Which term refers to the properties of pathogens that distinguish them from normal flora?

• A. Virulence factors
• B. Commensalism
• C. Opportunism
• D. Antibiotic resistance

Answer: (A)

Verified step by step guidance

1. Understand the key terms in the question: 'properties of pathogens that distinguish them from normal flora' refers to specific characteristics that enable pathogens to cause disease, unlike harmless or beneficial microbes.
2. Define 'Virulence factors': These are molecules produced by pathogens that contribute to their ability to cause disease, such as toxins, adhesion molecules, and enzymes that damage host tissues.
3. Review the other options: 'Commensalism' describes a relationship where one organism benefits and the other is unaffected, 'Opportunism' refers to normally harmless microbes causing disease under certain conditions, and 'Antibiotic resistance' is the ability of microbes to survive antibiotic treatment.
4. Compare the definitions to the question: Since the question asks for properties that distinguish pathogens from normal flora, the term that best fits is 'Virulence factors' because they directly relate to pathogenicity.
5. Conclude that 'Virulence factors' is the correct term describing the unique properties of pathogens that enable them to cause disease, setting them apart from normal flora.