Certified Instrument Specialist (CIS) Practice Exam 2025 - Free CIS Practice Questions and Study Guide

Prions are unique infectious agents composed primarily of misfolded proteins, and one of their most notable characteristics is their remarkable resistance to various environmental stressors. They are particularly resistant to extreme heat and cold, which typically inactivate most conventional pathogens, including bacteria and viruses. This resistance means that common sterilization methods that would effectively destroy other infectious agents may not work on prions, allowing them to persist in the environment for extended periods.

This characteristic is crucial for understanding the challenge that prions pose in medical and laboratory settings, as their resilience necessitates specific protocols for decontamination and handling. While prions are also resistant to disinfection processes, standard cleaning methods, and antibiotics, the question specifically highlights extreme heat and cold as a significant factor in their resistance profile. This is why the first option is the most accurate representation of prion resilience.