The development of three ruthenium-based antimicrobial metallodrugs: Design, synthesis, and activity evaluation against Staphylococcus aureus

2021 ◽  
pp. 174751982110550
Author(s):  
Liqiang Wang ◽  
Bin Huang ◽  
Xuemin Duan ◽  
Guijuan Jiang ◽  
Yanshi Xiong ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Minimal Inhibitory Concentration ◽  
Biofilm Formation ◽  
Inhibitory Concentration ◽  
Rabbit Erythrocyte ◽  
Design Synthesis ◽  
Widespread Occurrence ◽  
Active Complex ◽  
Minimal Inhibitory Concentrations ◽  
Toxin Secretion

The development of new classes of antimicrobial is urgently needed due to the widespread occurrence of multi-resistant pathogens. In this study, three novel ruthenium complexes: [Ru(dmob)2(BTPIP)](PF6)2 (Ru(II)-1), [Ru(dbp)2(BTPIP)](PF6)2 (Ru(II)-2), and [Ru(dpa)2(BTPIP)](PF6)2 (Ru(II)-3) (dpa = 2,2’-dipyridylamine, dmob = 4,4’-dimethoxy-2,2’-bipyridyl, dbp = 4,4’-di- tert-butyl-2,2’-dipyridyl, BTPIP = 4-(benzo[ b]thiophen-2-yl)phenyl-1 H-imidazo[4,5- f][1,10]phenanthroline) are synthesized and investigated as antimicrobial metallodrugs. We demonstrate that all three complexes have significant antimicrobial activity against Staphylococcus aureus by testing their minimal inhibitory concentrations = 0.0015–0.0125 mg/mL. The antibacterial activity of the best active complex Ru(II)-3 is 13 times that of ofloxacin (minimal inhibitory concentration = 19.5 μg/mL). Importantly, Ru(II)-3 not only increases the susceptibility of Staphylococcus aureus to existing common antibiotics but also shows noticeably delayed and decreased resistance in Staphylococcus aureus since the minimal inhibitory concentration values of Ru(II)-3 only increased eightfold times after 20 passages. Furthermore, the biofilms formation and rabbit erythrocyte hemolysis assays verified that Ru(II)-3 also efficiently inhibit the biofilm formation and toxin secretion of Staphylococcus aureus.

Evidence that the mechanisms of fungitoxicity of 8-quinolinol and its bischelate with copper(II) are different

1985 ◽  
Vol 31 (8) ◽  
pp. 707-710 ◽  
Author(s):  
Herman Gershon ◽  
Anthony T. Grefig ◽  
David J. Cady
Keyword(s):  
Minimal Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Graphite Furnace ◽  
Trichoderma Viride ◽  
Atomic Absorption Spectrophotometry ◽  
Test System ◽  
Growth Media ◽  
Minimal Inhibitory Concentrations ◽  
Absorption Spectrophotometry ◽  
Inhibition Of Growth

The copper(II) contents of the growth media, Sabouraud dextrose and Czapek–Dox broths, and of the spore inocula of Aspergillus niger (ATCC 1004), Aspergillus oryzae (ATCC 1011), Trichoderma viride (ATCC 8678), and Myrothecium verrucaria (ATCC 9095) were determined by atomic absorption spectrophotometry in a graphite furnace. The test systems composed of Sabouraud dextrose broth and spore inocula of the four fungi contained only a little over 3% of the copper(II) required to form a minimal inhibitory concentration of bis(8-quinolinolato)copper(II). The test system of Czapek–Dox broth and A. oryzae contained slightly less than 65% of the copper(II) required to form a minimal inhibitory concentration of the bischelate of 8-quinolinol with copper(II). When the minimal inhibitory concentrations of 8-quinolinol and bis(8-quinolinolato)copper(II) were added simultaneously to the test system of Czapek–Dox broth and A. oryzae, 10% of the combined mixture of toxicants caused complete inhibition of growth indicating synergism between the toxicants. These results together with the observation that α-lipoic acid as well as small aliphatic thiol-containing compounds (cysteine, glutathione, dithioerythritol, and dithiothreitol) reversed the toxicity of 8-quinolinol but not the toxicity of bis(8-quinolinolato)copper(II) led to the conclusion that the mechanisms of fungitoxicity of both toxicants are different.

Antimicrobial Activity of N,N'-bis(decylmethyl)- α,ω-alkanediamine Dioxides [1]

1983 ◽  
Vol 38 (1-2) ◽  
pp. 151-152 ◽  
Author(s):  
Ferdinand Devínsky ◽  
Ivan Lacko ◽  
Ludovít Krasnec ◽  
Dušan Mlynarčík
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Minimal Inhibitory Concentration ◽  
Inhibitory Concentration

Antimicrobial activity of N,N′-bis(decylmethyl)-α,ω-alkanediamine dioxides determined on Staphylococcus aureus, Escherichia coli, and Candida albicans is presented as minimal inhibitory concentration (MIC). The effect of the length of linking alkylene chain on this activity has been followed.

Oropharyngeal Bacterial Colonization after Chlorhexidine Mouthwash in Mechanically Ventilated Critically Ill Patients

2018 ◽  
Vol 129 (6) ◽  
pp. 1140-1148 ◽  
Author(s):  
Béatrice La Combe ◽  
Anne-Claire Mahérault ◽  
Jonathan Messika ◽  
Typhaine Billard-Pomares ◽  
Catherine Branger ◽  
...  
Keyword(s):  
Minimal Inhibitory Concentration ◽  
Critically Ill ◽  
Bacterial Growth ◽  
Critically Ill Patients ◽  
Inhibitory Concentration ◽  
Bacterial Colonization ◽  
Contamination Level ◽  
Ventilator Associated Pneumonia ◽  
Minimal Inhibitory Concentrations ◽  
Salivary Concentration

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Oropharyngeal care with chlorhexidine to prevent ventilator-associated pneumonia is currently questioned, and exhaustive microbiologic data assessing its efficacy are lacking. The authors therefore aimed to study the effect of chlorhexidine mouthwash on oropharyngeal bacterial growth, to determine chlorhexidine susceptibility of these bacteria, and to measure chlorhexidine salivary concentration after an oropharyngeal care. Methods This observational, prospective, single-center study enrolled 30 critically ill patients under mechanical ventilation for over 48 h. Oropharyngeal contamination was assessed by swabbing the gingivobuccal sulcus immediately before applying 0.12% chlorhexidine with soaked swabs, and subsequently at 15, 60, 120, 240, and 360 min after. Bacterial growth and identification were performed, and chlorhexidine minimal inhibitory concentration of recovered pathogens was determined. Saliva was collected in 10 patients, at every timepoint, with an additional timepoint after 30 min, to measure chlorhexidine concentration. Results Two hundred fifty bacterial samples were analyzed and identified 48 pathogens including Streptococci (27.1%) and Enterobacteriaceae (20.8%). Oropharyngeal contamination before chlorhexidine mouthwash ranged from 103 to 107 colony-forming units (CFU)/ml in the 30 patients (median contamination level: 2.5·106 CFU/ml), and remained between 8·105 (lowest) and 3·106 CFU/ml (highest count) after chlorhexidine exposure. These bacterial counts did not decrease overtime after chlorhexidine mouthwash (each minute increase in time resulted in a multiplication of bacterial count by a coefficient of 1.001, P = 0.83). Viridans group streptococci isolates had the lowest chlorhexidine minimal inhibitory concentration (4 [4 to 8] mg/l); Enterobacteriaceae isolates had the highest ones (32 [16 to 32] mg/l). Chlorhexidine salivary concentration rapidly decreased, reaching 7.6 [1.8 to 31] mg/l as early as 60 min after mouthwash. Conclusions Chlorhexidine oropharyngeal care does not seem to reduce bacterial oropharyngeal colonization in critically ill ventilated patients. Variable chlorhexidine minimal inhibitory concentrations along with low chlorhexidine salivary concentrations after mouthwash could explain this ineffectiveness, and thus question the use of chlorhexidine for ventilator-associated pneumonia prevention.

scholarly journals Effects of oregano, carvacrol and thymol on Staphylococcus aureus and Staphylococcus epidermidis biofilms

2007 ◽  
Vol 56 (4) ◽  
pp. 519-523 ◽  
Author(s):  
Antonia Nostro ◽  
Andrea Sudano Roccaro ◽  
Giuseppe Bisignano ◽  
Andreana Marino ◽  
Maria A. Cannatelli ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Essential Oil ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Inhibitory Concentration ◽  
Oregano Essential Oil ◽  
Planktonic Growth ◽  
Subinhibitory Concentrations

The aim of this study was to evaluate the effect of oregano essential oil, carvacrol and thymol on biofilm-grown Staphylococcus aureus and Staphylococcus epidermidis strains, as well as the effects of the oils on biofilm formation. For most of the S. aureus (n=6) and S. epidermidis (n=6) strains tested, the biofilm inhibitory concentration (0.125–0.500 %, v/v, for oregano, and 0.031–0.125 %, v/v, for carvacrol and thymol) and biofilm eradication concentration (0.25–1.0 %, v/v, for oregano and 0.125–0.500 %, v/v, for carvacrol and thymol) values were twofold or fourfold greater than the concentration required to inhibit planktonic growth. Subinhibitory concentrations of the oils attenuated biofilm formation of S. aureus and S. epidermidis strains on polystyrene microtitre plates.

scholarly journals Reduced Triclosan Susceptibility in Methicillin-Resistant Staphylococcus epidermidis

2004 ◽  
Vol 48 (4) ◽  
pp. 1397-1399 ◽  
Author(s):  
Molly B. Schmid ◽  
Nachum Kaplan
Keyword(s):  
Staphylococcus Aureus ◽  
Minimal Inhibitory Concentration ◽  
Staphylococcus Epidermidis ◽  
Inhibitory Concentration ◽  
Clinical Isolates ◽  
Methicillin Resistant

ABSTRACT Triclosan MIC determination showed that recent Staphylococcus aureus clinical isolates (n = 100) were highly susceptible to triclosan, with a 50% minimal inhibitory concentration (MIC50) of 0.12 μg/ml and a MIC90 of 0.25 μg/ml. Staphylococcus epidermidis isolates (n = 96) were less susceptible, with a MIC50 of 0.12 μg/ml and a MIC90 of 8 μg/ml. Decreased susceptibility to triclosan was more prevalent among methicillin-resistant S. epidermidis than among methicillin-sensitive S. epidermidis isolates.

scholarly journals Chemical composition of essential oil in Mosla chinensis Maxim cv. Jiangxiangru and its inhibitory effect on Staphylococcus aureus biofilm formation

2018 ◽  
Vol 13 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Liang Peng ◽  
Yunhao Xiong ◽  
Mei Wang ◽  
Manman Han ◽  
Weilan Cai ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Chemical Composition ◽  
Essential Oil ◽  
Biofilm Formation ◽  
Quantitative Method ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Components ◽  
Major Chemical

AbstractThe essential oil of Mosla chinensis Maxim cv. Jiangxiangru is known for its antibacterial ability. This study aimed to investigate the chemical composition of Jiangxiangru essential oil and its inhibitory effect on Staphylococcus aureus biofilm formation. Gas chromatography/mass spectrometry (GC–MS) was used to determine the chemical composition of Jiangxiangru essential oil. Subsequently, the eight major chemical components were quantitatively analyzed using GC– MS, and their minimum inhibitory concentration (MIC) values against S. aureus were tested. Biofilm formation was detected by crystal violet semi-quantitative method and silver staining. Of the 59 peaks detected, 29 were identified by GC–MS. Of these peaks, thymol, carvacrol, p-cymene, γ-terpinene, thymol acetate, α-caryophyllene, 3-carene, and carvacryl acetate were present at a relatively higher concentration. The results of the quantitative test showed that thymol, carvacrol, p-cymene, and γ-terpinene were the major components of the essential oil. Among the eight reference substances, only thymol, carvacrol, and thymol acetate had lower MICs compared with the essential oil. Essential oil, carvacrol, carvacryl acetate, α-caryophyllene, and 3-carene showed the better inhibition of S. aureus biofilm formation. When one fourth of the MIC concentrations were used for these substances (0.0625 mg/mL for essential oil, 0.0305 mg/mL for carvacrol, 1.458 mg/mL for carvacryl acetate, 0.1268 mg/mL for α-caryophyllene, and 2.5975 mg/mL for 3-carene), the inhibition rates were over 80%. However, thymol, γ-terpinene, thymol acetate, and p-cymene showed a relatively poor inhibition of S. aureus biofilm formation. When 1× MIC concentrations of these substances were used, the inhibition rates were less than 50%. In conclusion, Jiangxiangru essential oil and its major components, carvacrol, carvacryl acetate, α-caryophyllene, and 3-carene, strongly inhibited biofilm formation in S. aureus.

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