Gram Stain Review

1. Gram Stain Review

2. Abscess 1000x

3. Abscess 1000x GPC Resembling Staphylococci in a cluster of intact and degenerate PMNs

4. Lung Aspirate 1000x

5. Lung Aspirate 1000x GPC resembling streptococci. Notice how many of the cocci are over-decolorized - this is common with streptococci, however, based on the morphology you still know they are strep (gram negative cocci do not chain). Also note how round these strep are (these are not S. pneumoniae). If you only saw pairs, and not the chains, you would not be able to call these GPC resembling Strep (since staph also are quite round) and would have to just report GPC

6. Sputum 1000x

7. Sputum 1000x Gram positive cocci resembling pneumococci. In a respiratory sample, anytime you see GPC occurring in pairs and short chains, and the cocci look elongated (almost football shaped), there is a good chance they are S. pneumoniae. If you see a capsule around the organism (not visible in this slide) you can be absolutely certain.

8. Sputum 1000x

9. Sputum 1000x Like other streptococci, pneumococci frequently overdecolorize. In this slide, you can see the capsule (which appears as a clear halos around the organisms) that gives S. pneumoniae its pathogenicity.

10. Sputum 1000x

11. Sputum 1000x Gram negative diplococci in a sputum. These generally are found to be Moraxella catarrhalis upon culture. Some good pairs are visible in this slide.

12. Sputum 1000x

13. Sputum 1000x The predominant organism in this slide are diptheroids (gram positive bacilli which are slightly club-shaped, and commonly are arranged in “V” or “fence-post” arrangements). They most commonly indicate that the specimen has been contaminated with mucosal or skin flora.

14. Sputum 1000x

15. Sputum 1000x Staph Diptheroids This gram stain has both gpc resembling staphylcoccci and diptheroids in it.

16. Necrotic Gall Bladder 1000x

17. Necrotic Gall Bladder 1000x Gram Positive Bacilli Note: Like streptococci, many of the GPB also overdecolorize easily. This specimen grew out a Clostridium species.

18. Peritoneal Abscess 1000x

19. Filamentous, beaded gram positive bacilli suggest either Nocardia sp. or Actinomyces sp.. This specimen grew Actinomyces sp. (Note: although the organism almost looks fungal-like, the filaments are only 1-1.5 u wide - much smaller than the hyphae of a fungus.) Peritoneal Abscess 1000x

20. Sputum 1000x

21. Sputum 1000x Gram-negative bacilli resembling haemophilus. It is easy to overlook these tiny, gram negative coccobacilli (they aren’t always quite this tiny). Lots and lots of little pink dots - if you have to ask yourself “is it a cocci or a rod?” it is probably Haemophilus. In this circle there are at least 6 tiny rods

22. Sputum 1000x

23. Sputum 1000x GNB The predominant organism here is gram positive cocci resembling staphylococci. Note that the organisms are round, and appear in pairs, tetrads, and clusters. There are also a few GNB in this field GNB PMN GPC resembling staphylococci

24. Sputum 1000x

25. Sputum 1000x In this specimen we see both encapsulated GPC resembling pneumococci, and GNB resembling haemophilus. Pneumococci Haemophilus

26. Sputum 1000x

27. Sputum 1000x Gram negative bacilli - too large to be haemophilus

28. Sputum 1000x

29. Sputum 1000x More GNB, again, too large to be haemophilus

30. Leg Wound 1000x

31. Leg Wound 1000x Small, not very refractile, GNB. If this specimen source was sputum these organisms would possibly be mistaken for Haemophilus sp. In a leg wound this is unlikely (and in fact this culture grew Pseudomonas aeruginosa)

32. Sputum 1000x

33. Sputum 1000x This specimen contains gram positive cocci resembling pneumococci, and gram negative bacilli. (Note, the fuzzy appearance of the gram negative bacilli is due to the presence of a capsule on the organism. Gram negative capsules commonly stain a fuzzy pink color). This specimen grew out Streptococcus pneumoniae and Klebsiella pneumoniae. Gpc resembling pneumococci Gram negative bacilli

34. Urethral Discharge 1000x

35. Urethral Discharge 1000x Gram negative diplococci. To designate organisms as gram negative cocci you must be able to distinguish a “kissing kidney bean” morphology in some of the pairs. In a urethral discharge from a male, this is virtually diagnostic of gonorrhoeae Kissing Kidney Beans

36. Sputum 1000x

37. Sputum 1000x Yeast (one with bud) Yeast in a gram stain are 3-5 u in size (3-5x larger than gram positive cocci). Many times buds or pseudohyphae will be visible Gpc resembling staph

38. Sputum 1000x

39. Sputum 1000x These yeast have budded and have produced pseudohyphae Pseudohyphae Crystal violet precipitate

40. CSF gram stain

41. CSF gram stain These are yeast, (note the buds). The pinkish material around them is capsule, which suggests possible Cryptococcus.

42. CSF gram stain from 2 day old infant

43. CSF gram stain from 2 day old infant These are short gram positive bacilli. Based on the specimen and age, think Listeria.

44. Gram stain of urine

45. Gram stain of urine These look like strep, and they could be GBS in a urine specimen. More likely, however, is that they are enterococci.

46. Sputum 1000x

47. Sputum 1000x pneumococci Another patient whose sputum revealed both GPC resembling pneumococci and GNB resembling haemophilus haemophilus

48. Histologic stain of lung tissue

49. Histologic stain of lung tissue 45 degree branching suggest Aspergillus.

50. Darkfield examination