Question | Answer |
Enterobacteriaceae | gram postive rods, non spore forming, grow on peptone media, grow on macconkey agar, usually faculatative anaerobes, ferment glucose with gas production, catalase +, oxidase -, reduce nitrate. |
Friedlander's Bacillus ("brick red" sputum) | K. pneumoniae |
endotoxin shock (symptoms) | fever, leucopenia, capilary hemorrhage, hypotension, circulatory collapse |
limulus lysate assay | reagent prepared from the ameboctytes of the horseshoe crab (Limulus polyphemus). Tests for endotoxin shock |
lipid A | toxic portion of lipopolysaccharide of gram negative cell wall that produces endotoxin |
Flagellar antigen | H antigen |
Capsular antigen | K antigen |
Somatic antigen | O antigen |
Ewig | developed the concept of tribes with Enterobacteriaceae |
tribe I | Eschericheae |
tribe II | Edwardsielleae |
tribe III | Salmonelleae |
tribe IV | Citrobactereae |
tribe V | Klebsielleae |
tribe VI | Proteeae |
tribe VII | Yersinieae |
Methyl Red Test | tests for mixed acid fermentation (red below pH 4.4 and yellow above pH 6.2) |
Voges Proskauer Test | tests for butanediol fermentation |
Embden-Meyerhof pathway | series of glycolytic cleavages that result in the production of pyruvic acid from glucose |
ONPG-galactose test | tests for beta galactosidase and beta galactoside permease, (+ = yellow, - = colorless) |
enzyme needed for fermentation of lactose | beta galactoside permease and beta galactosidase |
Kligler Iron Agar (KIA) | contains lactose and glucose (10:1), ferrous sulfate, and phenol red |
KIA: alkaline slant (red)/ alkaline butt(red) | no carbohydrate fermentation |
KIA: alkaline slant (red)/ acid butt (yellow) | glucose fermented but lactose not (ex. Shigella) |
KIA: alkaline slant (red)/ acid butt (black) | glucose fermented but lactose not, production of hydrogen sulfide (Salmonella, Citrobacter, and Proteus) |
KIA: acid slant (yellow)/ acid butt (yellow) | glucose and lactose fermented (ex. E. coli, Klebsiella, and Enterobactor) |
MacConkey Agar | differential media for selection and recovery of Enterobacteriaceae |
MacConkey Agar: red colonies | strong lactose fermenters (ex. Escherichia, Klebsiella, Enterobactor) |
MacConkey Agar: pink colonies | weak lactose fermenters (ex. Citrobactor, Providencia, Serratia, and Hafnia) |
MacConkey Agar: colorless colonies | Non lactose fermenters (ex. Proteus, Edwardsiella, Salmonella, Shigella) |
Eosin Methylene Blue Agar | differentiates between lactose and non lactose fermenters (similar to MacConkey Agar in the detection and differentiation of Enterobacteriaceae) |
Eosin Methylene Blue Agar: green black colonies with metallic sheen | Strong lactose fermenters (E. coli) |
Eosin Methylene Blue Agar: purple colonies | weak lactose fermenters |
eosin methylene Blue Agar: purple to black colonies | sucrose fermenters and non lactose fermenters (ex. Yersinia enterocolitica) |
Hektoen Agar | highly selective for recovery for Enterocacteriaceae (green media). Good for enhanced recovery of Salmonella and Shigella from material with heavy numbers of normal flora. |
Hektoen Agar: bright orange, pink | rapid lactose fermenters (E. coli) |
Hektoen Agar: blue green colonies with black centers | Salmonella |
Hektoen Agar: more green colonies | Shigella |
Xylose lysine deoxycholate agar | highly selective media for isolation of enterics, less inhibitory than HE agar (low conc. of bile salts), designed to detect shigellae in feces after enrichment in gram-negative broth. |
Selenite Broth | used for recovery of Salmonella and Shigella from feces or sewage. maintain predominant E. coli in lag phase |
ingredient in Selenite broth that inhibits E. coli | sodium selenite |
indole | produced by the breakdown of trptophan, also produce is pyruvate and ammonia |
tryptophanase | enzyme that breaksdown tryptophan |
Kovac's reagent | p-dimethylaminobenxaldehyde, used in the detection of indole (red = +) |
Citrate utiliatization | tests ability of strain to utilize citrate as a sole carbon and energy source |
Citrate utilization: positive result | blue color |
E. coli | indole +, methyl red +, VP -, Citrate - |
Enterobacter aerogenes | indole -, methyl red -, VP +, citrate + |