IN VITRO SCREENING OF BACTERIAL STRAINS FOR THE REMOVAL OF CIPROFLOXACIN (CPX) FROM WATER.

Ciprofloxacin (CPX), is a broad-spectrum fluoroquinolone antibiotic widely used to treat bacterial infections in humans and animals. In recent years, ecological problems caused by the disposal of CPX-waste product have attracted increasing attention. This study aimed to evaluate the ability of different bacteria to remove CPX from water. The ability of five bacterial strains namely; Acenitobacter sp., Acenitobacter lwofii, Bacillus. pumilus, Burkholderia phytofirmans, and Mesorihizobium sp. were examined in this study. Tests were performed on Luria Bertani (LB) as well as on Mueller-Hinton (MH) agar at different CPX concentrations (20-100 mg L^-1). All five tested bacterial strains showed growth on LB as well as on MH agar plates at all concentrations between 20 to 100 mg L^-1 CPX. Three bacterial species: Acenitobacter lwofii, Bacillus pumilus, and Mesorihizobium sp. were reported more resistant to CPX of the five strains tested. In a shake flask study, the strain B. pumilus initially showed higher degradation rate (75.53%) followed by Acenitobacter lwofii (72.3%), Mesorihizobium sp. (70.32), Burkholderia phytofirmans (67.10%), and Acenitobacter sp. (63.2%) at low CPX concentration (5 mg L^-1) in minimal saline media. However, Mesorihizobium sp. showed higher degradation efficiency (76.32%) at a higher CPX concentration (10 mg L^-1). A group of three bacterial strains, A. lowfi, B. pumilus, and Mesorihizobium sp. showed good CPX degradation rate (95.4%), and achieved higher degradation efficiency than the single strains at 20 mg L^-1 CPX concentration. Overall, the results suggest that using a combination of bacteria may be a useful tool for the remediation of antibiotic pollution. In addition, this study reveals the ability of previously isolated bacteria to biodegrade CPX as a sole source of carbon, providing new insights into the biodegradation of CPX. [ABSTRACT FROM AUTHOR]