Download Fastidious Gram Negative Rods

Aerobic Gram-Positive Bacilli
Part II
Division of Medical Technology
Carol Larson MSEd, MT(ASCP)
Differentiation of
Major GPR Genera
• Gram stain
– Morphology
– Arrangement
• Formation of spores
• Catalase reaction
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
GPR Discussed in This Lecture
• Nonspore-forming GPR, catalase negative
– Gardnerella species
– Erysipelothrix species
– Lactobacillus species
• Branching Nocardioform GPR
– Nocardia species
– Streptomyces species
GPR, pleomorphic, Non-spore forming, Catalase negative
Erysipelothrix rhusiopathiae
Gram Stain
• Two types
– Short GPR
– Long, filamentous
GPR
• Non-sporulating
GPR, pleomorphic, Non-spore forming, Catalase negative
Erysipelothrix rhusiopathiae
Colony Morphology
• Grows on BAP
– Nonhemolytic or
alpha hemolytic
• Microaerophilic
GPR, pleomorphic, Non-spore forming, Catalase negative
Erysipelothrix rhusiopathiae
Identification
• Catalase negative
• Motility
– Nonmotile
– Test-tube brush growth pattern in
semisolid motility tube at 48 hours
• H2S positive in KIA/TSI (only GPR)
• Sucrose non“F”
GPR, pleomorphic, Non-spore forming, Catalase negative
Erysipelothrix rhusiopathiae
Clinical Significance
• Zoonotic
– Swine erysipelas (fatal to pigs)
• Man – skin disease
– Erysipelas
– Direct contact with infected animal
– Rarely disseminates causing septicemia
with arthritis or endocarditis
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”
GPR, pleomorphic, Non-spore forming, Catalase negative
Lactobacillus species
Gram Stain
• Two types
– Long slender GPR in chains
– Short GPCB
• Non-sporulating
GPR, pleomorphic, Non-spore forming, Catalase negative
Lactobacillus species
Colony Morphology
• Grows on BAP
– Multiple colony morphologies
– Nonhemolytic or alpha hemolytic
• Microaerophilic
GPR, pleomorphic, Non-spore forming, Catalase negative
Lactobacillus species
Identification
• Catalase negative
• Sucrose “F”
• Vancomycin “R”
GPR, pleomorphic, Non-spore forming, Catalase negative
Lactobacillus species
Clinical Significance
• Normal flora
– Mouth
– GI tract
– Female vaginal tract
• Rarely pathogenic
– Endocarditis
– Meningitis
What is the clinical significance of
Lactobacillus species?
It is considered normal flora of the mouth,
gastrointestinal tract, and female genital tract
Review
• Nonspore-forming GPR, catalase negative
– Gardnerella species
– Erysipelothrix species
– Lactobacillus species
Branching Nocardioform GPR
• Actinomycetes
– Nocardia species
– Streptomyces species
Branching Nocardioform GPR
Nocardia species
Gram Stain
• Pleomorphic, branching, fine, delicate
filaments with fragmentation GPR
• Often appears beaded
Branching Nocardioform GPR
Nocardia 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
Branching Nocardioform GPR
Nocardia species
Identification
• Partially acid-fast positive
• Presence of granules in specimen
• Catalase
positive
Branching Nocardioform GPR
Nocardia species
Clinical Significance
• Habitat: soil and water
• Mycetoma (actinomycetoma)
– Tissue swelling
– Draining sinus tracts
– Presence of granules
• Immunocompromised patients
– Pulmonary and disseminated infections
What is the key characteristic in
identifying Nocardia species?
Branching GPR that is partially acid fast positive
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
Branching Nocardioform GPR
Streptomyces species
Gram Stain
• GPR with extensive branching, chains
and spores
• Does not fragment easily
Branching Nocardioform GPR
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
Branching Nocardioform GPR
Streptomyces species
Identification
• Acid-fast negative
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Branching Nocardioform GPR
Streptomyces species
Clinical Significance
• Habitat: soil and decaying vegetation
• Mycetoma (actinomycetoma)
• Rarely:
– Pericarditis
– Bacteremia
– Brain abscess
How can you differentiate
Streptomyces from Nocardia?
Streptomyces is acid-fast negative and
Nocardia is partially acid-fast positive
Aerobic GPR
Summary
• Nonspore-forming GPR, catalase
negative
– Gardnerella species
– Erysipelothrix species
– Lactobacillus species
• Branching Nocardioform GPR
– Nocardia species
– Streptomyces species
Who am I?
BAP, growth at 2 days
Gram Stain
Motility Tube: “test-tube brush” pattern of growth
Erysipelothrix rhusiopathiae
TSI
Who am I?
LJ agar at 1 week
Acid Fast Stain
Gram Stain
Causes Actinomycetoma
Nocardia species