Fig. 1.

Distinguishing VAP from colonization—the presence of intraepithelial bacteria. Discarded tracheal aspirate fluid (TAF) samples were used to prepare cytospins from a patient with severe BPD when VAP was diagnosed (a) and after the completion of a 7-day course of intravenous antibiotics (b). TAF cytospins stained with a modified Giemsa stain demonstrate intracellular bacteria in epithelial cells (red arrows) in the pretreatment (a) but not the posttreatment sample (b). Epithelial cells demonstrate squamous cell morphology, which is characteristic of squamous cell metaplasia seen in severe BPD. Both TAF samples grew Acinetobacter baumannii and Staphylococcus aureus. The first sample was treated as an infection and the second was regarded as colonization. Notably intracellular bacteria are absent from neutrophils in both samples. Scale bar, 25 µm