalyzed efflux of ethidium in E. coli at a concentration of 15 g/ml (995), and similar activity was seen with chlorpromazine (996). Recently, 40 new phenothiazine derivatives were tested with E. coli, and some appeared to inhibit AcrB significantly on the basis of ethidium accumulation assays (997).…”

Section: Other Compounds That Inhibit Rnd Pumpsmentioning

confidence: 98%

The Challenge of Efflux-Mediated Antibiotic Resistance in Gram-Negative Bacteria

2015

View full text Add to dashboard Cite

SUMMARY The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.

show abstract

“…Extremely low-frequency magnetic fields can cause accumulation of the intracellular minerals such as calcium (5,6). Calcium ions (Ca 2+ ) are essential in the membrane for ATPases activity that provides energy for efflux pumps and ion channels (7). The intrinsic resistance to antibiotic substances is essential because of the efflux pumps that enables bacteria to stay alive in the presence of these toxic agents (8,9).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the 900 MHz Radiofrequency Radiation Effects on the Antimicrobial Susceptibility and Growth Rate of Klebsiella pneumoniae

et al. 2017

View full text Add to dashboard Cite

Introduction: Drug resistance to one or more antibiotics is mainly believed to be a serious threat to global public health which occurs by various mechanisms. The electromagnetic field as a nonchemical tool is capable of altering the antimicrobial susceptibility of bacteria. The aim of this study is the evaluation of the antimicrobial susceptibility of the Klebsiella pneumoniae to antibiotics before and after exposure to 900 MHz radiofrequency (RF) radiation produced by a mobile phone.Methods: Antimicrobial susceptibility of the bacteria to antibiotics disks were performed after exposure to 900 MHz radiofrequency radiation. Antimicrobial susceptibility was carried out by Kirby-Bauer and the inhibition zone of each antibiotic disk was measured (as mean). Additionally, growth variations under exposure were recorded and an outgrowth curve was drawn.Results: Based on the results, after 12 hours of exposure to 900MHz radiofrequency, there was observed a maximum increase in the sensitivity of K. pneumoniae and shown that radiofrequency (RF) radiation can change antimicrobial sensitivity significantly (P < 0.05). Also, the radiofrequency radiation effect on the bacterial proliferation was evaluated and showed that exposure enables the bacteria to grow faster in the exponential phase than the non-exposed bacteria. Conclusions:The findings of the study indicated that the sensitivity of K. pneumoniae was significantly increased to the various antibiotics after 12 hours of exposure to 900 MHz radiofrequency radiation. These observations could be interpreted by the concept of non-linearity in the responses of K. pneumoniae to different antibiotics after exposure to electromagnetic radiofrequency radiation and can be useful in the management of serious infectious diseases.

show abstract

Role of calcium in the efflux system of Escherichia coli

Cited by 41 publications

References 25 publications

Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent

Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent

The Challenge of Efflux-Mediated Antibiotic Resistance in Gram-Negative Bacteria

Evaluation of the 900 MHz Radiofrequency Radiation Effects on the Antimicrobial Susceptibility and Growth Rate of Klebsiella pneumoniae

Contact Info

Product

Resources

About