Aerobic Gram-Positive Bacilli Part II

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Aerobic Gram-Positive BacilliPart II

• Division of Medical Technology
• Carol Larson MSEd, MT(ASCP)

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Differentiation ofMajor GPR Genera

• Gram stain
• Morphology
• Arrangement
• Formation of spores
• Catalase reaction

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GPR Discussed in Student Lab

• 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

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GPR Discussed in This Lecture

• Nonspore-forming GPR, catalase negative
• Gardnerella species
• Erysipelothrix species
• Lactobacillus species
• Branching Nocardioform GPR
• Nocardia species
• Streptomyces species

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Erysipelothrix rhusiopathiae Gram Stain
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Two types
• Short GPR
• Long, filamentous GPR
• Non-sporulating

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Erysipelothrix rhusiopathiae Colony Morphology
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Grows on BAP
• Nonhemolytic or alpha hemolytic
• Microaerophilic

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Erysipelothrix rhusiopathiae Identification
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Catalase negative
• Motility
• Nonmotile
• Test-tube brush growth pattern in semisolid
  motility tube at 48 hours
• H2S positive in KIA/TSI (only GPR)
• Sucrose nonF

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Erysipelothrix rhusiopathiae Clinical
Significance
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Zoonotic
• Swine erysipelas (fatal to pigs)
• Man skin disease
• Erysipelas
• Direct contact with infected animal
• Rarely disseminates causing septicemia with
  arthritis or endocarditis

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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
nonF
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Lactobacillus speciesGram Stain
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Two types
• Long slender GPR in chains
• Short GPCB
• Non-sporulating

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Lactobacillus speciesColony Morphology
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Grows on BAP
• Multiple colony morphologies
• Nonhemolytic or alpha hemolytic
• Microaerophilic

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Lactobacillus speciesIdentification
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Catalase negative
• Sucrose F
• Vancomycin R

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Lactobacillus speciesClinical Significance
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Normal flora
• Mouth
• GI tract
• Female vaginal tract
• Rarely pathogenic
• Endocarditis
• Meningitis

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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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Review

• Nonspore-forming GPR, catalase negative
• Gardnerella species
• Erysipelothrix species
• Lactobacillus species

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Branching Nocardioform GPR

• Actinomycetes
• Nocardia species
• Streptomyces species

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Nocardia speciesGram Stain
Branching Nocardioform GPR

• Pleomorphic, branching, fine, delicate filaments
  with fragmentation GPR
• Often appears beaded

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Nocardia species Colony Morphology
Branching Nocardioform GPR

• 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

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Nocardia species Identification
Branching Nocardioform GPR

• Partially acid-fast positive
• Presence of granules in specimen
• Catalasepositive

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Nocardia species Clinical Significance
Branching Nocardioform GPR

• Habitat soil and water
• Mycetoma (actinomycetoma)
• Tissue swelling
• Draining sinus tracts
• Presence of granules
• Immunocompromised patients
• Pulmonary and disseminated infections

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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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Streptomyces speciesGram Stain
Branching Nocardioform GPR

• GPR with extensive branching, chains and spores
• Does not fragment easily

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Streptomyces species Colony Morphology
Branching Nocardioform GPR

• 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

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Streptomyces species Identification
Branching Nocardioform GPR

• Acid-fast negative

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Streptomyces species Clinical Significance
Branching Nocardioform GPR
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• Habitat soil and decaying vegetation
• Mycetoma (actinomycetoma)
• Rarely
• Pericarditis
• Bacteremia
• Brain abscess

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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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Aerobic GPRSummary

• Nonspore-forming GPR, catalase negative
• Gardnerella species
• Erysipelothrix species
• Lactobacillus species
• Branching Nocardioform GPR
• Nocardia species
• Streptomyces species

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Who am I?
BAP, growth at 2 days
Gram Stain
TSI
Motility Tube test-tube brush pattern of
growth
Erysipelothrix rhusiopathiae
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Who am I?
LJ agar at 1 week
Gram Stain
Acid Fast Stain
Causes Actinomycetoma
Nocardia species