The Microbiome Overview

Questions and Answers

What distinguishes transient microflora from resident microflora?

Transient microflora can reproduce rapidly.

Transient microflora are usually unable to multiply. (correct)

Transient microflora have a longer lifespan in the body.

Transient microflora are always present on the skin.

At what point is the human body typically microbe free?

At birth, in the blood and tissues. (correct)

At infancy after twelve months.

Before colonization occurs.

During the early childhood phase.

What largely influences the development of different microflora in neonates?

Breast- or bottle-feeding methods. (correct)

Environmental pollution exposure.

Genetic predisposition to certain microflora.

Types of food consumed in infancy.

Which of the following best describes the nature of the human microbiome?

It evolves over time and is influenced by various factors. Signup and view all the answers

What is the primary source of colonization for neonates immediately after birth?

Contact with the birth canal and caregivers. Signup and view all the answers

Which of the following is NOT considered a member of the microbiota?

Phages Signup and view all the answers

What was the primary goal of the Human Microbiome Project?

To catalogue all microorganisms of the human body Signup and view all the answers

What does the uniqueness of individual microbiomes suggest about human health?

Microbiomes are highly personalized and can vary significantly. Signup and view all the answers

How many human genes are estimated to be present compared to the genes in the gut microbiome?

22,000 human genes vs 3.3 million microbiome genes Signup and view all the answers

Which of the following microbial sites was NOT studied in the Human Microbiome Project?

Lung Signup and view all the answers

Which organization sponsored the Human Microbiome Project?

National Institutes of Health (NIH) Signup and view all the answers

What is the approximate percentage of human genomes that are identical across individuals?

99.9% Signup and view all the answers

What is included as members of the microbiome but NOT as part of the microbiota?

Viroids Signup and view all the answers

What is one way that normal flora prevents harmful organisms from invading the body?

By competing for attachment receptors Signup and view all the answers

Which of the following substances is NOT produced by the normal microbiome to inhibit the growth of harmful microbes?

Enzymes that promote pathogen growth Signup and view all the answers

How does the normal microbiome contribute to pH regulation in the body?

By maintaining a low pH to prevent fungal growth Signup and view all the answers

What role does bacterial interference play in the function of the microbiome?

It forms a protective layer across tissue surfaces Signup and view all the answers

Which mechanism is NOT related to the protective role of the normal microbiome?

Production of harmful toxins Signup and view all the answers

What is meant by the term 'microbiome'?

A functional collection of different microbes in a system Signup and view all the answers

What is the difference between microbiome and microbiota?

Microbiome encompasses a wider range than microbiota Signup and view all the answers

Which of the following is included in the composition of the microbiome?

Bacteria, viruses, fungi, and protozoa Signup and view all the answers

What is the approximate number of genes in a human microbiome compared to the human genome?

It has 200 times the number of genes as the human genome Signup and view all the answers

What is one characteristic of transient microflora compared to resident microflora?

Transient microflora remains in the host for a short duration Signup and view all the answers

Which of the following best describes the weight of the human microbiome?

Up to 2 kilograms Signup and view all the answers

What type of organisms does the term 'microbiota' encompass?

Prokaryotes and eukaryotes Signup and view all the answers

What role do movable genetic elements play in the microbiota?

They contribute to genetic diversity and adaptability Signup and view all the answers

What is one role of Lactobacillus species in the gut?

Decreases gut pH through fermentation Signup and view all the answers

Which factor is NOT known to affect the microbiome?

Favorite color Signup and view all the answers

How does a limited diet influence microbial diversity in the gut?

Reduces microbial diversity Signup and view all the answers

What is one benefit of having a diverse gut microbiome?

Better absorption of carbohydrates Signup and view all the answers

How does exercise impact the gut microbiome?

Increases microbial diversity Signup and view all the answers

What correlation does aging have on microbial diversity?

Decreased microbial diversity Signup and view all the answers

Which of the following statements regarding gut flora is true?

Gut flora can produce vitamin K Signup and view all the answers

What lifestyle factor has been shown to alter the gut microbiome positively?

Cohabitation with pets Signup and view all the answers

What do signaling molecules produced by gut flora indicate?

Satiety and hunger Signup and view all the answers

What effect does stress have on the microbiome?

Increases the permeability of the intestine Signup and view all the answers

What percentage of carriers of aureus are categorized as persistent carriers in the nose?

20% Signup and view all the answers

Which of the following is NOT a component of the tear film's antimicrobial properties?

Tear lipids Signup and view all the answers

Which bacterium is listed as part of the most common microbiota found on the eye?

Propionibacterium Signup and view all the answers

Which statement accurately describes normal microbial microflora?

Normal microflora inhabit both skin and mucous membranes. Signup and view all the answers

What is the primary way neonates begin to develop their microbiome post-birth?

By direct contact with caregivers and the environment. Signup and view all the answers

What is the estimated weight of the microbial flora of the gastrointestinal tract?

1 kilogram Signup and view all the answers

What is the primary role of the natural defense mechanisms of the eye against microbes?

Eliminate harmful microbes Signup and view all the answers

Which factor differentiates the composition of microflora in breast-fed versus bottle-fed infants?

The types of microbes introduced during feeding. Signup and view all the answers

Which of the following statements about transient microflora is correct?

Transient microflora can be beneficial but are not essential for health. Signup and view all the answers

How does the colonization of microflora occur immediately after birth?

Microbes are transferred from the birth canal and caregivers. Signup and view all the answers

What is the primary role of prebiotics in the human gut?

To provide a source of nutrients for beneficial bacteria Signup and view all the answers

How can the administration of antibiotics during early development impact a child's health?

It can predispose the child to allergies and immune system complications Signup and view all the answers

Which of the following statements about probiotics is true?

Probiotics can provide potential health benefits to the host when consumed Signup and view all the answers

What significant change can occur in normal microflora due to the use of antibiotics?

Significant alterations in gut, vaginal, and skin microbiomes Signup and view all the answers

Which of the following best describes a potential effect of probiotics on host health?

They may support digestive health and balance microbial populations Signup and view all the answers

What defines the microbiome in contrast to the microbiota?

Microbiome encompasses a wider range of components. Signup and view all the answers

How is the genetic material of the microbiome compared to that of the human genome?

It is about 200 times the number of human genes. Signup and view all the answers

Which of the following best describes the weight of the human microbiome?

Can weigh up to 2 kilograms. Signup and view all the answers

What components are included in the definition of 'microbiota'?

Microbial structures, metabolites, and genetic elements. Signup and view all the answers

What is a significant function of microbial diversity in the gut?

Enhances the immune response to food antigens. Signup and view all the answers

What are resident microflora best characterized by?

Permanent inhabitants of specific body sites. Signup and view all the answers

Which statement about the composition of the microbiome is true?

It includes a variety of organisms including bacteria and fungi. Signup and view all the answers

Which of the following statements accurately reflects the importance of genetic elements in the microbiota?

They enable horizontal gene transfer among microorganisms. Signup and view all the answers

What effect does a diet rich in plants and vegetables have on microbial diversity in the gut?

It increases microbial diversity. Signup and view all the answers

Which of the following lifestyle factors is associated with a reduction in inflammation?

Regular exercise Signup and view all the answers

How does aging affect microbial diversity in the gut?

It reduces microbial diversity. Signup and view all the answers

Which of the following statements regarding the function of gut bacteria is incorrect?

Gut bacteria are solely responsible for blood clotting. Signup and view all the answers

What role does the gut microbiome play in relation to the immune system?

It plays a crucial role in modulating immune functions. Signup and view all the answers

Which factor is not typically recognized as influencing the microbiome?

Clothing material Signup and view all the answers

How do signaling molecules produced by gut flora affect human behavior?

They influence emotional states and stress levels. Signup and view all the answers

Which statement about Lactobacillus species is true?

They contribute to maintaining low pH levels. Signup and view all the answers

What is one consequence of living in close contact with pets for children?

Altered gut microbiome leading to improved immune response. Signup and view all the answers

Which of the following best describes the relationship between stress and the microbiome?

Stress increases intestinal permeability, impacting gut health. Signup and view all the answers

Explain how the human microbiome develops over time and what initial factors contribute to its colonization.

The human microbiome develops rapidly after birth, primarily influenced by contact with the birth canal, caregivers, and the hospital environment. Signup and view all the answers

What differentiates the roles of resident microflora and transient microflora in the human body?

Resident microflora can multiply and persist in the body, while transient microflora are temporary and typically do not multiply. Signup and view all the answers

Discuss how breastfeeding or bottle-feeding influences the composition of a neonate's microbiome.

Breastfeeding typically promotes the growth of beneficial bacteria like Lactobacillus, whereas bottle-feeding results in different microbial colonization. Signup and view all the answers

What is the role of colonization in the early stages of life with respect to the immune system?

Colonization by microbial flora plays a crucial role in developing and training the immune system during early life. Signup and view all the answers

Describe one method by which normal flora protects the body from harmful organisms.

Normal flora inhibit harmful microbes through competitive exclusion, effectively occupying niches that pathogens might otherwise exploit. Signup and view all the answers

How does S.epidermidis contribute to the prevention of S.aureus colonization?

S.epidermidis produces antibiotics that inhibit colonization and can prevent S.aureus biofilm formation. Signup and view all the answers

What role do protease production and antimicrobial peptides play in the immune response against S.aureus?

Protease production signals the immune response to produce antimicrobial peptides, which kill S.aureus. Signup and view all the answers

Which microbial species are primarily found in the feet, and how do they differ from other body areas?

The feet host more species of fungi such as Malassezia and Trichophyton, compared to other skin areas. Signup and view all the answers

What are the typical bacteria and fungi present in the nasal cavity?

Common bacteria include Staphylococcus and Corynebacterium, while typical fungi are generally not specified. Signup and view all the answers

How do small molecules produced by Propionibacterium affect S.aureus?

They promote S.aureus aggregation and biofilm formation, which can exacerbate infections. Signup and view all the answers

What are examples of entities included in the microbiome but NOT part of the microbiota?

Phages, viruses, plasmids, free DNA, prions, and viroids. Signup and view all the answers

Why is the study of the microbiome considered highly personalized?

Microbiomes vary significantly among individuals, with estimates of 80-90% differences. Signup and view all the answers

What was the primary motivation behind the Human Microbiome Project?

The goal was to catalogue all microorganisms in the human body. Signup and view all the answers

How many human genes are estimated compared to the gut microbiome's genes?

Approximately 22,000 human genes compared to 3.3 million genes in the gut microbiome. Signup and view all the answers

What does the significant genetic difference between human genomes and microbiomes suggest?

It suggests that microbial genes may play critical roles in human health and physiological functions. Signup and view all the answers

In terms of study subjects, how was the Human Microbiome Project conducted?

It involved the study of major microbial sites from 300 healthy individuals. Signup and view all the answers

What institution sponsored the Human Microbiome Project?

The National Institutes of Health (NIH) in the U.S.A. Signup and view all the answers

What percentage of human genomes is considered identical across individuals?

Approximately 99.9% of human genomes are identical. Signup and view all the answers

What are opportunistic pathogens, and how do they differ from normal pathogens?

Opportunistic pathogens are normally non-pathogenic organisms that can cause disease when provided the right opportunity, whereas normal pathogens are typically always associated with disease. Signup and view all the answers

List two common portals of entry for pathogens in the human body.

Mouth and gastrointestinal tract, and skin. Signup and view all the answers

Identify three factors that can increase the risk of Candida albicans infection.

Pregnancy, diabetes, and the use of corticosteroids. Signup and view all the answers

What disease is commonly associated with Staphylococcus aureus and can lead to severe skin damage?

Scalded Skin Syndrome. Signup and view all the answers

Why are patients with compromised immune systems particularly at risk from Pseudomonas aeruginosa?

They are more susceptible to severe infections due to their weakened defenses against pathogens. Signup and view all the answers

How does Lactobacillus species contribute to the gut environment?

Lactobacillus species contribute by performing acid fermentation, leading to low pH and protection against harmful microbes. Signup and view all the answers

How can the skinfold areas of individuals become infected with Candida albicans?

Infections can occur due to hot, humid weather, poor hygiene, and wearing tight clothing. Signup and view all the answers

What are the two key contributions of gut bacteria to human health?

Gut bacteria help harvest nutrients from food and produce vitamin K essential for blood clotting. Signup and view all the answers

What is a significant complication that may arise from a Candida infection in individuals with weakened immunity?

Life-threatening systemic candidiasis. Signup and view all the answers

Describe the role of biofilms in Pseudomonas aeruginosa infections.

Biofilms protect the bacteria, making them more resistant to treatment and immune responses. Signup and view all the answers

What impact does diet have on the diversity of gut microbiome?

A diet rich in plants and vegetables promotes high microbial diversity, while a limited diet results in lower diversity. Signup and view all the answers

How does aging affect the microbial diversity in the gut?

Aging is associated with decreased microbial diversity, which can correlate with increased inflammation and frailty. Signup and view all the answers

In what way does living with pets influence the gut microbiome?

Cohabitation with pets, especially dogs, can alter the gut microbiome and reduce allergy development in children. Signup and view all the answers

What role do chemicals produced by gut flora play in human behavior?

Chemicals produced by gut flora act as signaling molecules that inform the brain about hunger and fullness. Signup and view all the answers

How does stress influence the gut microbiome?

Stress can change the gut microbiome by increasing intestinal permeability, potentially leading to dysbiosis. Signup and view all the answers

What lifestyle factor can help reduce inflammation in the gut?

Regular exercise has been shown to reduce inflammation within the gut microbiome. Signup and view all the answers

Name one effect of antibiotic therapy on microbiome composition.

Antibiotic therapy can lead to a significant reduction in microbial diversity in the gut. Signup and view all the answers

What is the relationship between a person's standard of living and their gut microbiome?

A person's standard of living influences their microbiome composition through factors like diet and environmental exposure. Signup and view all the answers

How do microbiomes differ from microbiota in terms of their definition?

Microbiomes encompass a broader range of microbes and genetic material than microbiota, which is more specifically defined. Signup and view all the answers

What is the estimated total weight of the human microbiome, and what significance does this weight suggest?

The human microbiome can weigh up to 2 kg, indicating its substantial presence and role in human health. Signup and view all the answers

Identify the primary sources contributing to the development of the human microbiome in infancy.

The primary sources include maternal contact, the environment, and nutrition, particularly through breastfeeding. Signup and view all the answers

Explain the role of metabolic activities of microbiomes in human health.

Microbiomes contribute to metabolic activities that aid digestion, synthesize vitamins, and protect against pathogens. Signup and view all the answers

Discuss how the genetic material found in microbiomes compares to that in the human genome.

The genetic material in the microbiome is about 200 times greater than that in the human genome. Signup and view all the answers

What is the significance of prokaryotes and eukaryotes in the concept of microbiota?

Prokaryotes and eukaryotes are essential components of microbiota, reflecting the diversity of life forms that interact within microbial ecosystems. Signup and view all the answers

Describe the importance of movable genetic elements within microbiota.

Movable genetic elements facilitate genetic transfer among microbes, enhancing adaptability and resilience in microbial communities. Signup and view all the answers

Discuss how the environment at birth influences the initial colonization of neonates' microbiomes.

The environment at birth, including contact with the birth canal and caregivers, rapidly introduces microbes to neonates, establishing the foundation for their microbiomes. Signup and view all the answers

Explain the difference in microbial colonization patterns between breast-fed and bottle-fed infants.

Breast-fed infants tend to develop a microbiome rich in beneficial bacteria like Lactobacillus, while bottle-fed infants may have a different microbial profile due to the formula used. Signup and view all the answers

What is one major impact of antibiotics on normal microbiota?

Antibiotics can significantly alter normal microbiota, potentially leading to reduced microbial diversity and increased susceptibility to infections. Signup and view all the answers

What role does transient microflora play in the human body compared to resident microflora?

Transient microflora can provide temporary benefits and protection against pathogens but do not usually multiply, unlike resident microflora which establish long-term populations. Signup and view all the answers

Analyze the impact of antimicrobial substances produced by normal flora on pathogen invasion.

Antimicrobial substances produced by normal flora inhibit the growth of harmful microbes, reducing the risk of infections in the host. Signup and view all the answers

Describe the significance of microbial diversity in the human gut and its relation to health.

Microbial diversity in the gut is crucial for metabolic functions, immune responses, and can prevent diseases, indicating a healthy microbiome. Signup and view all the answers

What is one major goal of the Human Microbiome Project?

To catalogue all the microorganisms of the human body. Signup and view all the answers

How does the diversity of an individual's microbiome compare to another?

It is estimated that 80-90% of microbiomes are different between individuals. Signup and view all the answers

Which non-microbial entities are included in the broader definition of the microbiome?

Phages, viruses, plasmids, free DNA, prions, and viroids. Signup and view all the answers

What significant difference exists between human genes and gut microbiome genes?

Humans have approximately 22,000 genes, while the gut microbiome contains about 3.3 million genes. Signup and view all the answers

Why is the microbiome considered to be highly personalized?

Because microbiomes of individuals can differ by 80-90%, despite human genomes being 99.9% identical. Signup and view all the answers

What is the main sponsorship source for the Human Microbiome Project?

The National Institutes of Health (NIH) in the U.S.A. Signup and view all the answers

What does the term 'microbiota' specifically refer to?

It refers to the collection of microbial communities living in a specific environment within the body. Signup and view all the answers

In what way does the human microbiome impact immunity?

It interacts with the immune system, helping to prevent infections and maintain health. Signup and view all the answers

What are pathogens and how are they typically specific to their hosts?

Pathogens are microorganisms that cause disease and are usually host-specific, meaning they infect particular species, such as humans or felines. Signup and view all the answers

Name one pathogen and the disease it causes.

Yersinia pestis causes bubonic plague. Signup and view all the answers

How can different pathogens result in similar diseases, particularly with meningitis?

Different pathogens such as N. meningitidis and H. influenzae type b can cause meningitis, showing that various organisms can lead to the same clinical syndrome. Signup and view all the answers

What distinguishes virulent strains of pathogens from less virulent ones?

Virulent strains cause more severe disease and have greater potential to cause harm compared to less virulent strains. Signup and view all the answers

Discuss the relationship between beneficial microbes and potential pathogens.

Many beneficial microbes can also act as potential pathogens under certain conditions, indicating a dual nature. Signup and view all the answers

What is a common viral cause of meningitis?

Most common viral causes of meningitis can include various types of viruses without specific treatments. Signup and view all the answers

Explain why most microorganisms are considered non-pathogenic.

Most microorganisms are non-pathogenic as they do not cause disease and often live symbiotically with their hosts. Signup and view all the answers

Provide examples of two bacteria that can cause meningitis.

N. meningitidis and Streptococcus pneumoniae are two bacteria that can cause meningitis. Signup and view all the answers

What percentage of the faecal population in breast-fed newborns is predominantly made up of Bifidobacterium?

90-99% Signup and view all the answers

Which types of microbes are typically found in greater variety in bottle-fed babies compared to breast-fed babies?

Mixed and varied population of microbes. Signup and view all the answers

What role does microbial antagonism play in the human body?

It helps compete with pathogens for nutrients. Signup and view all the answers

What primarily influences the development of different microflora in neonates?

Exposure to maternal and environmental factors. Signup and view all the answers

In which bodily areas are transient microflora typically found?

Eyes, upper urinary tract, kidneys, and bladder. Signup and view all the answers

What is the main source of microbial colonization in neonates immediately after birth?

Contact with the mother and surrounding environment. Signup and view all the answers

What impact does sebum content have on skin microbial populations?

It influences the diversity and types of microbes present. Signup and view all the answers

How does competition for nutrients affect the presence of pathogenic microbes?

It limits their ability to establish and grow. Signup and view all the answers

What distinguishes resident microflora from transient microflora in terms of presence duration?

Resident microflora are permanent, while transient microflora are temporary. Signup and view all the answers

What is one way that the skin microbiome contributes to overall health?

By preventing colonization of harmful pathogens. Signup and view all the answers

Study Notes

Overview of the Microbiome

Microbiome consists of various microbes in a system, including bacteria, viruses, fungi, and protozoa.
Contains genetic material from all microbes in and on the human body, with about 200 times more genes than the human genome.
Total weight can reach up to 2 kg.

Microbiome vs. Microbiota

Microbiota includes prokaryotes and eukaryotes, comprising microbial structures, metabolites, and movable genetic elements.
The microbiome encompasses a broader range, including elements not found in microbiota like phages, plasmids, free DNA, prions, and viroids.

Human Microbiome Project

Aims to catalog all microorganisms in the human body, extending the Human Genome Project.
Sponsored by the National Institutes of Health (NIH) in the USA.
Studies major microbial sites in 300 healthy individuals, including skin, mouth, nose, colon, and vagina.

Personalization of Microbiome

Microbiomes of individuals can differ 80-90%, despite human genomes being 99.9% identical.
The human gut microbiome contains approximately 3.3 million genes compared to 22,000 human genes.

Development of the Microbiome

At birth, neonates are microbe-free; rapid colonization occurs through contact with the birth canal and caregivers.
Types of feeding (breast vs. bottle) lead to different developments in microflora.

Benefits of the Microbiome

Established resident flora provides a barrier against external pathogens and opportunistic infections.
Bacterial interference may occur through competition for nutrients, receptor binding, and production of inhibitory substances (e.g., fatty acids, bacteriocins).
Normal flora prevents harmful microbial invasion by competing for resources and maintaining low pH environments.

Functions of Gut Bacteria

Help harvest nutrients from food, breaking down carbohydrates that humans cannot digest, contributing to approximately 30% of caloric intake.
Produce vitamin K for normal blood clotting.
Generate signaling chemicals that regulate hunger, satiety, and neurotransmitters like serotonin.

Factors Affecting the Microbiome

Diet: Long-term dietary habits can alter gut microbiome; plant-rich diets enhance microbial diversity, while limited diets reduce it.
Age: Aging is associated with decreased microbial diversity, linked to increased inflammation and frailty.
Lifestyle Influences:
- Cohabitation with pets: Exposure to pets can reduce allergy development and modify gut microbiome.
- Exercise: Promotes microbial health and reduces inflammation.
- Sleep deprivation: Correlates with adverse changes in the gut microbiome.
- Stress: Increases intestinal permeability, altering microbiome composition.
- Occupational factors and social environment can also impact the microbiome.

Definition and Composition of the Microbiome

The microbiome is a functional collection of diverse microbes, including bacteria, viruses, fungi, and protozoa, present in a system.
It contains genetic material from all microbes associated with the human body, with the number of genes being 200 times greater than those in the human genome.
The total weight of the microbiome can reach up to 2 kg.

Differences between Microbiome and Microbiota

Microbiota, defined in 2020 by a panel of over 100 experts, refers to the microbial structures, metabolites, and movable genetic elements, including both prokaryotes and eukaryotes.
Microbiomes encompass a broader range than microbiota.

Development of the Microbiome

At birth, neonates are microbe-free, but rapid colonization occurs through contact with the birth canal, caregivers, and the hospital environment.
Different feeding methods (breast vs. bottle) contribute to distinct microbial flora.
Example of early colonizers: Streptococcus haemolyticus within 4-12 hours after birth and persistent S. aureus found in about 20% of individuals.

Microbial Flora in the Eye

Bacterial presence on the eye surface is minimal due to effective natural defenses.
Key defense components include lysozyme, antimicrobial peptides, and immunoglobulins.
Common bacterial species found in the eye include Propionibacterium, Corynebacteria, Staphylococcus, and Streptococcus.

Gut Microbial Flora

Microbial flora in the gastrointestinal tract can weigh approximately 1 kg and constitutes 60% of the dry mass of feces.
Lactobacillus species aid in acid fermentation, resulting in a low pH, thus protecting against harmful microbes.

Benefits of Gut Bacteria

Gut bacteria assist in nutrient harvesting, breaking down carbohydrates that humans cannot digest, contributing to 30% of processed calories.
They produce vitamin K, essential for normal blood clotting.
Gut microbiota also generate signaling molecules that influence hunger signals and produce neurotransmitters like serotonin.
They play a crucial role in balancing beneficial and harmful bacteria, impacting immune functions and metabolism.

Factors Affecting the Microbiome

Various factors influence normal flora composition, including:
- Sex
- Diet: Long-term diets can significantly alter the gut microbiome; plant-rich diets boost microbial diversity.
- Age: Increased age leads to reduced microbial diversity, linked to inflammation and frailty.
- Lifestyle Choices:
  - Cohabitation with pets: Exposure to dogs can positively affect the gut microbiome and reduce allergy risks.
  - Exercise: Known to lower inflammation levels.
  - Sleep deprivation: Correlates negatively with a healthy microbiome.
  - Stress: Increases intestinal permeability, altering the microbiome.
  - Occupation: Differences in microbiomes seen between farmers and office workers.

Effects of Antibiotics

Antibiotics can disrupt both targeted pathogens and normal microbiota, leading to significant shifts in microbial composition across gut, vaginal, and skin flora.
Early antibiotic administration may hinder the development of normal microflora and the immune system, potentially increasing susceptibility to allergies and autoimmune disorders.

Probiotics and Prebiotics

Prebiotics: Specific non-digestible carbohydrates that serve as nourishment for beneficial microbes, stimulating their growth.
Probiotics: Live microorganisms that may confer health benefits upon consumption, such as Bifidobacterium and Lactobacillus species.

Microbiome Overview

Includes entities like phages, viruses, plasmids, free DNA, prions, and viroids that are NOT part of the microbiota.
The human microbiome project aims to catalog all microorganisms in the human body, extending the human genome project and funded by NIH, USA.
Study involved 300 healthy individuals across major microbial sites: skin, mouth, nose, colon, and vagina.

Personalization of Microbiomes

Individual microbiomes are highly personalized with estimates stating 80-90% differences across individuals.
Human genomes are 99.9% identical whereas the gut microbiome consists of about 3.3 million genes compared to 22,000 human genes.

Normal Microbial Flora

Normal flora includes both resident and transient microorganisms.
Resident flora can multiply, while transient flora usually cannot.
The human body provides diverse habitats suitable for different microbial populations.

Microbiome Development

At birth, the neonate starts microbe-free; rapid colonization occurs via the birth canal and environment.
Breastfeeding or bottle-feeding leads to distinct microflora development.
Early colonizers include a-haemolytic Streptococcus within hours post-birth.
Coagulase-negative Staphylococcus can inhibit the colonization of more harmful microbes like S. aureus.

Microbiota of the Feet

Foot microbiota are distinct, harboring more fungal species than other body areas.
Common bacteria include Corynebacteriaceae, Micrococcaceae, and Propionibacteriaceae, with fungi such as Malassezia, Cryptococcus, Aspergillus, Trichophyton, and Candida.

Nasal Microbiota

Microbial composition of the nose resembles that of skin.
Approximately 20-30% of the population are carriers of S. Lactobacillus species, which contribute to low pH via acid fermentation.

Benefits of Gut Bacteria

Gut bacteria assist in digesting nutrients humans cannot, accounting for 30% of caloric processing.
They produce vitamin K essential for blood clotting and signaling molecules related to hunger and satiety.
Gut flora play roles in immune response and metabolic functions, maintaining a balance between good and bad bacteria.

Factors Affecting Microbiomes

Diet significantly influences gut microbiome diversity; plant-rich diets enhance microbial variety.
Aging correlates with decreased microbial diversity, linked with inflammation and frailty.
Lifestyle factors including cohabitation with pets can reduce allergies and alter gut microbiome.

Pathogenic Microorganisms

Opportunistic pathogens like Candida albicans and Staphylococcus aureus can cause infections under conducive conditions.
Candidates for infection include: poor hygiene, tight clothing, and corticosteroid use increase vulnerability.
S. aureus is noted for conditions such as Scalded Skin Syndrome, Toxic Shock Syndrome, and MRSA prevalence.

Pseudomonas aeruginosa

Ubiquitous in various habitats, particularly in human and animal impacted environments.
It poses significant risks for immunocompromised individuals and can cause severe infections like microbial keratitis in contact lens wearers.

Terms to Know

Pathogenic: capable of causing disease.
Non-pathogenic: not capable of causing disease.
Contamination: presence of infectious agents.
Colonization: establishment of microorganisms.
Infection: invasion leading to disease.
Opportunistic pathogen: causes disease when host is compromised.

What is the Microbiome?

Defined as a functional collection of diverse microbes, including bacteria, viruses, fungi, and protozoa.
Contains genetic material from all microbes in and on the human body.
The human microbiome’s gene count is 200 times that of the human genome.
Microbiome can weigh up to 2 kg.

Microbiome vs Microbiota

Microbiota: Includes prokaryotes and eukaryotes, consisting of microbial structures, metabolites, and movable genetic elements.
Microbiome: A broader concept, containing additional elements not found in microbiota such as phages, viruses, plasmids, free DNA, prions, and viroids.

Human Microbiome Project

Aims to catalog all microorganisms in the human body.
An extension of the Human Genome Project, funded by the National Institutes of Health (NIH) in the U.S.
Studies major microbial sites across 300 healthy individuals, including skin, mouth, nose, colon, and vagina.

Personalization of the Microbiome

Microbiomes are highly personalized, with estimates indicating 80-90% difference between individuals.
Despite human genomes being 99.9% identical, gut microbiomes contain approximately 3.3 million genes compared to 22,000 human genes.

Normal Microbial Microflora

Normal flora includes both resident and transient microflora on human skin and mucous membranes.
Resident microflora: Permanently found, re-established if removed, plays a role in microbial antagonism.
Transient microflora: Temporarily present, influenced by the environment, not usually replicating significantly.

Development of the Microbiome

At birth, neonates are free of microbes; rapid colonization begins with contact from the birth canal and caregivers.
Breastfeeding establishes different microbial populations compared to bottle-feeding.
Bifidobacterium is predominant in breast-fed infants, making up 90-99% of fecal bacteria.

Microbial Populations of the Body

Normal microbiota may include pathogens even without causing symptoms.
Pathogens are specific microorganisms that can cause diseases such as Yersinia pestis (bubonic plague) or Treponema pallidum (syphilis).
Variability in skin characteristics affects microbial populations.

Beneficial Microbes and Pathogens

Many beneficial microbes can behave as potential pathogens under certain conditions.
Pathogens differ in virulence; some strains cause milder diseases compared to others.
Meningitis can be caused by various pathogens including bacteria and viruses, highlighting the complexity of microbial diseases.

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Description

This quiz introduces the concept of the microbiome, focusing on its definition, development, and the difference between resident and transient microflora. Explore how various microbes function collectively within biological systems, enhancing your understanding of this essential biological component.