Cytologic manifestation of an unusual bacterial form, Simonsiella species

Puzzling rodlike structures overlying benign squamous cells in exfoliative cytologic specimens from the upper gastrointestinal and respiratory tracts were initially considered to be fungi, protozoa, bronchodilator crystals, hemoglobin tactoids or plastic fragments. Their morphologic similarity to Simonsiella, a gram-negative bacterium frequently found in the oral cavity, was ultimately recognized. Further studies of smears and cultures obtained from the oral cavities of the authors and from the American Type Culture Collection confirmed the nature of the original findings. These giant bacterial forms were usually found in caterpillarlike side-by-side arrangements of 10 to 12 organisms. Cytologists should be aware of their appearance to avoid possible confusion with pathogenic organisms.