HEMAGGLUTININ, UREASE, AND HEMOLYSIN PRODUCTION BY PROTEUS-MIRABILIS FROM CLINICAL SOURCES

Proteus mirabilis, a common cause of urinary tract infection, can lead to serious complications including pyelonephritis. Adherence factors, urease, and hemolysinmay be virulence determinants. These factors were compared for bacteria cultured from 16 patients with acute pyelonephritis and 35 with catheter-associated bacteriuria and for 20 fecal isolates. Pyelonephritis isolates were more likely (P<.05) to express the mannose-resistant/Proteus-like (MRIP) hemagglutinin in the absence of mannose-resistant/Klebsiella-like (MR/K.) hemagglutinin than were catheter-associated or fecal isolates. Pyelonephritis isolates produced urease activity of 63 ± 27 (mean ± SD) μmol of NH3/min/mg of protein, not significantly different from catheter-associated or fecal isolates. Hybridization of Southern blots of P. mirabilis chromosomal DNA with two urease gene probes demonstrated that urease gene sequences were conserved in all isolates. Geometric mean of reciprocal hemolytic titers for pyelonephritis isolates was 279; for urinary catheter isolates, 18.0; and for fecal isolates, 55.7 (not significantly different, P >.1). Although in vivo expression of urease and hemolysin may not bereliable indexes of virulence, MR/P hemagglutination in the absence of MR/K hemagglutination may be necessary for development of pyelonephritis. © 1990, University of Chicago. All rights reserved.