Molecular Identification of Potential Pharmaceutical Products Cloxacillin Degrading Bacterial Isolates

The increasing presence of antibiotic contaminants in the environment needs the development of environmentally acceptable bioremediation techniques. This study aimed to isolate and molecularly identify soil bacteria capable of degrading pharmaceutical antibiotics, with a focus on cloxacillin. Using an enrichment culture approach, 43 bacterial isolates were isolated from antibiotic-contaminated soils: 10 for norfloxacin (NFX), 11 for levofloxacin (LFX), 13 for amoxicillin (AMX), and 9 for cloxacillin (CXC). Maximum Tolerance Level (MTL) screening found that 7 of the 9 CXC isolates could tolerate up to 500 ppm of cloxacillin, with isolates CXC-1a, CXC-2a, and CXC-7a exhibiting the highest tolerance and growth. Molecular identification using 16S rRNA gene sequencing revealed that the potent isolates were closely related to Bacillus cereus (CXC-7a), Escherichia coli (NFX-7a), Klebsiella pneumoniae (LFX-10a), and Bacillus amyloliquefaciens (AMX-2b). Phylogenetic study revealed their taxonomic and evolutionary ties. The findings indicate that natural soil bacteria, notably Bacillus cereus, have a high potential for bioremediation of cloxacillin-contaminated settings.