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context: superorganism
how are humans superorganisms or ecosystems
contains human cells AND virus, fungi, protozoa, and mostly bacteria
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context: superorganism
human body has >501 species/organism
broken into what species
- a. 1 species of human : 10 trillion human cells
- b. 500 species of bacteria : 100 trillion bacterial cells (2-3 lbs of bacterial cells) -
- the mouth has billions, skin is 10X more than mouth, GI has 1000X more than mouth
- (mouth < skin < GI)
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5 locations of normal flora
- 1. skin
- 2. GI tract
- 3. respiratory tract
- 4. female reproductive tract
- 5. urinary tract
- NOTE: location is key!
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context: 5 locations of normal flora
skin
everywhere
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context: 5 locations of normal flora
GI tract
oropharynx and large intestines (high) > small intestines (med) > stomach (low)
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context: 5 locations of normal flora
respiratory tract
- oropharynx (high)
- lungs (none)
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context: 5 locations of normal flora
female reproductive tract
- vaginal canal (high)
- uterus (none)
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context: 5 locations of normal flora
urinary tract
- urethra (low)
- bladder (none)
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symbiosis means living together
when is it good and when is babaddd to the bone
- good = colonization
- bad = infection
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context: symbiosis
good = colonization
- In normal flora with commensalism: microbes benefit, host unharmed
- ex: microbes on skin
- In normal flora/beneficial flora with mutualism: microbes and host benefits
- ex: microbes in intestines assist with vitamin K
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context: symbiosis
bad = infection
- In normal/harmful flora (OPPORTUNISTIC pathogens) with pathogenic.
- ex: microbes in mouth can cause cavities
- In exogenous pathogens from exposure with parasitism: microbes benefit, host is harmed
- ex: most viruses
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5 Sources of healthy flora for a newborn (a fetus is sterile and has no bacteria at all)
- 1. vaginal canal - lactobacillus (increase during pregnancy)
- 2. hands - lactobacillus, E. coli, bifidobacteria
- 3. nipples - bifidobacteria
- 4. mother's mouth - streptococci, Neisseria
- 5. everyone else
- Normal Flora in 1-2 years
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3 different reasons for diversity of normal flora
- 1. diversity with different locations - bacteria adapted for specific areas (via receptors, nutrients, pH)
- 2. diversity with different ages - bacteria change throughout lifetime (due to exposure, hormones, diet, lifestyle)
- 3. diversity with different individuals - not everyone has the same flora (due to genes: gender, race, polymorphisms)
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3 reasons to love normal flora/3 benefits of flora (or else you'll be dead in 2 weeks! and animals will die by 10 salmonella bacteria vs 1 million with flora)
- 1. inhibit invasion by pathogens (compete for attachment sites, create non-optimal pH)
- 2. inhibit colonization by pathogens (compete for nutrients, secrete bacteriocidal/static substances)
- 3. sources of vitamins (some synthesize B vitamins, vitamin K)
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C section vs vaginal delivery for infants getting flora
- C section: higher risk of asthma
- lower in : lactobacillus until day 10, bifidobacteria until day 30, B fragilis until day 180
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Formula vs breastmilk
- breastmilk fed tend to have better health
- nipples have flora not in formula
- breastmilk has nutrients/compounds not in formula (gut bacteria adjust to nutrition source)
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3 alterations to flora that can be dangerous!
- 1. antibiotics: 20% of users will develop antibiotic-associated diarrhea (to clean out tube from things that shouldn't be there, but too much can cause dehydration), increased risk of intestinal bacterial infection by clostridium difficile
- 2. mouthwash: cancer patients that use mouthwash have increased mucositis (inflammation of mucous membranes of G.I. tract
- 3. Douching: women who douche have higher rates of: vaginal irritation, vaginal infections, uterine infections
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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.
- so less dirty environmental exposures show up as those with possible asthma/allergies unlike dirty environments with those who have mild immune reactions.
- SO: less likely for asthma if:
- 1. born vaginally
- 2. more siblings or pets
- 3. day care first year (exposure, kids are germy)
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How to get an infection?
4 steps
- 1. adherence - attaches to host biomolecule (receptor) like to protein, carbohydrate, lipid
- 2. invasion - may release enzymes to: a) degrade "cement" with collagenase, hyaluronidase; b) decrease clotting of blood with streptokinase (streptococci), staphylokinase (staphylococci); c) lyse white blood cell with phospholipases; d) increase clotting of blood (coagulase)
- 3. evasion - escape and/or survive phagocytosis by WBCs
- 4. toxigenesis - secrete exotoxin (created bacteria) and release endotoxin (piece of bacteria)
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what is an "obligate" pathogen?
- needs host to reproduce
- viruses: all
- bacteria: chlamydia, rickettsia
- protozoa: plasmodium
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virulence
- the relative ability of a pathogen to cause infection or disease
- –High virulence (infectivity): a small amount can easily overcome defenses
- –High virulence (morbidity): a pathogen that strongly compromises health
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3 types of virulence under morbidity (vs infectivity)
- 1. High virulence (morbidity)
- ex: Anthrax, ebola, marsburg, mad cow prion
- -Highly virulent pathogens are not that common, why?
- 2. Diminishing virulence (morbidity)
- ex: Syphilis first appeared in 1400s, worse then than now
- 3. Strategic virulence (morbidity) - Symptomatic: cough, sneeze, diarrhea, open sores V.S. Asymptomatic: no real signs of infection
- ex: HPV: 50% of all sexually active women will acquire it, 1% will show “warts”
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2 sources of infection
- 1. endogenous = opportunistic pathogens - compromised health (already sick, sleep deprived, stress will release high cortisol [glucocorticosteroid], medications that decrease defenses like glucocorticosteroids; compromised barriers - cuts, burns, catheters
- 2. exogenous = transmitted pathogens - Exposure + Compromised Health/Barriers; Exposure to
- High concentration; Exposure to High virulence (infectivity)
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context: 2 sources of infection
endogenous = opportunistic pathogens
- normal flora turns pathogenic 2 ways: 1. Increased concentration in normal location and 2. Presence
- in abnormal location
- Examples in 3 areas:
- 1. mouth - Streptococcus mutans : an increase can cause cavities/caries
- 2. pharynx - Streptococcus pneumoniae : if went to lungs (abnormal location) can cause pneumonia; Neisseria meningitidis : if went to brain membranes (abnormal location) can cause meningitis
- 3. lower intestine - bacteriodes : if went to peritoneal cavity (abnormal location) can cause peritoneal infection; Escherichia coli : if went to urethra (abnormal location) can cause UTI
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context: 2 sources of infection
exogenous = transmitted pathogens
4 types of disease
- 1. communicable disease (colds) - human to human through air, fluid, solids
- 2. zoonotic disease (rabies) - animal to human through teeth and beaks
- 3. vector disease (malaria) - insects to human through bugs and bites
- 4. food/water-borne disease (Salmonella) - food and/or water through ingestion/exposure
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2 places to get infection
- 1. community acquired: disease from OUTSIDE of healthcare facility
- 2. Nosocomial/hospital acquired/latrogenic: disease from INSIDE of healthcare facility
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context: 2 places to get infection: Nosocomial infections (vs. community acquired)
4 common types:
- 1. Urethra: Urinary Tract Infections –UTIs - (33%)
- 2.Wound: Surgical wound infection (17%)
- 3. Lungs: Lower RTI (pneumonia) (15%)
- 4. Blood: Septicemia (14%) - crosses bloodstream. Infection in entire blood circulatory system.
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context: 2 places to get infection: Nosocomial infections (vs. community acquired)
2 sections of most common infection pathogens
- 1) 34% caused by these 3 gram-positive cocci: Staphylococcus aureus, Enterococcus spp (species), Coagulase-negative staphylococcus
- 2) 32% caused by these 4 gram-negative bacilli: E. coli, enterobacter spp, klebsiella spp, Pseudomonas aeruginosa
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context: infection-related terminology (6)
morbidity rate
frequency of a disease
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context: infection-related terminology (6)
mortality rate (death rate)
frequency of death
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context: infection-related terminology (6)
sporadic disease
occurs occasionally
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context: infection-related terminology (6)
endemic disease
always present
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context: infection-related terminology (6)
epidemic disease
sudden/rare local outbreak
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context: infection-related terminology (6)
pandemic disease
sudden/rare global outbreak
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Genital chlamydia
bacteria
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Gonorrhea
bacteria
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Salmonellosis
bacteria
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Syphillis
bacteria
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Whooping cough
bacteria
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Tuberculosis
bacteria
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Lyme disease
bacteria
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
HPV
virus
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Herpes
virus
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Hepatitis A,B,C
virus
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
AIDS
virus
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
chickenpox
virus
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Trichomoniasis
protozoa
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Giardiasis
protozoa
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Tinea
- fungal
- ex: ringworm, athlete's foot, jock itch
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context: 16 common infections in U.S. (~900 human pathogens): bacterial/virus/protozoa/fungal/any type??
Pneumonia
any type
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