2024 SUMMARY - MICROBIOLOGY|VERIFIED EXAM GUIDE|SCORE GRADE A+|GUARANTEED SUCCESS
retinitis in patients ages 0-20: likely cause by a pathogen (bacterial/viral/fungal, insect-bite associated pathogens like Lyme disease, or Animal associated pathogens/parasites like Toxocariasis)
retinitis in p...
2024 SUMMARY -
MICROBIOLOGY|VERIFIED EXAM
GUIDE|SCORE GRADE
A+|GUARANTEED SUCCESS
retinitis in patients ages 0-20: likely cause by a pathogen (bacterial/viral/fungal,
insect-bite associated pathogens like Lyme disease, or Animal associated
pathogens/parasites like Toxocariasis)
retinitis in patients ages 20-50: 1. systemic autoimmune diseases 2. infection by
pathogens
retinitis in patients ages 50+: 1. vascular disease 2. systemic autoimmune diseases 3.
infection by pathogen - ANSWER-✔etiologies of retinitis (inflammation of the retina)
immune response, injury - ANSWER-✔bacterial infections also elicit an
___________ which can cause _______ itself (consider free radical release by PMNs)
mechanism for attachment to tissue and evasion of the immune system - ANSWER-
✔virulence definition
drug resistance, increase virulence - ANSWER-✔plasmids often contain genes for
what?
bacteria takes up fragments of DNA from the environment and incorporate it into its
genome - ANSWER-✔define transformation
the bacterial virus called a bacteriophage picks up DNA from one bacterium and
transfers it to another. - ANSWER-✔define transduction
genetic material transferred between bacteria through a sex pilus (conjugation can
transfer: 1. plasmid DNA 2. genomic DNA) - ANSWER-✔define conjugation
, 1. an F+ bacterium transfers its F plasmid through a pilus to an F- bacterium 2. after
conjugation, the recipient cell becomes an F+ bacterium (plasmid may confer
antibiotic resistance if it has those genes) - ANSWER-✔mechanism by which
plasmids are transferred by conjugation
1. F plasmid has integrated intot he chromosome to make an Hfr (high frequency
recombination). 2 during conjugation, part of the plasmid sequence is transferred to
a host cell (transferred DNA may also have antibiotic resistance genes - conferring
resistance) - ANSWER-✔mechanism by which genomic transfer occurs via
conjugation
jumping genes. they jump into, and out of genomic DNA - ANSWER-✔define
transposons
provides rigidity to the cell and inhibits osmotic lysis - ANSWER-✔why is
peptidoglycan essential for the viability of the cell?
composed of carbohydrates, teichoic acid and lipoteichoic acid. these anchor
bacteria to the host cells and are antigens (PAMPs) recognized by APCs. - ANSWER-
✔what are parts of the thick outer layer of peptidoglycan in gram-positive bacteria?
fever, septic shock (low BP), and DIC because it also activates platelets - ANSWER-
✔what can release of LPS do in high concentrations?
Streptococcus, Staphylococcus - ANSWER-✔what are the two most common gram-
positive bacteria?
Mycoplasma because they are wall-less bacteria that lack peptidoglycan - ANSWER-
✔antibiotics that target peptidoglycan walls are not effective in what cells and why?
Neisseria (cocci), Seratia and Proteus (bacillus, enterics), Haemophilus and
Pseudomonas (bacillus), Treponema and Borrelia (spirochetes), Chlamydia and
Rickettsiae (pleomorphic) - ANSWER-✔what are the most important Gram-negative
pathogens in optometry?
contain dipicolinic acid, which are unique to spores. and the pressure from an
autoclave is the only thing that can kill them. - ANSWER-✔what are special about
spores?
5 layers: 1. cytoplasmic membrane (inner) 2. cortex - peptidoglycan layers (lacks
water and lives in arid conditions. has dehydrated muramic acid - lactam). 3. outer
membrane 4. keratin protein coat 5. exosporium outer layer (this outer layer will
stain Gram positive even though it is NOT a typically gram positive cell) - ANSWER-
✔what are the layers of spore structure?
toxins - ANSWER-✔______ are proteins that can damage host cells
, endotoxins: are part of the bacterial membrane. when they are released, they cause
damage
exotoxins: proteins secreted by Gram-positive and Gram-negative bacteria -
ANSWER-✔what are the types of bacterial toxins?
Lipid A (part of LPS on gram-negative pathogens) - ANSWER-✔what is the most
famous endotoxin?
endotoxins released from dead bacteria directly stimulate vasodilation causing
hypotension/shock.
bacteria in the blood can stimulate complement activation causing vasodilation and
hypotension. this is an indirect mechanism - ANSWER-✔how does septic shock
cause systemic vasodilation
1. a carbon source like glucose (to produce ATP, NADH, and NADPH)
2. Nitrogen (to produce amino acids and nucleic acids)
3. optimal temperature
4. various ions, especially iron (many bacteria secrete siderophores which are
proteins that capture iron from the environment to aid in oxygen manipulation) -
ANSWER-✔what are the minimum growth requirements for all bacteria?
superoxide dismutase (SOD): O2- + 2H+ = H2O2
peroxidase and NAD+: H2O2 + O2 = H2O
catalase: H2O2 + O2 = H2O + O2 - ANSWER-✔what are the enzymes that degrade
ROS and what do they do?
obligate aerobes: must have O2 present. they have SOD, catalase, and peroxidase in
high concentrations
facultative anaerobes: can live with or without O2. they have SOD, catalase, and
peroxidase in lower concentrations
obligate anaerobes: will die in O2. they lack SOD, catalase, and peroxidase. they
must use fermentation/anaerobic respiration to produce ATP - ANSWER-✔how do
we classify bacteria based on the presence/absence of the enzymes that degrade
ROS?
they are also more likely to survive ROS bombardment by our PMNs and
macrophages - evade the immune system - ANSWER-✔since obligate aerobes
contain a lot of the enzymes that can degrade ROS, what does this mean?
prefer to grow aerobically but have the "faculty" (ability) to grow in anaerobic
conditions - ANSWER-✔what do facultative anaerobes prefer to grow in?
1. initiation period = bacteria elongates
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