[Antimicrobial activity in Staphylococcus epidermidis biofilms on polyvinyl chloride catheters].
OBJECTIVE
We have evaluated the effect of polyvinylchloride (PVC) catheters on the activity of eight antimicrobials. Secondly the activity of these antimicrobials against Staphylococcus epidermidis biofilms on PVC catheters was also studied.


METHODS
The MIC and MBC values of amikacine, clindamycine, cloxacilline, ciprofloxacine, vancomycine, teicoplanine, daptomycine and rifampicine was evaluated by a microdilution assay in the presence of 0.5 cm length segments of PVC catheters. Catheter segments with bacteria attached for different periods of time were used as inocula for the studies of antimicrobial activity against bacterial biofilms. Both slime producing and non-producing strains were evaluated.


RESULTS
The presence of PVC did not affect the activity of the antimicrobials evaluated against S. epidermidis. For the non-slime producing strains MBC values against sessile bacteria were significantly higher than those against planktonic bacteria. For the slime-producing strain MBCs of ciprofloxacine, amikacine and teicoplanine against both bacterial populations were similar. At high concentrations (16 x MBC), clindamycine was the only antimicrobial that sterilized non-slime producing S. epidermidis biofilms on PVC. Against the slime producing strains ciprofloxacine yielded the highest reduction on bacterial viability (99.9%).


CONCLUSIONS
S. epidermidis biofilms on PVC were more resistant to antimicrobials than planktonic bacteria. Slime production is not the only factor involved in this phenomenon.
Ramírez de Arellano
E
E
Departamento de Microbiología, Facultad de Medicina, Sevilla.
Pascual
A
A
Martínez-Martínez
L
L
Perea
E J
EJ
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D002404:Catheterization / Q000295:instrumentation*; D004352:Drug Resistance, Microbial; D004866:Equipment Contamination; D008826:Microbial Sensitivity Tests; D011135:Polysaccharides, Bacterial / Q000032:analysis; D011143:Polyvinyl Chloride; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000502:physiology
D000900:Anti-Bacterial Agents; D011135:Polysaccharides, Bacterial; D011143:Polyvinyl Chloride