Mode of action of an antimicrobial biomaterial for use in hydrocephalus shunts.
OBJECTIVE
Infection remains a major complication of shunting for hydrocephalus. The causative bacteria, mainly staphylococci, gain access to the shunt at operation and colonize the shunt tubing. This leads to biofilm development requiring shunt removal. As there is no clear evidence to support antibiotic prophylaxis, we have developed an impregnated antimicrobial shunt material. This study aimed to elucidate its mode of action in terms of bacterial adherence and killing kinetics.


METHODS
Plain and impregnated material, with and without plasma protein conditioning film, were exposed to Staphylococcus epidermidis. Bacterial adherence was determined by scanning electron microscopy, chemiluminescence and culture. Time taken to kill 100% of bacteria (tK(100)) was determined by serial chemiluminescence, culture and the use of differential viability microscopy.


RESULTS
The antimicrobial material did not reduce bacterial adherence. However, 100% of attached bacteria were killed in 48-52 h, even in the presence of a conditioning film.


CONCLUSIONS
Impregnated antimicrobial material is likely to reduce shunt infection rates significantly without the risks and side effects of systemic antibiotics.
Bayston
Roger
R
Biomaterials-Related Infection Group, Division of Orthopaedic and Accident Surgery, C Floor West Block, University Hospital, Nottingham NG7 2UH, UK. roger.bayston@nottingham.ac.uk
Ashraf
Waheed
W
Bhundia
Catherine
C
D000890:Anti-Infective Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D001672:Biocompatible Materials / Q000494:pharmacology*; D002557:Cerebrospinal Fluid Shunts / Q000009:adverse effects*; D015169:Colony Count, Microbial; D006849:Hydrocephalus / Q000601:surgery; D008163:Luminescent Measurements; D008855:Microscopy, Electron, Scanning; D012826:Silicone Elastomers; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013997:Time Factors
D000890:Anti-Infective Agents; D001672:Biocompatible Materials; D012826:Silicone Elastomers