Test Method for Determining the Antimicrobial Activity of Antimicrobial Agents Under Dynamic Contact Conditions

10.1520/e2149 ◽  
2008 ◽  
Author(s):  
2019 ◽  
Vol 27 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Muhammet Murat Celik ◽  
Nizami Duran

Abstract Aim: The aim of this study was to investigate the in-vitro efficacy of Glycyrrhetinic acid against Helicobacter pylori (H. pylori) strains, as compared with conventional antibacterial agents. Methods: A total of 41 H. pylori isolates were used, 6 of which were of standard strains (NCTC 1637), 8 of which were drug-sensitive, and 27 were resistant to drugs isolates. Clarithromycin and metronidazole resistance in all strains of H. pylori were determined by the Epsilometer test (E-test) method. MIC study was performed by using microdilution broth method. Results: Glycyrrhetinic acid was found to be effective against H. pylori NCTC 1637 in doses of 12.0±4.38 µg/mL, while the MIC value of clinical H. pylori isolates susceptible to antimicrobials was 20.8±10.11 µg/ml. It was found that the MIC values for antimicrobial-sensitive clinical H. pylori isolates was higher when compared with H. pylori NCTC 1637 strains. The MIC values of the standard antimicrobial agents against drug-resistant H. pylori strains were higher than H. pylori NCTC 1637 strains and drug-sensitive H. pylori strains. The MIC value was found to be 14.22±7.77 µg/ml for metronidazole, 3.89±1.90 µg/ml for clarithromycin, 2.33±1.0 µg/ml for amoxicillin, 2.44±0.88 µg/ml for levofloxacin and 4.89±2.47 µg/ml for tetracycline, whereas the MIC value of Glycyrrhetinic acid was 26.67±8.0 µg/ml in metronidazole-resistant H. pylori isolates. Besides, MIC values of the antimicrobials and 18ß-Glycyrrhetinic acid among the strains resistant to clarithromycin were as follows: 3.25±2.12 µg/ml for metronidazole, 9.71±4.54 µg/ml for clarithromycin, 2.06±1.32 µg/ml for amoxicillin, 3.88±4.22 µg/ml for levofloaxacin and 3.25±1.04 µg/mL for tetracycline and 22.0±11.11 µg/ml for Glycyrrhetinic acid. Conclusion: Glycyrrhetinic acid had significant antimicrobial activity against H. pylori strains. Although further in-vivo studies are needed on antimicrobial activity of Glycyrrhetinic acid, increased resistance to drugs currently used in treatment suggests that Glycyrrhetinic acid may be a potential agent for the treatment of H. pylori.


2019 ◽  
Author(s):  
Julian-Dario Rembe ◽  
Vivian-Denise Thompson ◽  
Nina Hauer ◽  
Ewa Klara Klara Stuermer

Abstract Background: Due to rising numbers microbial resistance to established antibiotics and first described tolerance developments for local wound antimicrobials a continuous need for alternative antimicrobial agents exists. Due to complex conditions in the microenvironment of especially chronic wounds, such as high protein levels, novel antimicrobials need to meet advanced requirements. Aim: Compare the antimicrobial efficacy of Cetylpiridinium-chloride (CPC) and miramistin (MST) to established antimicrobials under protein-challenge in-vitro. Methods: Antimicrobial activity of octenidin-dihydrochloride, povidon-iodine, polyhexamethylene-biguanide hydrochloride, chlorhexidine, cetylpiridinium-chloride and Miramistin after 0.5, 1, 3, 5 and 10 min of exposure against S. aureus, P. aeruginosa, E. coli, E. faecium and C. albicans was tested, using a quantitative suspension method with either 0.3% or 3% bovine albumin challenge, based on DIN EN 13727 (‘Chemical disinfectants and antiseptics - Quantitative suspension test for the evaluation of bactericidal activity in the medical area - Test method and requirements (phase 2, step 1)’). Results: CPC and MST demonstrated no inferiority to the established agents in-vitro. Especially CPC showed equal reduction rates as octenidin and povidon-iodine and achieved significantly higher reduction rates within shorter exposure times than polyhexanide and chlorhexidine (p ≤ 0.01) for S. aureus, P. aeruginosa, E. faecium and C. albicans. Both agents demonstrated no significant loss of efficacy under high protein-challenge (3% albumin). Conclusion: In terms of antimicrobial activity cetylpyridinium-chloride and miramistin proved to be at least equally effective as established agents. No protein error was detected in the tested concentrations. More complex in-vitro assays and comprehensive in-vivo and clinical studies will be needed to determine their clinical value.


Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.


2019 ◽  
Vol 10 (04) ◽  
pp. 646-650
Author(s):  
Hyeusoo Kim ◽  
Kyeong Won Yun

The fruit of Rosa multiflora has been used as traditional herbal medicine in Asian countries. The present investigation was undertaken to study the antimicrobial activity and total polyphenol content of hexane, ether, ethyl acetate, water fraction of methanol extract of fruit and flower from Rosa multiflora and Rosa wichuraiana. Antimicrobial activity of the mentioned fractions against 3 gram-positive and 4 gram-negative bacteria using disk diffussion method. The measurement of minimal inhibition concentration (MIC) showed that the ethyl acetate fraction of the two Rosa species is the most effective against the tested bacteria. The total polyphenol content of ethyl acetate fraction of the two Rosa species is higher than the other fractions. The results indicate the antimicrobial activity was related with the total polyphenol content and the fruit and flower of the two Rosa species can be considered as a natural source of antimicrobial agents.


Author(s):  
Dibyajit Lahiri ◽  
Moupriya Nag ◽  
Sayantani Garai ◽  
Rina Rani Ray

: Phytocompounds are long known for their therapeutic uses due to their competence as antimicrobial agents. The antimicrobial activity of these bioactive compounds manifests their ability as an antibiofilm agent and is thereby proved to be competent to treat the wide spread of biofilm-associated chronic infections. Rapid development of antibiotic resistance in bacteria has made the treatment of these infections almost impossible by conventional antibiotic therapy, which forced in the switch over to the use of phytocompounds. The present overview deals with the classification of the huge array of phytocompounds according to their chemical nature, detection of their target pathogen, and elucidation of their mode of action.


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