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Levels of microbial contamination on surgical instruments

W A Rutala1, M F Gergen, J F Jones

  • 1Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, USA.

American Journal of Infection Control
|May 19, 1998
PubMed
Abstract

Insights

Standard cleaning effectively reduces microbial load on surgical instruments to less than 100 colony-forming units (CFU). This indicates that new sterilization methods will likely prevent cross-transmission of infections from nonlumen instruments.

Area of Science:

  • Microbiology
  • Infection Control
  • Surgical Instrument Reprocessing

Background:

  • Surgical instruments require thorough cleaning to prevent healthcare-associated infections.
  • Standard cleaning protocols involve washer sterilizers and sonic cleaning.

Purpose of the Study:

  • To determine the microbial load and types of microorganisms on used surgical instruments after standard cleaning.
  • To assess the effectiveness of washer sterilizer and sonic cleaning methods.

Main Methods:

  • Prospective experimental study at a university hospital.
  • Used surgical instruments were cultured using Peptamin Tween broth and filtered.
  • Quantitative cultures and standard microbiological identification techniques were employed.

Main Results:

  • 72% of instruments had 0-10 colony-forming units (CFU) post-cleaning.
  • 14% had 11-100 CFU, and 14% had over 100 CFU.
  • Coagulase-negative staphylococcus (56%) was the most common organism, followed by Bacillus (22%) and diphtheroids (14%).

Conclusions:

  • Most nonlumen surgical instruments harbor fewer than 100 CFU of relatively nonpathogenic microbes after cleaning.
  • Current cleaning methods are effective in reducing microbial burden.
  • New low-temperature sterilization technologies are expected to be highly effective for nonlumen instruments.

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