Proteus mirabilis fimbriae: identification, isolation, and characterization of a new ambient-temperature fimbria

Abstract

Urinary tract infections involving Proteus mirabilis may lead to complications including bladder and kidney stones, acute pyelonephritis, and bacteremia. This bacterium produces a number of fimbriae, two of which, MR/P fimbria and P. mirabilis fimbria, have been shown to contribute to the ability of this pathogen to colonize the bladder and kidney. We have now purified and characterized a previously undescribed fimbria of P. mirabilis, named ambient-temperature fimbria (ATF). Electron microscopy of a pure preparation and immunogold labeling of cells demonstrated that ATF was fimbrial in nature. The major fimbrial subunit of ATF has an apparent molecular weight of 24,000. The N-terminal amino acid sequence, E-X-T-G-T-P-A-P-T-E-V-T-V-D-G-G-T-I-D-F, did not show significant similarity to that of any previously described fimbrial protein. ATF was expressed by all eight P. mirabilis strains examined. Culture conditions affected expression of ATF, with optimal expression observed in static broth cultures at 23 degrees C. This fimbria was not produced by cells grown at 42 degrees C or on solid medium. Expression of ATF did not correlate with mannose-resistant/Proteus-like (MR/P) or mannose-resistant/Klebsiella-like (MR/K) hemagglutination and represents a novel fimbria of P. mirabilis.

Repression of motility during fimbrial expression: identification of 14 mrpJ gene paralogues in Proteus mirabilis

“…Both MR/P fimbriae and UCA/NAF were also found to vary in expression within a swarming colony of P. mirabilis (Latta et al, 1999). The ATF are preferentially expressed during static culture at 23°C in rich medium, but not culture at 42°C in minimal medium, or when grown on solid medium (Massad et al, 1994b). Mannose-resistant/ Klebsiella-like (MR/K) fimbriae, which are likely PMF , are known to be produced during static culture (Adegbola et al, 1983); however, because MR/K fimbriae were only characterized by erythrocyte binding (i.e.…”

“…The remaining 12 potential fimbriae encoded by P. mirabilis (Pearson et al, 2008) remain uncharacterized. Multiple types of fimbriae can be expressed simultaneously (Adegbola et al, 1983;Massad et al, 1994b;Tolson et al, 1995). It is intriguing to consider whether MrpJ or its paralogues may contribute to regulation of fimbrial expression in addition to regulation of flagella, particularly in light of the different fimbrial appearances exhibited by mrpJ or ucaJ overexpression strains (Fig.…”

“…These swarmer cells also exhibit reduced expression of fimbriae (Mobley et al, 1996;Jansen et al, 2003), suggesting possible co-ordinate expression between flagella and fimbriae. Prior to the sequencing of the P. mirabilis genome, expression of five different fimbriae had been documented in P. mirabilis: MR/P fimbriae (Adegbola et al, 1983;Bahrani et al, 1994), uroepithelial cell adhesin (UCA, also known as non-agglutinating fimbriae or NAF) (Wray et al, 1986;Cook et al, 1995), P. mirabilis fimbriae (PMF) (Adegbola et al, 1983;Massad et al, 1994a), ambient temperature fimbriae (ATF) (Massad et al, 1994b) and P. mirabilis P-like pili (PMP) (Bijlsma et al, 1995). The MR/P fimbria is encoded by an operon containing nine genes (Bahrani et al, 1994).…”

Functional analysis of Escherichia coliYad fimbriae reveals their potential role in environmental persistence

“…Indeed, we showed that yad is more strongly expressed at 308C and temperatures below that. Temperature is an important regulatory condition known to modulate multiple virulence factors, as well as other bacterial fimbriae which expression are higher at lower temperatures sometimes through the action of the H-NS silencing protein (Massad et al, 1994). In addition to H-NS temperature-dependent regulation, thermosensing mechanisms can act at different levels.…”

Virulence of a Proteus mirabilis ATF isogenic mutant is not impaired in a mouse model of ascending urinary tract infection

“…Mannose-resistant Proteus-like ¢mbriae (MR/P) and Proteus mirabilis ¢mbriae (PMF) have been proposed as important for virulence in UTI caused by P. mirabilis [3,10]. Ambient temperature ¢mbriae (ATF) were so named as their optimal expression temperature is 23³C (ambient temperature) [11]. The nucleotide sequence of the atf gene cluster revealed three genes: atfA, encoding a structural subunit (AtfA), atfB, encoding a chaperone (AtfB), and atfC, encoding a molecular usher (AtfC) [12].…”