Urease Activity of Enterobacteriaceae: Which Medium to Choose

Abstract

Detection and intensity of urease activity in enterobacteriaceae greatly varies as a function of the media or techniques used, or both. A comparative investigation on several solid and liquid media led us to the following conclusions. (i) Detection of Proteus spp. can be adequately performed with the highly selective solid medium described by Cook (1948), as well as with the different liquid media described (Stuart standard and rapid media; Elek medium). (ii) Detection of Klebsiella should be based upon urease production on solid media with low buffer capacity (Christensen, 1946). (iii) For the identification of Yersinia , either the solid Christensen urea agar or the rapid Elek technique give optimal results.

Red cabbage extract-mediated colorimetric sensor for swift, sensitive and economic detection of urease-positive bacteria by naked eye and Smartphone platform

“…This case indicates that the color imaging processing system detects the presence of the corresponding pathogen when even the human eye fails. It is worth to mention that our colorimetric results uncovered much urease production performance of K. pneumoniae strains compared to P. mirabilis strains 24 .…”

Potential for breath test diagnosis of urease positive pathogens in lung infections

“…A lowered cytosolic pH directly activates the urease, which shows a pH maximum of 5.5 (in permeabilized cells) [164] allowing instantaneous protection from low pH as it does not depend upon transcription and translation. Proteus mirabilis and other Proteus species are urease positive [130,[165][166][167] and are relatively rare lung pathogens [168,169]. The enzyme has been isolated and the K m for urea reported as 13 mM, higher than many other lung pathogens, but in accord with its usual role as a urinary tract pathogen.…”

Proteus mirabilis and Klebsiella pneumoniae as pathogens capable of causing co-infections and exhibiting similarities in their virulence factors

“…Urease is also produced by other Enterobacterales which are a part of human intestinal microflora but the level of the enzyme activity is species-specific and varies with the medium used ( Vuye and Pijck, 1973 ). For example, among Escherichia coli strains, only 1% have been identified as urease-positive ( Konieczna et al., 2012 ).…”

“…strains, urease action is delayed more than in the case of Klebsiella spp. strains ( Vuye and Pijck, 1973 ). Despite the fact that Providencia morganii and P. rettgeri are regarded to be as effective urease producers as P. mirabilis , the urease activity, structure and genetic organization of the enzyme genes are well-known for Klebsiella and Proteus spp.…”