Aerobic Gram-Positive Bacilli Part II

1. Aerobic Gram-Positive BacilliPart II Division of Medical Technology Carol Larson MSEd, MT(ASCP)

2. Differentiation ofMajor GPR Genera • Gram stain • Morphology • Arrangement • Formation of spores • Catalase reaction

3. 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

4. GPR Discussed in This Lecture • Nonspore-forming GPR, catalase negative • Gardnerella species • Erysipelothrix species • Lactobacillus species • Branching Nocardioform GPR • Nocardia species • Streptomyces species

5. GPR, pleomorphic, Non-spore forming, Catalase negative Erysipelothrix rhusiopathiae Gram Stain • Two types • Short GPR • Long, filamentous GPR • Non-sporulating

6. GPR, pleomorphic, Non-spore forming, Catalase negative Erysipelothrix rhusiopathiae Colony Morphology • Grows on BAP • Nonhemolytic or alpha hemolytic • Microaerophilic

7. 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”

8. 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

9. 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”

10. GPR, pleomorphic, Non-spore forming, Catalase negative Lactobacillus speciesGram Stain • Two types • Long slender GPR in chains • Short GPCB • Non-sporulating

11. GPR, pleomorphic, Non-spore forming, Catalase negative Lactobacillus speciesColony Morphology • Grows on BAP • Multiple colony morphologies • Nonhemolytic or alpha hemolytic • Microaerophilic

12. GPR, pleomorphic, Non-spore forming, Catalase negative Lactobacillus speciesIdentification • Catalase negative • Sucrose “F” • Vancomycin “R”

13. GPR, pleomorphic, Non-spore forming, Catalase negative Lactobacillus speciesClinical Significance • Normal flora • Mouth • GI tract • Female vaginal tract • Rarely pathogenic • Endocarditis • Meningitis

14. What is the clinical significance of Lactobacillus species? It is considered normal flora of the mouth, gastrointestinal tract, and female genital tract

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

16. Branching Nocardioform GPR • Actinomycetes • Nocardia species • Streptomyces species

17. Branching Nocardioform GPR Nocardia speciesGram Stain • Pleomorphic,branching, fine, delicate filaments with fragmentation GPR • Often appears beaded

18. Branching Nocardioform GPR Nocardia speciesColony 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

19. Branching Nocardioform GPR Nocardia speciesIdentification • Partially acid-fast positive • Presence of granules in specimen • Catalasepositive

20. Branching Nocardioform GPR Nocardia speciesClinical Significance • Habitat: soil and water • Mycetoma (actinomycetoma) • Tissue swelling • Draining sinus tracts • Presence of granules • Immunocompromised patients • Pulmonary and disseminated infections

21. What is the key characteristic in identifying Nocardia species? Branching GPR that is partially acid fast positive

22. 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

23. Branching Nocardioform GPR Streptomyces speciesGram Stain • GPR with extensive branching, chains and spores • Does not fragment easily

24. Branching Nocardioform GPR Streptomyces speciesColony 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

25. Branching Nocardioform GPR Streptomyces speciesIdentification • Acid-fast negative

26. Branching Nocardioform GPR Click icon for audio Streptomyces speciesClinical Significance • Habitat: soil and decaying vegetation • Mycetoma (actinomycetoma) • Rarely: • Pericarditis • Bacteremia • Brain abscess

27. How can you differentiate Streptomyces from Nocardia? Streptomyces is acid-fast negative and Nocardia is partially acid-fast positive

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

29. Who am I? BAP, growth at 2 days Gram Stain TSI Motility Tube: “test-tube brush” pattern of growth Erysipelothrix rhusiopathiae

30. Who am I? LJ agar at 1 week Acid Fast Stain Gram Stain Causes Actinomycetoma Nocardia species