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Aerobic Gram-Positive Bacilli Part II Division of Medical Technology Carol Larson MSEd, MT(ASCP) Please click audio icon to hear Carol’s narration
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Gram stain –Morphology –Arrangement Formation of spores Catalase reaction Click icon for audio Differentiation of Major GPR Genera
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Spore-forming GPR, catalase positive –Bacillus species –Bacillus anthracis –Bacillus cereus Nonspore-forming GPR, catalase positive –Listeria monocytogenes –Corynebacterium species (diphtheroids) –Corynebacterium diphtheriae –Corynebacterium jekeium Click icon for audio GPR Discussed in Student Lab
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Nonspore-forming GPR, catalase negative –Gardnerella species –Erysipelothrix species –Lactobacillus species Branching Nocardioform GPR –Nocardia species –Streptomyces species Click icon for audio GPR Discussed in This Lecture
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Two types –Short GPR –Long, filamentous GPR Non-sporulating Click icon for audio Erysipelothrix rhusiopathiae Gram Stain GPR, pleomorphic, Non-spore forming, Catalase negative
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Erysipelothrix rhusiopathiae Colony Morphology Grows on BAP –Nonhemolytic or alpha hemolytic Microaerophilic Click icon for audio GPR, pleomorphic, Non-spore forming, Catalase negative
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Catalase negative Motility –Nonmotile –Test-tube brush growth pattern in semisolid motility tube at 48 hours H 2 S positive in KIA/TSI (only GPR) Sucrose non“F” Click icon for audio Erysipelothrix rhusiopathiae Identification GPR, pleomorphic, Non-spore forming, Catalase negative
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Zoonotic –Swine erysipelas (fatal to pigs) Man – skin disease –Erysipelas –Direct contact with infected animal –Rarely disseminates causing septicemia with arthritis or endocarditis Click icon for audio Erysipelothrix rhusiopathiae Clinical Significance GPR, pleomorphic, Non-spore forming, Catalase negative
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What are the key biochemical reactions that identify Erysipelothrix rhusiopathiae? Two gram stain morphologies (GPR), two colony types on SBA, catalase negative, H2S positive, test-tube brush pattern in motility tube, sucrose non“F”
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Two types –Long slender GPR in chains –Short GPCB Non-sporulating Click icon for audio Lactobacillus species Gram Stain GPR, pleomorphic, Non-spore forming, Catalase negative
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Grows on BAP –Multiple colony morphologies –Nonhemolytic or alpha hemolytic Microaerophilic Click icon for audio Lactobacillus species Colony Morphology GPR, pleomorphic, Non-spore forming, Catalase negative
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Catalase negative Sucrose “F” Vancomycin “R” Click icon for audio Lactobacillus species Identification GPR, pleomorphic, Non-spore forming, Catalase negative
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Lactobacillus species Clinical Significance Normal flora –Mouth –GI tract –Female vaginal tract Rarely pathogenic –Endocarditis –Meningitis Click icon for audio GPR, pleomorphic, Non-spore forming, Catalase negative
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What is the clinical significance of Lactobacillus species? It is considered normal flora of the mouth, gastrointestinal tract, and female genital tract
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Nonspore-forming GPR, catalase negative –Gardnerella species –Erysipelothrix species –Lactobacillus species Click icon for audio Review
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Actinomycetes –Nocardia species –Streptomyces species Click icon for audio Branching Nocardioform GPR
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Nocardia species Gram Stain Pleomorphic, branching, fine, delicate filaments with fragmentation GPR Often appears beaded Click icon for audio Branching Nocardioform GPR
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Grows on SBA, Mycology media and LJ media Aerobic growth appears at 3-30 days Waxy, bumpy or velvety rugose forms, yellow to orange colonies Click icon for audio Nocardia species Colony Morphology Branching Nocardioform GPR
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Nocardia species Identification Partially acid-fast positive Presence of granules in specimen Catalase positive Click icon for audio Branching Nocardioform GPR
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Nocardia species Clinical Significance Habitat: soil and water Mycetoma (actinomycetoma) –Tissue swelling –Draining sinus tracts –Presence of granules Immunocompromised patients –Pulmonary and disseminated infections Click icon for audio Branching Nocardioform GPR
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What is the key characteristic in identifying Nocardia species? Branching GPR that is partially acid fast positive
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What primary disease does Nocardia cause and what 3 symptoms are seen? Mycetoma (aka actinomycetoma). Triad of symptoms: tissue swelling, draining sinus tracts, and the presence of granules
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GPR with extensive branching, chains and spores Does not fragment easily Click icon for audio Streptomyces species Gram Stain Branching Nocardioform GPR
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Streptomyces species Colony Morphology Grows on SBA, Mycology media and LJ media Aerobic growth appears at 3-30 days Waxy, bumpy or velvety rugose forms, yellow to orange colonies Click icon for audio Branching Nocardioform GPR
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Acid-fast negative Click icon for audio Streptomyces species Identification Branching Nocardioform GPR
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Streptomyces species Clinical Significance Habitat: soil and decaying vegetation Mycetoma (actinomycetoma) Rarely: –Pericarditis –Bacteremia –Brain abscess Click icon for audio Branching Nocardioform GPR
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How can you differentiate Streptomyces from Nocardia? Streptomyces is acid-fast negative and Nocardia is partially acid-fast positive
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Nonspore-forming GPR, catalase negative –Gardnerella species –Erysipelothrix species –Lactobacillus species Branching Nocardioform GPR –Nocardia species –Streptomyces species Click icon for audio Aerobic GPR Summary
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Who am I? BAP, growth at 2 daysGram Stain Erysipelothrix rhusiopathiae Motility Tube: “test-tube brush” pattern of growth TSI
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Who am I? LJ agar at 1 weekGram Stain Nocardia species Causes Actinomycetoma Acid Fast Stain
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