![]() In addition, real-time PCR and FISH allowed identification of morphologically nontypical isolates of P. In conclusion, molecular methods are superior over biochemical tests for identification of gram-negative, oxidase-positive rods in CF patients. aeruginosa-specific probe had a sensitivity and specificity of 100%. Bacteria with Oxidase Positive / Negative. aeruginosa-specific probe showed a sensitivity and specificity of 98.1% and 100%, respectively. Negative reaction : absence of coloration or coloration beyond 30 seconds. Therefore, rapid molecular diagnostic techniques like real-time PCR and fluorescence in situ hybridization (FISH) were evaluated in this particular group of bacteria for identification of the clinically most relevant pathogen, P. Version 1.0 of the database incorporates 71 genera and species of Enterobacteriaceae, 11 genera and species of oxidase-positive glucose-fermenting bacilli. Fifty-two isolates of morphological and biochemical nontypical Pseudomonas aeruginosa, representing 59% of all isolates investigated, were not identifiable or misidentified in the API 20NE. Even API results classified as "very good identification" or "good identification" showed a high rate of misidentification (67% and 84%). Agreement between the API and the 16S rRNA gene sequencing results was high only in isolates with an API result classified as "excellent identification". Exceptions do exist to these general rules See Biochemical Tests for Gram Negative Organism ID Job aid for positive and negative result reference. ![]() spp: Oxidase positive, Urease positive, Catalase positive. Which gram-negative rods are lactose fermenters E. Oxidase negative, Catalase negative or weakly positive. Lactose-negative gram negative rods may suggest Pseudomonas. Pseudomonas aeruginosa is a motile (single polar flagella) gram-negative bacillus that is oxidase positive and a strict aerobe. The API 20NE allowed correct identification of the bacterial species in 15 out of 88 (17%) isolates investigated. Lactose-positive gram negative rods may suggest Enterobacteriaceae, such as E. aeruginosa, from respiratory secretions of CF patients. Therefore, we compared the results of biochemical identification by API 20NE with 16S rRNA gene sequencing in 88 gram-negative, oxidase-positive rods, other than morphologically and biochemically typical P. ![]() Phenotypic identification of gram-negative bacteria from Cystic Fibrosis (CF) patients carries a high risk of misidentification. ![]()
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