The expression of lipopolysaccharide (LPS) and the binding capacity of anti-LPS monoclonal antibodies (MAbs) to grown in the presence or absence of subinhibitory concentrations of various antibiotics was studied. Four strains (three clinical blood-culture isolates and an isogenic, non-capsulate mutant of the O18:K1 parent) were grown in the presence of the β-lactam antibiotic, ampicillin, the aminoglycoside gentamicin, the fluoroquinolone ciprofloxacin and chloramphenicol. The techniques of silver staining, immunoblotting, whole-cell ELISA and flow cytometry were all used to monitor the expression of LPS on the bacteria and the binding of the anti-LPS MAbs. Treatment with ampicillin, chloramphenicol and ciprofloxacin resulted in enhanced binding of anti-core reactive MAbs to most strains. Overall, treatment with gentamicin produced the least effect on MAb binding. The presence of chloramphenicol decreased the expression of high molecular mass O-antigen or increased the expression of low molecular mass substituted LPS or both. These results further illustrate that LPS core, especially the inner-core region, becomes more accessible to antibodies when bacteria are grown in the presence of certain antibiotics. Possible synergy between antibodies and antibiotics for treatment of septicaemia and septic shock remains an intriguing possibility.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error