Detecting Bioburden and Biofilm on Surgical Instruments Prior to Sterilization

Data from the Centers for Disease Control and Prevention (CDC) indicates that over 30,000 patients die annually from surgical infections. Many of these surgical infections are caused by surgical instruments that remain contaminated with bioburden and/or biofilm after reprocessing. Even more troubling is the fact that when patients died from a surgical infection “77% of the deaths were reported to be related to the infection, and the majority (93%) was serious infections involving organs or spaces accessed during the operation.”1

The CDC’s “Guideline for the Prevention of Surgical Site Infection” points out that “Microbial contamination of the surgical site is a necessary precursor of a surgical infection.”2 When dead, sterile bioburden and/or biofilm gets deposited into a patient’s body from a contaminated instrument during a surgical case, the foreign, organic material begins to decompose inside the body and is attacked by phagocytes. This process is frequently seen in a post-surgical patient who presents with a fever of unknown origin and an elevated white blood cell count within 24 to 48 hours of a surgical case.

Inadequate, incomplete or improper cleaning of surgical instruments prior to sterilization also has the potential to allow for residual bioburden to be sequestered in bodily fluids that may be contaminated with gram-negative bacteria. You can sterilize the instrument, but you may fail to destroy microbial endotoxins that are heat-stable and can survive the sterilization process. This is another source of patient contamination from an instrument whose cleaning IFUs have not been validated to ensure a thoroughly decontaminated, clean, sterile, moisture-free instrument after every reprocessing cycle.

Any and all steps taken by reprocessing personnel to reduce the risk of an instrument contaminated with bioburden and/or biofilm being returned to surgery will result in reduced patient risk of contracting a dangerous, painful and costly infection. The first step in reducing the risk of a surgical infection caused by a contaminated instrument being returned to surgery involves a thorough review of the instrument manufacturer’s cleaning IFUs.

Almost all surgical instrument manufacturers’ cleaning IFUs call for a ‘visual inspection’ of the instrument after cleaning to ensure that the instrument is free of bioburden and biofilm. Regretfully, ‘visual inspection’ alone will not ensure a clean instrument because the human eye is physically incapable of visualizing microscopic bioburden and/or biofilm.

When dealing with surgical instruments whose cleaning IFUs rely on ‘visual inspection’ to detect bioburden and biofilm, CS/SPD professionals need additional help and technologies to see what is not visible by the human eye alone.

The Association for the Advancement of Medical Instrumentation (AAMI) publication “Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities” states in AAMI ST 79 that “The use of methods that are able to measure organic residues that are not detectable using visual inspection should be considered in facility cleaning policy and procedures.”3

The most commonly used method to solve the visual inspection ‘problem’ is to provide each and every reprocessing workstation with a lighted magnifying glass. In order to deal with more complex instruments, CS/SPD departments should also invest in a borescope or flexible camera that can be used to look down the lumens and into the channels of complex instruments (laparoscopic instruments, Kerrison Rongeurs, etc.).

The International Association of Healthcare Central Service Materiel Management (IAHCSMM) points out in its CRCST Self-Study Lesson Plan, Understanding Biofilm, “Even with the use of most visual enhancing tools, microorganisms will still not be seen.4 Therefore, “other tests have been developed to help verify that cleaning quality standards have been attained.”5 These include protein tests and adenosine triphosphate (ATP) bioluminescence tests, both of which test for residual soils and which might also be suggestive of biofilm formation.

There are products that test beyond what you can see visually and are particularly helpful for lumens and other devices that are difficult or impossible to visually inspect,” said Ralph Basile [Vice President, Healthmark]. “For example, we have reagent tests that test for protein and hemoglobin, and another 3-in-1 test for lumen devices that test for blood, protein and carbohydrate all at the same time.”6

A less costly, more efficient solution to ensuring the elimination of bioburden and biofilms is to only use surgical instruments whose cleaning IFUs have been validated to ensure clean, sterile, moisture-free instruments on every reprocessing cycle. In order to be reliable, such validation testing must be conducted by an independent testing laboratory using FDA and AAMI validation testing protocols. The validation testing must use soils that are relevant to the clinical use conditions of the instruments and should include the worst-case (least rigorous) implementation and execution of the cleaning process. 7

Just because an instrument is sterilized is no guarantee that it can’t harm a patient if it still contains residual bioburden and/or biofilm after cleaning. When it comes to instrument cleaning and reprocessing, instrument reprocessing personnel must remember that “If it isn’t clean, it can’t be safe!” The best way to ensure safe instruments on every reprocessing cycle is to only use instruments whose IFUs have been validated to provide bioburden and biofilm-free instruments for every patient, every time.

1“Guideline For The Prevention Of Surgical Site Infection” Center For Disease Control, 1999


2 Op. cit.



5 Op. cit.

6 “Validated, It’s Complicated” Kara Nadeau, HPN, April 2017

7 FDA Publication “Reprocessing Medical Devices in Health Care Settings: Validation Methods and Labeling”

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