Synthesis and biological evaluation of sulfonamide thiazole and benzothiazole derivatives as antimicrobial agents

Several thiazoles and benzothiazoles carrying a benzenesulfonamide moiety at position 2 of the heterocyclic nucleus were synthesised and tested as antimicrobial agents. All sulfanilamides and some of the nitro substituted sulfonamides have effective antibacterial properties against Gram positive bacteria (MIC 0.3-100 mu g/mL) such as several bacilli, staphylococci and streptococci, including methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis strains. On the contrary, no inhibition of Gram negative Escherichia coli and fungi is detected up to the concentration of 100 mu g/mL. Synergistic inhibitory activity occurs when the active antibacterial sulfonamides are tested in combination with trimethoprim against both Bacillus subtilis and Staphylococcus aureus.