Antibacterial Activity of Some Selected 1,2,4-Triazole Derivatives Against Standard, Environmental, and Medical Bacterial Strains

Abstract Recently, four heterocyclic compounds containing 1,2,4-triazole (designated as Y2, Y3, Y30, and Y32) were synthesized by our lab. Previous data showed that 1,2,4-triazole nucleus posses a wide range of pharmacological activities such as antioxidant, antiviral, antitumor and antibacterial activities. Currently, the need for triazole derivatives with a broad spectrum of antibacterial activity are in the rise. Therefore, these data encouraged us to test newly synthesized 1,2,4-triazole compounds for their antibacterial activity against three types of bacteria: standard, environmental and medical bacteria. Both well diffusion and broth dilution methods were employed to examine the potential antibacterial activity against the aforementioned types of bacteria. The standard bacteria include Staphylococcus aureus ATCC 29213, Staphylococcus epidermis ATCC 12228, and Bacillus 292 Jacob H. Jacob et al. cereus ATCC11778, whereas environmental bacteria include Citrobacter sp., Bacillus pumilis, and Yersinia enterocolitica. The medical bacteria consists of three pathogenic bacteria (assigned as CS1, CS2, and CS3) isolated from medical samples obtained from a local hospital. These strains were further identified by means of biochemical tests and 16S rDNA sequencing. Based on these analyses, the CS1, CS2, and CS3 strains were Escherichia coli, Shigella sonnei and Pseudomonas aeruginosa, respectively. Data revealed that the compound Y2 and Y3 were effective against all tested bacterial strains except E. coli. Interestingly, compound Y3 was found to have antibacterial activity higher than penicillin G (the positive control) against P. aeruginosa and similar to penicillin G against B. cereus. However, the compounds Y30 and Y32 has no recognizable antibacterial effect. The antibacterial activity of Y2 and Y3 was appeared to be attributed to the type and the position of substituent groups.