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Gram-negative Rods: Glucose nonfermenting

Gram-negative Rods: Glucose nonfermenting. Karen Honeycutt, M.Ed., MT(ASCP)SM MT 418 Clinical Microbiology Student Laboratory Session. GNR: Glucose nonfermenters. General Information. Predominantly opportunistic Debilitated host

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Gram-negative Rods: Glucose nonfermenting

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  1. Gram-negative Rods:Glucose nonfermenting Karen Honeycutt, M.Ed., MT(ASCP)SM MT 418 Clinical Microbiology Student Laboratory Session Microbiology

  2. GNR: Glucose nonfermenters General Information • Predominantly opportunistic • Debilitated host • Nomenclature changes rapidly (usually known by 2 names for 5-10 years) • Will grow on BAP, 22-35°C, 24-72 hours • Categories based upon: glucose, oxidase & ability to grow on MAC Microbiology

  3. GNR: Glucose nonfermenters General Information • 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? Microbiology

  4. GNR: Glucose nonfermenters Glucose “O”, oxidase +, MAC + • Pseudomonas sp. • Pseudomonas aeruginosa most commonly isolated nonfermenting GNR • Grows in moist environments (soap) • Aerobic • Motile w/polar flagella Microbiology

  5. GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa • Nosocomial infections • Usually not part of normal flora • Colonization can occur (upper respiratory tract, skin, GI tract) Microbiology

  6. GNR: Glucose “O”, Oxidase +, MAC + P. aeruginosa - Pigments • 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 Microbiology

  7. BAP Oxidase Glucose OF = “O” GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa Id MAC Microbiology

  8. GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa Id Moeller base decarboxylase/dehydrogenaseArginine +Ornithine (-)Lysine (-) Glucose “O”Green pigment Microbiology

  9. BAP Oxidase GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa RapidId Rough & beta-hemolytic on BAPPigmentGrape-like smell Microbiology

  10. GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa infections • Cystic fibrosis patients – serious lung infections • Immunosuppressed • Burn wounds • Osteomyelitis • UTI, septicemia, • Corneal ulcers (blindness) • Swimmer’s ear, folliculitis Microbiology

  11. GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa infections • Corneal ulcers (blindness) Photo from Images.MD Microbiology

  12. GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa infections • Burn wound Photo from Images.MD Microbiology

  13. GNR: Glucose “O”, Oxidase +/-, MAC + Burkholderia cepacia • 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 Microbiology

  14. GNR: Glucose nonfermenters Glucose “O” or “I”, oxidase (-), MAC + • Stenotrophomonas maltophilia • Strong maltose oxidizer • Nosocomial • Opportunistic • 3rd most common glucose non-fermenter isolated in clinical lab Microbiology

  15. GNR: Glucose “O” or “I”, oxidase (-), MAC + Stenotrophomonas maltophilia • 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) Microbiology

  16. GNR: Glucose “O” or “I”, oxidase (-), MAC + 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 Microbiology

  17. GNR: Glucose “O” or “I”, oxidase (-), MAC + Acinetobacter sp. • Gram stain morphology: plump gnr in pairs (can be mistaken for GNDC) • Oxidase (-) • Nitrate reduction (-) • Glucose • “O” Acinetobacter baumannii • “I” Acinetobacter lwoffii Microbiology

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