Bacterial taxonomics/INfection & Epidemiology Flashcards
What are the four groups of microorganisms?
Photoautotrophs, Chemoautotrophs, Photoheterotrophs, and chemoheterotrophs
Which of the four groups of microorganisms use light as an energy source?
Photoautotrophs and photoheterotrophs
Which of the four use chemical compounds as an energy source?
Chemoautotrophs and Chemoheterotrophs
Which of the four groups of microorganisms use Carbon dioxide directly as their carbon source?
Photoautotrophs and chemoautotrophs
Which of the four groups of microorganisms use organic compounds as their carbon source?
Photoheterotrophs and chemoheterotrophs
What are the three domains of life?
Bacteria, Archaea, and Eukarya
What do we call this?
Phylogenetic tree
How are phylogenetic trees created?
Comparing rRNA of different plants/animals
How do we determine where the deeply branching bacteria go on the phylogenetic tree?
rRNA sequences and characteristics indicate these guys branched off early in the tree of life
Are the deeply branching bacteria autotrophic and why is this significant?
Yes; because they couldn’t eat other things at this time. There was nothing to eat.
Many types of bacteria live in hot acidic anaerobic environments and can withstand large degrees of UV radiation, why is this significant?
There was no O zone to protect the planet from sun radiation, so early organisms had the mechanisms available to withstand this harsh environment.
What type of bacteria acquire energy by converting light energy into chemical energy through pigment molecules?
Phototrophic bacteria
Where are the pigments embedded in the phototrophic bacteria?
Thylakoids
The color of bacteria is determined how?
Determined by wavelengths NOT absorbed.
What is white light?
Combination of the entire visible specrta
What is black?
The absence of colors and absorbs all colors. That’s why it gets hot.
Name this phototrophic bacteria:
Cyanobacteria
Name this phototrophic bacteria:
Green and purple phototrophs (waste product is sulfur and this gives a shiny purple hue.
purple due to the hydrogen sulfide (sulfur)
(Some green phototrophs do not use sulfur)
What is it called when there is no oxygen produced?
Anoxygenic
What are the two types of gram-positive bacteria?
Low G+C and High G+C
How are the two types of gram-positive bacteria determined?
All depends on G-C content of DNA on chromosomes
<50% G-C=Low
>50% G-C=High
Name some Low G+C Gram-positive Bacteria:
Clostridia
Mycoplasmas
Bacillus
Lactobacillus
Listeria
Name some High G+C gram-positive Bacteria:
Corynubacterium
Mycobacterium
Actinomycetes
Name the Low G+C bacteria:
-Rod shaped, obligate anaerobes
-Frequently form endospores
Types: C. tetani (tetanus), C.perfringens (gangrene), C. botulinum (botulism), C.difficile (severe diarrhea)
Clostridia
Name the Low G+C bacteria:
-Lacking cell wall- DNA sequencing still groups them with the gram-positives
-mucus membranes in the respiratory tract
(Mycoplasma pneumoniae)
Mycoplasmas
Name the Low G+C bacteria:
Endospore forming; peritrichous flagella; common in soil.
Bacillus
what is Bt toxin?
Can act as a pesticide in the soil to kill insects in the soil and save plants (bacillus; Gram-positive Low G+C)
Name the Low G+C bacteria:
-Rod-shaped; no endospores
-Can live in the freezer/cold temperatures and contaminate food
Famous member: L. monocytogenes (can invade white blood cells)
Listeria
Name the Low G+C gram-positive bacteria:
-Rod-shaped; no spores, naturally occurring in stomach, mouth, intestinal tract, vagina
Lactobacillus
Microbial antagonist: protects the body from growth of pathogens
Name the High G+C gram-positive bacteria:
Rod-shaped or pleomorphic (famous species: C. diphtheria)
Reproduced by snapping division (seen as V-shapes or palisades)
Acid-fast stain to identify mycobacterium
Corynebacterium
Name the high G+C gram-positive bacteria:
-Exclusively aerobic species; slightly curved straight rods
-Take months to grow on plates
Famous member: M. leprae and M. tuberculosis
Mycobacterium
Name the High G+C gram-positive bacteria:
-Form branching filaments (look like fungi)
-Reproduce by spores at ends of filaments
-3 sub groups: Actinomyces, Norcardia, Streptomyces(produces anti-bodies)
Actinomycetes
Name the gram-negative bacteria:
-Aerobes that can survive with little nutrients
-Prossess protheca
Alphaproteobacteria
Famous member: Rhizobium (a nitrogen fixer)
Alphaproteobacteria
Neisseria(Gonorrhea), Bordatella (Pertussis)
Beta-proteobacteria
Pseudomonas, Legionella (Legionnaire’s disease, Pontiac Fever)
Gamma-proteobacteria
Flexible, spiral shaped bacteria; corkscrew motility
Spirochetes
Trepnnema (Syphillis)
Borrelia (Lyme Disease)
When individuals of two or more species live in direct contact with one another
Symbiosis
Both individuals obtain a net benefit from the interaction
Mutualism (+/+)
Only one individual benefits, the other receives a neutral result
Commensalism (+/0)
One individual benefits, the other receives a net loss
Parasitism (+/-)
How can normal microbiota become opportunistic pathogens?
Normal flora can get in the wrong place and cause disease or a sudden change in equilibrium or pH.
Introducing a member of normal microbiota into an unusual site in the body.
Where can humans get disease?
Animal reservoirs -vectors can carry but not get sick and transmit it to others.
Human carriers
Non-living reservoirs
Transmission of pathogen from animal (wild or domestic) to humans:
zoonoses
HUmans giving disease to other humans
Human carriers
Examples of non-living reservoirs:
soil, water, food
often holding dispersal stages of pathogens
solutions: boiling water, cooking food
Much more common in parts of the world with poor sanitation methods
The presence of microbes in or on the body
Contamination
Successful invasion of the body following contamination
Infection
What are the portals of entry:
Broken skin
insect bite
mouth
nose
eyes
urethra
anus
ear
vagina/penis
placenta
major points:
-skin
-mucous membranes
-placental
-parenteral
What is the primary portal of entry?
Mucous membranes -lines every body cavity that’s exposed to the outside world
How can parenteral route of entry happen?
Direct deposit of pathogen into tissues beneath the skin or mucous membrane (punctures with nails, thorns, needles)
When infections multiple and in doing so, affect body function; any change from a state of health
Disease(morbidity)
Subjective characteristics of disease (only the patient can feel them)
Symptoms
Objective, measurable characteristics of a disease
Signs
A group of symptoms that collectively characterizes a specific disease
Syndrome
The ability to cause disease
Pathogenicity
The degree of pathogenicity
Virulence (determined by virulence factors)
What are some virulence factors?
Enzymes
Toxins
Antiphagocytic factors
Name the virulence factor being described:
Secreted proteins that help pathogen dissolve chemicals or structures of the body
Enzymes
Name the virulence factor being described:
Chemicals that harm tissues or trigger host immune responses and cause damage
Toxins
toxemia: when toxins enter the blood stream and affect many sites
When immune cells “eat” the pathogen
Phagocytosis
(antiphagocytic factors)
Study the stages of infectious disease:
What are the modes of infectious disease transmission?
Direct contact transmission
Indirect contact transmission-through fomites (inanimate objects that carry pathogens)
Droplet transmission
Name the types of vector transmission and define them:
Biological vectors: If the microbe needs that vector in order to spread
Mechanical vector: Does not need a host to spread
Develops rapidly, lasts for a short period of time
Acute disease
develops slowly (less severe symptoms), but are continual or recurrent
Chronic disease
Durations and severities in between acute and chronic
Subacute disease
pathogen remains inactive for a long period of time
Latent disease
when an infectious disease comes from another infective host (directly or indirectly)
Communicable disease
A communicable disease that is easily transmitted between hosts (ex. chickenpox)
Contagious disease
Arise outside of hosts or from normal microbiota (ex. E.coli, tetanus, acne, tooth decay)
Non-communicable disease
The study of where and when diseases occur, and how they spread with populations.
Not limited to disease- not used to consider injuries and deaths related to automobiled, fireworks, cigarette smoking etc…
Epidemiology
number of cases after a period of time
Incidence and prevalance
number of new cases in a certain area
Incidence by geography
How are epidemics determined?
By comparison of actual cases with expected cases
Infections acquired by patients or healthcare workers when they are in healthcare facilities
10% of Americans get these each year
Nosocomial Infections
