Human Normal Flora

• Human Microbiome:

  • Microbiome is the community of microorganisms that exist in a particular host environment on or in the human body
  • Also known as the human microbiome, microbiome, and normal flora
  • Members of normal flora are low virulence organisms
  • Includes the genetic composition of these organisms
  • Blood, CSF, urine, and internal body organs are sterile parts of the human body
• Factors Affecting Normal Flora:

  • Age
  • Diet
  • Geographic location
  • Gender
  • Immune conditions
  • Disease
  • Pregnancy
  • Smoking
  • Use of antibiotics
• Types of Normal Flora:

  • Resident Flora:
  • Always present in our body
  • Acquired rapidly during or after birth
  • More stable microorganisms that are not pathogenic but are opportunistic
  • Transient Flora:
  • Live in our body for a short amount of time (hours, days, weeks)
  • Varies from time to time and environment to environment
  • Reasons for not staying include competition with other microbes, elimination by body defense mechanisms, and chemical and physical changes in the body
• Vertical Transmission:

  Mother to offspring
• Horizontal Transmission:

  Person to Person
• Symbiosis

  • The relationship between two different species

  • These organisms are called symbionts

  • These organisms live together

  • Both partner get benefit

  ● Example: Escherichia coli produces Vitamin K and Vitamin B in our Body while using our body as its shelter
• Mutualism

  • The relationship between two different species

  • Both the partners get benefit
• Commensalism

  • This is the relationship between two different speices

  • One partner is benefited while the other partner is neither benefited nor harmed

  ● Example: Staphylococcus on skin
• Parasitism

  • The relationship between two different species

  • One partner is benefited while the other is harmed