The relationship between holding time and the bacterial load on surgical instruments

Area of Science:

• Microbiology
• Healthcare Associated Infections
• Sterilization Science

Background:

• Surgical instrument reprocessing is critical for patient safety.
• Understanding bacterial persistence on instruments informs cleaning protocols.
• Inadequate cleaning can lead to surgical site infections.

Purpose of the Study:

• To quantify bacterial load on used surgical instruments.
• To assess the impact of holding time on bacterial contamination.
• To establish optimal pre-cleaning intervals for instruments.

Main Methods:

• Evaluation of 36 instrument sets to determine average bacterial counts per cm².
• Experimental contamination of sterile stainless steel with three bacterial species in sheep blood.
• Incubation of contaminated samples for up to 48 hours to monitor bacterial growth.

Main Results:

• Initial bacterial counts ranged from 10 to 250 CFU/cm², varying by operation site.
• Significant bacterial load increase observed after 6 hours of holding time.
• A 3-log10 CFU/cm² increase in bacterial load was recorded at 12 hours post-contamination.

Conclusions:

• Prompt cleaning of surgical instruments within 6 hours is imperative.
• Extended holding times dramatically increase bacterial load, compromising disinfection.
• Adherence to a 6-hour pre-cleaning window is essential for effective sterilization.