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Microbiology -- Lecture 25 to 32


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How are soilborne bacterial diseases transmitted?
1. Through a wound or cut
2. inhalation
3. or ingestion
Why do these bacteria must resist environmental extremes?
Becaue they live in the soil, very hardy environment.
(T/F)These hardy bacterias are often spore-formers
Describe the Causative agent for anthrax.
Bacillus anthracis spores. Aerobic spore-forming rod
What would be the name for the anthracis spore that is inhaled into the lungs?
Pulmonary anthrax
What are the symptoms for pulmonary anthrax?
flu like symptoms, then blood infection with hemorrhaging.
What are the symptoms for skin anthrax?
black crusted lesions. Very rarely does it get into blood--->death.
What would be the name of the disease if it is contact with spores in abrasions?
Skin anthrax
What happen if anthrax spores are ingested?
Major GI problems, they get into blood. Huge lesions on the GI tract(tissue destruction)
(T/F) Transmission is from person to person for anthrax.
False, transmission is not from person to person.
What happens to anthrax spores when they are in contact with human tissues?
they vegetate on contact with human tissue.
What does the anthrax spore has that makes it hard to phagocytose?
A thick capsule (glycocalyx).
What will happen to the spore if macrophage swallowed them?
Spores would divide inside, released into body.
How does the anthrax react once it hits the blood?
Invasive once hit the blood, make toxins.
What kind of toxins are made by anthrax?
What are the three types of exotoxins?
Lethal factor, protective antigen, and edema factor.
What are protective antigen?
They are the carrier into host cell receptors; binding to receptors on host cells like a ligand.
What is the function of edema factor?
Causes the overproduction of cyclic AMP in cell.
What is the purpose of AMP in cell?
AMP level keeps the cell at the right level.
With the overproduction of cyclic AMP in the cell, what happens to the salt and water?
They start to shoot out of cell like crazy, and the cell floods itself.
What is the function of the lethal factor?
to kill the cell. THe exact mechanism is unknown.
Are the edema factor and the lethal factor cause the serious damage independently of the protective antigen?
No, they could not do without the protective antigen (ligand) to bind to the receptor.
What is the primary treatment for anthrax?
Antibiotics such as CIPRO.
Why does one need to take the CIPRO early?
Need to take it early on to keep the population of B. anthracis low in the body
How can one prevent from getting anthrax?
Vaccine only available to the military. Spores are hard to get rid of, and they last years (Grinard island story). Cremation, burying in lime, burning the whole field are ways to destroy the anthrax spores.
What is the causative agent for C. Tetanus?
CLostridium tetani, gram-positive anaerobic spore formers.
Where are C. Tetanus originally found?
in the intestine of many animals/humans, feces excreted into soil.
What happens when C. Tetanus enter a deep cut/gash?
since it is O2 free, so it revert to vegetative bacilli. These gashes usually result from animal bites, rusty nail (spores clinging to rough edges), glass, etc.
What is the pathogenicity of C. tetani?
produces toxins, cells not invasive--stays in wound but toxin spreads throughout body.
What is the most important exotoxin?
tetanospasmin (2nd most powerful toxin after botox.
What does tetanospasmin do?
inhibits relaxation pathway following muscle contraction by blocking release of inhibitory neurotransmitters. so continuous muscle contraction--->death
What are the symptoms of C. Tetani?
general muscle stiffness develop within rapidly after infection (several hours), reduced ventilation, lockjaw, sardonic smile, death.
What are the treatments for C. Tetani?
Antitoxin (to stop toxin) and antibiotic (to stop the bacterial growth, stop the factory)
How do you immunized from tetanus?
Inject DtaP-tetanus toxoid, and it should be renewed every 10 years.
Why should DtaP be renewed every ten years?
To keep immunity high (BOOSTER).
What is DtaP?
Tetanus toxoid, a toxin treated with formaldehyde.
What are the common sense to prevent getting C. Tetanus?
Wash out cuts thoroughly with anticeptic, and get a booster every 10 years.
What is the natural defense against dental disease?
Acquired enamel pellicle that has net negative charge from glycoproteins and calcium phosphate.
What is the function of basic saliva?
To neutralize acid.
What is the natural enemy of mouth flora (bacteria)
What makes up sucrose?
Fructose and glucose. When they are together is worse than when they are separated.
What does caries mean?
Which two components give the acquired enamel pellicle the net negative charge?
Glycoproteins, calcium phosphate.
How many microbes are in your mouth?
50 to 100 billion.
What is formed by the initial colonization of the enamel pellicle by streptococci?
What type of streptococci cause the initial colonization?
Streptococcus mutans.
What allows the bacteria to form biofilm?
What does the bacteria use on the pili that bind to the receptors on pellicle, especially in pits, fissures (protected area).
They use the adhesins on the pili.
What is the name of the enzyme that polymerizes glucose into glucan?
What is the enzyme that also breaks sucrose into fructose and glucose.
What is the function of glucan?
acts like cement to bind bacterial cells to each toher and to enamel to form plague (biofilm).
Why does the plague form?
So the bacteria is positioned for destruction.
Can remineralization take place? under what condition?
Only if minor demineralization take place.
When do patients start feeling pain from dental caries?
When cavities extend into dentin and pulp.
What dissolves the calcium phosphate salts in enamel that leads to cavity?
Concentrated acid created from fructose.
(T/F) Place is not acid impermeable.
Why do the younger kids get more cavities?
It is because the pits and fissures are deeper when young, but they get ground down by age.
What other component might contribute to getting cavities?
Inherited component.
What should you not eat to prevent cavities?
How many drugs are in the pipeline that will stop S. mutans from attaching o teeth?
What are the types of those two drugs that stop S. mutans from attaching to the teeth?
Decoy drug and excluder drug.
Which drug has the soluable copies of the enamel receptors?
Decoy drug.
Which drug is the soluble copies of adhesion ligands?
Excluder drug.
Where is the adhesion ligand located at?
They are on S. mutans
What can one also use in water form, or pill form that prevents cavities?
What does the fluoride replace in the enamel?
OH hydroxyl, and it becomes part of the enamel.
Why is fluoride better than hydroxyl?
They hold calcium phosphate more tightly than hydroxyl, and reduce solubility of enamel--->remineralization.
Which age group would especially benefit from having fluoride since fissures too deep for toothbrush?
Kids, fluoride=sealants
What must one do everyday to prevent cavities?
Brush and floss.
How does flora replacement work?
Adding to mouth a bacteriocin producing strain of S. mutans.
What substance can't this bacteriocin producing S. mutan produce?
Lactic acid.
What is the function of bacteriocin?
It kills other S mutans but not itself.
What is another word to describe S mutans recombinant strand's inability to produce lactic acid?
They can't fermant.
What is the PHK for periodontal disease?
What does ANUG stands for?
Acute necrotizing ulcerative gingivitis.
What is ANUG?
Really bad gingivitis, trench mouth.
What does periodontal mean?
Gingivitis inflammation of gums around the tooth.
What is the main species that invade?
Porphyromonas ginigivalis.
What kind of bacteris is porphyromonas?
Invasive anaerobes.
How does the bacteria create an anaerobic environment to thrive in?
Plaque formation at the gumline.
What kind of plaque is formed at the gumline?
calcified plaque aka tartar aka calculus.
What does the bacteria produce at the gumline plaque, the anaerobic area?
Toxins, hyaluronidase, proteases.
What is the purpose of each of these substance?
Toxins to kill gumline cell, hyaluronidases help the "carving the meat" and the proteases is to get the proteins for bacteria energy source.
Why is there foul odor and putrid smell associated with ANUG?
Because proteins are being broken down.
What happens after the inflammation of gums?
Major ligament and one destruction takes place, and may lose tooth.
What other factors are associated with ANUG?
Malnutrition, smoking, mental stress, poor oral hygiene.
Who's report showed that the microbial makeup of periodontal plague of ANUG is different from mild gingivitis?
Paul Keyes report.
How do you control the calcified plaque formation?
frequent plaque removal, brush, and floss.
What treats ANUG?
According to Keye's report, mild gingivitis(normal plaque)contain what sort of microorganisms?
Cocci, no spirochetes, no protozoans.
According to Keye's report, severe gingivitis such as ANUG contains what kind of microorganisms?
Lots of spirochetes, protozoans-like mobile amoebas+trichomonads.
What is the name of the heart disease may result from oral infection and dental work?
Bacterial Subacute Endocarditis.
What is endocarditis?
Inflammation of membranes in the heart.
What two types of endocartitis are there?
Acute (fast acting), and subacute (slow acting).
What is an example of acute endocartitis?
Rhematic fever.
What is an example of subacute endocartitis?
Valve problem, heart defect due to congenital or acquired.
What is the pathogen that attacks in subacute endocartitis?
It is not a pathogen, it is a normal flora infecting the heart that affects people with genetically weaker heart.
Subacute bacterial endocarditis targets what kind of people?
People with defective heart.
How does the normal flora (oral strep or staph) gets into the bloodstream?
From cleaning procedure or bad infection.
Wher does the bacteria get caught resulting in a biofilm?
Near the faulty valve. *A very slow process*
What is the result of biofilm forming in the defective heart valve?
Tissue damage, maybe clotting.
For the bacterial subacute endocartitis patients, how do they feel as their heart function slowly decreases?
Tired and weak over many weaks, and then eventually death if not stopped.
How long usually when the heart function slowly decreases in BSE?
Slowly, usually months, a very long process
What is the prevention when going through dental work for those with heart defects?
Few large doses of antibiotic.
Why is it controversial to give antibiotics to patients before doing dental work?
Many medical fields believe that this will build tolerance.
What are the associations that support giving antibiotics as a preventive measure?
Am Heart Association and American Dental Association.
Why do medical field believe that this preventive measure will build tolerance?
Chance of dying from this type of heart disease is so slim.
Is temporary bacterial halitosis chronic?
No, it's not chronic.
When is the saliva produxn low?
When one is sleeping.
What sort of microbe cause TBH?
Gram negative strict anaerobes.
Where do these gram negative strict anaerobe live?
Usually on the back of tongue.
when do these gram negative take over the mouth that gets the morning breath??
When the saliva produxn is slow, like when you are sleeping.
What is a preventive measure to temporary bacterial halitosis?
Use tools to brush the back of the tongues, and to increase saliva produxn by chewing sugarless gum.
What do the STD required for transmission to occur usually? Why?
Person-to Person contact because bacteria cannot remain alive outside the body for very long.
Can STD be normally transmitted by fomites?
No, not noramlly by fomites.
What are the 2 drawbacks in terms of perpetuating STDs when using oral contraceptives?
Offer no defense against disease (unlike condoms), and increase the pH of vagina.
What is the pH like normally in the vagina to prevent other bacteria to grow in it?
The pH is low.
How many annually are infected with chlamydia?
4 million.
What is the definition for chlamydia?
Infection of the urogenital tract characterized by inflammation and discharge.
What is the causative agent of chlamydia?
Chlamydia trachomatis.
What kind of microbes are chlamydia trachomatic?
obligate intracellular parasite.
Can the obligate intracellular parasite be grown in normal lab?
No, it can only be grown in livin tissue because it is a specific parasite of humans; it cannot be grown on LB plate.
(T/F) Chlamydia has short incubation time.
False, it has long incubation time.
How does chlamydia accelerate spread up the genital tract?
They ride sperms.
How long is the incubation time for the chlamydia?
1-3 weeks.
In women, what kinds of symptoms are associated with chlamydia?
Most symptomatic, but some assymptomatic.
What causes the painful urination in women?
Chlamydia infection of urethral epithelial cells.
What causes the cervix inflammation in women?
When the chlamydial bacteria infect the cervix.
What does salpingitis mean?
Scarring and blockage of fallopian tubes.
How many percentage of the untreated women have ectopic pregnancy from salpingitis?
15-30% of untreated women.
Why does ectopic pregnancy results from salpingitis?
Blockage of fallopian tubes result in prevention of embryo to reach the uterus, so embryo grows in fallopian tubes instead.
What kind of bacteria are chlamydia trachomatis?
Slow moving but invasive bacteria.
Where else can chlamydia trachomatis go other than uterus and fallopian tubes?
possibly to the abdomen, and to the liver.
What happens when chlamydia infects the urethral cells in men?
It will result in thick pusfilled discharge.
How will chlamydia cause extreme pain and sterility in men?
With the inflammation up through seminal tubules and testes.
What will chlamydia cause in the newborns?
chlamydial opthalmia which can lead to blindness in baby.
How did the baby get chlamydial opthalmia?
From the infected mother as they go through birth canal.
What is the treatment for chlamydia?
How would one control the spread of chlamydia?
Abstinence, condom use, treating individuals quickly.
Why is there no long term immunity for chlamydia?
Because of several different chlamydia strain exist.
How many gonorrhea are reported each year?
350,000 cases reported each year.
What is the causative agent for gonorrhea?
Neisseria gonorrheae.
What kind of microbe is Neisseria gonorrheae?
Fragile organism, not intracellular parasite, a little tougher than chlamydia, but still weak.
How does a chlamydia trachomatis size compare to mycoplasma?
Chlamydia is pretty small, a little bigger than mycoplasma.
In men and women, why does the bacterium uses pili?
To attach to epithelial cells of urogenitial tract.
Where does the gonorrhea start the infection?
Start on the outside and they stay extracellular.
How does gonorrhea differ from chlamydia?
They stay on the outside and not on the inside like chlamydia.
What enzymes does gonorrhea secrete that causes tissue destruction?
Proteases, lipases.
How does gonorrhea spread?
They spread in seminal and vaginal fluids.
How long is the incubation time for gonorrhea?
2-6 days.
How does the symptoms compare to chlamydia?
Similar but milder than chlamydia, painful urination and vaginal discharge.
How does the gonorrhea attach to the epithelial cells.
They attach to epithelial cells' receptors with pili.
Where does the gonorrhea cells infect in women?
Mainly the cervix, and it can spread to the Fallopian tubes and the surrounding tissues.
What can gonorrhea also lead to?
Salpingitis, or very rarely liver disorder.
How many percent of the women are asymptomatic?
50% shows no symptoms or are carriers.
How long can one be a carrier?
For months up to years. May transmit disease without knowing.
What does gonorrhea cause in the newborns?
Gonococcal opthalmia.
Since urethra is the primary affected area for gonorrhea, what are the symptoms in men?
frequent painful urination, discharge as cells damaged.
What happens when gonorrhea progresses in men?
Pain and infection of the epididymis an testes may lead to sterility.
What is the treatment for gonorrhea? What is the downside?
Antibiotics, but high resistance.
What is one thing N. gonorrhea do that makes it hard to develop immunity towards the pathogen?
They have many different pili genes, so different antigen gene displayed over time.
What is the phrase that describes the superb advantage that only N. gonorrhea has?
Antigenic variation/shuffling.
What two other things does N. gonorrhea do that makes it so "tough" on body immunity?
OPA proteins that mess up T helper receptor, enzymes for IgA destruction.
What are the methods to control the spreading of gonorrhea?
*See chlamydia*.
How is gonorrhea different from chlamydia generally?
Gonorrhea hangs on outside of cell, and it is not as demanding as chlamydia, BUT they cause more symptoms.
How is sebum secreted?
Sebum is sebaceous gland production, and it is released through pore.
With the sebum overproduction, what will clog the pore causing the build up of sebum inside?
Dead cells and dirt clogging the pore will cause the build up.
What is the name of the normal flora that breaks down sebum into fatty acids to grow which will then grow?
Propionibacterium acnes, an anaerobic bacteria.
What happen when this skin normal flora proliferate?
It triggers the inflammatory response, causing acne.
What is the size of the virus?
20-250 nm.
What is the name of the virus that is 250nm and is the same size as chlamydia and mycoplasma?
What is the shape of the virus?
Virus shape varies.
What is the name for completely assembled virus outside of host cells?
What are the components of a generalized virus?
The genome and the capsid, some virus have envelopes (can acquire this from the host), with or without spikes.
What is the name for genome+capsid, and it must be presented along with the proteins inside?
What are the components of a virus envelope?
Lipid and protein membrane that covers over the capsid.
This viral envelope structure contains enzymes that is used for attachment.
Where can the viral envelope be acquired from?
It can be acquired from the host.
What won't take place if there is no envelope?
No envelope, no infect (think hands).
What is the sole goal of a virus?
To replicate.
What is capsid?
The surrounding protein coat of a virus.
List the possible combinations of viral genome.
ssDNA, ssRNA, dsDNA, dsRNA
What is one impossible thing about viral genome?
It is impossible to have both DNA and RNA.
What does it mean when we describe vrus "travel light, live off the 'land'"?
Viral genome only contain a few genes.
How does a virus get itself replicated?
They use and abuse host machinery (ribosomes, etc).
How many stages is the viral replication in bacteriophage? What is it similar to?
5 stages, and it is similar to replication in animal cells.
Briefly describe the structure of the T4 bacteriophage.
Complex virion with a head and a tail, but no envelope.
What is the burst size of an infected bacterial cell?
50-200 new phages are made and released.
Define burst time.
ATtachment to release.
Define burst size.
Number of new phages made and released by 1 bacterial cell.
What are the 5 steps of viral replication?
Attachment, Penetration, Biosynthesis, Maturation, and Release.
What happens in attachment stage of viral replication?
Tail or viral capsid binds receptor on host cell wall.
What happens during penetration stage in viral replication?
Viral DNA injected intracellularly, capsid stays extracellular.
What happens during biosynthesis stage of viral replication?
Make viral proteins DNA degraded host nucleic acid.
What happens during maturation stage of viral replication?
Viral assembly.
What happens during the release stage of viral replication?
Host destroyed, new viruses released.
What are viral spikes like? What structure is it similar to in a human body?
Like a hand.
What are the two major methods for replicating in animal cells?
Fusion and endocytosis.
Describe the process of fusion of viral replication.
Spikes interact with host cell membrane, then envelope fuses with host cell membrane, left behind.
Describe the process of endocytosis of viral replication.
Entire enveloped virus endocytosed, and envelope removed (uncoated) in cytoplasmic endosome of host cell.
What is a gimmick to remember fusion method of viral replication?
Leaving your coat at the door.
What kind of virus infection cause a slow death?
Viruses with evelopes bud from cell without lysing host.
What kind of virus infection cause a quick death?
Non-enveloped viruses rupture host cell membrane--destroy host.
What are the two types of genome found in viruses?
DNA and RNA.
Where is the DNA genome made in the host?
Host nucleus.
Where is the capsid made in the host?
Made in the cytoplasm.
Where is the nucleocapsid assembled at?
Where did the envelope came from in the host?
Envelope comes fom nuclear or plasma membrane.
What does the (+)-strand (sense) RNA virus use as a template for translation?
The genome act as mRNA.
What does the (-)-strand (antisense) RNA virus makes from encoded RNA polymerase?
I makes the complementary strand of RNA, and (-) strand becomes (+) strand in host cell.
What is a retrovirus?
Viral-encoded reverse transcriptase takes RNA genome and makes dsDNA from it.
Why does retrovirus make the complimentary strand?
To yield dsDNA.
How does the viral DNA of retrovirus becomes a provirus?
By integrating into host cell genome.
What is the state of provirus?
Lysogenic state.
When does retrovirus get replicated?
Whenever chromosome copied.
Why are antibiotics no effective against viral infections?
It is because viruses use host enzymes and machinery, and viruses have no cell wall.
Why is it difficult to find targets of selective toxicity?
It's because viruses rely almost exclusively on the host cell's metabolic machinery for heir replication.
What are the three major classes of virus antibiotics?
Neurominidase inhibitors, uncoating inhibitors, and base analogs.
What is an example of neurominidase inhibitor?
What is the function of neurominidase inhibitor?
To prevent attachment of influenza virus to new cell and release from infected cell.
What does the spike of flu virus contain?
Neuraminidase inhibitor.
What is the mechanism of neurominidase inhibitor?
Clog site on host where virus attaches; like a pillow on door knob.
What is an example of uncoating inhibitors?
What does uncoating inhibitors do for influenza viruses?
It blocks uncoating in the endosomes of endocytosis.
What is an example of base analogs?
Azidothymidine (AZT).
What is AZT most commonly used for?
What is another example for base analogs other than azidothymidine?
What does base analogs look like?
What is the function of base analogs?
Stops synthesis of nucleic acids; like dead ends.
What is an example of reverse transcriptase inhibitors?
What is the function of reverse transcriptase inhibitors?
To bind and inhibit reverse transcriptase, and blocks replication of retroviruses.
What is Squinivir an example of?
Protease inhibitors.
Why is Saquinivir derimental to HIV?
Because protease function required for HIV capsid construction.
What are protease inhibitors at microscopic level?
Look like peptide bond that is normally attacked by protease, decoys that are undigestable.
How many proteins are produced by the body cell (made recombinantly) in response to viral invasion?
20 proteins are produced by the body cell.

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