Bioburden of Surgical Devices

Guideline for Disinfection and Sterilization in Healthcare Facilities (2008)

In general, used medical devices are contaminated with a relatively low bioburden of organisms179, 911, 912. Nystrom evaluated medical instruments used in general surgical, gynecological, orthopedic, and ear-nose-throat operations and found that 62% of the instruments were contaminated with <101organisms after use, 82% with <102, and 91% with <103. After being washed in an instrument washer, more than 98% of the instruments had <101organisms, and none >102 organisms911. Other investigators have published similar findings179, 912. For example, after a standard cleaning procedure, 72% of 50 surgical instruments contained <101 organisms, 86% <102, and only 6% had >3 × 102912. In another study of rigid-lumen medical devices, the bioburden on both the inner and outer surface of the lumen ranged from 101 to 104 organisms per device. After cleaning, 83% of the devices had a bioburden £102 organisms179. In all of these studies, the contaminating microflora consisted mainly of vegetative bacteria, usually of low pathogenicity (e.g., coagulase-negative Staphylococcus)179, 911, 912.

An evaluation of the microbial load on used critical medical devices such as spinal anesthesia needles and angiographic catheters and sheaths demonstrated that mesophilic microorganisms were detected at levels of 101 to 102 in only two of five needles. The bioburden on used angiographic catheters and sheath introducers exceeded 10CFUs on 14% (3 of 21) and 21% (6 of 28), respectively907.