Induction of staphylococcal β-lactamase in response to low concentrations of methicillin under simulated diving environments

1977 ◽  
Vol 23 (1) ◽  
pp. 116-121
Author(s):  
James R. Wild

The influence of simulated diving environments on the antimicrobial activity of a variety of penicillin and cephalosporin congeners was studied in Staphylococcus aureus. Pressure reduced bacteriostatic action provided the antibiotic was susceptible to β-lactamase hydrolysis and the bacterium was inducible for penicillinase. Ethidium bromide curing of the penicillinase plasmid of an inducible strain eliminated the hyperbaric effect. The minimal inhibitory concentration of benzylpenicillin increased about threefold with increasing hyperbaric pressure from 17 to 136 atm. Additional pressurization to 204 atm did not change antibiotic efficacy further. The efficacy of benzylpenicillin was reduced by 68 atm of hyperbaric helium, nitrogen, or a mixture of neon and helium, but was slightly increased by 68 atm of argon, removal of the gas phase, or 68 atm of hydrostatic pressure. Hyperbaric helium had no effect on β-lactamase activity in vitro. An effect was demonstrated upon induction by suboptimal concentrations of methicillin. The concentration of methicillin required for the induction of half-maximal levels of penicillinase in late log cultures of S. aureus was reduced from 0.15 μg/ml at 1 atm to 0.06 μg/ml at 68 atm. The basis of increased resistance to antibiotics exhibited by S. aureus in hyperbaric environments appears to be enhanced efficiency of penicillinase induction.

1983 ◽  
Vol 38 (1-2) ◽  
pp. 151-152 ◽  
Author(s):  
Ferdinand Devínsky ◽  
Ivan Lacko ◽  
Ludovít Krasnec ◽  
Dušan Mlynarčík

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.


2012 ◽  
Vol 9 (2) ◽  
pp. 749-755 ◽  
Author(s):  
Riyaz Ahmad Dar ◽  
Krishna Kumar Raj

The electrochemical behaviour of the complex of Cu(II) with 4-chlorobenzylidene-4-aminoacetanilide (CAA) was studied. It was observed that CAA forms 1:1 complex with Cu(II) in between pH 6.5 to 7.1. It was found that the reduction process of Cu(II)- CAA complex is two electron reversible reduction process at D.M.E. The logarithm value of stability constant of Cu(II)-4-Chlorobenzylidene-4-aminoacetanilide (CAA) complex has been found to be 4.85.The redox properties of the complex was extensively investigated by electrochemical method using cyclic voltammetry (CV).The Cu(II) complexes exhibited quasi-reversible single electron transfer process.The Schiff base and its complex has been screened for theirin-vitroantibacterial (Escherichiacoli,Staphylococcus aureus,Vibrio choleraeandBacillus subtilis) and antifungal (Aspergillus nigerandPenicillium liliacinum) activities by minimum inhibitory concentration (MIC) method.


2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Andréia Vieira Pereira ◽  
Marcelo Biondaro Góis ◽  
Tatiane Kelly Barbosa Azevêdo ◽  
Fabiana Nabarro Ferraz ◽  
Suellen Laís Vicentino Vieira ◽  
...  

ABSTRACT: The association of natural compounds isolated from medicinal plants with conventional antibiotics, both with similar mechanisms of action, have become a viable alternative strategy to overcome the problem of drug resistance. This study aimed to evaluate the in vitro antimicrobial activity of tannic substances present in the bark of Anacardium occidentale and Anadenanthera colubrina against samples of Staphylococcus aureus when in combination with cephalexin. These combinations were evaluated by determining the minimum inhibitory concentration (MIC). For this purpose, tannins and cephalexin were serially dissolved in distilled water at concentrations ranging from 0.976 mg/mL to 500 mg/mL and 2 mg/mL to 512 mg/mL, respectively. When combined, the compounds inhibited S. aureus growth forming halos ranging from 0.9 to 46 mm with an MIC of 7.8 mg/mL (tannins) and 4 µg/mL (cephalexin). The resulting effect of the combination of natural and synthetic substances with similar mechanisms of action presented better results than when tested alone. Thus, the conclusion is that both the tannins and cephalexin had their antimicrobial action enhanced when used in combination, enabling the use of lower concentrations while maintaining their antibacterial effect against strains of S. aureus.


2021 ◽  
Vol 50 (2) ◽  
pp. 383-393
Author(s):  
Anis Asmi Azman ◽  
Nurul Nadiah ◽  
Andi Rifki Rosandy ◽  
Afnani Alwi ◽  
Nurkhalida Kamal ◽  
...  

The research study regarding antimicrobial activity of pure compounds and LCMS data comparison from extract of lichen Parmotrema praesorediosum in Bangi, Selangor, Malaysia. Antimicrobial activity of acetone, ethanol, and methanol extracts as well as five compounds, namely methyl divaricatinate, methyl haematommate, methyl chlorohaematommate, methyl β-orsellinate, and vinapraesorediosic acid from methanol extract were identified for the microbial activity against four bacterial species, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Enterobacter aerogens, and Escerichia coli as well as two fungal species, Candida albicans and Candida parapsilosisbased on standards. The determination of IC50 using minimal inhibitory concentration (MIC) by broth microdilution method was carried out. For acetone extract, 201 μg/mL concentration was required to inhibit 50% (IC50) growth of positive gram bacteria, S. aureus while the concentrations of 430 and 480 μg/mL were able to inhibit 50% (IC50) growth of C. albicans and C. parapsilosis, respectively. Ethanol and methanol extract as well as five pure compounds did not inhibit 50% (IC50) of bacterial and yeast growths. Five pure compounds were first reported to determine IC50 of minimal inhibitory concentration (MIC) from lichen, Parmotrema praesorediosum in Malaysia. The comparison of LC-MS data between ethanol and acetone extracts showed that there was a peak of the main compound, atranorin in the acetone extract, but was invisible in the ethanol extract where the main bond broke down and produced other compounds. Result of pure compounds from antimicrobial activity and LCMS data comparison from extract of lichen Parmotrema praesorediosum were first reported in Bangi, Selangor, Malaysia. Data produced from this study will be used to show the comparison and latest result that will provide ongoing body of research into the issue of natural product.


2000 ◽  
Vol 47 (1) ◽  
pp. 87-94 ◽  
Author(s):  
A Orzeszko ◽  
R Gralewska ◽  
B J Starościak ◽  
Z Kazimierczuk

A series of fourteen derivatives of adamantane was synthesised. The new compound 4-(adamant-1-ylmethoxycarbonyl)phthalanhydride obtained from 1-adamantane-methanol and trimellitic anhydride chloride appeared very useful for preparation of a number of N-substituted phthalimides. Antimicrobial activity of the newly obtained derivatives such as, for example, 4-(adamant-1-ylmethoxycarbonyl)-N-(5-carboxypentamethylene)p hthalimide or 4-(adamant-1-ylmethoxycarbonyl)-N-(L-alanyl)phthalimide was tested against Staphylococcus aureus, Bacillus sp., Micrococcus flavus and Enterococcus faecium. The minimal inhibitory concentration (MIC) for these compounds against S. aureus were 0.022 and 0.05 microg/ml, respectively.


Dose-Response ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 155932582090485 ◽  
Author(s):  
Syed Ali Raza Naqvi ◽  
Syed Muhammad Ali Shah ◽  
Laiba Kanwal ◽  
Muhammad Saeed ◽  
Atta-ul-Haq ◽  
...  

Multidrug resistance has increased globally in the communities. Bacterial infections associated with health care have weakened the existing antimicrobial therapy and demand the search for alternative therapies. In the present investigation, the medicinal plant Pulicaria gnaphalodes from Quetta, Pakistan, has been screened for antimicrobial potential. In vitro antimicrobial efficacy of P gnaphalodes extracts (methanol and ethanol) was quantitatively evaluated on the basis of zone of inhibition against different bacteria and minimum inhibitory concentration (MIC). In vivo, antihypercholesterolemic activity is determined in different rat groups. The results of the study indicated that the ethanol extract of P gnaphalodes showed maximum zone of inhibition for Bacillus subtilis of 12.1 ± 1.1 mm from all others. The methanol extract showed maximum zone of inhibition for Staphylococcus aureus of 11.9 ± 1.0 mm and rifampicin showed maximum zone of inhibition of 23.1 ± 0.9 mm. The results of ethanol and methanol extract of P gnaphalodes against different bacteria revealed that this plant has greater antimicrobial activity. However, the plant extract shows nonsignificant antihypercholesterolemic activity. The extract of this plant can be utilized as medicine to inhibit several infections caused by some bacterial pathogens found in human body.


2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500
Author(s):  
Janetsy Borroto ◽  
Ricardo Salazar ◽  
Alejandro Pérez ◽  
Yemeys Quiros ◽  
Martha Hernandez ◽  
...  

The dichloromethane extract and seven anthraquinones isolated from in vitro cultured roots of Morinda royoc L. were tested for their antimicrobial activity against seven yeast and seven bacterial strains. The extract showed a minimum inhibitory concentration (MIC) value of 15.6 μg/m against all species of Candida tested; except C. glabrata (MIC 1.95 μg/mL), and it inhibited the growth of oxacillin-resistant Staphylococcus aureus (MIC 31.2 μg/mL). Only morindone showed activity against all yeast strains (MIC 1.9 μg/mL), and against oxacillin-resistant Staphylococcus aureus (MIC 15 μg/mL).


2015 ◽  
Vol 69 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Olgica Stefanovic ◽  
Ivana Radojevic ◽  
Ljiljana Comic

This study deals with synthesis of methyl cinnamate, butyl cinnamate, and p-methoxy methyl cinnamate and testing of their in vitro antimicrobial activity. Antimicrobial activity was examined towards 29 microorganisms using microdilution method. It is shown that antimicrobial activity of methyl cinnamate and p-methoxy methyl cinnamate was better than that of butyl cinnamate. Sarcina lutea, Bacillus subtilis ATCC 6633, B. subtilis and B. subtilis IP 5832 (probiotic) were the most sensitive bacteria. It is established that p-methoxy methyl cinnamate can be a new, potential anti-Staphylococcus aureus agent with minimum inhibitory concentration of 62.5 ?g/ml. Methyl cinnamate and p-methoxy methyl cinnamate inhibited the growth of Aspergillus restrictus, A. flavus and A. fumigatus in the concentration range from 62.5 ?g/ml to 250 ?g/ml.


2007 ◽  
Vol 72 (5) ◽  
pp. 459-466 ◽  
Author(s):  
S.O. Podunavac-Kuzmanovic ◽  
D.M. Cvetkovic

Zinc(II) chloride was reacted with some 1-benzylbenzimidazole derivatives (L) to give complexes of the formula ZnL2Cl2. All the ligands and their zinc(II) complexes were evaluated for their in vitro antibacterial activity against Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus aureus and Sarcina lutea. Themajority of the investigated compounds displayed in vitro antimicrobial activity against very persistent microorganisms. It was found that all the tested compounds were more active against gram-positive than gram-negative bacteria. The minimum inhibitory concentration (MIC) was determined for all ligands and their complexes. The effect of the structure of the ligands and complexes on the antimicrobial activity is discussed. The complexes were found to be more toxic than the ligands.


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