OCTC-Micro-Chapter 14

What anatomical sites in the body are axenic?
Heart and circulatory system, Liver, Kidneys and urinary bladder, Lungs, Brain and spinal cord, Muscles, bones, Ovaries and testes, Glands (pancreas, salivary, thyroid),
Sinuses, middle and inner ear, internal eye
What fluids in the body are axenic?
Blood, Urine in kidneys, ureters, and bladder, CSF, Saliva prior to entering oral cavity, Semen prior to entering urethra,Amniotic fluid surrounding the embryo and fetus
Pathogens are:
-are disease-causing organisms
-are microbes that infect the body and cause disease.
-produce virulence factors (toxins, enzymes) that help invade and damage host cells.
Pathogens spread by:
direct or indirect methods
Pathogens spread by involving:
Infected people
Pathogens may be found residing:
in humans, animals, food, soil, and water
in humans, animals, food, soil, and water
science that deals with cause of disease
Manner in which disease develops
The structural and functional changes brought about by the disease
The final effects on the body
invasion or colonization of the body (the host) by potentially pathogenic microbes
Infection multiplication of a parasitic organism or virus in or on the body of the host with or without:
the production of a disease
Parasitic organism =
Any change from a state of health…
when the body is not properly adjusted or
Capable of performing its normal functions
Disease results:
When an adequate number of pathogenic cells enter the body
Through a specific route and grow
Disrupt tissues and cause signs and symptoms
ID =
infectious dose
Mutualistic relationship ex:
E. coli in intestines
One member benefits w/out significantly affecting the other
Commensalism ex:
ex. Staphylococcus epidermidis living on skin
Three types of Symbiosis:
1. Mutualism
2. Commensalism
3. Parasitism
Mutualism = both members benefit from the:
Mutualism Example:
Bacteria in our colon have warm, moist nutrient rich environment to live in
When bacteria die, they release vitamins:
K and B vitamins that we absorb
One member benefits w/out significantly affecting the other
Commensalism ex. :
Staphylococcus epidermidis living on skin
Other Names for Normal Microbiota include:
Normal microbiota
Normal flora
Normal microbial flora
Indigenous microbiota
Normal flora =
population of microbes found on and in the body of healthy peoples
Resident Flora =
inhabit body sites for extended periods of time; throughout life
Transient flora =
only temporary
Two types of Normal Microbiota in Human Host:
1. Resident microbiota
2. Transient microbiota
Resident Microbiota are a part of the ___________ throughout life.
normal microbiota
Resident Microbiota are found on:
skin, mucous membranes of GI, respiratory tract, urethra, and vagina
Most resident microbiota are:
Why are Normal Microbiota in Human Host?
These organisms (bacteria, fungi, protozoa) colonize the body’s surfaces without normally causing disease.
Most normal Microbiota in Human Host are:
A few normal Microbiota in Human Host are pathogenic but:
held in check by antagonism
Normal microbial flora benefits the human host by:
Preventing the overgrowth of harmful microorganisms and Stimulating the immune system
What is Transient Microbiota?
Remain in the body for only hours, days, or months before disappearing.
Transient microbiotia may be present for a time then disappear because:
they cannot compete with resident microbiota
Transient bacteria are found in the same regions as:
resident microbiota
Why can’t Transient Microbiota persist in the body?
Competition from other microorganisms
Elimination by the body’s defenses cells
Chemical (changes in pH of vagina)
Physical changes (urination, defecation, vomiting) in body that dislodge them
As we development in the womb, it is free of:
microbes (axenic)
Microbiota begins to develop during:
the birthing process.
By 12 hours after birth:
Lactobacilli have colonized neonate.
Bottle fed infants acquire:
coliforms, lactobacilli, enteric streptococci and staphylococci.
Breast fed acquire:
Bifidobacterium: Which protects the infant from infection of certain intestinal pathogens.
Much of one’s resident microbiota is established during:
the first months of life
Establishment of normal flora continues with:
teething and solid food
Two types of Pathogens:
1. True Pathogens
2. Opportunistic Pathogens
A microbe that has a parasitic relationship with host that results in disease is called a:
True pathogens =
primary pathogens
True Pathogens are capable of causing disease in healthy person with:
normal immune defenses.
Coronavirus causes:
common cold
Influenza virus causes:
Malarial protozoan causes:
Opportunist pathogens only cause diseases:
1. When host’s immune defenses are weakened or host is immunocompromised
2. When introduced into an unusual location
Opportunist pathogens:
May be members of the normal flora or common in the environment
Examples of Opportunist pathogens:
1. Candida
2. E. coli
3. Pseudomonas = common in environment
Our normal flora maintain:
microbial antagonism or microbial competition.
The nonpathogenic microbes hold:
the pathogenic microbes in check.
What are the Three conditions when normal flora become opportunistic pathogens?
1. Immune suppression
2. Changes in normal microbial flora
3. Normal flora in unusual area
Immune suppression includes:
Disease, malnutrition, emotional, physical stress
Very old or very young
Radiation, chemotherapy
Immunosuppressive drugs in transplant patients
HIV virus
Immune suppression can enable opportunist pathogens to:
become pathogens
Changes in the normal microbiota:
Normal microbiota
Use nutrients
Take up space
Release toxic waste
That usually out compete pathogens
Changes in the normal microbiota: This is called:
Microbial antagonism
Microbial competition
Changes in relative abundance of normal microbiota may allow some members of the normal microbiota to become:
an opportunist pathogen
ex. Long term use of antibiotic :
C. difficile
Killed off sensitive non pathogenic flora, now C. difficile has:
nutrients and room to multiply and cause a disease
Introduction of normal microbiota into unusual site in the body Example:
E. coli or Enterococcus feacalis
E. coli or Enterococcus feacalis are mutualistic:
in colon
But if E. coli or Enterococcus feacalis enter urethra then bladder:
They becomes parasitic and may cause UTI
Mere presence of microbes in/on body
Contaminants reach body in:
Food, drink, air, via wounds, arthropod bites, sexual intercourse
What is the outcome of the Contaminants?
1. Become part of the normal flora
2. Remain in body a short period of time as part of transient microbiota
3. Overcome body’s external defenses, multiply, become established in the body
The successful invasion of the body by a microbial contaminant is called an:
The infection may or may not:
result in disease (which has signs and symptoms).
Portals of Entry =
getting in, sites where pathogens enter the body, usually the same regions that support normal microbial flora.
Attaching to the Host =
staying in
Surviving Host Defenses =
defeat host’s defenses
Causing the Disease =
damage the host
Portals of Exit =
getting out, transmitted to another host
What are Four major sites of Portals of Entry
1. Skin
2. Mucous membranes
3. Placenta
4. Parenteral route
Stratum corneum : Outer layer of packed, dead, skin cells usually acts as:
a barrier to pathogens
Some pathogens can enter through openings or:
cuts, nicks, abrasions.
Some pathogens can enter through:
hair follicles and sweat glands.
Larvae of some parasitic worms create their own portal using:
digestive enzymes and burrow into skin to reach the deeper tissues
Insect bites, tick and spider bites use their:
probiscus to pierce through the epidermis
Some fungi can digest:
the keratin in the outer layers of skin to reach the deeper, moister dermis
Mucous membranes line:
GI, respiratory, urinary, reproductive tracts and conjunctiva
Mucous membranes are ____________ and provide a _____________ that is an easier portal of entry
thinner than skin; moist, warm environment
Respiratory tract:
Most commonly used site of entry
Bacteria, viruses, fungi, and protozoa:
Enter nose, mouth in air, on dust, in drops of moisture
Cold, influenza viruses can enter:
eye first, then respiratory tract
Some protozoa, helminths, bacteria, and viruses are able to survive:
the acidic pH of the stomach
Some protozoa, helminths, bacteria, and viruses may use the gastrointestinal tract as:
a route of entry
Pathogens that enter via GI tract are adapted to survive:
Digestive enzymes and changes in pH
Enteric bacteria:
Salmonella, Shigella, Vibrio, and E. coli (gastroenteritis)
Enteric Viruses:
poliovirus, hepatitis A virus, echovirus, and rotavirus (rotavirus = gastroenteritis)
Enteric Protozoans:
Entamoeba histolytica and Giardia intestinalis (gastroenteritis)
Respiratory tract portal of entry for:
greatest number of pathogens
Microbes are transferred from:
upper respiratory tract, to sinuses, to auditory tube then middle ear
Portal of entry for greatest number of pathogens is:
Respiratory tract.
Bacteria, Fungi, Protozoa, Viruses can enter through:
respiratory tract
Bacterial, fungal, and viral:
Bacterial diseases:
strep throat, pneumococcal pneumonia, anthrax, diphtheria, TB, bronchitis, whooping cough
Fungal diseases:
blastomycosis, coccidioidomycosis, histoplasmosis, pneumocystis pneumonia
Viral diseases:
common cold, SARS, mumps, influenza, respiratory syncytial disease
STDs enter skin or mucosa of:
penis, external genitalia, vagina, cervix, or urethra.
Syphilis/gonorrhea were once:
the prominent STDs.
Now ____________ lead the list.
genital warts, chlamydia, herpes, HIV, Hepatitis B, Trichomoniasis
Some yeast infections caused by:
Candida albicans
Some not all Candida albicans are considered:
NOT All urogenital infections are STDs, some are:
UTI and yeast infections
The placenta is usually an effective barrier against microbes in the:
maternal circulation.
Some microbes can cross the placenta cause:
Spontaneous abortion (miscarriage), Congenital abnormalities, Brain, damage, Premature birth, Stillbirths
Other = Chlamydia, Hepatitis B, HIV
Herpes simplex (Hepatitis B, HIV)
Parenteral Route not a true portal of entry but a means by which:
portals can be circumvented
To enter the Parenteral Route:
Pathogens are deposited directly into tissues beneath the skin or mucous membranes by:
Pathogens are deposited directly into tissues beneath the skin or mucous membranes by:
Nail, Thorn, Hypodermic needle, Bites, Stab wounds, Surgery
After entering the body, microbes must __________ in order to establish _______.
adhere to host cells ; colonies
Categories: Microbiology