Which type of microorganisms are generally most resistant to sterilization methods?

Bacterial spores are considered the most resistant microorganisms to sterilization methods due to their unique structural and metabolic features. These spores enter a dormant state, allowing them to survive extreme conditions including high temperatures, radiation, desiccation, and chemical agents that typically destroy other types of cells.

The spore’s thick protective coat and low metabolic activity contribute to its robustness. In contrast, other microorganisms such as viruses, fungi, and pathogenic bacteria lack the same level of resistance. While some viruses can be quite resilient and certain bacteria can form protective capsules, they do not match the resistance of bacterial spores. As a result, the presence of spores poses significant challenges in infection control and sterilization processes, making them a focus in the healthcare and laboratory environments for effective sterilization practices.