Efflux pump inhibitory activity of flavonoids isolated from Alpinia calcarata against methicillin-resistant Staphylococcus aureus

Biologia ◽  
2016 ◽  
Vol 71 (5) ◽  
Author(s):  
Harmandeep K. Randhawa ◽  
Kanwarpreet K. Hundal ◽  
Pallavi N. Ahirrao ◽  
Sanjay M. Jachak ◽  
Hemraj S. Nandanwar
Keyword(s):  
Staphylococcus Aureus ◽  
Inhibitory Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Efflux Pump ◽  
Methicillin Resistant

AbstractMethicillin-resistant

Frequency of efflux pump genes mediating ciprofloxacin and antiseptic resistance in methicillin-resistant Staphylococcus aureus isolates

2017 ◽  
Vol 111 ◽  
pp. 71-74 ◽  
Author(s):  
Sepideh Hassanzadeh ◽  
Rahil Mashhadi ◽  
Masoud Yousefi ◽  
Emran Askari ◽  
Maryam Saniei ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Efflux Pump ◽  
Methicillin Resistant

scholarly journals Antibacterial Activity and Mode of Action of Lactoquinomycin A from Streptomyces bacillaris

Marine Drugs ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 7
Author(s):  
Beomkoo Chung ◽  
Oh-Seok Kwon ◽  
Jongheon Shin ◽  
Ki-Bong Oh
Keyword(s):  
Staphylococcus Aureus ◽  
Dna Damage ◽  
Inhibitory Activity ◽  
Mode Of Action ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Dependent Manner ◽  
Mobility Shift ◽  
Concentration Dependent Manner ◽  
Methicillin Resistant

This study aims to isolate and identify the structure of antibacterial compounds having potent activity on methicillin-resistant Staphylococcus aureus (MRSA) from marine actinomycetes, and also to identify their mode of action. Lactoquinomycin A (LQM-A) (compound 1) and its derivatives (2–4) were isolated from marine-derived Streptomyces bacillaris strain MBTC38, and their structures were determined using extensive spectroscopic methods. These compounds showed potent antibacterial activities against Gram-positive bacteria, with MIC values of 0.06–4 μg/mL. However, the tested compounds exhibited weak inhibitory activity against Gram-negative bacteria, although they were effective against Salmonella enterica (MIC = 0.03–1 μg/mL). LQM-A exhibited the most significant inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) (MIC = 0.25–0.5 μg/mL), with a low incidence of resistance. An in vivo dual-reporter assay designed to distinguish between compounds that inhibit translation and those that induce DNA damage was employed to assess the mode of action of LQM-A. LQM-A-induced DNA damage and did not inhibit protein synthesis. The gel mobility shift assay showed that LQM-A switched plasmid DNA from the supercoiled to relaxed form in a time- and concentration-dependent manner. These data suggest that LQM-A intercalated into double-stranded DNA and damaged DNA repair.

scholarly journals Dihydrostilbenes from Indigofera Pulchra

2008 ◽  
Vol 3 (5) ◽  
pp. 1934578X0800300
Author(s):  
Aliyu Musa ◽  
A. K. Haruna ◽  
M. Ilyas ◽  
Augustine Ahmadu ◽  
Simon Gibbons ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Nmr Spectroscopy ◽  
Structure Elucidation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Efflux Pump ◽  
2D Nmr ◽  
Multidrug Resistant ◽  
Methicillin Resistant ◽  
Weak Activity

A mixture of two new dihydrostilbenes, 3-methoxy-4,5-methylenedioxy-4′- O-(2ξ,3-dihydroxy-3-methylbutyl)-dihydrostilbene (1) and 3,5-dimethoxy-4′- O-(2ξ,3-dihydroxy-3-methylbutyl)-dihydrostilbene (2), was isolated from Indigofera pulchra as an inseparable mixture. Several isolation strategies, including multiple preparative TLC, SPE and finally HPLC were undertaken in an attempt to separate these metabolites, but to no avail. Structure elucidation on the mixture was conducted and we were able to establish the structures of these compounds unambiguously by MS and a series of 1D and 2D-NMR analyses. The mixture of these dihydrostilbenes was analyzed by NMR spectroscopy and 1 and 2 were in a ratio of 52:48, respectively, and this was evaluated against a panel of methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant variants of this organism, including a strain over-expressing the NorA efflux pump; weak activity was observed.

scholarly journals Recurrent Methicillin-Resistant Staphylococcus aureus Cutaneous Abscesses and Selection of Reduced Chlorhexidine Susceptibility during Chlorhexidine Use

2015 ◽  
Vol 53 (11) ◽  
pp. 3677-3682 ◽  
Author(s):  
Ryan C. Johnson ◽  
Carey D. Schlett ◽  
Katrina Crawford ◽  
Jeffrey B. Lanier ◽  
D. Scott Merrell ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Disease Prevention ◽  
Clinical Isolate ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Efflux Pump ◽  
Methicillin Resistant ◽  
Content Type ◽  
Selection Of

We describe the selection of reduced chlorhexidine susceptibility during chlorhexidine use in a patient with two episodes of cutaneous USA300 methicillin-resistantStaphylococcus aureusabscess. The second clinical isolate harbors a novel plasmid that encodes the QacA efflux pump. Greater use of chlorhexidine for disease prevention warrants surveillance for resistance.

scholarly journals Fluoroquinolone resistant mechanisms in methicillin-resistant Staphylococcus aureus clinical isolates in Cairo, Egypt

2013 ◽  
Vol 7 (11) ◽  
pp. 796-803 ◽  
Author(s):  
Rasha A Hashem ◽  
Aymen S Yassin ◽  
Hamdallah H Zedan ◽  
Magdy A Amin
Keyword(s):  
Health Care ◽  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Clinical Isolates ◽  
Local Health ◽  
Methicillin Resistant ◽  
Persistent Problem ◽  
Health Care Settings

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is a persistent problem in community and health care settings. Fluoroquinolones are among the drugs of choice used to treat MRSA infections. This study aims to identify different mechanisms of fluoroquinolne resistance in local MRSA random sampling isolates in Cairo, Egypt. Methodology: A total of 94 clinical isolates of S. aureus were collected from two major University hospitals in Cairo. Identification was confirmed by appropriate morphological, cultural, and biochemical tests. The antibiotic susceptibility pattern was determined for all isolates. The possible involvement of efflux pumps in mediating fluoroquinolone resistance as well as changes in the quinolone resistance determining region (QRDR) of gyrA and gyrB genes were investigated Results: A total of 45 isolates were found to be MRSA, among which 26 isolates were found to be fluoroquinolone-resistant. The MIC values of the tested fluoroquinolones in the presence of the efflux pump inhibitors omeprazole and piperine were reduced. Measuring the uptake of ciprofloxacin upon the addition of the efflux pump inhibitor omeprazole, an increased level of accumulation was observed. Non-synonymous and silent mutations were detected in the QRDR of gyrA and gyrB genes. Conclusions: These results shed light on some of the resistance patterns of MRSA strains isolated from local health care settings in Cairo, Egypt. The resistance of these MRSA towards fluoroquinolones does not depend only on mutation in target genes; other mechanisms of resistance such as the permeability effect, efflux pumps and decreased availability of quinolones at the target site can also be involved.

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