A novel method for differentiating L-form bacteria from their parental form using the Hucker Gram staining technique

L‐forms of Enterococcus faecium, Bacillus subtilis and Pseudomonas syringae pv. phaseolicola were differentiated from their parent, cell‐walled forms by a modified Gram staining technique. The addition of glutaraldehyde to the culture medium fixed the cells to prevent lysis of the L‐forms. The cell‐walled forms exhibited typical Gram staining reactions whereas the L‐forms remained red due to the counterstain. L‐forms were easily differentiated from cell‐walled forms by their size and morphology which was made more obvious by the staining procedure. This is a very rapid and easy technique which distinguishes L‐form bacteria from cell‐walled organisms.