Gram-negative Rods: Glucose nonfermenting

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Gram-negative RodsGlucose nonfermenting

• Karen Honeycutt, M.Ed., MT(ASCP)SM
• MT 418 Clinical Microbiology
• Student Laboratory Session

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General Information
GNR Glucose nonfermenters

• Predominantly opportunistic
• Debilitated host
• Nomenclature changes rapidly (usually known by 2
  names for 5-10 years)
• Will grow on BAP, 22-35C, 24-72 hours
• Categories based upon glucose, oxidase
  ability to grow on MAC

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General Information
GNR Glucose nonfermenters

• Gram stain morphology taken from non-inhibitory
  agar
• Can be difficult to treat, can rapidly develop
  antibiotic resistance to drugs used for treatment
• Many genera
• Commercial system reliability?

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Glucose O, oxidase , MAC
GNR Glucose nonfermenters

• Pseudomonas sp.
• Pseudomonas aeruginosa most commonly isolated
  nonfermenting GNR
• Grows in moist environments (soap)
• Aerobic
• Motile w/polar flagella

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Pseudomonas aeruginosa
GNR Glucose O, Oxidase , MAC

• Nosocomial infections
• Usually not part of normal flora
• Colonization can occur (upper respiratory tract,
  skin, GI tract)

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P. aeruginosa - Pigments
GNR Glucose O, Oxidase , MAC

• Usually produces
• Pyoverdin (fluorescein) yellow/green visualize
  with UV light Other Pseudomonas sp. can also
  produce
• Pyocyanin blue-green pigment only produced by
  P. aeruginosa
• May produce
• Pyorubrin pink to red/maroon pigment only
  produced by P. aeruginosa

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Pseudomonas aeruginosa Id
GNR Glucose O, Oxidase , MAC
MAC
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Pseudomonas aeruginosa Id
GNR Glucose O, Oxidase , MAC
Moeller base decarboxylase/dehydrogenaseArginine
Ornithine (-)Lysine (-)
Glucose OGreen pigment
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Pseudomonas aeruginosa Rapid Id
GNR Glucose O, Oxidase , MAC
Rough beta-hemolytic on BAPPigmentGrape-like
smell
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Pseudomonas aeruginosa infections
GNR Glucose O, Oxidase , MAC

• Cystic fibrosis patients serious lung
  infections
• Immunosuppressed
• Burn wounds
• Osteomyelitis
• UTI, septicemia,
• Corneal ulcers (blindness)
• Swimmers ear, folliculitis

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Pseudomonas aeruginosa infections
GNR Glucose O, Oxidase , MAC

• Corneal ulcers (blindness)

Photo from Images.MD
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Pseudomonas aeruginosa infections
GNR Glucose O, Oxidase , MAC

• Burn wound

Photo from Images.MD
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Burkholderia cepacia
GNR Glucose O, Oxidase /-, MAC

• Nosocomial infections
• CF patient colonized/infected with severe
  social ramifications person to person spread
  established
• Some CF once infected with fulminant decline
  of pulmonary function
• Resistant to many antibiotics

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Glucose O or I, oxidase (-), MAC
GNR Glucose nonfermenters

• Stenotrophomonas maltophilia
• Strong maltose oxidizer
• Nosocomial
• Opportunistic
• 3rd most common glucose non-fermenter isolated in
  clinical lab

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Stenotrophomonas maltophilia
GNR Glucose O or I, oxidase (-), MAC

• BAP may produce a pale yellow to lavender
  pigment
• Oxidase negative
• Arginine (-), Ornithine (-), Lysine ()
• DNase ()
• Polymyxin B S
• Disk diffusion susceptibilities now standardized
  (SXT S drug of choice)

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Glucose O or I, oxidase (-), MAC
GNR Glucose O or I, oxidase (-), MAC

• Acinetobacter sp.
• 2nd most common glucose non-fermenter isolated in
  clinical lab
• Nosocomial
• Opportunistic
• Normal flora skin, vaginal tract

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Acinetobacter sp.
GNR Glucose O or I, oxidase (-), MAC

• Gram stain morphology plump gnr in pairs (can
  be mistaken for GNDC)
• Oxidase (-)
• Nitrate reduction (-)
• Glucose
• O Acinetobacter baumannii
• I Acinetobacter lwoffii