Analysis Of Relationship Between Mutations In OmpC,β-lactamases And E.cli Antibiotic Resistance

Objective Characterization the isolates with respect to their antibiotic resistance mechanisms,and deduce a potential pathway,for their evolution from the original infecting organism.Methods Characterization of Extended-spectrumβ-lactamases.Agar dilution method was used to determine the minimum inhibitory concentration(MIC)of severel antibiotics.the low copy number plasmid containing the wild type E.coli K-12 ompC gene was transformed into the two different clinical isolates.Increased expression of OmpC,indicating expression of the chromosomal copy and the plasmid copy of the gene,was confirmed by carrying out outer membrane preparations and running SDS-PAGE gels.Results To In the isolate 1 there were no significant changes in MIC with or without the wild type OmpC The isolate 7 however did show significant decreases in MICs for the carbapenem antibiotics,meropenem and imipenem,when wild type OmpC was expressed.It appears that the expression of wild type OmpC in the last isolate at least partially restores permeability allowing antibiotics into the cell and reducing the level of antibiotic resistance.This result indicates that at least one of the amino acid changes present in the last isolate 7.Conclusion Prliminary data suggest that changes in the amino acid sequence of the contribute to antibiotic resistance via the modulation of ompC active.