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Microbiology 255 - Part 1 of course 2021
Module 1

Microorganisms - organisms that too small to be seen with just the eye - usually think of bacterial cells


-decompose organic waster


-producers in the ecosystem by photosynthesis


-produce industrial chemicals ie ethyl alcohol and acetone


-produce fermented foods ie vinegar, cheese, bread


-produce products used in manufacturing and treatment ie insulin


-a few are pathogenic, disease - causing

**Understand so allow humans to prevent disease occurrence — led to aseptic techniques in
labs and medicine

Germ- rapidly growing cell, generically used for microbes (pathogen)

Scienti c naming


-Linnaeus est
...
Organism has 2 names : the genus [broader category] and speci c epithet (species
- have most if not all same characteristics; ex
...
The genus is capitalized and the species name is lower
case


-Latinized and used worldwide


-May be descriptive or honor scientist


-After rst use, scienti c names may be abbreviated w/ rst letter of the genus and the
speci c epithet
...
coli) — problem is same letter but 2 di names

-3 domains of life (cell types):


-Bacteria (prokaryote)


-Archae (prokaryote)


-Eukarya



-protists (slime molds, protozoa)



-plants (mosses, ferns , owering plants)



-fungi (unicellular yeasts, multicellular molds, mushrooms)



-animal (sponges, insects , worms, vertebrates)



-algae

Woese-Fox classi cation system - 3 domains of life


-Phylogeny - degree of relatedness between groups of living things



-shows much better view of common ancestry and relatedness

Bacteria


-prokaryotes


-peptidoglycan cells walls
...
Pasteurization

Germ theory of disease: microorganisms cause disease


-Bassi - silkworm disease was caused by fungus


-Pasteur - another silkworm disease caused by protozoan


-Semmelweis - advocated hand washing to prevent transmission of puerperal fever
(uterine in ammation) from one OB patient to another during childbirth


-Lister - used chemical disinfectant to prevent surgical wound infections ; treat bandages and wounds with phenyl

-Koch - provided proof that a bacterium causes anthrax and provided the experimental steps , Koch’s postulates, used to provide that a speci c microbe causes a speci c disease (working w/cattle that died from bacterial infection/anthrax, cultured
microorganism that causes diseases’ and injected this into healthy cattle, harvested that
blood when cattle got sick and found same organism)

Edward Jenner and Immunity

-dairymaids who had mild cowpox infections were protected from smallpox

-Hypothesis: cowpox infection provides protection against smallpox

-Expt(1798): inoculated boy w/ cowpox uid and later challenged w/ smallpox uid

-Result: boy did NOT get smallpox

-Called Vaccination from vacca for cow [pasteur developed this name] —> lead to immunity


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Treatment w/ chemicals is chemotherapy:

Chemotherapeutic agents used to treat infectious disease can be synthetic drugs (prepared
from chemicals in the lab) or antibiotics (chemicals produced by bacteria and fungi that inhibit
or kill microbes)

-Ehrlich - developed synthetic arsenic drug , Salvarsan to treat syphilis


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-Hypothesis that living organisms arise from nonliving matter = spontaneous generation [a ‘vital
force’ forms life]

-Alternative hypothesis that living organisms arise from preexisting life = Biogenesis


-Sulfonamides were synthesized in 1930s - inhibit enzymes of folate metabolism in microbes
but humans don’t have same metabolic pathway

-Fleming - discovered 1st antibiotic; observed that Penicilium fungus made an antibiotic , penicillin that killed S
...
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Use harmless virus to carry missing or new gene into certain host cells, where the
gene is picked up and inserted into the appropriate chromosome (use for SCID, ADA)
...
Bacteria and fungi can produce a variety of proteins including vaccines and enzymes through this

Genetically modi ed organisms often use bacterial genetic components to protect crops from
insects, chemicals and freezing

temp, ph , and presence or absence of chemical cmpds determine if microbiota stay

Transient microbiota

Antibiotics used to treat bacterial infections but have NO impact on viruses and other microbes

When looking at unicellular life, rapid progress made in genetics


microbial genetics - mechanisms by which microorganisms inherit traits


molecular biology - looks at how genetic info is carried in molecules of DNA


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Sewage treatment - uses microbes to recycle water

Bioremediation - uses microbes to clean up pollutants


Insect pest control by microorganisms

Resistance - ability to ward o disease

Bio lm - microbial community that forms as a slimy layer on the surface


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Antibiotic resistance


MRSA and less sensitivity to vancomycin —> vancomycin resistant S
...
4 and 13

2
...
2

Prokaryotic cells —- BACTERIA

-avg size: 0
...
0 micro meters x 2-8 micro meters

-monomporphics shapes: all cells have constant shape


-coccus = round


-bacillus = rod shape
...
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3

Prokaryotic Structures:

Always require: cytoplasm, plasma membrane, 70S Ribosomes, nucleoid containing DNA

^Glycocalyx
...
Paired cocci within capsule

^Flagella —Use for movement


-Outside cell wall


-Made of chains of agellin


-Attached to a protein hook


-Anchored to the wall and membrane by the basal body


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Motic Cells


-Rotate agella to run or tumble




-CCW: swimming motion, CW: bacterial cell change direction


-Move toward or away from stimuli (chemotaxis)


-Flagella proteins are H antigens
...
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- agella w/in cell, wrapped around body of cell beneath plasma membrane


-Endo agella


-in spirochetes


-anchored at one end of a cell


-rotation causes cell to move

Fimbriae and Pili
...
Allow attachment



-Gliding motility



-Twitching motility


-Pili - used to transfer DNA from one cell to another

2
...
— UNIQUE TO PROKARYOTIC CELLS

-Prevents osmotic lysis

-made of peptidoglycan (in bacteria) - around plasma membrane


-Peptid
...
Cell wall


-thick peptidoglycan layer (located on exterior surface of the cell)


-Teichoic acids

-Gram neg
...
— all cells take up crystal violet stain and

become purple


2) add alcohol


-Gram pos
...
__PINK OR RED



-Alcohol dissolves outer membrane and leaves holes in peptidoglycan



-CV-I, washes out (bc degrades LPS layer and purple color leaves so cells are
clear, then colored red or pink by stain saccharin)


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Atypical cell walls


-Acid fast cell walls



-Like gram pos cell walls



-Waxy lipid (mycolic acid) bound to peptidoglycan








-Mycobacterium (tuberculosis)


—Use acid fast stain for this unique cell wall


Damage to cell wall


-Lysozyme digests disaccharide in peptidoglycan


-Penicillin (many antiobiotics) inhibits peptide bridges in peptidoglycan


-Protoplast - wall-less cell


-Spehroplast - partially wall-less cell



-Protoplasts and Spheroplasts are susceptible to osmotic lysis


-L Forms - wall-less cells that swell into irregular shapes

2
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6 inside the cell

-Nuclear area w/ DNA (nucleoid) -[not enclosed in membrane bc prokaryote]



-Bacterial cell can have chromosome and plasmids (smaller circular DNA, contain
genes that have nothing to do w/ basic fn of cells but control external processes: antibiotic resistance)

-Ribosomes for protein synthesis


-70S (composed of over 30 proteins and rRNA)


-S = svedburg units (centrifuge sedimentation)



-50S (large subunit) + 30S (small subunit) subunits = 70S

[Eukaryotic 80S (60S and 40S)]

-Cytoplasm is the substance inside the plasma membrane

-No nucleus so transcription (conversion of DNA to RNA) and translation (ribosomes read RNA
for protein) can be coupled/occur in tandem

-Inclusions/Deposits found in some bacteria [these substances become insoluble at high concentration]
...
——therefore, much more di cult to ght o bacteria that can create
spores bc if unfavorable envt then can become dormant

-Metabolically inactive (still alive)

-resistant to desication, heat and chemicals

-sporulation occurs during stress (unfavorable envt)

-Bacillus, Clostridium —— these species will create spores

-Sporulation: Endospore formation

-Germination: return to vegetative state (occurs when spore nd a favorable envt)

2
...
— CAN CAUSE DISEASE


-Molds



-the fungal thallus (growth) consists of hyphae ; a mass of hyphae is mycelium


-Yeast
...
- classi ed by site of infection rather than by the organism


-Systemic mycoses - deep within the body


-subcutaneous mycoses - beneath the skin


-cutaneous mycoses - a ect hair, skin , nails


-super cial mycoses - localized ie hair shafts



-opportunistic mycoses - caused by normal microbiota or fungi that are usually not
pathogenic




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...
— very speci c, only infect 1 kind of plant or animal and then only
infect 1 cell type within that organism

-evolve quickly

-Capsid - the protein shell that encloses the viral genome


-build from proteins called Capsomeres (glycoproteins)

-Some viruses also have lipid membranes


-Viral envelope — don’t necessarily need this



-contains capsid - protein cap



-aids entry to cell

**All have genetic material and capsid

*all viruses constructed same way but can con gure selves di erently


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Prions - proteins that cause brain diseases in mammals [not viruses]

-infectious proteins that build up in nervous tissue - proteins misfold and clump together, nonliving , contain no genome (RNA, DNA)

-propagate by converting normal proteins into the prion version —- cause degradation of nervous system

-Creuzfeldt Jakob disease - acquired (vCJD) or inherited

-PRNP gene —> PrP normal protein

-Scrapie; Mad cow Disease (BSE)


Module 3 - read chs 5-6

3
...
5, molds and yeast grow between pH 5 &
6, acidophiles grow in acidic envts


-Osmotic pressure



-hypertonic envts - increase salt or sugar, cause plasmolysis [plasma membrane
pulls away from cell wall]; honey -very much sugar, high osmotic pressure for any bacteria in
that substance = inhospitable to bacteria so honey very rarely spoil



-extreme or obligate halophiles require high osmotic pressure



-facultative halophiles tolerate high osmotic pressure

3
...
—candle produces extra CO2


-CO2 - packet — gas generator


3
...
— use CFU (colony forming units)

-bacteria mainly undergoes binary ssion - single cell to 2 cells 1-> 2-> 4 -> 8

—1 bacteria could create a colony in less than a day but cannot grow forever

-Growth plots are linear on a log scale (y-axis = log of binary ssion events of cells; x-axis =
generations) —- log gives better indication of the trend - see exponential growth


-Log Phases:



-Lag Phase
...
Bc # of organisms w/in a culture can be
very high
...
Find best plate = most statistically signi cant plate - the plate comes from ex
...
4 Bio lms

-microbial communities; forming along solid surfaces ; in natural or industrial settings

-form slime or hydrogels(if excessively hydrated w/water-] [composed by macromolecules:
polysaccharides, proteins etc]


-bacteria communicate by chemicals via quorum sensing — get community of bacteria
to work in unison

-share nutrients

-bio lms allow sheltered from harmful factors


-environmental waste products, antibiotics


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3
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6 Enzymes

-Activation energy
...
Collision energy required for chemical rxn to occur


-collision theory states that chemical rxns can occur when atoms, ions and molecules
collide
...
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7 Enzymatic activity —inside cell = endo-enzymes

-enzymes can be denatured by temp and pH (protein shape will change) — prevent enzyme
from working properly and that part of metabolism will also stop - can lead to death of cell


-In uenced by temp, pH, substrate concentration (-saturation)—bc enzymes can only
work so fast



-Competitive inhibition - competitive inhibitor t into substrate site where it
binds



-(Allosteric inhibition )noncompetitive inhibition - inhibitor select portion of enzyme that’s not location where substrate binds — protein/enzyme changes shape a bit and this
shape change prevents substrate from binding at its location



-Feedback inhibition/ end product inhibition - nal product of metabolic pathway
can act as inhibitor at early step by binding to early on enzyme - this is normal mechanism of
cellular control ; when enough product is made = metabolic pathway can stop to conserve energy and resources
...
8 Energy


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-metabolic pathway - sequence of enzymatically catalyzed chemical reactions in a cell; determined by enzymes


-enzymes are encoded by genes


-breakdown of carbs to release energy : Respiration (aerobic)
...
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1 into to genetics

Genetics - study of what genes are, how they carry info, how info is expressed, and how genes
are replicated

Gene - segment of DNA that encodes a functional product, usually a protein

Genome - all of genetic material in a cell


1st fully sequenced organism was a bacterium in 1995 [since have very small genome
size]

Genomics - molecular study of genomes

Genotype - genes of an organism

Allele - variant of a gene

Phenotype - expression of the genes

DNA

-polymer of nucleotides: adenine, thymine, cytosine, guanine

-double helix associated w/proteins

-backbone is deoxyribose-phosphate


-sugar phosphate

-2 strands held together by hydrogen bonds between AT and CG

-strands are antiparallel


-5’ (free phosphate group) and 3’ (free hydroxyl group) at opposite ends

*nucleotides: phosphate group, carbohydrate, nitrogenous base (A,T,C,G)

4
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New strand used to create new DNA
strands [each new dNA molecule is identical to the original one]

- Semiconservative - ea
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3 microbial genetics

-How genes expressed and regulated in Prokaryotic cells

-Plasmids — independent from bacterial chromosome [but also circular, but smaller]



-conjugative plasmid - carries genes for sex pili and transfer of the plasmid


-Dissimilation plasmids - encode enzymes for catabolism [break down carbs/nutrients]
of unusual compounds


-R factors - encode antibiotic resistance

-Flow of genetic info options:


-Vertical gene transfer - how genetic info/dna transferred parent to o spring



-pairs up w/process of replication previously discussed


-horizontal gene transfer - transfer dna to unrelated organisms that exist in the same
generation [Recombination- exchange of DNA and incorporation of that DNA into the host
genome/chromosome]


-cell reading coded message in own genes and make expected products

-DNA is transcribed to make RNA (mRNA, tRNA, rRNA)
...
[ribosome attach to mRNA at speci c sequences] to create protein


-one such sequence is shine dalgarno sequence



-Each codon corresponds to one amino acid




-Amino acids form long chain to make protein

*prokaryotes = no nucleus in bacterial cells SO can have transcription and translation occurring
in tandem w/one another; nearly no processing of mRNA molecule

Regulation of bacterial gene expression

-constitutive enzymes/proteins are expressed at a xed rate

-other enzymes are expressed ONLY as needed


-Repressible enzymes


-Inducible enzymes —- Lać operon {lactose operon} - genes transcribed here required
for lactose breakdown ; allolactose binds repressor/operator (trigger conformational change;
protein no longer binds to operator so…
...
4 genetic Mutations


-change in the genetic material

-DNA polymerase delity - the ability to make an exact copy of the chromosome

-Mutations can be neutral, bene cial or harmful

-Mutagen - agent that causes mutations

-Spontaneous mutations - occur in absence of a mutagen

-spontaneous mutation rate: 1 in 10^9 replicated base pairs of 1 in 10^6 replicated genes


-Mutagens increase this rate to 1 in 10^5 or 1 in 10^3 per replicated gene

-STOP codons: UAA, UGA, UAG


-redundancy built into system but product/protein could be changed



-change codon but still get same amino acid

-START codon: AUG (a
...
=Met)

-Mutation — point mutations:


-Base substitution (point mutation) - change in 1 nitrogenous base/nucleotide


-Silent mutation - no amino acid change


-Missense mutation - change codon such that result in change in amino acid



-nonsense mutation - results in a nonsense codon [stop codon] - don’t get full protein
being created


—Frameshift mutation: - insertion or deletion of 1 or more nucleotide pairs



—-catastrophic disruption of protein


—Ionizing Radiation (x rays and gamma rays) - causes the formation of ions that can
react w/nucelotides and the deoxyribose phosphate backbone
...
— spot chemical mutagens/carcinogens

*experimental tube (take mutated bacteria usually salmonella - can’t produce a
...
histodine)
and control tube


-mutate DNA such that gene that disrupted to initially make it a mutant, and revert that
bacteria back to its original state


—Take these tubes of His- salmonella and put on medium lacking histamine and if see
colony growing from experimental group, means the mutagen that you chose worked to make
it His+

4
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Even though plasmid integrated
can still be transferred, part of HFR can give part of DNA to recipient cell [recipient cell still recombinant cell even if got only partial or full genes from donor cells]

-Transduction - Use Virus as means to transfer DNA from 1 cell to another cell (need infection
process) —- bacteriophage (viruses target only bacteria) - delivers own genetic material into
cell, codes for protein, breaks chromosome down - -if virus brings broken down chromosome
to new cell then that cell becomes recipient cell/make recombinant cell

-Transformation - some bacteria have RECEPTORS for DNA incorporation/incorporate exogenous dna (naked DNA) - Competent bacteria; holes in the cell membrane can allow the DNA to
enter


-in lab: use heat, electrical shock, chemicals i
...
salt to create holes in membrane

Transposons aka jumping genes


-segment of DNA that can move from one region of DNA to another - movement mediated through enzyme: transposase - cut DNA and allow for incorporation of DNA into new region ie insert antibiotic resistance gene


-contain insertion sequences for cutting and resealing DNA (transposase)


-complex transposons carry other genes


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Plasmids, viruses, transposons [ie insert gene of interest into plasmid - make recombinant DNA molecule] - mimics natural process/that process in nature

-Clone: population of cells arising from 1 cell; each carries the new gene


-genetically identical cells (puri ed colonies considered clonal or clones)

*some bacteria changed/manipulated to clean up toxic waste ETC

AND sometimes gene grown in bacteria to then be extracted and transferred to other organisms - give to something that wouldn’t make product normally

AND sometimes just want new protein - harvest the protein [ex
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1 – control terminology

--how better control mirobial growth

Sepsis – microbial contamination

Asepsis – absence of signi cant contamination

Aseptic surgery techniques – prevent microbial contamination of wounds

Sterilization – removal of ALL microbial life


-commercial sterilization – remove endspores too [applied to can foods to prevent food
poisoning]

Disinfection – removal of pathogens from inanimate objects

Antispesis – removal of pathogens from living tissue {disinfection of living tissues}

Degerming – mechanical removal of microbes from a limited area via washing or chemical antispetic

Sanitization – lower microbial counts - to safe level for public health (clean public restroom/
utensils at a restaurant)

Biocide/Germicide – kills microbes [su x -cide]

Bacteriostasis – inhibiting, not killing, microbes


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E ectiveness of antimicrobial tx depends on:

-Bacterial populations die at a constant logarithmic rate


-number of microbes


-envt (organic matter, temp, bio lms) – i
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other molecules in the area might inhibit effect of disinfectant


-Time of exposure – of microbe and disinfectant have to spend time w/each other


-microbial characteristics -- i
...
glycocalyx, endospore


5
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3 micrometers


-Membrane ltration removes microbes >0
...
3 – Chemical control
Principles of e ective disinfection:


-concentration of disinfectant


-organic matter


-pH



-contact


-time [that the contact is taking place]


-identity of microbe [bacterial or fungus or virus etc]

Evaluating a disinfectant


-disk-di usion method – zone of inhibiton [ea
...
Lysol – modify phenols

-Bisphenols, hexachlorophene, triclosan


-Disrupt plasma membrane

-Biguanides ex
...
Ag, Hg, Cu


-oligodynamic action – even in very low concentrations, the heavy metal can still exert
antimicrobial activity
...
Ethanol, isopropanol --- good for degerming process


-denature proteins, dissolve lipids and plasma membrane


*need speci c concentration and amt of time

-Aldehydes


-Inactivates proteins by cross linking w/ functional groups (-NH2, -OH, -COOH, -SH)


Ex
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4 Antibiotics
--means of microbial control
-chemotherapy – use of drugs to treat disease [paul ehrlich]

-antimicrobial drugs – interfere w/ growth of microbes w/in host

-antibiotic – substance produced by a microbe that in small amts , inhibits another microbe


-Selective toxicity – drug that kills harmful microbes w/o damagine the host

1928- eming discovered penicillin produced by penicllium


-plate contaminated w/ mold and noted that growth was inhibited

1940 – howard orey and Ernst chain performed rst clinical trials of penicillin

Some sources of antibiotics:


-gram-positive rods (bacteria)


-fungi

Coverage or spectrum of antibiotics:

-antibiotics are speci c (same w/disinfectants)

-narrow spectrum – speci city dictated by cell wall structure, work against bacteria (prokaryotes)—have di erent cell structure from us so harm them but not us


-for eukaryotics harder to nd drugs since cell structure is similar to our own


-for viruses – most di cult to develop bc viruses don’t carry out own metabolism/not
alive

-Broad spectrum

-a ects many gram positive and gram negative organisms; target pathogens and eliminate our normal ora

!Superinfection



-infection w/other organisms not sensitive to drug (kill sensitive pathogens and
select for pathogens that live/drug resistant)



-opportunists or drug resistant strains

Types of antibiotics:
-Bactericidal – kills bacteria directly

-Bacteriostatic – stops growth of bacteria long enough for body defense to get rid of it


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bacitracin


-antimycobacterial antibiotics -target synthesis of mycolic acid [found in mycobacterium cell wall]

-target protein synthesis /ribosome structure – broad spectrum


-chloraphemicol – interacts w/ large ribosome subunit (50S) and a ects growing
polypeptide chain by inhibiting bond between a
...



-aminoglycocide ex/ streptomycin – interfere w/ small portion of ribosome (30S) and
inhibit RNA from being read properly (gram neg bacteria)


-Tetracycline – interfere w/ tRNA docking with ribosome, inhibit a
...
Ampicillin – changes structure enough to a ect gram pos
and gram neg bacteria


-penicilinase (Beta-lactamase)



-penicillin and related drugs are Beta-lactams (beta lactam rings -CH/-CH/-C/N)



-clavulanic acid – non-competitive inhibitor of beta-lactamase/penicilinase

-added to some beta-lactams (augmentin)


-use penicillin derivative to kill cell/cell wall creation while @ same
time stop defensive enzyme of bacteria


*amoxicillin w/clavulanic acid = augmentin


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1 Principles of Disease

Disease – abnormal state in which body is not functioning normally

Pathology – study of disease

Pathogenesis – development of disease

Etiology – study of the cause of a disease

Epidemiology – study of where and when disease occurs

Infection – colonization of the body by pathogens

Normal microbiota permanently colonize the host

Transient microbtiota may be present for days, weeks or months

Symbiosis is the relationship between normal microbiota and the host


-Commensalism – 1 organims is bene ted and the other is una ected


-mutualism – both organisms bene t ex those that feed in our intestines on digested
food/produce vitamins


-parasitism – 1 organism is bene ted at the expense of the other


-some normal microbiota are opportunistic pathogens – can become disease causing
pathogens under correct conditions: if host defenses fail, or if organism gets into wrong spot

Microbial antagonism is competition between microbes

Normal microbiota protect the host by:


-occupying niches that pathogens might occupy


-producing acids


-producing bacteriocins

Probiotics are live microbes applied to or ingested into the body, intended to exert a bene cia
e ect


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Robert Koch’s postulate used to prove the cause of an infection disease


-if a speci c microbe cause of anthrax that a ect animals and humans



-particular bacillus cell in every cow w/anthrax so isolated it, studied characteristics, and injected it into healthy cattle, and cattle develop anthrax and die, recover same
bacillus from dead animals



-look into TB too


POSTULATES:

-the same pathogen must be present in every case of the disease



-the pathogen must be isolated from the diseased host and grown in pure culture



-pathogen from the pure culture must cause the disease when inoculated into a
healthy susceptible lab animal




-the pathogen must be isolated from the inoculated animal and shown to be the
original organism

**caveats: some diseases caused by more than 1 organism ie pneumonia , some organisms
cause more than 1 type of disease , in lab not always able to grow organism in pure culture –
some don’t grow well in this , some microbes ONLY cause human disease (may not be a lab
animal model to use)

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Measles

Severity or duration of disease:

-Acute disease – symptoms develop rapidly (severely)

-chronic – disease develops slowly i
...
hepatitis, mono

-subacute – symptoms between acute and chronic

-latent – disease w/ a period of no symptoms when the pathogen is inactive ex
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3 Disease transmission

Reservoirs of infection:continual sources of infection

-human e
...
AIDS, gonorrhea


-carriers may have inapparent infections or latent diseases

-animal e
...
rabies, lyme disease


-some zoonoses (wild or domestic) may be transmitted to humans

-nonliving – e
...
botulism , tetanus, cholera


-soil and water

Transmission of disease:

-contact


-direct -requires close association between infected and susceptible host eg STD



-droplet – transmission via airborne droplets [travel short distance and direct
person to person ]


-indirect – spread by formites/inanimate object – pathogen spread to person touching
object




-Vehicles – transmission by a medium (food, water , air, body uids)

-vectors -arhtropods especially eas, ticks, and mosquitoes


-mechanical – arthropod carries pathogen on feet


-biological – pathogen reproduced in vector

-Nosocomial (hospital-acquired) infection


-acquired as result of hospital stay


-5-15% of all hospital patients acquire these


-come from di erent types of procedures or objects use in this setting ; infections can
be diverse; microbes often resistant to common antibiotic txs---use aseptic techniques


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Emerging infectious disease (EID)


-disease that are new, increasing in incidence, or showing a potential to increase in the
near future


-contributing factors:



-evolution of new strains or genetic recombination



-inappropriate use of antibiotics and pesticides




-antibiotic resistant strains



-changes in weather patterns/climate change --- insect vectors can move into
new regions where wouldn’t normally nd them



-modern transportation [can move lots of people around the world quickly]



-ecological disaster , war, expanding human settlement










-animal control measures


-lyme disease

-public health failure –ppl not get vaccinated or not get booster shots etc


CDC









-collects and analyzes epidemiological info in the US

-published morbidity and mortality weekly report

-morbidity – incidence of a speci c noti able disease


-noti able disaease – doctors must reports these to US public health authority

-mortality – deaths from noti able diseases

-morbidity rate - # of ppl a ected/total population in a given time period

-mortality rate - # of deaths from a disease/total population in a given time


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coli; endocytosis may occur in some cases


-M protein -------mycolic acid


-Opa protein


-Tapered end [use own cellular shape to adhere – in spirochete]


Host evasion: Capsules


-prevent phagocytosis by host

Enzymes -- microbes produce and secrete these to escape from being sequestered by immune system etc [virulence factors]


-coagulase - coagulate blood


-kinases (speci c) - digest brin clots


-hyaluronidase – hydrolyses hyaluronic acid – break down host tissue


-collagenase – hydrolyzes collagen – break down host tissue


-IgA proteases - destroy IgA antibodies – defend against host immune system antibody
(1st line AB to be secreted)

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