ABSTRACT
We report here the characterisation of eight newly synthesized thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid and the evaluation of the in vitro antimicrobial activity of the new compounds against Gram-positive [Listeria monocytogenes,Staphylococcus aureus, Bacillus subtilis], Gram-negative [Psedomonas aeruginosa,Escherichia coli, Salmonella enteritidis], as well as Candida spp., using both reference and clinical multidrug resistant strains to establish the minimal inhibitory concentration (MIC)values. Our results showed that the tested compounds exhibited specific antimicrobial activities, both concerning the spectrum of antimicrobial activity and the corresponding MIC values, which ranged widely between 1024 and 32 mug/mL, depending on the nature and position of the substituents on the benzene ring. The most active compounds were N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(2,6-dichlorophenyl)-thiourea (5 g) and N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(4-bromophenyl)-thiourea (5h), which showed a broad spectrum of antimicrobial activity against enterobacterial strains (E. coli and S. enteritidis),P. aeruginosa, S. aureus and Candida spp. All the tested compounds except 5f were highly active against S. aureus (MIC=32 mug/mL), suggesting their possible use in the treatment of MRSA infections. Four of compounds also exhibited antifungal activity (MIC =256-32 microg/mL) against C. albicans, but L. monocytogenes as well as B. subtilis were resistant to all tested compounds. Our studies thus demonstrated that among other biological activities,the thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid also exhibit selective and effective antimicrobial properties that could lead to the selection and use of these compounds as efficient antimicrobial agents, especially for the treatment of multidrug resistant infections.
Subject(s)
Anti-Bacterial Agents/pharmacology , Benzoates/chemical synthesis , Benzoates/pharmacology , Benzoic Acid/pharmacology , Hydrocarbons, Fluorinated/chemical synthesis , Hydrocarbons, Fluorinated/pharmacology , Thiourea/chemical synthesis , Thiourea/pharmacology , Annexin A5/metabolism , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Antifungal Agents/chemical synthesis , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Bacteria/drug effects , Benzoates/chemistry , Benzoic Acid/chemical synthesis , Benzoic Acid/chemistry , Chlorophenols , Flow Cytometry , Fungi/drug effects , HeLa Cells , Humans , Hydrocarbons, Fluorinated/chemistry , Magnetic Resonance Spectroscopy , Microbial Sensitivity Tests , Thiourea/chemistryABSTRACT
The aim of the present study was to investigate the dental plaque formed on natural teeth surfaces by optic and confocal laser scanning microscopy (CLSM), to quantify the microbial density by viable cell counts, to identify the recovered microbial strains, the antibiotic susceptibility testing and their pathogenicity features (i.e. adherence and invasion capacity on HeLa cells, adherence on prostetic substrata used in oral medicine by original experimental models, production of extracellular enzymes and exotoxins). results: The CLSM revealed a very complex and highly organized architecture of dental plaque. The direct optic examination of Gram-stained smears revealed a great diversity of morphological types (82.5% of cases), with comparative levels of microbial densities. 50% of recovered microbial strains exhibited ability to adhere to three different polimeric inert substrata used in oral medicine, but reduced adherence and invasion capacity of HeLa cells and scared expression of soluble enzymatic factors.
