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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 Karen Honeycutt, M.Ed., MT(ASCP)SM MT 418 Clinical Microbiology Student Laboratory Session Microbiology
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
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 Microbiology
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
GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa • Nosocomial infections • Usually not part of normal flora • Colonization can occur (upper respiratory tract, skin, GI tract) • Produces pigment • Pyocyanin • Pyoverdin • Pyomelanin • Pyorubrin Microbiology
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
BAP Oxidase Glucose OF = “O” GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa Id MAC Microbiology
BAP Oxidase GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa Id Rapid IDRough & beta-hemolytic on BAPPigmentGrape-like smell Microbiology
BAP Oxidase GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa Id Pigment production:Pyoverdin (fluorescent)Pyocyanin(blue)Pyomelanin (brown)Pyorubrin (red) Pyoverdin (fluorescent)+Pyocyanin (blue)=green or metallic sheen on BAP, CHOC Microbiology
GNR: Glucose “O”, Oxidase +, MAC + Pseudomonas aeruginosa Id Moeller base decarboxylase/dehydrogenaseArginine +Ornithine (-)Lysine (-) Glucose “O”Green pigment Microbiology
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
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” Microbiology
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
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 calcaaceticus/baumannii • “I” Acinetobacter lwoffii Microbiology