1. Microbiology Gram-negative rods: Enterobacteriaceae Part III Karen Honeycutt, M.Ed., MT(ASCP)SM MT 418 Clinical Microbiology Student Laboratory Session

2. Microbiology Isolation Growth on BAP at 24 hrs, ambient air, CO 2 or anaerobically (facultative anaerobe) In general colony morphology: large, gray, beta- or nonhemolytic (normally larger than Staph, Strep, & Enterococci) GNR: Enterobacteriaceae

3. Microbiology Characteristics Utilization of glucose (OF Glucose): GNR: Enterobacteriaceae

4. Microbiology Characteristics Oxidase reaction: GNR: Enterobacteriaceae

5. Microbiology Characteristics GNR: Enterobacteriaceae Growth on MAC: Yes

6. Microbiology Characteristics GNR: Enterobacteriaceae Nitrate reduction: NO 3 to NO 2

7. Microbiology Characteristics GNR: Enterobacteriaceae Flagellar arrangement: peritrichous

8. Microbiology 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 GNR: Enterobacteriaceae

9. Microbiology 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? GNR: Enterobacteriaceae NO 3 to NO 2 Organism

10. Microbiology Biochemicals – Nitrate After nitrate rgt addition: Zinc will reduce nitrate to nitrite Add zinc dust What did the work? GNR: Enterobacteriaceae Zinc Therefore, the organism is:Nitrate negative

11. Microbiology Biochemicals – Nitrate After nitrate rgt addition: Zinc will reduce nitrate to nitrite Add zinc dust What did the work? GNR: Enterobacteriaceae Organism reduced nitrate to nitrogen gas Therefore, the organism is:Nitrate positive

12. Microbiology Identification – Categories Lactose “F” Lysine, phenyalalanine or tryptophane deaminase positive? Lactose NF & LDA/TDA/PDA negative GNR: Enterobacteriaceae

13. Microbiology Identification GNR: Enterobacteriaceae Motile HE KIA LIA ODC Indole Salmonella sp.Identification =

14. Microbiology Identification GNR: Enterobacteriaceae Indole CitrateLIA Motile ODC KIA Escherichia coliIdentification =

15. Microbiology Identification GNR: Enterobacteriaceae Indole ODC MacConkey KIA LIA Urea Proteus vulgarisIdentification =