and Viruses, Fungi, Protozoas, and Bacteria (MOSTLY)
How many species live within and on us?
about 501 species/orgnaism:
1 species of Human: 10 trillion human cells
500 species of bacteria:100 trilion bacerials cells
2-3 lbs of bacterial cells
Mouth=billions of bacertial cells
Skin= 10x more than mouth
GI= 1000x more than mouth
Locations of Normal Flora
Skin
EVERYWHERE
Locations of Normal Flora
G.I. Tract
Oropharynx- HIGH
Stomach- Low (b/c of stomach acids)
Small Intestine- Medium
Large Intestine- HIGH
** HIGH because open to enviroment (TOP and BOTTOM)***
Locations of Normal Flora
Respiratory tract
Oropharynx: HIGH
Lungs: NONE (should be sterile)
Locations of Normal Flora
Fermale Reproductive Tract
Vaginal Canal: High
Uterus: None
Locations of Normal Flora
Urinary Tract
Urethra: Low
Bladder: None
Locations of Normal Flora
Nervous, Bone and Muscle... SHOULD BE STERILE!!!
Why are UTIs, respiratory infections and middle ear infections so common?
UTI- opening to the bladder (urethra) are so close to dirty regions
Respiratory infections- Close to a dirty region... oropharynx
Ear infections- Eustation tube (tube that connects the middle ear to oropharynx)
SYMBIOSIS- Living Together
Colonization:
Normal flora:
Commensalism: micro benefits, host is unharmed (ex. some microbes on skins are harmless, nonbeneficial
Normal/beneficial flora
Mutualism: microbe and host benefit (ex. some microbes in intestinne assist with Vitamin K)
Symbosis: Living Together
Infection
Normal/Harmful Flora (aka OPPORTNISTIC pathogens)- normal flora turns pathogenic (ex. some microbes in mouth can cause cavities)
Exogenous Pathogens (usually require "exposure");
----Parasitism: microbes benefits, host is harmed (most viruses)
Microbe benefits, host is unharmed:
A. Commensalism
Microbe benefits, host is harmed
C. Parasitism
Some microbes in intestines assist with vitamin K is an example of....
Mutualism (BOTH mutual... BENEFIT)
An example of opportunistic pathogen:
Some microbes in the mouth can cause cavities
Sources of Healthy Flora
Fetal vs. Adult Intestions
Fetal: 100% have NOOOOOO bacteria (sterile)
Adult: 100% HAAAVVVE bacteria in LARGE amounts
Sources of Healthy Flora:
Newborn:
Vaginal cana- Lactobacillus (increase during pregnancy)
Hands- Lactobacillus, E.Coli, Bifidobacteria
Nipples- Bifidobacteria
Mothers's mouth- Streptococi, Neisseria
Everyone else
Normal flora in 1-2 years
Diversity of Normal Flora:
-Diversity w/ different locations: Bacteria adapted for specific areas(via receptors, nutrients, pH)
-Diversity w/ different ages: Bacteria change throughout lifetime (due to exposure, hormones, diet, lifestyle)
-Diversity w different individual: Not eveyone has same flora (due to genes, gender, race, polymorphisms)
Benefits of Flora:
-Inhibit invasion by pathogens: Compete for attachment sites, Create non-optimal pH
-Inhibit colonization by pathogens: Compete for nutrients, Secrete bacteriocidal/static substances (keeps it from replicating)
-Sources of vitamins- Some synthesize vitamin B and K
LOOOOVE your flora!
- Animal experiments:
w/ flora: can take 1 million salmonella bacteria to kill it
w/out flora: can take 10 salmonella bacteria to kill it
-Humans
W/out flora: would be dead in 2 weeks if all flora removed.
How long would it take for us to die without flora?
2 weeks
Altering Infant Flora
-C-Section (vs. Vaginal Delivery)
Vaginal delivery born have lower risk of asthma
C-section born fecal bacteria:
Lactobacillus lower until day 10
Bifidobacteria lower until day 30
B fragilis lower until day 180
Which of the following is lower until day 180 in children born from c-section delivery?
A. B. Fragilis
Which of the following is lower until day 10 in children born from c-section delivery?
B. Lactobacillus
Which of the following is lower until day 30 in children born from c-section delivery?
A. Bifidobacteria
Altering Infant Flora:
Breastmilk vs. Formula
Breastmilk-fed tend to have better health
Nipples have flora not in formula
Breastmilk has nutrients/compounds not in formula- so gut bacteria may adjust to nutrition source
Altering Adult Flora; Dangers of Cleanliness
Antibiotics
20% of users will develop antibiotic-associated diarrhea
Increased risk of intestinal bacterial infection by clostridium difficile
Antibiotics increase risk of intestinal bacterial infection by ________________
A. Clostridium difficile
Altering Adult Flora: Dangers of Cleanliness
Mouthwash
Cancer patients that use mouthwash have an increased mucositis (inflamation of mucous membranes of G.I. Tract)
-Because they are immune suppressed and the mouth is a reservoir for healthy flora, so if you kill it all there is a chance that bacteria can get in.
Altering Adult Flora: Dangers of Cleanliness
Douching
Women who douche have higher rates of :
Vaginal irritation, vaginal infections and uterine infections
The Hygiene Hypothesis
Immune systems aren't being challenged by disease and dirt early in life, so the body's natural defenses overreact to small irritants such as pollen
Hygiene Hypothesis
Support (-Relationship of environment to immune reactions)
Wild mice/rats=very dirty environment (very mild immune reactions -4X more antibodies than lab rodents)
Lab mice/rats= Dirty environment (mild immune reactions... nibble on turds<--- good thing )
Average Human= Sorta dirty enviroment- (medium immune reactions)
Some Humans= Less Dirty Enviroment(strong immune reactions.. asthma , allergies)
SO BOTTOM LINE: too clean/dirty is BAD
Hygiene Hypothesis
Humans are less likely to have asthma if as a child, you:
Born by vaginal delivery (rather than c-section)
Had more siblings or pets
Entered day care in your first year
Infection: 1. Adherence
2. Invasion
3. Evasion
Infection:
Adherence
Attaches to host biomolecule ("receptor")
- anything outside of the cell can be used as a receptor ie. protein, crbohydrate, lipid
Infection:
Invasion
May release enzymes to:
Degrade "cement" between cells: ex: secrete enzymes such as collagenase, hyaluronidase
Decrease clotting of blood: (Imporatant mechanism to clot and seal off -containment) ex. Streptokinase (from streptococci) , Staphylokinase (from staphylococci)
Lyse with white blood cells: ex. Phospholipases
Increase clotting of blood ( to trap WBC in and they could invade)- ex. Coagulase
Which of the following enzyme(s) degrade "cement" between cells:
1. Collagenase
2. Hyaluronidase
3. Coagulase
4. Phospholipases
5. Staphylokinase
1. Collagenase
2. Hyaluronidase
Which of the following enzyme(s) lyse white blood cells:
1. Collagenase
2. Hyaluronidase
3. Coagulase
4. Phospholipases
5. Staphylokinase
4. Phospholipases
Which of the following enzyme(s) increase clotting of blood
1. Collagenase
2. Hyaluronidase
3. Coagulase
4. Phospholipases
5. Staphylokinase
3. Coagulase
Which of the following enzyme(s) decrease clotting of blood
1. Collagenase
2. Steptokinase
3. Coagulase
4. Phospholipases
5. Staphylokinase
2. Steptokinase
5. Staphylokinase
Infection:
Evasion
Escape and/or survive phagocytosis by WBCs
Infection:
Toxigenesis (stimulate inflammation in body)
Seccrete exotoxin (created by bacteria)
Release endotoxin (piece of bacteria_
Infection:
"Obligate" pathogen
Need host to reproduce:
Viruses: all
Bacteria (some: Chlamydia, rickettsia
Prozoan: plasmodium
Virulence
The relative ability of a pathogen to cause infection or disease
High virulence (infectivity)- a samll amount can easily overcome defenses
High virulence (mobidity): a pathogen that stongly compromises health
High Virulence (MOBIDITY)- extremely dangerous ... higher chance of mortality
Anthrax, ebola, marsburg, mad cow prion
Highly virulent pathogens are not that common because they kill their host early and can't spread... burn themselves out.
Diminishing Virulence (morbidity)
Syphilis first appread in the 1400s and would kill its host but now it has mutated into a less virulent form which benefits it
Strategic Virulence (morbidity)
Symptomatic: Cough, sneeze, diarrhea, open sores (Benefits both the species and the microbe)
Asymptomatic: NO real signs of infection: HPV 50% of all sexually active women will aquire it, only 1% will show "warts"
Sources of Infection:
Endogenous= opportunistic pathogens (b/c coming from within our body)
