Evaluation of residual antimicrobial activity and acute toxicity during the degradation of gatifloxacin by ozonation

Abstract

The concerns regarding the occurrence of pharmaceuticals in wastewater treatment plants have been increased in the last decades. Gatifloxacin (GAT), the fourth generation of fluoroquinolones, has been widely used to treat both Gram-positive and Gram-negative bacteria and has a limited metabolization. The present study aimed to evaluate the ozonation as a technique to degrade GAT. A UHPLC-MS/MS method was used to quantify the residual of GAT and to assess its degradation products. The removal efficiency was higher at alkaline condition (pH = 10), reaching up to 99% of GAT after 4 min. It was also observed that the first ozone attack on the GAT molecule was through the carboxylic group. In contrast, at acid conditions (pH = 3), the ozone attack was first to the piperazinyl ring. The antimicrobial activity was evaluated using Escherichia coli and Bacillus subtilis as test organisms, and it was observed that the residual activity reduced most at the alkaline conditions. In contrast, the best condition to remove the residual toxicity evaluated for the marine bacteria V. fischeri was the acidic one. Due to this, the ozonation seemed to be an exciting process to remove GAT at aqueous media.

The role of gut microbiota in intestinal disease: from an oxidative stress perspective

“…As an illustration, it has been determined that Enterococcus faecalis is capable of generating hydroxyl radicals (•OH) (Huycke and Moore, 2002;Bianco et al, 2017). The gram-positive bacterium under consideration is accountable for the production of substantial quantities of extracellular oxygen, resulting in the formation of hydrogen peroxide (H 2 O 2 ) and •OH (Caianelo et al, 2017). In instances of colorectal adenocarcinoma (CAC), alterations affecting the Wnt/β-catenin signaling pathway manifest exclusively during advanced disease stages, subsequent to the occurrence of mutations in the TP53 and K-Ras genes (Intarajak et al, 2019).…”