Ved komplicerede urinvejsinfektioner kan dannelse af biofilm desuden spille en vigtig rolle, fordi følsomheden af de patogene bakterier her er flere gange lavere end af planktoniske celler eller renkulturceller.
In addition, in complicated UTI, biofilm formation may play an important role where susceptibility of the pathogens is several folds reduced compared with planctonic or pure culture cells.