PPT12 Normal Flora - Micro

What is normal flora?

are the microorgs that naturally inhabit various sites of the human body without causing disease under normal conditions

What is the difference between resident and transient flora?

resident flora are microorgs that are permanently present in a particular location of the body, while transient flora are temporary residents that can be washed away or displaced

Where is normal flora typically found in the human body?

normal flora are found in areas such as the skin, mouth, gi tract, respiratory tract, and urogenital tract

What is the the role of normal flora in human health?

normal flora help in digesting food, synthezing vitamins, stimulating the immune system, and preventing the growth of harmful pathogens

How can normal flora become pathogenic?

under certain conditions, such as a weakend immune system, injury, or when normal flora enters normally sterile area, they can become opportunitstic pathogens and cause disease

What is an example of an opportunistic pathogen that is part of normal flora?

candida albicans. which is part of normal flora in the mouth and gi tract, can use infections like trush or vaginal yeast infections in immunocompromised individuals

What factors can alter the balance of normal flora?

antibiotics, diet, illness, hygiene

What are some common areas where normal flora is found?

skin, mouth, throat, intestines, respiratory tract and genital

What is the significance of normal flora in preventing infections?

compete with pathogenic orgs for resources and space, helping to prevent infections by outcompeting harmful micobes

What is another term for the “microbiome”?

normal flora

Approx how many prokaryotic and euk microrgs does the human body harbor?

about 10¹⁴ microorganisms.

What are three types of env microbial contact with body?

implant, transient, and invade

Why is the human body a favorable habitat for microorganisms?

bc of stable temp, pH, nutrients, water, large surface area

What was the main finding of the microbiome project (2014)?

normal microbial diversity promotes health, while dysbiosis promotes diease

What does the hygiene hypothesis suggest?

that antibiotics and lifestyle choices that decrease microbial exposure predispose people to autoimmune diseases

How do antibiotics affect the microbiota?

they distrub the mitochondria and disrupt the co-evolutionary relationship between our immune system and the symbiotic migrogs we host

How can mitochondria modify its microhabitat?

by altering pH and oxygen tension, excreting chemicals (acids/alcohols/antibiotics/bacteriocins), creating barriers both chemical and physical

Bacteriocins

antibiotics where bacteria kills off close relatives

What are the overall features of normal flora?

protective, nutritional and promotes health

What differs somewhat in quality and quantity between individuals?

normal flora

Nf is _ stable

relatively

What affects the stability of NF?

antibiotics, diet, exercise, stress, sleep

Where are viruses found as part of the normal flora?

in feces and on mucosal surfaces

How stable aer viral genes over time?

viral gene are relatively stable

What is the variability of bacteriophages in the human microbiome?

less than 5% suggesting a symbiotic relationship

What percentage of viruses found have never been reported?

over 80%

How do viruses influence bacterial metabolism through transduction?

carry genes for cho metab and aa synth

How do viruses complicate the study of disease processes like IBD (Irritable Bowel Disease)?

they affect/decrease bacterial diversity and increase bacteriophage numbers, leading to dysbiosis.

Before 2025, what was the belief about the babys env before birth?

babies were believed to be in a sterile env

According to research after 2015, where can bacterial colonization occur before birth?

in the placenta, cord blood, and womb

Where does colonization occurs?

before birth

What happens after birth regarding microbiome acqusition?

the newborn is colonized firther as contact with the env continues

What part of the body is initially colonized by normal flora after birth?

the large intestine

What type of microbial population colonizes bottle fed infants?

a mixed one

Name three coliforms (gram neg rods) that initially colonize the large intestine?

escherichia coli, enterobacter species, klebsiella species

What additional bacteria are involved in early colinization?

lactobacillus, enteric streptococcus, and staphylcoccus

What role do bacteria have in the human body?

in development of gut

In a breastfed baby what does intestinal flora begin with?

e. coli and streptococci

After a short time, which bacteria primarily dominate the gut of a breastfed baby?

primarily bifidobacterium and also lactobacillus

How many different oligosaccharides does breastmilk produce?

over 200 different oligosaccharides (short-chain sugars)

In what ways do the oligosaccharides in breastmilk vary?

in concentration and content

Why can formulas not imitate breastmilk effectively?

bc breastmilk’s oligosaccharides are complex and dynamic

What advancement has research made regarding breastmilk oligosaccharides?

researchers identified 2 oligosaccharides and incorporated them into formula

What are the beneficial properties of bifidobacterium and lactobacillus in adults and babies?

maintain the normal intestinal balance, improve lactose tolerance, antitumorigenic activity (reduces cancer), reduce serum cholesterol levels, promotes calcium absorption, synthesis of b complex vitamins, reduce/prevent the excretion of rotaviruses

What is the purpose of oral administration of probiotics?

to promote health and reestablish the natural balance

Non-digestible dietary fiber is also known as

prebiotics

Which is host specific: probiotics or prebiotics?

probiotics

What microorg maintains desirable microbial community, stabilize gut barriers, prodice of inhibitory substances, and stimulate immune response?

probiotic microorg

What are attributes of probiotic bacteria?

nonpathogenic, no toxin produced, efffective, easily cultured, and cn withstand acid and bile

What are good sources of prebiotics?

insulin, onions, garlic, leeks, apples, bananas, cocoa, flaxseed, sauerkeaunt, kefir

What microorg are found in a lot of sites around the body?

staphylcoccus and streptococcus

What type of bacteria does skin have?

gram pos and yeast

What is the most diverse part of the body?

the skin

What are the distinct microbiomes of the skin?

moist, oily, dry

Why is the skin not a favorable environment for most microorgs?

bc it is not very diverse

Why is the skin not diverse?

periodic drying, slightly acidic pH, sweat=hi salt causes osmotic stress. lysozyme breaks down B1-4 linkages between NAG and NAM (cuts cell wall)

What is lysozyme?

enzyme in all body secretions

What is P. acnes?

protective strain on normal skin

What does P. acnes produce?

thiopeptides which block other grampos bacteria

What conditions exist in the oil glands of theskin that affect bacterial growth?

anaerobic conditions

What does normal skin produce to block other gram pos bacteria?

protective tripeptides

What happens when the microbiome on the skin is unhealthy?

overgrowth of bacteria like staphylococcus and skin inflam

Where do Staphylococcus bacteria tend to grow in the skin?

in oil glands under anaerobic conditions.

What do oil glands secrete, and how is this related to acne?

they secrete complex lipids that are partially degraded by gram pos bacteria, leading to oil and inflam

How does P.acnes contribute to acne formation?

it metabolizes oil into violate fatty acids, causing skin inflammation and acne

Treatment for acne?

skin probiotics

Which is very limited to flora and nonpathogenic?

the eye

Which exposed mucosal surfaces are populated?

all including the eye

The _ has a huge variation of bacteria

eye

What happens to an eye during infection?

decrease in bacterial diversity and increase in pseudomonas sp

What is Pseudomonas sp., an indicator of?

eye infection

What bacteria is often seen on the outer ear?

staphylcoccus and streptococcus

What bacteria is often seen on the middle ear and cause swimmer’s ear?

presudomonas aeruginosa

Recipe for homemade ear drops?

alcohol 70%, vinegar, hydrogen perozide

What cause a middle ear infection?

increase in bacteria and fluids

When taking antibiotics for ear infection what occurs?

kills bacterial but doesn;t remove fluids

In an adult what protects against bacteria from the throat?

a bend in the eustachian tube

In regards to the ear, what is not as firmly developed in children?

eustachian tube

Large population with many different microbiomes is known as…

the mouth

How do organisms survive mechanical removal?

swallowing by adhering

What is saliva made of?

streptococci, staphylococci, neisseria, lactobacilli, several fungi, and protozoans

What can happen if normal flora are wiped out by antibiotics?

Overgrowth of opportunistic organisms like Candida, leading to candidiasis (a fungal infection).

What is the structure of microbiome for the mouth?

in layers

What forms the first layer of structure for the mouth?

streptococcus sp.

What is biofilm formation?

a community of bacteria that excrete a sticky matrix for attachment and persistence (antibiotic resistant)

What can plaque cause?

cardiovascular disease

Which bacteria contributes dental plaque, dental carries, gingivitis, and periodontal disease?

streptococcus sp

What does biofilm formation increase?

pathogenesis

What are biofilms?

community of bacteria that excrete a sticky matrix for attachment and persistence

Thwarts Immune Response

phagocytes repelled, inflam response = damages host cells