Bacterial Adherence in Foreign Body Infection

Summary

Foreign body infection is a special clinical problem because with few exceptions standard treatment (debridement and antibiotics) normally effective for most bodily infections is ineffective. Prosthetic implants are common and infection is the second most common reason for failure. The reason that prosthetic infections fail to resolve with antibiotic therapy has remained a mystery, but new insights are beginning to penetrate this enigma. Antibiotics will not kill sensitive bacteria in a test tube when they are attached to an object in the test tube or the walls of the test tube. Evidence suggests that once attachment has taken place bacteria may proliferate in the presence of bactericidal antibiotic concentrations. The extracellular matrix of bacteria, glycocalyx, may in some instances, such as with Staphylococcus epidermidis, enhance survival of bacteria. Glycocalyx appears to promote rapid attachment to foreign bodies under some circumstances. Attachment itself seems to confer upon the bacteria the ability to survive normally lethal concentrations of antibiotics. Critical insights as to the mechanism for this invulnerability are likely to result from investigating genomic expression of the bacteria at the time of attachment.