Vancomycin is a glycopeptide antibiotic that inhibits bacterial cell wall synthesis by binding to the D-alanyl-D-alanine terminus of the peptidoglycan precursor. E. coli is generally susceptible to vancomycin, but there have been reports of vancomycin-resistant strains of E. coli.
The resistance of E. coli to vancomycin is primarily due to the modification of the peptidoglycan precursor, which reduces the binding affinity of vancomycin to the cell wall. Specifically, vancomycin-resistant E. coli strains have modified their cell wall precursor by substituting D-alanine with D-lactate, which decreases the binding affinity of vancomycin to the cell wall and reduces its effectiveness.
Moreover, some E. coli strains can acquire vancomycin resistance genes through horizontal gene transfer mechanisms such as conjugation, transduction, and transformation. These genes encode enzymes that modify the peptidoglycan precursor or alter the permeability of the bacterial membrane, allowing them to resist vancomycin.
It is important to note that while vancomycin resistance in E. coli is rare, it poses a significant threat to public health as it limits treatment options for infections caused by this bacterium.
In conclusion, E. coli can become resistant to vancomycin through modifications in its cell wall precursor or through acquiring resistance genes through horizontal gene transfer mechanisms.