Numerous laboratory findings indicate that microbial biofilms may be encountered in several types of human
infections, affecting the activity of
antimicrobial agents. We evaluated the clinical evidence regarding the effectiveness of antimicrobial
therapy for
infections documented to be biofilm-associated, by performing a review of 15 relevant studies, excluding dental and
eye infections. In a clinical trial, a significant difference was noted in the effectiveness of
antibacterial agents used for
catheter-related
urinary tract infections in which substantial bacterial adherence on uroepithelial cells was observed. In case series and case reports, 28 patients with biofilm-associated
infections documented by electron microscopy scanning were identified.
Infection sites included ear, urinary tract, CNS, bloodstream and
foreign body implantation site. Pseudomonas and Staphylococcus spp. were the predominant microorganisms among the bacterial or fungal causative pathogens. In 24 cases,
infections related to the presence of
foreign bodies. Treatment failure or recurrence was noted in all eight patients in whom targeted antimicrobial
therapy was instituted before
foreign body removal.
Foreign body removal coupled with antimicrobial
therapy was effective in all ten relevant cases. In four cases of native tissue
urinary tract infections, the outcome of the initial antimicrobial
therapy was poor. The limited available relevant clinical evidence indicates that conventional antimicrobial
therapy alone is not adequately effective against documented biofilm-associated
infections. Although some regimens might be more appropriate in this setting, further research on novel therapeutic strategies is needed to improve the outcome of patients with biofilm-associated
infections.