scholarly journals On the Mechanism of Berberine–INF55 (5-Nitro-2-phenylindole) Hybrid Antibacterials

2014 ◽  
Vol 67 (10) ◽  
pp. 1471 ◽  
Author(s):  
Naveen K. Dolla ◽  
Chao Chen ◽  
Jonah Larkins-Ford ◽  
Rajmohan Rajamuthiah ◽  
Sakthimala Jagadeesan ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Antibacterial Activity ◽  
Multidrug Resistance ◽  
Inhibitory Activity ◽  
Antibacterial Drug ◽  
Antibacterial Mechanism ◽  
Antibacterial Effects ◽  
Antibacterial Drug Resistance

Berberine–INF55 hybrids are a promising class of antibacterials that combine berberine and the NorA multidrug resistance pump inhibitor INF55 (5-nitro-2-phenylindole) together in one molecule via a chemically stable linkage. Previous studies demonstrated the potential of these compounds for countering efflux-mediated antibacterial drug resistance but they didn’t establish whether the compounds function as originally intended, i.e. with the berberine moiety providing antibacterial activity and the attached INF55 component independently blocking multidrug resistance pumps, thereby enhancing the activity of berberine by reducing its efflux. We hypothesised that if the proposed mechanism is correct, then hybrids carrying more potent INF55 pump inhibitor structures should show enhanced antibacterial effects relative to those bearing weaker inhibitors. Two INF55 analogues showing graded reductions in NorA inhibitory activity compared with INF55 were identified and their corresponding berberine–INF55 hybrids carrying equivalent INF55 inhibitor structures synthesised. Multiple assays comparing the antibacterial effects of the hybrids and their corresponding berberine–INF55 analogue combinations showed that the three hybrids all show very similar activities, leading us to conclude that the antibacterial mechanism(s) of berberine–INF55 hybrids is different from berberine–INF55 combinations.

scholarly journals An Evaluation of the Antibacterial Properties of Tormentic Acid Congener and Extracts From Callistemon viminalis on Selected ESKAPE Pathogens and Effects on Biofilm Formation

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Tafadzwa Chipenzi ◽  
Genuine Baloyi ◽  
Tatenda Mudondo ◽  
Simbarashe Sithole ◽  
Godloves Fru Chi ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Biofilm Formation ◽  
Antibacterial Properties ◽  
Extracellular Dna ◽  
Dilution Method ◽  
Antibacterial Drug ◽  
Antibacterial Effects ◽  
Callistemon Viminalis ◽  
Eskape Pathogens ◽  
Tormentic Acid

ESKAPE pathogens, namely, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, are responsible for a majority of all healthcare-acquired infections (HAI). The bacteria cause nosocomial infections in immunocompromised patients. Extracts from Callistemon viminalis have been shown to have antibacterial, antifungal, and anti-inflammatory activities. Tormentic acid congener, a pentacyclic triterpene saponin, was isolated from C. viminalis leaves. This study aimed to investigate the antibacterial effects of tormentic acid congener and leaf extracts on biofilm formation by A. baumannii, S. aureus, S. pyogenes, and P. aeruginosa. The antibacterial effects were determined by the microbroth dilution method, and ciprofloxacin was used as the standard antibacterial drug. Biofilm formation and detachment assays were performed using crystal violet staining. Production of extracellular polymeric DNA and polysaccharides from biofilms was also determined. Tormentic acid congener showed time-dependent antibacterial activity against P. aeruginosa with a MIC of 100 µg/ml and caused significant protein leakage. Antibacterial activity was found when tormentic acid congener was tested against both S. aureus and P. aeruginosa. The MICs were found to be 25 µg/ml and 12.5 µg/ml for P. aeruginosa and S. aureus cells, respectively. S. pyogenes was found to be susceptible to tormentic acid congener and the hydroethanolic extract with an MIC of 100 µg/ml and 25 µg/ml, respectively. A. baumannii was found not to be susceptible to the compound or the extracts. The compound and the extracts caused a significant decrease in the biofilm extracellular polysaccharide content of S. pyogenes. The extracts and tormentic acid congener caused detachment of biofilms and decreased the release of extracellular DNA and capsular polysaccharides from biofilms of P. aeruginosa and S. aureus. Tormentic acid congener and extracts, thus, have significant antibacterial and antibiofilm activities on these selected ESKAPE bacteria and can act as source lead compounds for the development of antibacterial triterpenoids.

scholarly journals Regulatory opportunities to encourage technology solutions to antibacterial drug resistance

2011 ◽  
Vol 66 (9) ◽  
pp. 1945-1947 ◽  
Author(s):  
R. Finch ◽  
M. Blaser ◽  
O. Carrs ◽  
G. Cassell ◽  
N. Fishman ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Antibacterial Drug ◽  
Antibacterial Drug Resistance

scholarly journals Evolution of antimicrobial resistance in departments with high risk of cross infections in Tunisia

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
N Haddad ◽  
F Azouzi ◽  
A Ben Chaikh ◽  
S Kahloun ◽  
A Rania ◽  
...  
Keyword(s):  
Health Care ◽  
Drug Resistance ◽  
High Risk ◽  
Antimicrobial Resistance ◽  
Methicillin Resistance ◽  
Public Health Problem ◽  
Resistant Bacteria ◽  
Antibacterial Drug ◽  
Health Care Associated Infections ◽  
Antibacterial Drug Resistance

Abstract Background Antimicrobial resistance is actually a real and ever-changing public health problem. The microbiology laboratory plays a key role to achieve collaboration with clinical services and the prevention and control of infection team. Objective Describe the bacterial ecology of departments with high risk of Health care associated infections and analyze the evolution of antimicrobial resistance. Methods A descriptive and retrospective study was carried out in the university hospital Sahloul. It concerned all strains isolated in departments with high risk of Health care associated infections. The study period was spread over 7 years from January 1st, 2010 to December 31th, 2016. Results A total of 6108 non-redundant bacterial strains were isolated. Isolated pathogens were mainly from the urology departement (n-2651, 43.4%).The most frequent isolated pathogens were Escherichia coli (n = 1329, 21,8%), K. pneumoniae (n = 992, 16,2%), and Acinetobacter baumannii (n = 763, 12,5%). Concerning these main isolated species, significant statistical differences were noticed in bacterial resistance evolution over the years. With E. coli, the evolution was essentially represented by an increase of amoxicillin, amoxicillin clavulanic, cefotaxime, gentamicin, and fluoroquinolones resistance. With K. pneumoniae, cefotaxime resistance was stable, however resistance to imipenem and gentamicin was increasing. There was also a significant increase in fluoroquinolone and aminoside resistance. With S. Aureus, an increase in methicillin resistance was detected from 11.1% in 2010 to 20% in 2016. Conclusions Antibacterial Drug Resistance is a dynamic and rapidly evolving phenomenon in our hospital. The most common MDR bacteria studied were enterobacteriaceae producing carbapenemase. The emergence of glycopeptid resistance in enterococci must be controlled in order to prevent its spread to the community and the transfer of staphylococcus resistance genes. Key messages Antibacterial Drug Resistance is a dynamic and rapidly evolving phenomenon in our hospital. The most common multi drug resistant bacteria studied were enterobacteriaceae producing carbapenemase.

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