Gram positive bacilli morphology and classification

Gram positive bacilli

1. Other GPB
Dr. Mohammed Elkady
Clinical Pathology Consultant,
M.B.B.CH, EFCpath

2. •Actinomyces •Listeria
•Erysipelothrix
•Gardnerella
•Nocardia
•Actinomadura
•Streptomyces

3. Actinomycetes
•Actinomycetes :
–large group (Nocardia, Actinomadura, Streptomyces,
Actinomyces)(All cause mycetomaexcept Actinomyces)
–Gram positive bacteria
–form
•branchingfilaments (like fungi)
•chains
•fragmented forms (like diphtheroids)

5. Actinomycetes
•Growth requirements:
–Aerobes: Nocardia, Actinomadura and
Streptomyces species are.
–Anaerobes: Actinomyces species

6. Nocardia species
•Pathogenicity
–Actinomycetoma:
•Chronic granulomatousdisease
•Affecting subcutaneous and deep tissues:
–pulmonaryand lympho-cutaneous infection.
•specimen =mucopus, sputum, and
infected tissue

7. Mycetoma
•Granulomatous
disease caused by
actinomycetesand
fungi

8. Mycetoma, sampling

9. Nocardia species
•Morphology
–non-motile
–branchingthreads.
–Gram positive but often stain unevenly.
–weak acid fast.
•In mycetoma: small granulesare
discharged in the pus.

10. Nocardia species

11. Nocardia species

12. Nocardia species

14. Nocardia species
•Culture
–Obligate aerobic.
–45 ºC(help to isolate Nocardia from
specimens that contain commensals) as well
as at 35–37 ºCand room temperature.
–Can be cultured on Sabouraudagar at 35–37
ºC. for 3–14 days,
–Orange to pink, waxy folded colonies
•Catalase positive and urease positive

15. Nocardia species, blood agar

16. Nocardia species, Sabouraud
agar

17. Actinomadura species
•Pathogenicity
–mycetoma
•Specimens: Pusfrom draining sinuses

18. Actinomadura species
•Morphology
–non-motile and
–branching threads.
–NOTacid fast.

20. Actinomadura species
•Culture
–Grow slowly
–Require an enriched medium.
–Leathery appearance
–Redpigmentation
•Urease negative

21. Actinomadura species

22. Streptomyces
•Pathogenicity
–mycetoma

23. Streptomyces
•Morphology
Like other actinomycetes:
–nonmotile.
–branching threads.
–From specimen: NOTacid fast,
–Form cultures:are usually acid fast.

24. Streptomyces
•Culture
–Sabouraudagar
–room temperature or 35–37ºC.
–creamy or brown and have aerial hyphae,
giving them a heapedappearance.
•Urease negative.

25. Streptomyces

26. Streptomyces

27. Actinomyces israelii
•Pathogenicity:
–actinomycosis
•chronic granulomatousinfection
•Pus (in granules) is discharged through sinuses which open
on the surface of the skin.
•commonly affecting the jaw, following the extraction of a
tooth, abdomen, brain and lungs
–Specimens: Depending on the site of infection,
specimens include pus, sputumor infected tissue.

28. Actinomyces israelii
•Morphology
–morphologically resemble other
actinomycetes.
–non-motile
–thin branches are easily fragmented.
–notacid fast,
–but the club-shaped forms that surround the
colony are acid fast.

29. Actinomyces israelii
•Gram stain

30. Actinomyces israelii
•Culture
–anaerobicand microaerophilic.
–culturing granules on blood agar
–slow-growing, 5–7 days
–35–37 ºC.
–On Blood agar: small, cream or white colonies, adhere to the
medium.
•catalase, indole, urease negative.
•It hydrolyzes aesculin and ferments glucose, lactose,
mannitol, and several other sugars.
•Should be sent to a Reference Laboratory.

31. Actinomyces israelii

32. •For all granulomatous infection:
–Granules→culture

33. Listeria monocytogenes
•Pathogenicity
–meningitis
–septicaemia
•mainly in neonates, pregnant women (abortion), the
elderly and immunosuppressed persons.
•sources of infection:
–contaminated meats, chicken, soft cheeses and vegetables.
•specimens: Mainly CSFand bloodfor culture.

34. Listeria monocytogenes
•Morphology
–Gram positive
–non-capsulate
–small rod or coccobacillus
–stains unevenly and is easily decolorized.
–resemble diphtheroids.
–Motility:
•At 35–37 ºC: nonmotile
•At low temperature (18–22 ºC) it is motile(tumbling and rotation
motility)
•Cerebrospinal fluid: In Listeria meningitis, only a few bacteriamay
be present. The c.s.f. will usually contain lymphocytes and, or,
polymorphs. The c.s.f. total protein is raised.

35. Gram stain

36. Gram stain

37. Listeria monocytogenes
•Culture
–facultative anaerobe.
–3–45 ºC with an optimum of 30 ºC.
–Bloodagar:
•small, grey, translucentdrop-like colonies
•small zone of beta-haemolysis
•Incubation for up to 48 h required to produce
visible growth.

38. Beta hemolysis
Blood agar

39. Beta hemolysis
Blood agar

42. Listeria monocytogenes
•Biochemical reactions
–Catalase positive(diff from BH sterpt.)
–Indole, oxidase and urease negative.
–Ferments glucose and maltose with acid production.
•Note: The characteristic motilityand cultural
characteristics of L. monocytogenes are usually
sufficientto identify it without the need to use
many biochemical tests.

43. Erysipelothrix rhusiopathiae
•Pigs and other animals,
•Humans :
–erysipeloid(cellulitis)
–bacteraemia.
•In smears:
–long thin Gram positive rod,
–sometimes beaded
–non-motile.
•Blood agar
–CO2
–30–35 ºC
–alpha-haemolytic

46. •Gram stain

47. Alphahemolysis
Blood agar

49. Gardnerella vaginalis
•Bacterial Vaginosis
•Gram variablecoccobacilli
•Positive whiff testwith KOH
•Clue cells
•Beta hemolytic colonies

50. •Clue cell