Comparative efficacy of hand hygiene agents in the reduction of bacteria and viruses

Abstract

Background: Health care-associated infections most commonly result from person-to-person transmission via the hands of health care workers.

Methods: We studied the efficacy of hand hygiene agents (n = 14) following 10-second applications to reduce the level of challenge organisms (Serratia marcescens and MS2 bacteriophage) from the hands of healthy volunteers using the ASTM-E-1174-94 test method.

Results: The highest log 10 reductions of S marcescens were achieved with agents containing chlorhexidine gluconate (CHG), triclosan, benzethonium chloride, and the controls, tap water alone and nonantimicrobial soap and water (episode 1 of hand hygiene, 1.60-2.01; episode 10, 1.60-3.63). Handwipes but not alcohol-based handrubs were significantly inferior from these agents after a single episode of hand hygiene, but both groups were significantly inferior after 10 episodes. After a single episode of hand hygiene, alcohol/silver iodide, CHG, triclosan, and benzethonium chloride were similar to the controls in reduction of MS2, but, in general, handwipes and alcohol-based handrubs showed significantly lower efficacy. After 10 episodes, only benzethonium chloride (1.33) performed as well as the controls (1.59-1.89) in the reduction of MS2.

Conclusions: Antimicrobial handwashing agents were the most efficacious in bacterial removal, whereas waterless agents showed variable efficacy. Alcohol-based handrubs compared with other products demonstrated better efficacy after a single episode of hand hygiene than after 10 episodes. Effective hand hygiene for high levels of viral contamination with a nonenveloped virus was best achieved by physical removal with a nonantimicrobial soap or tap water alone.

Fig 1

Schematic of experimental design that defines “baseline,” “episode,” and “evaluation.”

Fig 2

Efficacy of hand hygiene agents in the log reductions of gram-negative bacteria (S marcescens) after 1 episode, with 95% confidence intervals. Hand hygiene agents tested were as follows: (A) 60% ethyl alcohol (n = 5); (B) 61% ethyl alcohol (n = 5); (C) 62% ethyl alcohol (n = 5); (D) 61% ethyl alcohol/1% CHG (n = 5); (E) 70% ethyl alcohol/0.005% silver iodide (n = 5); (F) 0.4% benzalkonium chloride (n = 5); (G) 0.5% PCMX/40% SD alcohol (n = 5); (H) 0.75% chlorhexidine gluconate (n = 5); (I) 2% chlorhexidine gluconate (n = 5); (J) 4% chlorhexidine gluconate (n = 5); (K) 1% triclosan (n = 5); (L) 0.2% benzethonium chloride (n = 5); (M) nonantimicrobial control (n = 5); (N) tap water control (n = 5).

Fig 3

Efficacy of hand hygiene agents in the log reductions of gram-negative bacteria (S marcescens) after 10 episodes, with 95% confidence intervals. Hand hygiene agents tested were as follows: (A) 60% ethyl alcohol (n = 5); (B) 61% ethyl alcohol (n = 5); (C) 62% ethyl alcohol (n = 5); (D) 61% ethyl alcohol/1% CHG (n = 5); (E) 70% ethyl alcohol/0.005% silver iodide (n = 5); (F) 0.4% benzalkonium chloride (n = 5); (G) 0.5% PCMX/40% SD alcohol (n = 5); (H) 0.75% chlorhexidine gluconate (n = 5); (I) 2% chlorhexidine gluconate (n = 5); (J) 4% chlorhexidine gluconate (n = 5); (K) 1% triclosan (n = 5); (L) 0.2% benzethonium chloride (n = 5); (M) nonantimicrobial control (n = 5); (N) tap water control (n = 5).

Fig 4

Efficacy of hand hygiene agents in the log reductions of a nonenveloped virus (MS2) after 1 episode, with 95% confidence intervals. Hand hygiene agents tested were as follows: (A) 60% ethyl alcohol (n = 5); (B) 61% ethyl alcohol (n = 5); (C) 62% ethyl alcohol (n = 4); (D) 61% ethyl alcohol/1% CHG (n = 5); (E) 70% ethyl alcohol/0.005% silver iodide (n = 5); (F) 0.4% benzalkonium chloride (n = 5); (G) 0.5% PCMX/40% SD alcohol (n = 4); (H) 0.75% chlorhexidine gluconate (n = 3); (I) 2% chlorhexidine gluconate (n = 2); (J) 4% chlorhexidine gluconate (n = 3); (K) 1% triclosan (not tested); (L) 0.2% benzethonium chloride (n = 5); (M) nonantimicrobial control (n = 5); (N) tap water control (n = 4).

Fig 5

Efficacy of hand hygiene agents in the log reductions of a nonenveloped virus (MS2) after 10 episodes, with 95% confidence intervals. Hand hygiene agents tested were as follows: (A) 60% ethyl alcohol (n = 5); (B) 61% ethyl alcohol (n = 5); (C) 62% ethyl alcohol (n = 4); (D) 61% ethyl alcohol/1% CHG (n = 5); (E) 70% ethyl alcohol/0.005% silver iodide (n = 5); (F) 0.4% benzalkonium chloride (n = 5); (G) 0.5% PCMX/40% SD alcohol (n = 4); (H) 0.75% chlorhexidine gluconate (n = 3); (I) 2% chlorhexidine gluconate (n = 2); (J) 4% chlorhexidine gluconate (n = 3); (K) 1% triclosan (not tested); (L) 0.2% benzethonium chloride (n = 5); (M) nonantimicrobial control (n = 5); (N) tap water control (n = 4).