Further Studies on Urease Production byProteusand Related Organisms

Abstract

In 1941 Rustigian and Stuart reported a new medium for the detection of urease production by organisms of the genus Proteus. These investigators tested 151 Proteus cultures in the medium and all were positive. One urea-positive X strain, however, did produce a urea-negative variant, which after prolonged cultivation in urea medium regained its ability to produce urease. Using this medium Ferguson and Hook (1943) found that 29 cultures with the biochemical reactions of Proteus produced urease, whereas 75 Salmonella cultures did not. This urea medium, which contains the hydrogen ion indicator, phenol red, demonstrates production of urease by a decrease in the hydrogen ion concentration. Proteus vulgaris and Proteus mirabilis gave a positive reaction, pH 8.1 or more, in about 8 hours, whereas Proteus morganii required about 36 hours. Rustigian and Stuart (1943) found that, except for one strain, Proteus rettgeri attacked urea rapidly in about 12 hours.To date in this laboratory over 600 Proteus cultures have been tested in the urea medium. In addition to the two exceptions noted above, one old stock culture, positive when first received, became urea-negative four years later, and two strains of P. rettgeri, which on first test produced only weak reactions, pH 7.2 to 7.4, in 48 hours after serial transfers in the medium were positive in 12 hours. An occasional freshly isolated strain of P. rettgeri may require as much as 18 to 24 hours to give a positive reaction. Rustigian and Stuart (1943) tested in their medium 689 cultures representing all genera in the family Enterobacteriaceae exclusive of Proteus. A number of coliform cultures, particularly Aerobacter strains, attacked urea slowly and weakly, pH 7.0 to 7.2 in five days. To date an additional 418 cultures representing all genera in the family Enterobacteriaceae except Erwinia and exclusive of Proteus have been tested. A number of coliform cultures attacked urea slowly and weakly, whereas several cultures (to be described later in this report) gave a strong reaction in 4 to 7 days. Thus, in tests on over 1,000 cuItures in the family Enterobacteriaceae other than Proteus no culture was positive in the time prescribed for Proteus, 8 to 48 hours.

Redirection of Metabolism in Response to Fatty Acid Kinase in Staphylococcus aureus

“…Urease activity was determined according to the method of Onal Okyay et al (45), with minor adjustments. Briefly, overnight cultures were inoculated to an optical density at 600 nm of 0.5 in Stuart's broth (46). The suspensions were incubated at 37°C with shaking at 250 rpm for 24 h. Following incubation, the suspensions were centrifuged at 3,160 ϫ g for 10 min and the supernatants were removed and scanned.…”

A Taxonomic Study of Gardnerella vaginalis (Haemophilus vaginalis) Gardner and Dukes 1955

“…Growth on nutrient agar (Oxoid) and on peptone starch dextrose agar (Dunkelberg & McVeigh, 1969) was recorded after 2 d. Biochemical tests. The benzidine test was carried out using the method of Deibel & Evans (1960), oxidase and urease activity were tested as described by KovAcs (1956) and Stuart et al (1945), respectively, catalase formation by adding a drop of H,O, (3 %, v/v) to a loopful of bacteria on a glass slide, hydrogen sulphide production by suspending lead acetate paper strips above BM agar slopes supplemented with cysteine hydrochloride (0-25 %, w/v) and the formation of ammonia from peptone after 2 and 7 d as described by Jones…”

Several Hfq‐dependent alterations in physiology of Yersinia enterocolitica O:3 are mediated by derepression of the transcriptional regulator RovM

“…The production of urease was verified in urea broth (0.1% peptone, 0.1% glucose, 0.5% NaCl, 0.2% KH 2 PO 4 , 0.00012% phenol red, 2% urea) (Stuart et al, 1945). The broth was inoculated with the overnight cultures and incubated at RT or 378C with shaking.…”