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Hematology

Bacteria and Fungi in Blood Smears: Sepsis or Artifact?

How to distinguish true bacteremia in sepsis from blood smear contamination and staining artifacts. Analysis of microscopic findings and fungal spores.

Zebiniso Kholmuradova Zebiniso Kholmuradova 1 min
Blood smear, cluster of bacteria around a destroyed cell during microscopy
Blood smear, cluster of bacteria around a destroyed cell during microscopy
Blood smear, phagocytosis of bacteria by a leukocyte and a segmented neutrophil
Blood smear, phagocytosis of bacteria by a leukocyte and a segmented neutrophil
Blood smear, cluster of bacteria around a dye crystal, contamination
Blood smear, cluster of bacteria around a dye crystal, contamination
Blood smear, isolated colony of microorganisms in a clear field
Blood smear, isolated colony of microorganisms in a clear field
Blood smear, darkly stained fungal spores against a background of erythrocytes
Blood smear, darkly stained fungal spores against a background of erythrocytes
Blood smear, threads of septate fungal mycelium, slide contamination
Blood smear, threads of septate fungal mycelium, slide contamination
Blood smear, multicellular Alternaria conidia among erythrocytes
Blood smear, multicellular Alternaria conidia among erythrocytes
Blood smear, conidium of mold fungus against a background of erythrocytes and precipitate
Blood smear, conidium of mold fungus against a background of erythrocytes and precipitate
Blood smear, large multicellular fungal spore, staining artifact
Blood smear, large multicellular fungal spore, staining artifact

🔍 Guess where the real threat lies?

☠ Normally, there should be NO bacteria and NO fungi in a blood smear. Their appearance is always an alarming signal or an error.

These photos show two possible reasons:

  1. Infection in the blood, a life-threatening condition.
  2. Artifacts/contamination — the stain or slide was contaminated.

❗Look at the photos and try to determine which ones show true infectious agents and which are artifacts/contamination. 🔬 Write your answers in the comments!

🙏 Photos kindly provided by Zebiniso Kholmuradova, morphologist, 🇺🇿 Uzbekistan, Kashkadarya Multidisciplinary Children’s Medical Center.

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