Non-Fermentative Gram Negative Bacilli Flashcards
Non - fermenting gram negative bacilli general information
- Aerobic or Anaerobic?
- Where are they generally found?
- Do they colonize?
- Aerobic and non-spore forming
- Ubiquitous in nature
- Yes they colonize
Three major pathways where bacteria can metabolize glucose
- Embden-Meyerhof-Parnas Pathway
- Entner-Douderoff Pathway
- Hexose Monophosphate Pathway
Two facts about Fermentation
- no oxygen required
2. End products are strong acids in large amounts
Two facts about Oxidation
- oxygen required
2. End products are weak acids in small amounts
4 primary criteria for identification of nonfermenters
- Lack of glucose fermentation
- Positive Cytochrome Oxidase Test
- MacConkey Agar (will be clear unless pigmented)
- Gram Stain Morphology
5 types of OF media
- Oxidative - Fementative
- 1% Carbohydrate
- 0.2% Peptone
- 0.3% Agar
- Brom-Thymol Blue
Brom-Thymol Blue
- What color when its an acidic, basic, and neutral pH?
acid = yellow alkaline = blue neutral = green
Procedure for inoculation of OF media
- requires 2 tubes
- stab halfway down 3-4 times
- layer one with mineral oil
- incubate in ambient air incubator
Oxidizer/Saccharolytic media interpretations
- what color in what tube
Yellow in open tube, no change or blue in oiled tube
Non-oxidizer/Asaccharolytic media interpretations
- what color what tube?
no change or blue in both tubes
Fermenter media interpretations
- What color what tube?
yellow in both tubes, or yellow in oiled tube only
Other tests used for nonfermenter identification (what do they do?)
- catalase
- nitrate
- aesculin
- motility
catalase: add hydrogen peroxide and see if it bubbles
nitrate: test for NO3 to N2
* aesculin: black if it breaks down bile (positive); loss of florescence (positive)
motility: test for flagella or not
Other tests used for nonfermenter identification (what do they do?)
- Salmonella-Shigells Agar
- Cetrimide Agar
- Litmus Milk
- Gelatin
S-SA: help isolate organisms base on grow or no growth
CA: ?
Litmus Milk: measures enzymes that break down proteins (peptizing?); acid- red, alk-blue or purple
Gelatin: Looking for gelatinase
Other tests used for nonfermenter identification (what do they do?)
- Fluorescent Agar
- Technicolor Agar
Flo: promotes production or pyoverdin in nonfermenters (yellow, green)
Tech: promotes production of other pigments
Pigments produced by the technicolor agar (what color?)
- pyocyanin
- Pyorubin
- Melanin
- Carotenoids
- Violacein
- Phenazine
- pyocyanin: blue
- Pyorubin: red
- Melanin: brown
- Carotenoids: orange
- Violacein: violet
- Phenazine: yellow
Other tests used for nonfermenter identification (what’s its point?)
- Tryptone Glucose Yeast Extract Agar (TGY)
TGY: differentiate species by a determine range of temperatures; tests at 25, 35, and 42 degrees
Other tests used for nonfermenter identification (what are its parts and what do we use for indole? )
- KIA Series
- Citrate
- LOA’s
- Indole: xylene extraction, Erhlich’s
Why do we use Erhlich for Indole
Nonfermenters grow slowly and produce little of everything
- the Erhlich procedure is more sensitive
Identification Kits
- 3 types of manual kits
- API 20NE: bioMerieux
- Crystal E/NF: Bection Dickinson
- Rapid NF Plus: Remel
Identification Kits
- 3 types of automated
- Vitek-GN Card: bioMerieux
- MicroScan: Dade MicroScan Inc.
- Phoenix: Becton Dickinson
Most common nonfermenter in clinical lab
Pseudomonas aeruginosa
Where is Pseudomonas aeruginosa commonly found?
Ubiquitous but found in aqueous solutions
- Disinfectants
- Soaps
- Eyedrops
- Dialysis Fluids, nebulizers, catheters
9 infections of Pseudomonas aeruginosa
- Bacteremia
- Endocarditis
- Pulmonary
- Ear
- Burns
- Urinary Tract
- Gastroenteritis
- Eye
- Folliculitis
Pathogenicity of Pseudomonas aeruginosa
- Pili
- Capsules: alginate (slimy)
- Exotoxins
- Endotoxins
