Boron compounds are essential micronutrients for many organisms. However, they negatively affect plant, soil, and water microflora if excessive amounts exist in irrigation water. Therefore, this study aimed to define the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of boric acid and borax by selecting the bacteria that can survive in all environments. Materials and methods: The antibacterial efficacy of boric acid and borax against several bacterial strains was evaluated 3 times with the macrodilution broth method. Results: The MICs and MBCs of boric acid were obtained as 3.80 mg/mL, 3.80 mg/mL, 7.60 mg/mL, and 7.60 mg/mL against the bacterial activities of Staphylococcus aureus, Acinetobacter septicus, Escherichia coli, and Pseudomonas aeruginosa, respectively. The MICs and the MBCs of borax were obtained as 23.80 mg/mL, 23.80 mg/mL, 47.60 mg/mL, and 47.60 mg/mL against the above bacteria, respectively. Conclusion: Current results suggest that water containing boron compounds at levels lower than the MICs and MBCs can be used for irrigation. It also seems feasible to use this approach to decide whether irrigation water is needed to remove excessive boron compounds. Furthermore, current MIC and MBC results shed light on the medicinal use of boron. Future studies may open a new avenue in the use of boron compounds as novel antibiotic agents.

Boron compounds are essential micronutrients for many organisms. However, they negatively affect plant, soil, and water microflora if excessive amounts exist in irrigation water. Therefore, this study aimed to define the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of boric acid and borax by selecting the bacteria that can survive in all environments. Materials and methods: The antibacterial efficacy of boric acid and borax against several bacterial strains was evaluated 3 times with the macrodilution broth method. Results: The MICs and MBCs of boric acid were obtained as 3.80 mg/mL, 3.80 mg/mL, 7.60 mg/mL, and 7.60 mg/mL against the bacterial activities of Staphylococcus aureus, Acinetobacter septicus, Escherichia coli, and Pseudomonas aeruginosa, respectively. The MICs and the MBCs of borax were obtained as 23.80 mg/mL, 23.80 mg/mL, 47.60 mg/mL, and 47.60 mg/mL against the above bacteria, respectively. Conclusion: Current results suggest that water containing boron compounds at levels lower than the MICs and MBCs can be used for irrigation. It also seems feasible to use this approach to decide whether irrigation water is needed to remove excessive boron compounds. Furthermore, current MIC and MBC results shed light on the medicinal use of boron. Future studies may open a new avenue in the use of boron compounds as novel antibiotic agents.