Antimicrobial Efficacy of Activated Triclosan in Surfactant-Based Formulation versus Pseudomonas putida

Abstract

BACKGROUND: There is a need in healthcare settings for efficacious broad-spectrum antimicrobial handwash products. Experts agree on the importance of hand hygiene for the reduction or prevention of infection from bacteria. The antimicrobial activity of triclosan in surfactant-based formulations against Pseudomonas species has been questioned in the literature. Published articles have claimed that triclosan's activity is limited and not effective against gram-negative organisms, particularly Pseudomonas species. OBJECTIVE: We examined the efficacy of an “activated” 0.45% triclosan formula, compared to a formula containing 4% chlorhexidine gluconate (CHG). In vivo antimicrobial efficacy was assessed using the ASTM E-1174 (Healthcare Personnel Handwash) method, using Pseudomonas putida as the test organism. Efficacy was measured following a single as well as multiple (ten) 30-second handwashes. RESULTS: The activated triclosan formula achieved a 3.16 log10 reduction after a single wash and 3.30 log10 following ten consecutive washes. This compared to 2.53 log10 and 4.03 log10 reductions for the 4% CHG formula. The triclosan formula was significantly more effective following the single wash (p <0.001) while the 4% CHG was more effective after the tenth wash. CONCLUSIONS: This study demonstrates that a properly formulated triclosan containing product is effective at reducing gram-negative organisms such as Pseudomonas putida. In the 1994 Monograph for Healthcare Antiseptic Drug Products, FDA requires a 2 log10 reduction after a single wash and a 3 log10 reduction following ten washes. Both formulas met these criteria. The triclosan formula achieved the higher log reduction immediately, while the 4% CHG required ten washes.