150 likes | 478 Views
Gram-negative rods: Enterobacteriaceae Part III. Karen Honeycutt, M.Ed., MT(ASCP)SM MT 418 Clinical Microbiology Student Laboratory Session. GNR: Enterobacteriaceae. Isolation. Growth on BAP at 24 hrs, ambient air, CO 2 or anaerobically (facultative anaerobe)
E N D
Gram-negative rods:Enterobacteriaceae Part III Karen Honeycutt, M.Ed., MT(ASCP)SM MT 418 Clinical Microbiology Student Laboratory Session Microbiology
GNR: Enterobacteriaceae Isolation • Growth on BAP at 24 hrs, ambient air, CO2 or anaerobically (facultative anaerobe) • In general colony morphology: large, gray, beta- or nonhemolytic(normally larger than Staph, Strep, & Enterococci) Microbiology
GNR: Enterobacteriaceae Characteristics Utilization of glucose (OF Glucose): Microbiology
GNR: Enterobacteriaceae Characteristics Oxidase reaction: Microbiology
GNR: Enterobacteriaceae Characteristics Growth on MAC: Yes Microbiology
GNR: Enterobacteriaceae Characteristics Nitrate reduction: NO3 to NO2 Microbiology
GNR: Enterobacteriaceae Characteristics Flagellar arrangement: peritrichous Microbiology
GNR: Enterobacteriaceae Biochemicals – ONPG Rapid Lactose “F” requires permease enzyme ONPG similar to lactose, doesn’t require permease enzyme to enter the organism ONPG + beta-galactosidease = yellow color Slow lactose fermenter (appear as NLF on MAC, KIA, etc.) and Rapid lactose fermenter (appear as LF on MAC & KIA are POSITIVE Microbiology
GNR: Enterobacteriaceae Nitrate to Nitrite to Nitrogen Gas Inoculate to media with nitrate Incubate test 18-24 hrs Add reagent Reagent reacts with nitrite to form red color. This reaction indicates: What did the work? NO3 to NO2 Organism Microbiology
GNR: Enterobacteriaceae Biochemicals – Nitrate After nitrate rgt addition: Zinc will reduce nitrate to nitrite Add zinc dust What did the work? Zinc Therefore, the organism is: Nitrate negative Microbiology
GNR: Enterobacteriaceae Biochemicals – Nitrate After nitrate rgt addition: Zinc will reduce nitrate to nitrite Add zinc dust What did the work? Organism reduced nitrate to nitrogen gas Therefore, the organism is: Nitrate positive Microbiology
GNR: Enterobacteriaceae Identification – Categories Lactose “F” Lysine, phenyalalanine or tryptophane deaminase positive? Lactose NF & LDA/TDA/PDA negative Microbiology
ODC LIA KIA Indole GNR: Enterobacteriaceae Identification Motile HE Identification = Salmonella sp. Microbiology
ODC LIA Citrate KIA Indole GNR: Enterobacteriaceae Identification Motile Identification = Escherichia coli Microbiology
MacConkey ODC KIA LIA Urea Indole GNR: Enterobacteriaceae Identification Identification = Proteus vulgaris Microbiology