TABLE 1.

Methods that have been used for measurement of biofilms on catheters

MethodBasic protocolaAdvantageLimitation(s)Reference
Roll-plateRoll the catheter tip over the surface of a blood agar plateEasy to useExamines only catheter outer surface, inaccurate126
Vortex, then viable countCatheter section in PBS is vortexed then cultured on different mediaMeasures intraluminal and extraluminal biofilmRecovery efficiency unknown202
Sonicate, vortex, then viable countCatheter section in TSB, sonicate then vortex, then culture on blood agarMeasures intraluminal and extraluminal biofilmRecovery efficiency unknown178
Sonicate, vortex, homogenize, then viable countCatheter section in PBS, sonicate/vortex repeatedly, then homogenize and culture on blood agarRecovery efficiency determinedMeasures intraluminal biofilm only53
Acridine orange direct stainingFollowing roll-plate method, catheter section is stained with acridine orangeAllows direct examination of catheterMethod does not allow quantification224
Endoluminal brushBrush is introduced into the implanted catheter, removed, placed into PBS, sonicated, and platedAllows examination of indwelling catheterEffect of procedure on patient and recovery efficiency unknown102
Alginate swabSwab introduced into the implanted catheter, removed, then streaked over a blood agar plateAllows examination of indwelling catheterEffect of procedure on patient and recovery efficiency unknown25
  • a PBS, phosphate-buffered saline; TSB, Trypticase soy broth.