Table 7.

Factors involved in biofilm formation

Biofilm factor	Proposed role	Reference
Urease	Nickel metalloenzyme, local increase in pH causes mineral deposition which facilitates crystalline biofilms	5, 30, 356
MR/P fimbriae	Adherence and auto-aggregation; mutants are defective in biofilm formation	43, 152, 227, 228, 262
Fimbria 10 (PMI2210)	Adherence; mutant has increased biofilm (perhaps due to fimbrial cross-talk)	152
UCA, PMF, and ATF fimbriae	Mutations have varying effects on biofilms (CFU, matrix) depending on culture conditions	228
RcsBCD (RsbA) phosphorelay	Phosphorelay system that enhances extracellular polysaccharide production; may control biofilm formation via regulation of fimbriae	135, 152, 266
Pst transporter	High-affinity phosphate transporter, mutants are defective in biofilm formation	286
Capsule or extracellular polysaccharides	Facilitates mineral aggregation into crystalline biofilms and bacterial colonization	271–273
LPS	P. mirabilis with different LPS charges vary in biofilm formation; pmrI LPS modification mutant and waaE inner-core LPS biosynthetic protein mutant are biofilm-defective	268–270
RsmA	RNA-binding protein; expression of P. mirabilis rsmA in Escherichia coli suppresses biofilm	357
Ppk	Polyphosphate kinase; may act by regulating MR/P fimbriae	358
Hfq	RNA chaperone; may act by regulating MR/P fimbriae or motility	267
GlnE	Glutamate-ammonia ligase adenylyltransferase; mutant has increased biofilm	152
Lrp	Leucine-responsive regulator	152
NirB	Nitrate reductase; biofilm-deficient in crystal violet assay and takes longer to block catheters	152
Bcr	Multidrug efflux pump; mutant has increased biofilm but takes longer to block catheters	152
GltS	Sodium/glutamate symport carrier protein	152
PMI1551	Putative lipoprotein	152
PMI1608	Unknown; biofilm-deficient in crystal violet assay but blocks catheters more rapidly	152
PMI2861	Putative membrane protein	152
PMI3402	MuA-like DNA-binding protein; mutant has increased biofilm in crystal violet assay and blocks catheters more rapidly	152