Staphylococcus saprophyticus urease: characterization and contribution to uropathogenicity in unobstructed urinary tract infection of rats

Abstract

We studied the biochemical properties of the urease of Staphylococcus saprophyticus and the possible role of the urease in experimental urinary tract infections. For this purpose, the nonhemagglutinating and nonadherent strain 9325, which was isolated from a case of symptomatic urinary tract infection, was used. The urease was shown to have a Km of 6.64 mM urea and a V.ax of 4.59 ,umol NH3 minm mg'. The enzyme was

Inhibition of urease activity in the urinary tract pathogen Staphylococcus saprophyticus

“…The enzyme showed simple Michaelis-Menten kinetics in standard hyperbolic plots and in linearized double-reciprocal Lineweaver-Burke plots. The apparent K m for urea was 7Á4 mmol l À1 , which again was similar to that previously reported (6Á64 mmol l À1 by Gatermann et al 1989; 9Á5 mmol l À1 by Sch€ afer and Kaltwasser 1994).…”

“…The specific activity of the S 105 fraction used in most of these experiments (3Á14 AE 0Á02 lmol min À1 mg protein À1 ) was comparable with that previously reported for crude extracts of Staph. saprophyticus (4Á59 lmol min À1 mg protein À1 by Gatermann et al 1989; 2Á40 lmol min À1 mg protein À1 by Sch€ afer and Kaltwasser 1994). The enzyme showed simple Michaelis-Menten kinetics in standard hyperbolic plots and in linearized double-reciprocal Lineweaver-Burke plots.…”

“…1d). Gatermann et al (1989) concluded that AHA was a noncompetitive inhibitor of urease activity, but a summary of various kinetic analyses by Amtul et al (2002) indicated that inhibition is usually competitive. A detailed kinetic analysis of the inhibition of the purified urease from Klebsiella aerogenes showed that AHA was a slow-binding competitive inhibitor with a K i of 5 lmol l À1 (Todd and Hausinger 1989).…”

“…The virulence factors of Staph. saprophyticus include the adhesive and autolytic protein Aas (Hell et al 1998), the adherence factor and haemagglutinin UafA (Kuroda et al 2005), the collagen-and fibronectin-binding protein SdrI (Sakinc ß et al 2006(Sakinc ß et al , 2009, the surface-associated lipase Ssp (Sakinc ß et al 2007), the serine-rich adhesin UafB (King et al 2011), and the enzyme urease (Gatermann et al 1989). The first group of proteins allows the bacteria to attach to uroepithelial cells; in some cases, Staph.…”

“…saprophyticus then may become internalized within them (Szabados et al 2008). The urease is a Ni 2+ -containing complex of three subunits that catalyzes the breakdown of urea into ammonia and carbonic acid (Gatermann et al 1989;Mobley and Hausinger 1989;Sch€ afer and Kaltwasser 1994;Mobley et al 1995). Ammonia raises the pH, leading to precipitation of salts and formation of urinary stones (Hedelin 2002).…”