NonFermenting and Miscellaneous Gram (-) Bacilli

• General Characteristics of NF

  • Prefer moist or wet environment
  • considered opportunistic
  • fail to acidify an oxidative fermentative medium
  • TSI will remain k/k (alkaline) (red/red)
• Triple Sugar Ion (TSI) Agar

  • used for carbohydrate utilization
  • Slanted - lactose and sucrose
  • Butt portion - glucose fermentation
• Hugh and Leifson Medium

  T(1)

  • w/ sterile mineral oil
  • anaerobic environment
  • yellow = it acidifies the tube = the organism is a fermenter
• Hugh and Leifson Medium

  T(2)

  • w/o mineral oil
  • remained open when acidifying the tube
  • organism is oxidizer
• non-oxidizer

  asaccharolytic
• All species except B. mallei are motile, having one or several polar flagella
• Optimum temperature of Non-fermenters range at 30 to 37 degrees (mesophilic)
• Non-Fermenters

  • MAC (-) : Acidovorax facilis
  • Catalase (+) : Pseudomonas spp.
• Biochemical Characteristics and Identification

  • Oxidase (+) reaction although the reaction can be weak and variable.
  • Non reactivity in 24 hours in commercial multitest kit system used for identification of enteribacteriaceae
  • No acid production in slant, butt of TSI or KIA
• Biochemical Characteristics and Identification

  • Resistance to a variety of classes of antimicrobial agents such as
  • Aminoglycerides
  • Third generation cephalosporins
  • Penicillin
  • Fluoroquinolones
• Different classification system

  • growth on MAC agar
  • Base reaction with oxidase test
  • Result of glucose oxidation fermentation test
• Pigmentation: YELLOW

  • Chryseobacterium and Elizabethkingia spp.
  • Sphingomonas paucimobilis
  • Pseudomonas luteola
  • Pseudomonas oryzihabitans
  • Sphingobacterium spp.
  • Pseudomonas stutzeri
• Pigmentation: PINK

  • Methylobacterium spp.
  • Roseomonas spp.
• Pigmentation: PURPLE (MAC)

  • Acinetobacter sp.
• Pigmentation: BLUE - GREEN

  • Pseudomonas aeruginosa
• Pigmentation : VIOLET

  • Chromobacterium violaceum (fermenter)
• Pigmentation : Lavender - Lavender - green (Blood AgarAgar)

  • Sternotrophomonas maltophilia
• Pigmentation : TAN (occasionally)

  • P. stutzeri
  • Shewanella putrefaciens
• Wrinkled Colonies

  • P. stutzeri
  • P. oryzihabitans
  • Burkholderia pseudomallei
• Odor : SWEET

  • Alcaligenes faecalis
  • Mvroides odoratus
  • P. aeruginosa (fruity: grapes)
• Odor: POPCORN

  • EO-4
  • Neisseria zoodegmatis
• Non-Motile

  • Acinetobacter spp.
  • Moraxella spp.
  • Chryseobacterium and Elizabethkingia spp. (weak fermenters)
  • Sphingibacterium spp.
  • Oligella spp.
• Oxidase Negative

  • Acinetobacter spp.
  • S. maltophilia
  • Pseudomonas luteola and P. oryzihabitans
  • Pseudomonas cepacia
• H2S Positive

  • Shewanella putrefaciens
• Pseudomonas

  • Gram negative bacillus / coccobacillus
  • strictly aerobic metabolism
  • motile with polar flagellum or polar tuft
  • Oxidase (+) except: P. luteolus and P. oryzihabitans
  • Catalase (+)
  • Usually grows in MAC agar
  • Usually an oxidized of carbohydrates but some species are asaccharolytic
  • Produce water soluble pigment
• Pigment

  • Yellow-Green = Pyoverdin
  • Blue = Pyocyanin
  • Bright green = Pryoverdin + Pyocyanine
• Pseudomonas Fluorescent Group

  able to produce a yellow - green pigment (Pyoverdin)

  • P. aeruginosa
  • P. fluorescens
  • P. putida
  • P. monteilii
  • P. veronii
  • P. mosselii
• Pseudomonas Non-Fluorescent Group

  • P. stutzeri
  • P. alcaligenes
  • P. mendocina
  • P. pseudoalcaligenes
  • P. oryzihabitans
  • P. luteola
• Pseudomonas aeruginosa

  • pyoverdine & pyocyanin
  • motile & rod shape
  • sweetsweet, grapelike, taco like odor
  • Pyocyanin - non fluorescent pigment (bluish)
  • Pyoverdine - fluorescent pigment
  • Pyorubin - dark red
  • Pyomelanin - brown black
• P. aeruginosa growth characteristics

  • 37 to 42 C - can help to differentiate it from other P. spp.
  • doesn't ferment carbohydrates
  • many strains oxidize glucose
  • denitrification of nitrates and nitrites
  • (+): Oxidase and ADH
  • Citrate positivity
  • Acetamide utilizationutilization
  • Culture : Cetrimide Agar (Selective and Diff)
  • Cetrimide - Act as detergent and enhances the production of the two pigments
• Lipopolysaccharide is reposible for many endotoxin properties of microorganism
• Exotoxin

  • Most important
  • blocks protein synthesis
• P. aeruginosa : Clinical Findings

  • wounds and burns - blue - green pus
  • necrotizing pneumonia
  • cystic fibrosis - chronic pneumonia
  • mild otitis externa in swimmers
  • invasive (malignant) otitis externa in patients with diabetes
  • Fatal sepsis - infants
  • ecythema gangrenosum - presence of erythema
  • folliculitis - poorly chlorinated tub
• P. aeruginosa : TREATMENT

  • piperacillin and ticarcillin
  • third and fourth generation cephalosporins
  • carbapenems
  • fluoroquinolones
• P. fluorescens & P. putida

  • can be isolated from respiratory specimens
  • can grow at 4 C
  • produces pigment: pyoverdin or fluorescein
  • produces acid from xylose
  • can't produce nitrate to nitrogen gas
  • Gelatin hydrolysis:
  • P. putida - negative
  • P. fluorescens - positive
• P. mosellii

  • non pigmented
  • non hemolytic
  • (+): oxidase , catalase, ADH
  • optimal growth occurs at 30 C
• True or False: NF may fail to grow or show poor growth on McConkey Agar

  True
• Pseudomonas Aeruginosa will not be able to ferment

  the sugars that is contained in TSI (lactose, sucrose, glucose) so there will be no change in the rxn in the slant or butt meaning they are not able to degrade the sugars contained in the medium
• Pyoverdin is the most frequently isolated pigment produce by pseudomonas followed by pyoverdine combine with flourescin
• Hugh-Leifson OF Medium is a very important test for distinguishing oxidizers and fermenters belonging to the group non-fermenting, Gram-negative bacilli.