Lytic effect of Vibrio cholerae elastase on gram-positive and -negative bacteria.

Elastase of Vibrio cholerae caused the lysis of freshly grown cells of Gram-negative (Pseudomonas aeruginosa, Proteus vulgaris, Salmonella paratyphi A and Klebsiella pneumoniae) bacteria. Gram-positive (Staphylococcus aureus and S. epidermidis) organisms were resistant to this enzyme. Heat killed and lyophilized Gram-positive and -negative bacteria (except S. aureus and S. epidermidis) showed higher sensitivity to elastase. Both Gram-negative and -positive bacteria were lyzed maximally by elastase at pH 8.0. At this pH, lytic activity of elastase was maximum in Tris-HCl and glycine-NaOH buffers followed by Tris-maleate and cacodylate buffers.