Study on the removal efficacy and influencing factors of bacterial endotoxin on reusable surgical instruments

Bacterial endotoxins from reusable surgical instruments are key risk factors for postoperative fever and nosocomial infections, with unclear contamination and removal features. Conventional disinfection/sterilization has limited effects due to the endotoxins' strong thermal stability, threatening clinical safety.

To investigate the effects of different postuse placement times and processing procedures (cleaning, disinfection, and sterilization) on endotoxin contamination and removal efficiency of reusable surgical instruments, and to provide a scientific basis for optimizing clinical instrument handling protocols.

Three hundred reusable surgical instruments were randomly collected from 50 infectious and 50 clean surgeries (March-August 2023), and divided into three groups by postuse placement time: 0-2 h, 2-6 h, 6-12 h (N = 50 per group). A kinetic chromogenic limulus amoebocyte lysate assay was used to detect endotoxin levels at precleaning, postcleaning, postdisinfection and poststerilization stages.

Mean endotoxin levels at the four stages were 131.67, 33.17, 8.42, and 5.07 EU/i.e. with positive rates of 54.33%, 11.67%, 4.33%, and 3.67%, respectively. All positive samples after sterilization were from the 6-12 h group. Precleaning endotoxin levels in this group were significantly higher than those in the other two groups (P < 0.05). Endotoxin levels decreased gradually through processing, and the cleaning step achieved the highest removal rate (74.81%).

Postuse placement for more than 6 h leads to severe endotoxin contamination of reusable surgical instruments. Timely and standardized cleaning within 6 h is the core step for effective endotoxin removal. Conventional sterilization cannot fully inactivate heat-stable endotoxins, and medical institutions should optimize instrument-management protocols to strengthen clinical endotoxin control.