Direct examination showing local and contaminating materials, Atlas of Direct examination showing local and contaminating materials, SUBCLINICAL ATLAS, MICROBIOLOGY ATLAS, atlas in medical, atlas in microbiology, tuyenlab.net
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| Fig 1: Expectorated sputum, smear, Gram stain, light microscopy, low-power view (LPV). Purulence, none. Contaminating bacteria and epithelial cells, heavy. No pathogens seen. A carefully collected sample of lower respiratory tree material should be submitted. The sample is saliva, not sputum. There could be several reasons for submission of this sample to the laboratory. The patient could have been poorly directed and simply “spit” into the collection container, or the patient’s cough might not be productive of sputum. |
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| Fig 2: Amniotic fluid, cytocentrifuge preparation, Gram stain, light microscopy, medium-power view (MPV). Purulence, moderate. Local materials, moderate. No organisms seen. The presence of purulence (neutrophils or “polys”) indicates a process suspicious for infection. The absence of organisms in this normally sterile fluid is a critical observation. Squamous epithelial cells are local to this specimen type and confirm that the sample is amniotic fluid. The blue keratohyalin granules must never be mistaken for bacteria |
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| Fig 3: Expectorated sputum, smear, Gram stain, light microscopy, LPV. Purulence, none. Local materials, moderate. Contaminating bacteria and epithelials, heavy. No pathogens seen. The bolus of sputum, consisting of mucus with entrapped alveolar macrophages, confirms that lower respiratory tree material is present. There is no evidence of an infectious process. The sputum is heavily coated by contaminating materials from the oropharynx or mouth. Contaminating organisms will grow in a routine sputum culture. |
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| Fig 4: Aspirated sputum, smear, Gram stain, light microscopy, high-power view (HPV). Purulence, none. Local materials, moderate. No organism seen. The alveolar macrophages and mucus (pink-stained background) are the local materials from the tracheobronchial tree. This smear confirms that sputum was sampled and there is no suspicion for infection and no evidence of significant contamination. Routine culture of this specimen can grow insignificant oral flora because culture is more sensitive than direct examination. |
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| Fig 5: Cerebrospinal fluid (CSF), cytocentrifuge preparation, Gram stain, light microscopy, HPV. Purulence, moderate. No organisms seen. CSF is a sterile fluid and normally does not have purulence. The presence of neutrophils is critical. Careful observation for bacteria is mandatory. Acridine orange stain may be helpful in clinical settings in which bacteria are low in number and gramnegative. Cytocentrifuged sediments commonly have a concentration of organisms sufficient for routine microscopy (105/mL or greater). |
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| Fig 6: Expectorated sputum, smear, Gram stain, light microscopy, MPV. Purulence, heavy. Local materials, Curschmann’s spiral. No organisms seen. The Curschmann’s spiral is material local to the tracheobronchial tree but is not normal, so it is specifically reported. This spiral may present in a variety of sizes depending on the size of bronchus involved. Spirals can be particularly prominent following an asthmatic episode with bronchial constriction. |
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| Fig 7: Trauma eye, vitreous aspirate, smear, Gram stain, light microscopy, HPV. Purulence, none. No organisms seen. Local materials, light. The light protein background and the pigment-containing cell are normal material local to the vitreous of the eye. This local material confirms that the sample is representative. The ability to see this brown pigment cell in smear material is related to the eye trauma. The important emphasis is the absence of purulence. |
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| Fig 8: Eye, vitreous aspirate, smear, Gram stain, light microscopy, HPV. Purulence, light. Amorphous debris, moderate. Local materials, light. No organisms seen. This smear suggests that there has been an injury. The pigment has undergone phagocytosis and is seen within a large macrophage. Pigment must never be mistaken for bacteria, and bacteria must never be overlooked if mixed with local materials, such as pigment granules. |
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| Fig 9: Bronchoalveolar lavage (BAL), cytocentrifuge smear, Gram stain, light microscopy, HPV. Purulence, heavy. No organisms seen. Local materials, black particulate debris (BPD). This size and type of carbon particle is commonly seen in respiratory samples in small amounts and is usually not noted in a smear report. |
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| Fig 10: BAL, cytocentrifuge smear, Gram stain, light microscopy, HPV. Purulence, none. No organisms seen. Local materials, heavy BPD. This small-size carbon particle seen prominently in respiratory samples can be associated with smoking crack cocaine. The gross sample usually has a gray appearance. BPD should not be confused with gram-positive cocci. |
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| Fig 11: BAL, cytocentrifuge smear, Gram stain, light microscopy, HPV. Purulence, none. No organisms seen. Local materials, BPD moderate. This BPD is irregular in shape and usually varies in size. This type of carbon debris is commonly associated with smoke inhalation from house or other types of fires. In the early phase of smoke inhalation, much of the BPD will be extracellular. Later much of the debris will be intracellular within phagocytes. The golden-colored macrophage present contains yellow material associated with cigarette smoking. |
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| Fig 12: BAL, cytocentrifuge smear, Gram stain, light microscopy, HPV. Purulence, none. No organisms seen. Local materials, alveolar macrophages containing very small, light to golden yellow, refractile but not polarizing particles. These small, fine particles can be hemosiderin, sometimes deposited as small particles or other fine particles from the environment. Such refractile particles are not usually reported except in response to specific questions from the patient’s physician |
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| Fig 13: BAL, cytocentrifuge smear, Gram stain, light microscopy, HPV. Purulence, none. No organisms seen. Local materials, alveolar macrophages containing golden yellow to Gram’s safranin-colored chunky, irregular particles consistent with hemosiderin. This type of large particle hemosiderin deposition within lung phagocytes is commonly associated with blood in the lung as seen in heart failure or aspirated blood from large-volume nosebleeds. Blood and hemosiderin in a Gram-stained smear make smear viewing more difficult. |
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