Influence of ionizing radiation on the antimicrobial activity of the antibiotics sulfamethoxazole and trimethoprim. Academic Article uri icon


  • The response of the antimicrobial compounds sulfamethoxazole (SMX) and trimethoprim (TMP) - individually and in mixtures - to ionizing radiation was investigated using laboratory prepared mixtures and a commercial pharmaceutical formulation. The residual antibacterial activity of the solutions was monitored using Staphylococcus aureus and Escherichia coli test strains. Based on antibacterial activity, SMX was more susceptible to ionizing radiation as compared to TMP. The antibacterial activity of SMX and TMP was completely eliminated at 0.2kGy and 0.8kGy, respectively. However, when SMX and TMP were in a mixture, the dose required to eliminate the antibacterial activity was 10kGy, implying a synergistic antibacterial activity when these are present in mixtures. Only when the antibiotic concentration was below the Minimum Inhibitory Concentration of TMP (i.e., 2mol dm-3) did the antibacterial activity of the SMX and TMP mixture disappear. These results imply that the synergistic antimicrobial activity of antimicrobial compounds in pharmaceutical waste streams is a strong possibility. Therefore, antimicrobial activity assays should be included when evaluating the use of ionizing radiation technology for the remediation of pharmaceutical or municipal waste streams.

published proceedings

  • J Environ Sci Health A Tox Hazard Subst Environ Eng

author list (cited authors)

  • Sgi, G., Szabacsi, K., Szab, L., Homlok, R., Kovcs, K., Mohcsi-Farkas, C., ... Wojnrovits, L.

citation count

  • 3

complete list of authors

  • Sági, G||Szabacsi, K||Szabó, L||Homlok, R||Kovács, K||Mohácsi-Farkas, C||Pillai, SD||Takács, E||Wojnárovits, L

publication date

  • July 2018