EFFECT OF ANTIBIOTICS ON NONGROWING PLANKTONIC CELLS AND BIOFILMS OF ESCHERICHIA-COLI

Several classes of antibiotics were assessed for activity against non-growing Escherichia coli and cells grown as a biofilm. Antibiotics which had activity against non-growing cells also showed some activity against biofilms. Cephamycins were more active than other cephalosponns, but the most effective antibiotics were imipenem and ciprofloxacin, which were also active against steady state biofilms However, none of the antibiotics studied was capable of completely eradicating a biofilm. These results suggest that growth rate plays a role in mediating resistance of biofilms to antibiotics. © 1994 The British Society for Antimicrobial Chemotherapy.