Antimicrobial pressure of ciprofloxacin and gentamicin on biofilm development by an endoscope-isolated Pseudomonas aeruginosa

Abstract

This work aims at characterizing endoscope biofilm-isolated (PAI) and 2 reference strain P. aeruginosa (PA) adhesion, biofilm formation and sensitivity 3 to antibiotics. The recovery ability of the biofilm-growing bacteria subjected to 4 intermittent antibiotic pressure [ciprofloxacin (CIP) and gentamicin (GM)], as 5 well as the development of resistance towards antibiotics and benzalkonium 6 chloride (BC), were also determined. 7 The capacity of both strains to develop biofilms was greatly impaired in the 8 presence of CIP and GM. Sanitization was not complete allowing biofilm 9 recovery after the intermittent cycles of antibiotic pressure. The environmental 10 pressure exerted by CIP and GM did not develop P. aeruginosa resistance to 11 antibiotics nor cross-resistance towards BC. However, data highlighted that 12 none of the antimicrobials led to complete biofilm eradication, allowing the 13 recovery of the remaining adhered population possibly due to the selection of 14 persister cells. This feature may lead to biofilm recalcitrance, reinforce 15 bacterial attachment, and re-colonization of other sites.