Atlas of Direct examination in common bacterial infections, Direct examination in common bacterial infections, SUBCLINICAL ATLAS, MICROBIOLOGY ATLAS, atlas in Microbiology, atlas in medical, tuyenlab.net
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| Fig 1: Expectorated sputum, smear, Gram stain, light microscopy, MPV. Purulence, light. Amorphous debris, moderate. Gram-positive diplococci, encapsulated, extracellular. Impression: pneumococcal disease. This is a typical smear presentation for early pneumococcal pneumonia. The pneumococci have proliferated to high numbers, and the lung is responding with increased mucus and fluid release. There is early migration of the neutrophils, but phagocytosis of the diplococci is limited. Routine bacterial culture of this sample should yield a heavy growth of Streptococcus pneumoniae. |
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| Fig 2: Expectorated sputum, smear, Gram stain, light microscopy, HPV. Purulence, heavy. The presence of grampositive diplococci, intracellular morphology suggest antibiotic effect. Impression: pneumococcal disease. This is a typical smear presentation of a treated but unresolved pneumococcal pneumonia. Neutrophils cover the field, the diplococci are largely intracellular and partially digested, and the background amorphous material is gone. Routine bacterial culture of this sample may be negative for typical colonies of S. pneumoniae. A few colonies may be found by a careful search among the contaminating normal biota colonies. |
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| Fig 3: Aspirated sputum, smear, Gram stain, light microscopy, MPV. Purulence, light. Amorphous debris, heavy. Gram-positive cocci, pairs, encapsulated, extracellular. Initial antibiotic therapy can be directed toward streptococci and staphylococci (Stomatococcus). Routine bacterial culture isolated a pure growth of an encapsulated strain of Streptococcus pyogenes. The heavy amorphous background is protein-rich edema fluid from the capillary bed damaged by S. pyogenes toxins. The patient subsequently died of the infection despite correct antibiotic therapy and a correct diagnosis. |
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| Fig 4: Wound, smear, Gram stain, light microscopy, MPV. Purulence, moderate. Amorphous debris, moderate. Gram-positive cocci, chains, extracellular. Impression: streptococcal disease. The presence of typical chains of Streptococcus on a background showing purulence with poorly preserved “polys” and amorphous debris is suggestive of hemolytic streptococci with tissue cytotoxicity. Routine bacterial culture yielded a pure growth of S. pyogenes. |
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| Fig 5: Expectorated sputum, smear, Gram stain, light microscopy, MPV. Purulence, light. Local materials, moderate. Gram-positive cocci, pairs, groups, intracellular and extracellular. Impression: staphylococcal disease. Smear morphology is typical for staphylococci, but no staphylococcal colonies were present on the culture plates. Stomatococcus mucilaginosus colonies were present in high numbers. Careful correlation between direct and culture examinations demonstrated this organism to be the probable cause of infection. The presumptive report implying or suggesting staphylococci followed by a negative culture report without explanation raises doubts about the competence of the laboratory. |
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| Fig 6: Abscess aspirate, smear, Gram stain, light microscopy, MPV. Purulence, heavy. Gram-positive cocci, groups, extracellular. Impression: staphylococcal disease. Aerobic and anaerobic culture plates were negative at 24 hours. There was culture isolation of Staphylococcus aureus from this same abscess 5 days previously. The patient was being treated with clindamycin. Because the cocci in the smear did not appear antibiotic damaged, another species of gram-positive coccus was sought. The anaerobic culture grew Peptostreptococcus organisms, which are clindamycin resistant. |
This is a part of the book : Textbook of Diagnostic Microbiology 4th edition 2011 of authors: Connie R. Mahon, Donald C. Lehman and George Manuselis. If you want to view the full content of the book and support author. Please buy it here: http://amzn.to/2ctxo02
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