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Table 1 Mean reduction ± SD of Escherichia coli from artificially contaminated hands of 15 volunteers by reference treatment (2 × 3 ml of 60% iso-propanol for 60 s) or treatment with product A or product B (each 3 ml for 30 s); experiments differed only by the presence of valid neutralizers in the sampling fluid.

From: Insufficient neutralization in testing a chlorhexidine-containing ethanol-based hand rub can result in a false positive efficacy assessment

Preparation

Active agent(s) and concentration(s)

No neutralizers in sampling fluid

P-value (vs. reference)*

Neutralizers in sampling fluid

P-value (vs. reference)*

  

Samples without detectable test bacteria

Mean log10-reduction ± SD

 

Samples without detectable test bacteria

Mean log10-reduction ± SD

 

Product A

Ethanol (61%, w/w) chlorhexidine gluconate (1%, w/w)

9 / 15

4.8 ± 1.5

0.02

0 / 15

2.7 ± 0.4

0.033

Reference alcohol

Iso-propanol (60%, v/v)

0 / 15

3.7 ± 0.8

n.a.

0 / 15

3.5 ± 0.9

n.a.

Product B

Ethanol (85%, w/w)

0 / 15

3.3 ± 0.7

0.44

0 / 15

3.3 ± 0.7

0.11