Alcohol fixation of bacteria to surgical instruments increases cleaning difficulty and may contribute to sterilization inefficacy

Abstract

Background: Alcohol is frequently inappropriately used on surgical instruments to reduce bacterial contamination, but fixes protein to stainless steel. Here we compare the effect of air drying, prolonged soaking in water, and alcohol treatment on cleaning difficulty of contaminated forceps.

Methods: Haltsted-mosquito forceps were contaminated with only Staphylococcus aureus. Instruments were air-dried for 10 (control), 75, or 240 minutes, soaked in water, or air dried then treated with ethanol or isopropanol for 10 seconds. All instruments were prewashed for 15 minutes. Forceps contaminated with blood and S aureus or Pseudomonas aeruginosa were dried and then sprayed or wiped with ethanol, and prewashed. Bacterial viability and soiling were determined by standard plate culture and crystal violet staining, respectively.

Results: Soaking or spraying instruments with alcohol significantly reduced viable bacterial numbers, but significantly increased soil attached to forceps, as did air drying. Wiping instruments with alcohol had little effect on bacterial viability, but increased cleaning difficulty. Soaking in water for 75 or 240 minutes increased cleaning difficulty perhaps due to bacterial attachment to forceps.

Conclusions: Treating contaminated instruments with alcohol, allowing them to dry, or allowing them to soak in water for prolonged periods increases cleaning difficulty and should be discouraged.

Keywords: Decontamination; Delayed processing; Drying soil; Fixatives; Instrument pre-cleaning; Prolonged wetting.