<i>In vitro</i> effectiveness of the antibiotic lock technique (ALT) for the treatment of catheter-related infections by <i>Pseudomonas aeruginosa</i> and <i>Klebsiella pneumoniae</i>

초록

Objectives: To determine the adequate antibiotic treatment, the concentration of antibiotics and the duration of treatment with the antibiotic lock technique ( ALT) for treatment of central venous catheter-related infections caused by Klebsiella pneumoniae and Pseudomonas aeruginosa. Methods: To investigate the in vitro effectiveness of four candidate antibiotics, amikacin, ceftazidime, cefepime and ciprofloxacin, two isolates of both K. pneumoniae and P. aeruginosa forming biofilms were selected. The polyurethane ( PU) films were incubated for 5 days to allow for bacterial colonization or biofilm production. After 5 days, the biofilm-formed PU films were exposed to each of the antibiotics ( 1, 5 and 10 mg/mL) for 1, 3, 5, 7, 10 and 14 days. The presence of the remaining bacteria in the biofilm was evaluated by the determination of viable cell counts. Results: All of the antibiotic treatments effectively removed P. aeruginosa biofilm within 3-5 days. Among the four antimicrobial agents tested in this study, ciprofloxacin showed superior bactericidal activity. The biofilms of both species were eliminated by 5 mg/mL ciprofloxacin within 3 days. In all cases, P. aeruginosa strains were removed more rapidly than K. pneumoniae strains. All antibiotics eradicated the susceptible K. pneumoniae strain, K144, within 5 days. One strain of K. pneumoniae, K139, which was resistant to all tested antibiotics, was not eradicated by amikacin ( 1, 5 and 10 mg/mL) or 1 mg/mL ceftazidime. Conclusions: These results show that ciprofloxacin, cefepime, ceftazidime and amikacin might be used as an effective ALT for treatment of catheter-related infections caused by antibiotic-susceptible K. pneumoniae and P. aeruginosa. This study suggests that the duration of treatment against catheter-related infection by Gram-negative bacilli can be reduced to 3-5 days when using antibiotics to which the organisms are susceptible in vitro, even at a concentration of 1 mg/mL.

키워드