hymecromone and indole

Two commercially available media recommended for the isolation and rapid identification of Escherichia coli from urinary tract infections were supplemented with L-phenylalanine and L-tryptophan. The non-selective medium proved suitable for the direct detection of lactose fermentation, beta-glucuronidase and phenylalanine deaminase activities, indole production and the oxidase test. It was highly efficient in making a presumptive identification at species level of the most common gram-negative urinary pathogens, E. coli, Proteus mirabilis and Pseudomonas aeruginosa, that account for c. 85% of all urinary isolates. Among the gram-positive isolates, most colonies were non-fluorescent and could be separated into staphylococci and enterococci on the basis of the catalase test. Fluorescent colonies were found to be Staphylococcus haemolyticus isolates, 61% of which were fluorescent. The selective medium proved suitable for the same biochemical tests, with the exception of indole, which was not visible against the red colour of the medium. Therefore, the differentiation of P. mirabilis from other Proteus-Providencia species was impossible on this medium.

Topics: Amino Acid Oxidoreductases; Culture Media; Electron Transport Complex IV; Fluorescent Dyes; Glucuronidase; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Hymecromone; Indoles; Sensitivity and Specificity; Urinary Tract Infections

A rapid method for presumptive identification of black-pigmented gram-negative anaerobic rods was developed. Using filter paper spot tests for indole production, sialidase, alpha-glucosidase, beta-glucosidase, alpha-fucosidase, and trypsinlike enzyme activities, 100% of Porphyromonas gingivalis, Prevotella intermedia, and Bacteroides levii and 89% of Prevotella corporis isolates were correctly identified to the species level. Porphyromonas asaccharolytica and Porphyromonas endodontalis could not be differentiated from each other but could be distinguished from all other species tested. Similarly, Prevotella denticola, Prevotella loescheii, and Prevotella melaninogenica could not be differentiated from each other. The methods described are based on 4-methylumbelliferone derivatives of the various substrates and are simple to perform, rapid (less than 15 min), and applicable to difficult-to-cultivate anaerobic rods.

Topics: alpha-L-Fucosidase; Bacteriological Techniques; Evaluation Studies as Topic; Glucosidases; Gram-Negative Anaerobic Bacteria; Hymecromone; Indoles; Neuraminidase; Pigmentation

Topics: 1-Propanol; Binding Sites; Chymotrypsin; Electron Spin Resonance Spectroscopy; Enzymes, Immobilized; Hymecromone; Indoles; Kinetics; Spin Labels

Escherichia coli is the most common gram-negative microbe isolated and identified in clinical microbiology laboratories. It can be identified within 1 h by oxidase, indole, lactose, and beta-glucuronidase tests. The oxidase and indole tests are performed as spot tests, and lactose fermentation is read directly from MacConkey agar. It was found that 4-methylumbelliferyl-beta-D-glucuronide could be incorporated directly into a modified MacConkey agar to directly detect the presence of beta-glucuronidase. Other characteristics of MacConkey agar were not affected. The incorporation of 4-methylumbelliferyl-beta-D-glucuronide into modified agar obviated the need for manufacture, quality control, and incubation of reagent-containing test tubes. The time needed to identify E. coli strains was reduced from 1 h to 5 min, and the ability to detect this species in mixed specimens was also enhanced.

Topics: Agar; Culture Media; Escherichia coli; Fermentation; Fluorescence; Glucuronates; Glucuronidase; Hymecromone; Indoles; Lactose; Oxidoreductases; Time Factors