ANTIMICROBIAL ACTIVITY OF SOME NEW THIOUREIDES FROM 2-THIOPHENEACETIC ACID

The aim of this study was to evaluate the „in vitro” antimicrobial activity of nine new compounds derived from 2-thiopheneacetic acid using qualitative and quantitative methods. These compounds have been synthesized and characterized in a previous paper [7]. The qualitative screening of the susceptibility spectra of different microbial strains to these compounds was performed by three adapted diffusion methods: paper filter disk impregnation with the tested substances solutions in DMSO (dimethyl sulfoxide), the disposal of the tested solutions in agar wells and the spotting of the tested solutions on solid medium seeded with microbial inoculums. The quantitative assay of the antimicrobial activity was performed by broth microdilution method in 96-well microplates in order to establish the minimal inhibitory concentration (MIC).The antimicrobial activity was tested against Gram-positive strains (Staphylococcus (S.) aureus, Bacillus (B.) subtilis), Gramnegative (Escherichia (E.) coli, Pseudomonas (P.) aeruginosa, Klebsiella (K.) pneumoniae) and fungal strains (Candida (C.) albicans). As concerning the Gram positive strains, the tested compounds exhibited no significant antimicrobial activity against S. aureus, but two of these compounds were active on B. subtilis. All tested compounds exhibited antifungal activity against C. albicans and four of them against other Gram-negative clinical strains, especially K. pneumoniae. Rezumat Scopul acestei lucrări a fost evaluarea „in vitro” a activităţii antimicrobiene a nouă noi tioureide ale acidului 2-tiofenacetic, utilizând metode calitative si cantitative de determinare. Acesti compusi au fost sintetizaţi si caracterizaţi intr-o lucrare anterioară.[7] Screening-ului calitativ al spectrului de sensibilitate al diferitelor tulpini microbiene pe acesti compusi a fost realizat utilizând variante adaptate ale metodei difuzimetrice: impregnarea discurilor de hârtie de filtru cu soluţiile in DMSO (dimetilsulfoxid) ale substanţelor de testat, repartizarea soluţiilor testate in godeuri decupate in agar si repartizarea soluţiilor in spot pe mediul insămânţat cu cultura microbiană. Evaluarea cantitativă a activităţii antimicrobiane a fost realizată prin metoda microdiluţiilor in mediu lichid, in plăci cu 96 de godeuri, cu scopul de a stabili concentraţia minimă inhibitorie (CMI). Activitatea antimicrobiană a fost testată impotriva tulpinilor Gram-pozitive (Staphylococcus (S.) aureus, Bacillus (B.) subtilis), Gram-negative (Escherichia (E.) coli, Pseudomonas (P.) aeruginosa, Klebsiella (K.) pneumoniae) si pe tulpini fungice (Candida (C.) albicans).