It is important to note that boiling equipment items in water will not achieve sterilisation. Disinfection can also be achieved by using chemicals which however may themselves be toxic when allowed contact with skin or are inhaled. Chemical disinfectants may be supplied ready to use or may need accurate dilution to provide an appropriate solution. It must be remembered that disinfectants can decay and lose activity. Decay is more rapid at high temperatures and can be accelerated by the presence of impurities.
All disinfectants take time to work.
Gram positive bacteria e.g. Staphylococci, are more sensitive than gram negative bacteria e.g. Pseudomonas. Mycobacteria and spores are relatively resistant. Fungal spores are easily killed by disinfectants. Other bacterial spores e.g. Clostridia are resistant to most disinfectants in common use. Tubercle bacteria are more resistant to chemical disinfectants than other bacteria.