In vitro evaluation of the antibiotic lock technique (ALT) for the treatment of catheter-related infections caused by staphylococci.
OBJECTIVE
To investigate appropriate antimicrobial agents, the optimal concentration and treatment duration for the antibiotic lock technique (ALT) to treat catheter-related infections caused by Staphylococcus epidermidis and Staphylococcus aureus.


METHODS
We evaluated the bacterial killing activity of vancomycin, teicoplanin, ciprofloxacin, rifampicin, cefazolin, gentamicin, nafcillin and erythromycin against biofilms formed by two strains of S. aureus and two strains of S. epidermidis. The effectiveness of the antibiotic lock was assayed after exposure to antibiotics (1, 5 and 10 mg/mL) for 1, 3, 5, 7, 10 or 14 days using an in vitro model of biofilms on polyurethane film.


RESULTS
The biofilms were completely sterile after exposure to vancomycin (5 mg/mL) for 5 days and teicoplanin (5 and 10 mg/mL) for 7 days. Ciprofloxacin and rifampicin (both 5 mg/mL) achieved eradication of the biofilms of both staphylococcal species more rapidly than vancomycin or teicoplanin. Significant biofilm eradication was not achieved with cefazolin, nafcillin, gentamicin and erythromycin at any of the time exposures examined.


CONCLUSIONS
The data suggest that 5 mg/mL vancomycin, ciprofloxacin or rifampicin can eradicate S. epidermidis and S. aureus biofilms within 5 days. These findings warrant prospective clinical trials for the evaluation of the clinical efficacy of ALT for less than 10 days.
Asian-Pacific Research Foundation for Infectious Diseases (ARFID) Seoul, Korea.
Ji-Young
JY
Lee
Kwan Soo
KS
Ko
Kyong Ran
KR
Peck
Won Sup
WS
Oh
Jae-Hoon
JH
Song
D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D018441:Biofilms / Q000187:drug effects*; D002408:Catheters, Indwelling; D006801:Humans; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000209:etiology / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000187:drug effects*; D013212:Staphylococcus epidermidis / Q000187:drug effects*; D013997:Time Factors
D000900:Anti-Bacterial Agents