Chemical Methods of Microbial Control: Phenolics

Introduction

• Dr. O introduces the series focusing on chemical methods of microbial control.
• Previous discussions covered physical methods like heat and autoclaving.
• The focus will now be on phenolics and will be broken down into:
  • Phenol
  • Phenolics
  • Bisphenols
• Triclosan to be covered in a separate video.

Mechanism of Action

• Denaturation of Proteins:
  • Proteins unravel, losing their function.
• Disruption of Membranes:
  • Alters cell membranes, potentially causing holes and changes in structure.

Phenol

• Historical Context:
  • Used by Joseph Lister in the 1860s as carbolic acid to disinfect surgical areas.
  • Led to the creation of Listerine in the late 1870s.
• Current Use:
  • Still used as a mouthwash.
• Limitations:
  • Replaced by phenolics due to being more toxic and irritating.

Phenolics

• Advantages over Phenol:
  • More effective, less toxic, less irritating.
  • More stable and longer-lasting on surfaces.
• Example: O-phenylphenol
  • Found in Lysol since the late 1880s.
  • Effective in the presence of organic matter (e.g., blood, vomit, feces).

Bisphenols

• Example: Hexachlorophene
  • Effective against gram-positive bacteria (e.g., staph and strep on skin).
  • Previously used in nurseries for baby skin care.
• Replacement:
  • Often replaced by chlorhexidine due to toxicity concerns.

Conclusion

• Overview of the chemical methods covered:
  • Phenol
  • Phenolics (O-phenylphenol)
  • Bisphenol (Hexachlorophene)
• Mention of a future video on triclosan.

• Dr. O emphasizes the effectiveness and safety of phenolics over phenol and discusses the specific advantages of individual chemicals like O-phenylphenol and hexachlorophene.