Aerobic Gram-Positive Bacilli Part II Genital Culture Unit

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Aerobic Gram-Positive BacilliPart IIGenital
Culture Unit

• 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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Gardnerella vaginalis Gram Stain
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Pleomorphic gram-variable bacilli
• Non-sporulating
• Specimen gram stain
• Clue cells

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Gardnerella vaginalisColony Morphology
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Does not grow on sheep blood agar
• Human Blood Agar (V-agar, HBT-agar)
• Small colonies with diffuse zone of
  beta-hemolysis

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Gardnerella vaginalisIdentification
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Catalase negative
• Oxidase negative
• Sodium hippurate usually positive
• SPS sensitive

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Gardnerella vaginalisClinical Significance
GPR, pleomorphic, Non-spore forming, Catalase
negative

• Normal vaginal flora
• Bacterial vaginosis
• Polymicrobic infection with Mobiluncus and
  Bacteroides
• Diagnosis
• Homogeneous, gray discharge
• Clue cells
• Amine or fishy odor when add 10 KOH
• Culture not necessary for diagnosis

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What are the key identification characteristics
to determine if Gardnerella vaginalis is the
cause of bacterial vaginosis?
Examine vaginal specimen for presence of a
homogeneous, gray discharge, clue cells on the
Gram stain, and an amine or fishy odor when
adding 10 KOH. A culture is not recommended,
but if done, G. vaginalis grows on
V-agar/HBT-agar and it beta hemolytic.
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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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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?
HBT media shows beta-hemolysis
Gram Stain
Causes Bacterial Vaginitis
Gardnerella vaginalis