Triphenyltin Salicylate-Antimicrobial Effect and Resistance - The Pyrophosphatase Connection

Abstract

The effect of Triphenyltin salicylate (TPS) was tested against six bacteria, Escherichia coli, Sta-phylococcus aureus, Shigella flexneri, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella typhi and five fungi, Aspergillus flaws, Aspergillus fumigatus, Aspergillus niger, Rhodotorula spp. and Saccharomyces spp. Sensitivity tests were determined with 5–500μg/ml of TPS. All organisms were sensitive to the compound except Klebsiella pneumoniae, Pseudomonas aeruginosa, Rhodotorula spp. and Saccharomyces spp, The minimum dose of TPS that can kill 50% of the susceptible microorganisms is in the range 5–50 μg/ml.

Membrane bound pyrophosphatase(s) from the organisms was non-competitively inhibited by 5μM TPS with K₁ values of 7.6,18, 8.8 and 6.9 μM for Escherichia coli, Shigella flexneri, Aspergillus niger, and Aspergillus fumigatus, respectively.

The physiological index of efficiency of the enzyme (V_max/K_M) for TPS susceptible organisms was reduced by 17–68% in the presence of 5–10 μM of the compound. In contrast the index for the non-susceptible organisms was unaffected. The mode of action of TPS is discussed.

Key Words:

• Triphenlytin salicylate
• Pyrophosphatase inhibition