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Introductory Microbiology > Normal microbiome of humans > Flashcards

Normal microbiome of humans Flashcards

1
Q

Most microoganisms in human microbiome are

A

Most are commensals, few contribute to health (beneficial) and fewer pose direct threats to health

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2
Q

When do humans are colonized with microbiome and changes with

A

Colonized at birth

Changes over time and according to the condition of the host (diet, environment, sex, occupation, etc.)

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3
Q

Microorganisms in human gut are usually associated with

A

Human body tissue

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4
Q

What is the change of the microbiome through 2 years of life

A
  • At first only firmicutes (first 5 days)

- Then changes when there is fever or when introduced to solid food

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5
Q

What is the stability of the microbiome throughout the life

A

In infancy- the diversity is very low and the stability is low

Throughout the childhood and into the adulthood the stability increases

From the adulthood into the senior stability decreases

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6
Q

What is microbial cloud

A

The microbes that the person are emitting the organisms and you can differentiate two people with this clouds

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7
Q

Explain the structure of the skin

A

The upper layer->dead layer
Then underneath -> living actively replicating cells

Subaceous glands, apocrine sweat glands: secretes salt water, with various amounts of proteins, lipids, and sugars. Secrections are slightly acidic and have some antimicrobial effects (lipids and proteins)
Sebaceous glans surrounds the hair follicle

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8
Q

What is the purpose of the dead cell layer

A

Forms a tough layer barrier that prevents microorganisms from penetrating deeper tissues

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9
Q

What is the usual conditions on the skin

A

Dry, acid environment that does not support the growth of most microorganisms

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10
Q

The ducts that carry secretions to the surface are colonized by

A

A few well-adapted species (gram-positive)

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11
Q

The normal microbiome of the skin secretes

A

Bacteriocin that kills incoming competitors and protects- to a certain extent- against colonization by harmful bacteria

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12
Q

What anaerobes (aerotolerant) bacteria inhibit the skin

A

Propionobacterium acnes (in hair canals)

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13
Q

What organisms populate the skin

A

Yeasts, molds, bacteria

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14
Q

What organisms in specific populate the skin

A

Actinobacteria and firmicutes (gram-positive)

Proteobacteria -(gram-negative)

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15
Q

The type of microbiome on the skin depends on

A

The type of skin ( moist, etc.)

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16
Q

What bacteria populate the skin

A

Mycobacterium
Staphylococcus
Streptococcus

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17
Q

What niches are there in oral cavity

A

Aerobic and anaerobic

18
Q

The teeth consist of

A

A mineral matrices (enamel) surrounding living tissue (dentin and pulp)

19
Q

How bacteria colonize teeth surfaces

A

Firstly, they attach to acidic glycoproteins deposited there by saliva

20
Q

What is the dental plaque

A

Streptococci- a thick layer

In the presence of sucrose-from diet- Streptococcus mutans synthesizes extracellular polysaccharides (dextran) that aid its attachment to the tooth surface (form extracellular matrix,ECM)

21
Q

How do we get dental cavities

A

Plaque develops->anaerobic bacterial species begin to grow.

S.mutans and various lactobacilli-ferment sucrose and produce lactic acid that demineralizes the tooth enamel (solubilizes calcium)

22
Q

What is pH in 3 regions of GI tract

A

Stomach-2
Small intestine- pH4-5
Colon- pH-7

23
Q

What microorganisms you can find in the stomach, small intestine and colon

A

Stomach- helicobacter

Small intestine- enterococci, lactobacilli

Colon-Ruminococcus!!!

24
Q

In what microorganisms we can find Ruminococcus

A

Cows
Termites
Humans

25
Q

How mocroorganisms can get though to colonize the lower intestine if stomach is very acidic

A

In food particles

26
Q

What microorganisms can be found in colon

A

Mostly strict anaerobes or facultative aerobes: Bacterioides, enteric bacteria (E.coli),yeasts, anaerobic protozoa (Entamoeba coli)

Firmicutes (64%)

27
Q

What is the happening with microorganisms in the human colon and food?

A

Microorganisms digest complex carbohydrates (cellulose, starch, etc.) and produce volatile FAs

Intestinal microorganisms of the large intestina ferment VFAs and produce gas (CO2 and H2). Methanogens convert CO2 and H2 to CH4 (found in 1/3 of adults)

Sulfates and we do use serious and organisms that can ferment cysteine and methionine produce H2S. Organic sulfur compounds mythanethiol are responsible for the smell

28
Q

Intestinal microorganisms carry out a variety of essential metabolic functions what are they

A
  • Amino acids
  • Vitamin (B12, K , thiamine, riboflavin, etc.)
  • Contribute to maturing of GI
  • Affect early development, health, and predisposition to disease
  • May play role in obesity
29
Q

What is the difference in bacterial population in fat mice

A

Fat->less bacteroidetes

30
Q

Microbiome of the nose is similar to

A

Nasopharynx and mouth

31
Q

What is the microbiome in mouth and nose

A

Staphylococci, streptococci, corynebacteria

32
Q

What microorganisms may harbor potential pathogens that are under control by the host immune system for a healthy carrier

A

Streptococcus pneumoniae
Haemophilus influenzae
Neisseria meningitidis

33
Q

What the recent research found about lower respiratory tract

A

it was thought that it is sterile, but recent study showed that it harbors a microbiome (low biomass)

34
Q

Sterile zones in human body normally

A

Blood
Spinal fluid
Internal portion of urinary tract
Peritoneal cavity (gut cavity)

Pleural cavity(lung cavity)

Sinuses
Interior region of other body tissues (bones)

35
Q

Why genitourinary tract of men and the urinary tract of woman are generally free of microorganisms

A

Due in part to the flushing action of urine

36
Q

What can cause potential pathogens in the urethra to multiply and cause disease

A

change in pH

37
Q

WHat normal microorganisms of the gastrointestinal tract can cause urinary tract infections

A

E.coli

Proteus mirabilis

38
Q

What control the glycogen concentration of the vaginal epithelium

A

Hormones

39
Q

What do microorganisms do in vagina

A

Degrade glycogen and produce lactic acid which reduced the pH of the vaginal tract to 4.5

40
Q

What is the glycogen level and pH of vaginal secretion before puberty, sexually mature and after menopause

A

Before puberty and after menopause->low glycogen and alkaline environment

Sexually mature->high glycogen and acidic pH

41
Q

Microbial flora in vagina before puberty, sexually mature and after menopause

A

Before and after->staphylococci,streptococci,coliforms,corynebacteria
Mature->lactobacilli,streptococci,corynebacteria,Candida albicans

Introductory Microbiology (21 decks)

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