The ability of a Proteus mirabilis strain to invade the bloodstream is independent of its proticine production/proticine sensitivity type

Summary Proteus mirabilis strains frequently infect the upper urinary tract and some progress to invade the bloodstream. In an attempt to determine if these were features only of particular strains of P. mirabilis, isolates from the blood of 38 unrelated patients, many of whom had an underlying urinary tract infection, and eight from different sources and sites within the upper urinary tract, were analysed by proticine production/proticine sensitivity (p/s) typing. Twenty-six different p/s types were found among the 38 isolates from blood and seven among the eight isolates from the upper urinary tract. The p/s types found previously to be associated frequently with virulence for the upper urinary tract were not found. Analyses of the frequency of occurrence of the different p/s types and of their distribution showed no evidence that the p/s characteristics of a P. mirabilis strain conferred any advantage on its ability to infect the upper urinary tract or invade the bloodstream.