scholarly journals Can Gram-Negative Bacteria Develop Resistance to Antimicrobial Blue Light Treatment?

2021 ◽  
Vol 22 (21) ◽  
pp. 11579
Author(s):  
Aleksandra Rapacka-Zdonczyk ◽  
Agata Wozniak ◽  
Beata Kruszewska ◽  
Krzysztof Waleron ◽  
Mariusz Grinholc
Keyword(s):  
Blue Light ◽  
Bacterial Resistance ◽  
Light Treatment ◽  
Gram Negative Bacteria ◽  
Tolerance Development ◽  
Resistance Development ◽  
Gram Negative ◽  
E Coli ◽  
K 12 ◽  
Stable Feature

Antimicrobial blue light (aBL) treatment is considered low risk for the development of bacterial resistance and tolerance due to its multitarget mode of action. The aim of the current study was to demonstrate whether tolerance development occurs in Gram-negative bacteria. We evaluated the potential of tolerance/resistance development in Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa and demonstrated that representative Gram-negative bacteria may develop tolerance to aBL. The observed adaption was a stable feature. Assays involving E. coli K-12 tolC-, tolA-, umuD-, and recA-deficient mutants revealed some possible mechanisms for aBL tolerance development.

scholarly journals The effect of sucrose-induced osmotic stress on the sensitivity of Escherichia coli to bacteriocins

2019 ◽  
Vol 65 (12) ◽  
pp. 895-903 ◽  
Author(s):  
Tatyana Polyudova ◽  
Daria Eroshenko ◽  
Vladimir Korobov
Keyword(s):  
Escherichia Coli ◽  
Osmotic Stress ◽  
Morphological Changes ◽  
Sucrose Solution ◽  
Gram Negative Bacteria ◽  
Lytic Enzymes ◽  
Gram Negative ◽  
E Coli ◽  
Cell Counts ◽  
K 12

Bacteriocins are antimicrobial peptides, produced by Gram-positive bacteria such as lactococci and staphylococci, that have limited bactericidal action against Gram-negative bacteria. The aim of this paper was to study the sensitivity of three strains of Escherichia coli to bacteriocins: nisin (as Nisaplin®) and two staphylococcal peptides (warnerin and hominin) during sucrose-induced osmotic stress. We found that all peptides in a 0.3 g·mL−1 sucrose solution significantly reduced the number of viable E. coli. The most pronounced antibacterial effect was achieved by nisin against E. coli K-12 (3 log reduction). Slightly less bactericidal effects were observed with warnerin (1 mg·mL−1) and hominin (1 mg·mL−1) in sucrose solution. The lytic activity of staphylococcal peptides was detected by decreased optical density and viable cell counts. Moreover, it was confirmed by the increased amount of DNA and protein in the medium and the morphological changes detected by atomic force microscopy after 20 h of treatment. Zymographic analysis revealed the release of lytic enzymes from E. coli cells after treatment with staphylococcal peptides and sucrose. These results indicated that the antimicrobial action of peptides can be extended to Gram-negative bacteria via combination with high concentrations of sucrose.

scholarly journals Antiseptic quaternary ammonium compound tolerance by gram-negative bacteria can be rapidly detected using an impermeant fluorescent dye-based assay

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Branden S. J. Gregorchuk ◽  
Shelby L. Reimer ◽  
Daniel R. Beniac ◽  
Shannon L. Hiebert ◽  
Timothy F. Booth ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Close Association ◽  
Fluorescent Dye ◽  
Ammonium Compound ◽  
Gram Negative Bacteria ◽  
Cell Integrity ◽  
Resistance Development ◽  
Gram Negative ◽  
E Coli ◽  
Testing Standards

AbstractBiocides such as quaternary ammonium compounds (QACs) are potentially important contributors towards bacterial antimicrobial resistance development, however, their contributions are unclear due to a lack of internationally recognized biocide testing standards. Methods to detect QAC tolerance are limited to laborious traditional antimicrobial susceptibility testing (AST) methods. Here, we developed a rapid fluorescent dye-based membrane impermeant assay (RFDMIA) to discriminate QAC susceptibility among Gram-negative Enterobacterales and Pseudomonadales species. RFDMIA uses a membrane impermeant fluorescent dye, propidium iodide, in a 30-min 96-well fluorescent microplate-based assay where cell suspensions are exposed to increasing QAC concentrations. Our results demonstrate that RFDMIA can discriminate between QAC-susceptible and QAC-adapted Escherichia coli tolerant phenotypes and predict benzalkonium and cetrimide tolerance in all species tested except for intrinsically fluorescent Pseudomonas aeruginosa. RFDMIA identified a close association to minimum inhibitory concentration values determined by broth microdilution AST and increasing fluorescent dye emission values. RFDMIA emission values and scanning electron microscopy results also suggest that CET-adapted E. coli isolates have a CET dependence, where cells require sub-inhibitory CET concentrations to maintain bacilliform cell integrity. Overall, this study generates a new, rapid, sensitive fluorescent assay capable of detecting QAC-susceptible Gram-negative bacteria phenotypes and cell membrane perturbations.

scholarly journals Activity of ceftolozane/tazobactam against commonly encountered antimicrobial resistant Gram-negative bacteria in Lebanon

2020 ◽  
Vol 14 (06) ◽  
pp. 559-564
Author(s):  
George F Araj ◽  
Dana M Berjawi ◽  
Umayya Musharrafieh ◽  
Nancy K El Beayni
Keyword(s):  
Bacterial Resistance ◽  
Treatment Options ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Beta Lactamases ◽  
E Coli ◽  
Extended Spectrum Beta Lactamases ◽  
In Vitro Data

Introduction: In view of the continuous rise in Gram-negative bacterial resistance and limited treatment options, Ceftolozane/tazobactam (C/T) is a newly introduced antimicrobial agent in Lebanon for its demonstrated activity against resistant Gram-negative bacteria. However, in vitro data is not available about its activity against commonly isolated bacteria in this country. Methodology: The analysis included clinical isolates, multidrug–resistant (MDR) and extended-spectrum Beta-lactamases (ESBLs), representing 124 Escherichia coli, 75 Klebsiella pneumoniae and 100 Pseudomonas aeruginosa, identified using the MALDI-TOF. The minimum inhibitory concentration (MIC) for C/T was determined by the Etest (Liofilchem, Roseto degli Abruzzi, Italy). In addition, the disk diffusion (DD) test was used to determine the activity of C/T and of the antimicrobials routinely used to test for such pathogens. Results: The C/T activity against the ESBL producers E. coli and K. pneumoniae isolates were similar (MIC90 value of 1 and 1.5 µg/mL, respectively; susceptibility of 100% and 96%, respectively). However, the activity of C/T against the E. coli and K. pneumoniae MDR isolates was much lower (MIC90 value of 256 and 96 µg/mL, respectively; susceptibility of 54% for each). The C/T MIC90 value for the non-MDR P. aeruginosa isolates was 3 µg/mL and ≥ 256 µg/mL for the MDR P. aeruginosa isolates (susceptibility of 96% vs 42% respectively). Overall, the C/T activities show comparable or higher susceptibility to the routinely used antimicrobials. Conclusion: The high in vitro activity of C/T points out its value as a possible alternative to the antimicrobials currently used for treatment of infections caused by such pathogens and would help in minimizing toxicity and bacterial resistance.

Disinfection of Fruits with Activated Water

2019 ◽  
Vol 10 ◽  
pp. 1864-1872
Author(s):  
Prof. Teodora P. Popova
Keyword(s):  
Antimicrobial Activity ◽  
Aqueous Solutions ◽  
Antimicrobial Properties ◽  
The Other ◽  
Gram Negative Bacteria ◽  
High Antimicrobial Activity ◽  
Gram Negative ◽  
E Coli ◽  
Number Of Microorganisms ◽  
Lower Effect

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

scholarly journals Clonal Clusters, Molecular Resistance Mechanisms and Virulence Factors of Gram-Negative Bacteria Isolated from Chronic Wounds in Ghana

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 339
Author(s):  
Denise Dekker ◽  
Frederik Pankok ◽  
Thorsten Thye ◽  
Stefan Taudien ◽  
Kwabena Oppong ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Virulence Factors ◽  
Iron Uptake ◽  
Chronic Wounds ◽  
Sub Saharan Africa ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Secretion Systems ◽  
Gram Negative ◽  
E Coli

Wound infections are common medical problems in sub-Saharan Africa but data on the molecular epidemiology are rare. Within this study we assessed the clonal lineages, resistance genes and virulence factors of Gram-negative bacteria isolated from Ghanaian patients with chronic wounds. From a previous study, 49 Pseudomonas aeruginosa, 21 Klebsiellapneumoniae complex members and 12 Escherichia coli were subjected to whole genome sequencing. Sequence analysis indicated high clonal diversity with only nine P. aeruginosa clusters comprising two strains each and one E. coli cluster comprising three strains with high phylogenetic relationship suggesting nosocomial transmission. Acquired beta-lactamase genes were observed in some isolates next to a broad spectrum of additional genetic resistance determinants. Phenotypical expression of extended-spectrum beta-lactamase activity in the Enterobacterales was associated with blaCTX-M-15 genes, which are frequent in Ghana. Frequently recorded virulence genes comprised genes related to invasion and iron-uptake in E. coli, genes related to adherence, iron-uptake, secretion systems and antiphagocytosis in P. aeruginosa and genes related to adherence, biofilm formation, immune evasion, iron-uptake and secretion systems in K. pneumonia complex. In summary, the study provides a piece in the puzzle of the molecular epidemiology of Gram-negative bacteria in chronic wounds in rural Ghana.

scholarly journals Apomorphine Targets the Pleiotropic Bacterial Regulator Hfq

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 257
Author(s):  
Florian Turbant ◽  
David Partouche ◽  
Omar El Hamoui ◽  
Sylvain Trépout ◽  
Théa Legoubey ◽  
...  
Keyword(s):  
Small Rnas ◽  
Antibacterial Agents ◽  
Amyloid Fibrils ◽  
Noncoding Rnas ◽  
Amyloid Formation ◽  
Gram Negative Bacteria ◽  
Translation Efficiency ◽  
Gram Negative ◽  
Bacterial Adaptation ◽  
E Coli

Hfq is a bacterial regulator with key roles in gene expression. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, thanks to its binding to small regulatory noncoding RNAs. This property is of primary importance for bacterial adaptation and survival in hosts. Small RNAs and Hfq are, for instance, involved in the response to antibiotics. Previous work has shown that the E. coli Hfq C-terminal region (Hfq-CTR) self-assembles into an amyloid structure. It was also demonstrated that the green tea compound EpiGallo Catechin Gallate (EGCG) binds to Hfq-CTR amyloid fibrils and remodels them into nonamyloid structures. Thus, compounds that target the amyloid region of Hfq may be used as antibacterial agents. Here, we show that another compound that inhibits amyloid formation, apomorphine, may also serve as a new antibacterial. Our results provide an alternative in order to repurpose apomorphine, commonly used in the treatment of Parkinson’s disease, as an antibiotic to block bacterial adaptation to treat infections.

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