Microbio Test 4

Environmental Contact: What is Implant?

Microorganisms establish permanent residence in the body (e.g., biofilm on a medical implant or inside tissues). This usually leads to persistent infection.

Environmental Contact: What is Transient?

Microorganisms are temporarily present (e.g., on skin or surfaces). They do not necessarily cause harm unless they gain entry into the body or immune defenses are weak.

Environmental Contact: What is Invade?

Microorganisms enter and multiply inside host tissues, overcoming barriers like skin or mucous membranes. This typically leads to an active infection.

Why is the body a favorable habitat for and abundance of organisms?

Stable Temp. (homeostasis), pH, nutrients, H2O, surface area

Normal diversity promotes __ and _ promotes disease.

health, dysbiosis

What is dysbiosis?

Dysbiosis is an imbalance or disruption in the normal microbial community of the body—usually in the gut, but it can also occur on the skin, in the mouth, or other areas where microbes naturally live.

Hygiene Hypothesis: Antibiotics and lifestyle that lower microbial exposure -

Predisposes people to autoimmune disease

Hygiene Hypothesis: Antibiotics disturb microbiota meaning -

co-evolutionary relationship between our immune system and symbionts we host

Why should children be exposed to organisms (“go play in the dirt”)

So they can build their immune system

Microbiota can modify its microhabitat by:

-altering pH and oxygen tension

-excreting chemicals (acids/alcohols/antibiotics/bacteriocins)

-creating barriers (chemical and physical)

What are Bacteriocins?

Antibiotics where bacteria kill off close relatives

Overall, what does Normal Flora do?

Protect you (nutritional and promotes health)

Normal Flora is a complex mixture of:

Prokaryotes, eukaryotes, and viruses

Is everyone’s normal flora the same?

No, differs in quality and quantity between individuals

Although normal flora is relatively stable -

the flora fluctuates to a limited extent

What causes NF to fluctuate?

Antibiotics/drugs

Diet/nutrition

Exercise

Stress

Hydration

What does normal flora affect?

EVERYTHING

How high is the variability of bacteriophages?

<5% = symbiotic relationship

What is the role of viruses in NF?

They keep certain bacteria numbers low

What percent of viruses have never been reported?

>80%

Because viruses carry genes for carbohydrates and amino acid synthesis they -

influence bacteria metabolism

What is an example of Dysbiosis?

Irritable Bowel Disease

Because there are viral genes found in eukaryotic cells, this -

complicates studies on disease process

How is the disease process complicated?

See decrease in bacterial diversity and increase in bacteriophages meaning viruses have big effect

What did we used to think about the gut of babies vs. now?

Before 2015 we used to think babies were born sterile, now we know there is bacteria in the placenta/cord blood/ womb.

Colonization __ as contact continues

increases

Normal flora initially colonize the __ of bottle fed babies

large intestine

The mixed population of coliforms include:

(gram negative rods)

• E. Coli

• Enterobacter sp.

• Klebsiella sp.

What bacteria have a role in development of the gut?

Lactobacillus, enteric Streptococcus, Staphylococcus

What bacteria does intestinal flora start off with?

E.coli and Streptococci

Shortly after E.coli and Streptococci, what becomes the primary #1 and #2 species of bacteria in the intestines?

1. Bifidobacterium

2. Lactobacillus species

Breastmilk produces >200 different __

oligosaccharides

Oligosaccharides in breast milk vary in type and content making them:

complex and dynamic

Are formulas substitute for breastmilk

No, formula cannot imitate exactly breastmilk

Breastmilk organisms change as:

the baby develops over time

What are some beneficial properties of Bifidobacterium and Lactobacillus (in adults and babies)

• maintain the normal intestinal balance

• Improve lactose tolerance

• antitumorigenic activity

• Reduce serum cholesterol levels

• Promotes calcium absorption

• synthesis of B complex vitamins (metabolism cofactors)

• Reduce or prevent the excretion of rotaviruses

What should you look for when buying greek yogurt:

“live/active cultures”

What are probiotics?

Microorganisms taken orally that promote health and reestablish the natural balance of NF

What are prebiotics?

Nondigestible dietary fiber ie. inulin promotes growth of probiotics

What is the difference between PRO and PRE biotics?

PREbiotics serve as food for PRObiotics

What do probiotics mainly do?

– Maintain desirable microbial community

– Stabilize gut barriers

– Produce of inhibitory substances

– Stimulate immune response

Does the FDA regulate supplements?

No, but European countries do

What are the industry standards for probiotics?

Easy to produce in high numbers

No off flavors

Must retain function through manufacture, transport, and storage

What two bacteria are found in a lot of body sites?

Staphylococcus and Streptococcus

Although each person has unique NF, there are some patters in -

Bacteria, yeasts, and viruses

Although skin has no gram __ bacteria, it DOES have -

gram positive bacteria and yeasts

Skin is __ and _

acidic and salty

What part of the body is the most diverse? What 3 distinct microbiomes does it have?

Skin, 3 microbiomes: Moist, Oily, and Dry

Why is the skin not a favorable environment for most microorganisms making it not very diverse for microbes?

• periodic drying

• slightly acidic pH (~6.5)- bact metab releases acids

• Sweat = hi [salt] causes osmotic stress

• Lysozyme (enzyme in all body secretions)

– Breaks β1-4 linkages between NAG & NAM

What is the only enzyme that breaks that cut the cell wall (peptidoglycan)

Lysozyme

What does P. acnes (protective strains) produce on normal skin?

Protective thiopeptides which block other gram + bacteria

What do oil glands secrete?

Complex lipids partially degraded by the enz from certain gram + bacteria (Propionibacterium acnes)

What does Propionibacterium acnes contribute to?

Keeps other bacteria check

Healthy in low numbers

High oil during puberty is volatile

Oil metabolized into fatty acids

High skin inflammation = ACNE

What is the treatment for acne?

Skin probiotics

What does MRSA mean?

Skin infection

What did we used to think before about the Eye before and what do we know currently?

Before: very limited flora - nonpathogenic Corynebacteria and Staphylococcus epidermidis

Currently: All exposed mucosal surfaces are populated including the eys

If the gut has high diversity and the skin has low diversity, where does the eye’s diversity fall?

In the middle so medium

During infection: you see a __ in bacterial diversity and see an _ Pseudomonas aeruginosa sp. which is an:

decrease, increase: indicator / diagnostic for infection

The outer ear is populated with bacteria often seen on the __

skin

Pseudomonas aeruginosa in the middle ear causes:

swimmer’s ear

Breast fed babies have less ____ than bottle fed babies

ear infections

In adults, there’s a __ in the Eustachian Tube that protects against _

bend thats not present in children, bacteria in the throat

A middle ear infection is high in __ and _ leading to pressure and pain.

increase and fluids

Although antibiotics used to treat swimmers ear protect against bacteria, they don’t __

remove the fluids

Organisms in the mouth survive mechanical removal like swallowing how?

by adhering to the surfaces

What bacteria are present in saliva?

Streptococci, Staphylococci, Neisseria, Lactobacilli, several fungi and protozoans

The structure of the mouth’s microbiome is not random but __

in layers

What makes up the first layer of bacteria in the mouth?

Streptococcus

What is a Biofilm formation?

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

Streptococcus sp. causes:

dental plaque, dental caries, gingivitis, and periodontal disease

Bad dental hygiene can lead to __

heart disease

Biofilm formation increases __

Pathogenesis

What is Pathogenesis?

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

Why are biofilms antibiotic resistant?

o May not be able to penetrate

o Degradation

o Adsorbed onto matrix

o Changing microenvironment

o Anaerobic niches

o Acidic waste

How do you get rid of a biofilm in the mouth?

Mechanical scraping

The upper flora in the respiratory tract is similar to _

the oral cavity (streptococci)

Historically, lungs where considered to be _

sterile

How are microbes removed from the lungs?

– continuous stream of mucus generated by ciliated

epithelial cells (ciliary escalator)

– phagocytic action of alveolar macrophages

– lysozyme in mucus

–sIgA (Antibody- specific immune response

protein- found in all body secretions)= Ab protects

epith layer

What is the difference between Antibodies and Antibiotics?

Antibody - a protein the body makes

Antibiotic - something you give a patient

Although the lungs are populated by bacteria they are __ in numbers and _

not confluent but instead in islands / patches

Lungs coated with oily __ allows movement of lungs and acts as __

surfactants, acts as antimicrobial peptides (AMPs)

Someone with cystic fibrosis has:

not enough fluid in their lungs

The epiglottis is alcoholics is often lazy and stays open allowing;

bacteria/fluids into their lungs leading to infection

Lazy macrophages in alcoholics=

increase in bacteria

Smoking destroys __ meaning less removal of mucus and __ in pathogens and infections

cilia, decrease

Why do bladder infections occur predominantly in women?

Women have a shorter urethra than men, which means bacteria have less distance to travel to reach the bladder.

Additionally, the female urethra is located closer to the anus, increasing the chance of bacteria entering the urinary tract. 

complex microbiota in the female genital tract is in a state of __ due to _

Flux due to menstrual cycle (change in hormones & blood flow)

Estrogen stimulates glycogen production →

glycogen is then used by Lactobacillus to produce ____________=↓pH (~pH 5)

Lactic acid

What is predominate in the female genital tract?

Lactobacillus

Together births and preterm babies see __ lactobacillus and _ bacterial diversity

low, high

Low diversity is __ high diversity is

healthy, bad

Lifetime risk of HPV infection is ___

>50%

During the AID/HIV epidemic, what kind of cancer infections went up?

Throat because oral sex increased

How is HPV spread?

Through skin contact, but even without the virus can be spread

What is an instance where you can vaccinate a cancer?

HPV Vaccine

__ causes airway obstruction due to warts in the mouth, which requires laser excision to remove

Recurrent respiratory papillomatous (RRP)

Can HPV be spread to babies?

Yes

How can HPV be fatal?

Spread to distal airways and malignant

Vaginal spermicide, nonoxynol-9 (N-9), ↑↑↑ susceptibility=

disrupts __________

epithelium

Spermicide increases the chance of getting:

HIV/HPV