Degradation kinetics of cold plasma-treated antibiotics and their antimicrobial activity

Abstract

Antibiotics, such as ofloxacin (OFX) and ciprofloxacin (CFX), are often detected in considerable concentrations in both wastewater effluents and surface water. This poses a risk to non-target organisms and to human health. The aim of this work was to study atmospheric cold plasma (ACP) degradation of antibiotics in water and meat effluent and to explore any residual antimicrobial activity of samples submitted to the plasma process. The results revealed that ACP successfully degraded the studied antibiotics and that the reaction mechanism is principally related to attack by hydroxyl radicals and ozone. According to the disk diffusion assay, the activity of both antibiotics was considerably reduced by the plasma treatment. However, a microdilution method demonstrated that CFX exhibited higher antimicrobial activity after ACP treatment than the corresponding control revealing a potentially new platform for future research to improve the efficiency of conventional antibiotic treatments. Importantly, short-term exposures to sub-lethal concentrations of the antibiotic equally reduced bacterial susceptibility to both ACP treated and untreated CFX. As a remediation process, ACP removal of antibiotics in complex wastewater effluents is possible. However, it is recommended that plasma encompass degradant structure activity relationships to ensure that biological activity is eliminated against non-target organisms and that life cycle safety of antibiotic compounds is achieved.

Removal of Antibiotics from Real Hospital Wastewater by Cold Plasma Technique

“…However, the low removal efficiencies mentioned above may be explained by inadequate oxidant products for removing high concentrations of ofloxacin (41.23 mg/L) and amoxicillin (23.58 mg/L). e increase in the removal efficiency with an adequate increase in the applied voltage is consistent with the results reported by Sarangapani et al [21]; in their study, the authors have reported that with the rise in the voltage from 70 to 80 kV, the plasma degradation efficiency increased from 75% to 89% for ciprofloxacin and from 88% to 92% for ofloxacin. Even at an applied voltage of 35 kV, the highest removal efficiency was observed for ofloxacin and amoxicillin; however, the difference in removal efficiencies was not significant between the applied voltages of 30 kV and 35 kV.…”

“…Recently, the application of cold plasma-one of the AOPs-has attracted considerable attention for wastewater treatment due to its efficiency, less chemical requirements, and low sludge production [17]. Cold plasma has been employed for the degradation of recalcitrant pollutants in the wastewater generated from pesticide production [18], a slaughterhouse [19], textiles [20], and pharmaceuticals [21][22][23][24].…”

“…Kim et al [27] have employed a DBD system and reported the removal of 9 antibiotic compounds, namely, lincomycin, ciprofloxacin, enrofloxacin, chlortetracycline, oxytetracycline, sulfathiazole, sulfamethoxazole, sulfamethazine, and trimethoprim, respectively, from a synthesis solution, with removal efficiencies varying from 60% to 90%. In addition, Sarangapani et al have employed cold plasma for the high-efficiency mitigation of two widely used antibiotics (i. e., ofloxacin and ciprofloxacin, respectively) from water and meat effluents [21]. e results revealed that cold plasma successfully degrades the examined antibiotics and that plasma treatment considerably reduces the activity of both antibiotics.…”

Effect of Atmospheric Cold Plasma Treatments on Reduction of Alternaria Toxins Content in Wheat Flour

“…Species is generally identified as the main active species responsible for the effects of cold plasma, among which is degradation of chemical and biochemical compounds are atomic oxygen, ozone (O 3 ), hydrogen peroxides (H 2 O 2 ), hydroxyl radicals (•OH), as well as peroxynitrites and nitrogen oxides [23,24,41]. Some of the species, such as •OH, NO, O, after excitation emit in near UV-visual range and this emission is easily recordable by the optical emission spectroscopy (OES) technique.…”

“…Not long ago, the research focus of the plasma treatment was on its effects on pathogenic bacteria [21,22]. Lately, much attention has been paid to studies related to plasma effects on chemical and biological compounds which showed promising results [23][24][25]. Degradation of mycotoxins is being studied worldwide with different types of plasma sources.…”