Comparative in vitro efficacies of various antipseudomonal antibiotics based catheter lock solutions on eradication of Pseudomonas aeruginosa biofilms

Antibiotic lock technique (ALT) may be an adjunct therapy in treating catheter-related infections. The aim of this study was to determine the in vitro stability and efficacy of colistin, meropenem and levofloxacin alone or in combination with clarithromycin or heparin lock solutions against biofilm embedded Pseudomonas aeruginosa strains. The efficacy of antibiotic lock solutions was tested in an in vitro catheter biofilm model against P. aeruginosa isolated from catheter-related bacteremia. We observed that the use of meropenem, levofloxacin or colistin as a lock solution had potent bactericidal effects and could be prevented bacterial regrowth at 96 or 72 hours, respectively. When the tested antibiotics were used in combination with clarithromycin, the combinations were significantly more effective and rapid in eliminating P. aeruginosa colonization in biofilm than each of the antibiotics were used alone. Moreover, tested antibiotics in combination with heparin were not significantly different for killing effect against PA-1 and PA-27853 compared with that of each antibiotics alone. Tested catheter lock solutions may have promising adjuvants for treating infections caused by P. aeruginosa

Investigation of the effects of various antibiotics against Klebsiella pneumoniae biofilms on in vitro catheter model

Klebsiella pneumoniae continues to be an importantcause ofcommunity-acquired and nosocomial infection. This bacterium can cause catheterrelated infections by forming biofilmon the surface of catheter. The aim of our study is to determine the in vitro stability and efficacy of colistin, ciprofloxacin, tobramycin, doripenem and tigecycline alone, or in combination with clarithromycin or esomeprazole, as 24-h lock solutions against biofilm-embedded K. pneumoniae strains. The efficacy of antibiotic lock solutions was tested in an in vitro catheter biofilm model against K. pneumoniae. In our study, we observed that the use of doripenem and tobramycin as a lock solution had potent bactericidal effects. When colistin was used in combination with clarithromycin or esomeprazole, the combinations had a synergistic effect. No antagonistic effect was observed. The findings of our study have important information for effectiveness of tested antibiotic lock solution in the catheter-related infections with K. pneumoniae