Investigation of the efficacy of alcohol-based solutions on adenovirus serotypes 8, 19 and 37, common causes of epidemic keratoconjunctivitis, after an adenovirus outbreak in hospital

Background: Hand antiseptics are of great importance in the prevention of nosocomial infections. Due to the frequent occurrence of adenoviral epidemic keratoconjunctivitis outbreaks in the study hospital, it was necessary to investigate the efficiency of alcohol-based solutions on adenoviruses.

Aim: To investigate the efficacy of alcohol-based solutions commonly found in hand antiseptics against adenovirus serotypes 8, 19 and 37.

Methods: The efficacy of ethanol, isopropanol, chlorhexidine-digluconate, n-butanol and different combinations of these antiseptics on adenovirus serotypes that typically cause epidemic keratoconjunctivitis was investigated. The effect of antiseptic substances was investigated using a quantitative suspension test technique according to EN-14476. Antiseptics were prepared as follows: 70% ethanol, 70% isopropanol, 70% ethanol+0.5% chlorhexidine-digluconate, 70% isopropanol+0.5% chlorhexidine-digluconate, 60% ethanol+10% isopropanol, 60% ethanol+10% isopropanol+0.5% chlorhexidine-digluconate and 60% ethanol+10% isopropanol+1% n-butanol. The effect of antiseptics was evaluated at 30, 60 and 120 s.

Findings: The highest reduction in virus titre was detected with 60% ethanol+10% isopropanol+1% n-butanol. This caused a reduction of 2.5log₁₀, 3 log₁₀ and 2.5log₁₀ in adenovirus serotypes 8, 19 and 37, respectively. The lowest reduction in virus titre was detected with 70% ethanol+0.5% chlorhexidine-digluconate and 70% isopropanol+0.5% chlorhexidine-digluconate. These combinations caused a reduction of 1.62log₁₀ in adenovirus serotypes 19 and 37. All antiseptics showed efficacy levels below 4log₁₀ which is regarded as the efficiency limit by EN-14476.

Conclusion: The alcohol-based solutions tested in this study were not found to be sufficiently effective against adenovirus serotypes. Further studies to investigate the efficiency of different alcohol-based solutions are required.