BIOL-209 Medical Microbiology VCU Exam 1 Gharahmani

What are the types of symbiotic relationships?

mutualism, parasitism, commensalism

What is mutualism?

both species benefit

What is parasitism?

one species benefits, and the other is harrmed

What is commensalism?

one species benefits, and the other is unaffected

Who was the founder of modern nursing?

Florence Nightingale

- mortality due to infection

- led to epidemiology

Most fungal pathogens are _____________.

Opportunistic

The more virulent the pathogen the _______ they go through hosts.

quicker

lower LD50 = ______ virulence

takes ____ of the pathogen to kill 1/2 of infected

higher, less

Some pathogens (ex. tuberculosis) have adapted to live inside of cells, such as in its vacuoles (_______________) or in interstitial spaces (_______________)

- ___________ can live in gas filled spaces between muscle cells

intracellularly, extracellularly, clostridium

What is adherence?

how well a pathogen sticks once its inside a host

What is avoidance?

avoiding immune responses (macrophages, etc.) some pathogens allow themselves to be engulfed where they'll live and avoid detection

What is the prodromal phase?

symptoms begin to occur, number of microbes outnumbers immune response

What is the illness phase?

worst symptoms, peak number of microbes

What is the decline phase?

the worst symptoms are over, immune response ^^^

_________ infection (focal) may disseminate (spread through blood) and become a systemic infection. Multiple infections = mixed

localized

______ (inanimate object), _________ (carries pathogen, but isn't actually ill). Example of _________ is insects, animals, or humans

fomite, reservoir, reservoir

What are the different classes of microbes?

- eukaryotes (protists, fungi)

- bacteria

- archaea

- virus

What is a prion?

a misfolded protein

What are the roles of microbes?

- health: infectious disease and protection, digestion, and food spoilage, and food production

- biotech: drugs, hormones

- bioremediation: detoxification

- environment: energy capture (photosynthesis) and geochemical cycling (N+ fixation)

What is the role of microbes in the biosphere?

- microbes are producers and consumers

- They are found throughout the energy cycle

symbiotic prokaryotic cells orig. source of chloroplasts and mitochondria

- _____________ (phototrophic) were like chloroplasts

- ______________ (respiring) were like mitochondria

cyanobacteria, proteobacteria

both chloroplasts and mitochondria make their own bacteria, and ____________ have their own DNA

mitochondria

A _______ is any living thing that you need a microscope to see

microbe

What did Koch's germ theory of disease establish, and what other forms of it are there?

- established bacillus anthracis as cause of anthrax

- anthrax disease found in livestock can be transmitted to humans as cutaneous anthrax (on skin), which can be treated with antibiotics

- pulmonary anthrax (lungs) was later weaponized and is deadly

What are Koch's 4 postulates?

1.) microbe is found in all cases of the disease, but is absent from healthy individuals

2.) microbe is isolated from diseased host and grown in pure culture

3.) microbe causes same disease when introduced to a healthy host

4.) same strain of microbe is obtained from newly diseased host

the ability to _______ _ _______ is a key aspect of establishing it as the cause of disease because other microbes or pathogens may be present

isolate a microbe

What are primary pathogens?

They cause disease in an otherwise healthy host

What are opportunistic pathogens?

not typically associated with disease, ability to cause disease reliant on host resistance (immune function)

- fungal pathogens are usually opportunistic

What is virulence?

severity of disease

- highly virulent pathogens go through hosts very quickly

- virulence determined by the amount of pathogen required to cause death in 1/2 of those infected (LD50)

- low LD50 = high virulence

- filoviruses are extremely virulent, commonly lead to death

What is invasion?

growth inside of host cells (intracellularly)

- tuberculosis can grow/live inside a host cell's vacuoles

What is invasiveness?

the ability to spread to adjacent tissues (extracellularly)

- clostridium can grow in interstitial spaces between muscle cells

What is host range?

the species that a particular pathogen can infect

- may be multiple species

What is pathogenesis?

adherence, avoidance, growth (must accomplish for success)

What is adherence?

must attach to the inside of a host (using receptors at infection site)

What is avoidance?

must avoid host defenses (some allow themselves to be engulfed)

What is growth?

they gain nutrients from the host

What are the stages of disease?

incubation, prodromal, illness, decline, convalescence

What is the incubation stage of disease?

number of microbes decreases, immune response goes down, no symptoms, but may be contagious

What is the prodromal stage of disease?

very short stage. number of microbes increases, immune responses decreases, initial symptoms occur, microbes outnumber immune response, malaise (fatigue and discomfort) is common

What is the illness stage of disease?

number of microbes increases, immune response goes down, worst symptoms occur, peak # of microbes, fever is common

What is the decline stage of disease?

number of microbes decreases, immune response increases, immune response begins to outnumber microbes, worst symptoms are over. Temperature decreases, blood vessels dilate to lose heat

What is the convalescent stage of disease?

number of microbes decreases, immune response increases, symptoms disappear

What is the difference between signs and symptoms?

signs are directly measurable, ex: fever, rash etc.

symptoms are felt by the patient, ex: headache, fatigue, etc.

What are the types of infections?

- localized (focal), multiple pathogens (mixed), secondary infections, acute, chronic, nosocomial, latrogenic, latent, present, metastatic lesion, bacteremia, septicemia, viremia, toxemia, community

What is a localized (focal) infection?

- initial site of infection from which organisms can travel via bloodstream to another part of the body (boils, staphylococcus aureus)

- an infection that may disseminate (spread) and become systemic

What is a mixed infection?

an infection with multiple pathogens

What is a secondary infection?

opportunistic infection after a primary infection

What is an acute infection?

- comes on rapidly, with severe but short-lived effects (ex. is strep throat/streptococcus pyogenes)

What is a chronic infection?

symptoms appear gradually (weeks-months), and resolve slowly, long-lasting infection (3 months or more). Ex. is tuberculosis/mycobacterium tuberculosis

What is a nosocomial infection?

a hospital acquired infection, (ex. MRSA)

What is a latrogenic infection?

an infection that is transmitted by a healthcare worker

What is a latent infection?

- An infection that occurs after an acute episode ; organism is present, but symptoms are not

- An infection with the potential to become an active infection (such as some folks who carry TB, but do not show signs of it)

What is a metastatic lesion?

The site of infection resulting from a dissemination (ex. blastomycosis, fungi infection of lung can cause abcesses on extremities)

What is bacteremia?

bacteria in the blood, no replication (ex. streptococcus mutans and dental procedures)

What is septicemia?

presence and replication of bacteria in blood (ex. bubonic plague; versinia pestis)

What is viremia?

viruses in the blood (ex. is HIV)

What is toxemia?

toxins in the blood (ex. diphtheria, toxic shock)

What is community?

acquired

What are the different modes of transmission?

indirect transmission, direct transmission, vertical transmission, vehicle transmission, transmission through a reservoir, insect vectors

What is indirect transmission?

microbes transmitted indirectly by inanimate objects, by fomites, vehicle transmission, or insect vector

What is direct transmission?

microbes transmitted by direct contact or aerosolization

What is vertical transmission?

transmission of an infectious agent from an insect to its offfspring

What is vehicle transmission?

transmission through contaminated fomites, food, water, or air

What are insect vectors?

transmission from animal to animal

What does endemic mean?

- (of a disease or condition) regularly found among particular people or in a certain area.

- disease present at a constant level

What does epidemic mean?

- a widespread occurrence of an infectious disease in a community at a particular time.

- ^^ above baseline level

What does pandemic mean?

- A disease has spread over a large portion of the world

- disease is a worldwide epidemic

What are the roles of microbes?

- life on earth began with microbes, and has shaped our atmosphere, geology, and energy of ecosystems

- microbes generate O2, N, CO2, fix N, vitamins (B 12), primary producers of food webs (especially in oceans)

What is the range of the size of microbes?

range from mm down to .2 micrometers (um)

What are bacteria?

- prokaryotic cells (.2-20 micrometers (um))

- grow as single cells, filaments (chains) or as communities

- E. coli grows in human intestine, most strains are harmless (commensal) and aid digestion, but some cause acute gastroenteritis

- found all throughout biosphere

What are archaea?

- prokaryotic, evolved from bacteria and eukaryotes 3 billion years ago

- include extremophiles, methanogens (release methane) which live in the gut and are the source of "gas passed"

- don't cause disease

What are protozoa?

- single-celled (usually), motile heterotrophs

- ameba: may be free living or parasitic

- algae: eukaryotic, contain chloroplasts, essential base of food web

What are fungi?

- heterotrophic, nonmotile

- grow by absorbing nutrients from surroundings

- grow as single cells (yeasts) or filaments (bread mold), or complex structures such as mushrooms

- some cause infections, especially in people with lower immune systems

What are viruses?

- non-cellular microbes

- contains DNA and RNA that takes over metabolism of a cell to generate more virus particles

- some, such as papillomaviruses, consist of only a few molecular parts

- herpes virus, show complexity of a cell

- engineered viruses used for gene therapy

________ can grow as single cells, filaments, biofilms, or different structures

microbes

________ (prokaryotes) lack a nucleus, grow in all habitats

bacteria

_______ (prokaryotes) lack a nucleus, distantly related to other microbes, methanogens live in human intestine; _______ never cause disease

archaea, archaea

__________ microbes include protists (protozoa and algae) and fungi. Parasitic protozoa and fungi may infect humans

eukaryotic

_______ are noncellular microbes that must infect a host cell

viruses

Who was the first to study microbes in natural habitat (wetlands)

Sergei Winogradsky

What are lithotrophs?

feed solely on inorganic minerals

What is a disseminated infection?

caused by organisms traveling from focal infection; when affecting several organ systems it's systemic (tularemia/francisella tularensis)

What is a syndrome?

a collection of signs and symptoms that occur together and signify a particular disease

What is sequlae?

pathological consequences of an infection; strep throat can lead to heart or kidney damage

What is parenteral transmission?

pathogen enters through insect bite or needle injection

____ ______ __ _______: specific diseases are caused by specific microbes

germ theory of disease

What is the difference between eukaryotic and prokaryotic cells?

- prokaryotic cells do not have a nucleus, just a nucleoid region

- circular DNA is stored in the nuceoid region

- No/very few intracellular membranes

- Smaller in size

- Do not contain mitochondria

- Cell walls containing peptidoglycan

What is horizontal transmission?

from infected individuals to uninfected individuals

What is transplacental transmission?

pathogen transmitted to fetus through the placenta

What is parturition transmission?

transmitted during vaginal birth (ex. gonorrhea)

What are the different portals of entry?

eye (through conjunctiva), oral, respiratory, parenteral (bloodstream via insect vector or needle), skin (wounds), urogenital, oral-fecal

How many levels of biosafety?

4

What is a biosafety level 1 pathogen?

- little to no pathogenic potential and lowest level of containment

- basic sterile technique, nno mouth pipetting

- bacillus subtillis, E. coli K-12, Saccharomyces spp.

What is a biosafety level 2 pathogen?

- greater pathogenic potential; vaccines and treatments readily available

- level 1 procedures, limited access to lab, bio hazard safety cabinets, hepatitis vaccine recommended

- pertussis, chlamydia, dengue virus, diarrheagenic E. coli, helicobacter pylori, hepatitus, legionella pneumophila, listeria monocytogenes, mycoplasma peumonae, salmonella, shigella, staphaeurus

What is a biosafety level 3 pathogen?

- produces a serious or lethal disease, vaccines or therapy may be available

- level 2 procedures, directional air flow only into room, exhausted air directed outdoors, restricted access to lab

- anthrax, brucella, burkholderia, CA encephalitis virus, Q fever, EEE virus, tularemia, tuberculosis, rabies, typhus fever, Rift Valley virus, smallpox, poxviruses, VEE, west nile, yellow fever, versinia pestis

What is a Biosafety Level 4 pathogen?

- extremely dangerous, no treatment or vaccine available, higher risk of aerosol transmission

- level 3 procedures, 1 piece positive pressure suits, lab completely isolated

- ebola, guanarito virus, nantavirus, junin virus, lassa fever, machupo, marburg, tick-borne encephalitis

What is the zika virus?

- mosquito-borne viral disease

- symptoms: fever, rash, joint pain, last 2-7 days

- passed to sexual partner or fetus

- primary pathogen

- transmission for adults: parenteral. for infants: transplacental

- portal of entry: parenteral

What are some examples of macromolecules?

lipids, polysaccharides, proteins, nucleic acids👽👽👽

What are carbohydrates?

sugars and polysaccharides that store energy

What are simple sugars (monosaccharides)?

several linked Carbons with multiple hydroxyl groups (R-OH), and one carbonyl group (R-C=O)