Partial purification and environmental application of CTX-type ESBL beta-lactamases from wastewater-derived E. coli isolates.

BACKGROUND

Extended-spectrum beta-lactamases (ESBLs) of Escherichia coli give rise to resistance to broad-spectrum beta-lactam antibiotics, making treatment difficult clinically and complicating environmental management. Understanding hospital effluent as a reservoir and dissemination route for these resistant enzymes is therefore very vital.

METHODS

The crude beta-lactamase enzyme extracts were partially purified by ammonium sulfate precipitation and Sephadex G-100 gel filtration chromatography, enzyme activity was assessed for observed degradation of ceftriaxone by UV spectrophotometry. Protein content was quantified by the Lowry method, and enzyme purity analyzed by SDS-PAGE. The ability of the partially purified enzymes to degrade ceftriaxone in hospital wastewater was also assessed.

RESULTS

Crude enzyme extracts showed appreciable ceftriaxone degradation activity. Partial purification enhanced the specific activity of the enzyme while significantly reducing contaminating proteins. SDS-PAGE indicated a reduction in protein bands after purification. Partially purified enzymes showed remarkable ceftriaxone degradation in buffer and remained active, albeit to a lesser degree, in hospital wastewater.

CONCLUSION

This study demonstrates the partial purification and characterization of CTX-type ESBL beta-lactamases from E. coli isolates obtained from wastewater. Partially purified enzymes remain active and have potential for application in reducing -beta-lactam antibiotics in hospital wastewater, thus proposing an environmental approach for curbing antibiotic resistance.