Lab 33: Simulated Epidemic

Lab 33: Simulated Epidemic

1. Epidemic (level)=  the incidence of a disease in a population at greater than expected levels 

2. Endemic (level)= the expected low level of a disease  

-disease can transition from endemic to epidemic levels for a variety of reasons 

3.Pandemic=  when a disease travels globally and affects people on several continents

ex. influenza, AIDS

4. Epidemiology= field of science dedicated to studying the location and timing of diseases and how they spread

-using this info, epidemiologists can gather data to better understand diseases, in the hopes of controlling or preventing them

-one specific job they have is to find source of disease outbreaks, can be common sources like contaminated food, water, or a person

5. Index Case=  the first person to have a disease which has lead to an outbreak 

-In this lab, we simulated spread of an Epidemic by direct contact- handshaking, and tried to find index case 
--during data collection only half of the class cultured after the first round of handshaking- we did this bc, during the beginning of an outbreak it is rare for Epidemiologists to have all cases 

-Micrococcus luteus= bacteria used in our “outbreak”

       -grows yellow colonies when grown on agar 

Plate1 (on left)= Positive for Micrococcus luteus- its yellow

Plate 9 (on right) = Negative -small random colonies (not yellow)

Closer look at Micrococcus luteus

Lab 27 Identifying GM Crops

Two methods currently used to identify GM genomes

    1. Enzyme Linked Immunosorbent Assay (ELISA)

    2. Polymerase Chain Reaction (PCR) 

             -things needed for PCR: template DNA, nucleotides (ATCG), DNA Primer, DNA polymerase

Common regulatory sequences used to control GM Genes which include: 

   1. Promoter=35S promotor from cauliflower mosaic virus 

   2. Terminator= Nopaline synthase (NOS) terminator from Agrobacterium tumefaciens

ie. Promotor---gene –terminator 

- PCR checks that we have plant DNA by detecting PSII chloroplast gene

-then checks for GM by seeing if DNA has 35S promotor and NOS terminator 

-if yes (ie. Band) to both then food is GMO

-if no plant, then no conclusions can be made-must repeat test

-if no GMO DNA then not its not genetically modified 

We used PCR to detect 35 promoter, NOS terminator, and PSII chloroplast gene

 Then we used Electrophoresis to visualize DNA fragments 

 Machine Used to Run Current Through Gel   

Gel of GM Food Negative        

                                                                                          

Lab 32: Antibiotic Sensitivity

 Antibiotic= a natural substance (made by fungi or bacteria) that inhibits or kills microorganisms

-in common usage antibiotics are often equated with antibacterial drugs and synthetic drugs

      --in 1928, Alexander Fleming found a mold contaminant on an agar that inhibited growth of Staphylococcus aureus

-the mold was Penicillium chrysogenum and so the inhibitory chemical was named Penicillin

        -both Penicillin and Sulfas were developed during WWII, with derivatives also being developed 

         -antibiotics were thought to be the "magic bullet" to wipe out bacterial infections

         - However, bacteria are becoming resistant to traditional antibiotics 

Bacteria develop resistance through:

1. mutation 

2. acquisition of R plasmids 

        -resistance promoted from the misuse/overuse of antibiotics

Resistant Bacteria=

-S. aureus (from Flemings lab) is now major resistant bacteria 

-MRSA=methicillin resistant S. aureus

-VRSA= Vancomycin resistant S. aureus

       -Increased bacterial resistance, means that more antibiotics are needed, but drug companies don't want to produce        antibiotics because they are too expensive to make

                 -can take up to 10 years to make: must find, test, get approved, produce

                 -and after that bacteria can still develop resistance to drug

3 ways to treat infections

1. Trial and error approach= patient given a drug that may or may not work

2. giving them lots of antibiotics- ie kitchen sick= promotes drug resistance and has many side effects to          patient

3. Determining susceptibility is the best way to give patients the proper drugs in the proper dosage

Ways to Determine Susceptibility

1. Minimum Inhibitory Concentration (MIC)= the minimal concentration one is needed to inhibit growth of bacterium

used in:

a. Broth dilution methods-fill test wells with increasing concentration of antibioitic and with the same      concentration of bacterium, then look for turbidity, 1st well with no cloudiness= MIC

b. Kirby-Bauer Disk DIffusion test= small disks with standard concentrations of antibiotics are placed on agar with bacterium

-the antibiotics diffuse outward, creating a zone of inhibition (no growth) around disks

-the size of the zone cannot be directly compared due to the variable solubility and diffusion rates of the  drugs in the medium, so zones must be compared to a standardized chart to assess if the bacteria are sensitive or resistant

-ie. only tells you if bacteria is sensitive or resistant 

c. E test- small strips with quantified antibiotic gradients are used

-zones of inhibition form a teardrop (since high concentrations will diffuse farther than low concentrations)

-the smallest part of teardrop=MIC

-advantage of this test is that it is quantitative for MIC

In this Experiment- test selected antibiotics using the Kirby Bauer Disk Diffusion Test 

-ie. tells you if bacteria is sensitive/resistant and correct dose

-once we grew plates, we looked for zones of inhibition 

-then using a transparency, we overlaid the appropriate antibiotic disk diagram onto its antibiotic disk to determine if the bacteria are Sensitive (S), Intermediate (I) or Resistant (R) to each antibiotic

- The bacteria are S,I, or R if they are in the S,I, or R zone 

R-Resistant= Zone of inhibition with a diameter equal to or less than that of the inner circle

I- Intermediate=Zone of inhibition with a diameter greater than R, but less than that of the outer circle

S- Sensitive= Zone of inhibition with a diameter equal to or greater than that of the outer circle 

****note- Colonies growing WITHIN the zone of inhibition = bacterium resistant to antibiotic (Yikes!)

 -We had two plates

- antibiotic disks with NO ZOI are all Resistant to antibiotic

-so for #33 thats all but one disk 

Plate #16

 Sensitive

 Sensitive 

Sensitive

Resistant 

(I think some got Intermediate on this one)

 Plate #33 =Sensitive 

Plague Fighters

Plague Fighters

1. What was the cause of the epidemic? 

-Ebola= virus

2. Where and when did this epidemic occur? 

-Kikwit in Democratic Republic of Congo (Africa) in 1995 

3. What are the symptoms? 

-attacks vital organs- results in bleeding inside and out, rash, vomiting blood, eyes filled with blood, fixed stares (frozen facial expression), death after 10 days

4. How is it transmitted? 

-coming into direct contact with bodily fluids: tears, blood, surface of skin, sperm

5. How did the scientists prevent the spread of the epidemic?

- Found every case and isolated them ie. quarantine 

-used protective clothing to prevent spread and bleach to kill virus

-stopped ritual funerals where dead person was touched, instead dead were immediately body bagged and buried (no touching)

6. What is meant by “chain of death”?

- you could see the progression of primary care givers of the sick becoming sick

7. What is the natural host for the disease?

-unknown

8. Who was the index case for this outbreak, and what did he do for a living?

-Gaspar Menga- charcoal worker from Kikwit

9. What is the treatment for Ebola?

-None, just supportive care

10. How was nurse Nicole treated? Did she recover?

-blood transfusion from a survivor of Ebola, it contains antibodies against Ebola

11. What was the controversy surrounding her treatment?

- she could obtain other diseases the blood donor has like HIV, Hepatitis, Malaria

-they could have misdiagnosed her with Ebola and actually give her Ebola 

12. Could there be alternate reasons that the treatment was successful for the patients seen at the end of the epidemic?

-after going through many people- virus is less virulent at end

-late in epidemic people were getting smaller viral loads when infected- so didn’t get the virus as badly

13. What is the major concern about highly virulent diseases like Ebola (think about the Reston, Virginia, incident)?

-that they will be airborne

14. Why might Ebola outbreaks become more common in the future?

-bc people are moving into rain forests as populations expand

- brings us closer to whatever the source of Ebola is 

Rise of the Superbugs

Martin Lynch from CCC-  

HIV- in CCC the cases reported with HIV (ie. people who knew) were equal to the amount estimated to have HIV, but not know it 

ie. 600 people have HIV and know it, and estimated 600 have HIV and don’t know it

Rise of the Superbugs

Resistance

1. How does antibiotic resistance occur?

-misuse of drugs- people don’t take all of the antibiotics leaving stronger bacteria

- transfer of resistant plasmids in bacteria

2. Give some examples of superbugs?

-MDR-TB= Multidrug Resistant Tuberculosis

- MRSA= drug resistant staph

- XDR-TB= Extensive Drug Resistant TB

MDR-TB

1. Contrast traditional treatment of TB with treatment of MDR-TB.

- MDR-TB= resistant against most of the antibiotics used to treat traditional TB

-the drugs that are used to treat have toxic side effects, are very expensive, and more rare (2nd line drugs)

- MDR-TB is more toxic- ie. strain has more side effects than traditional TB

- in trial tx drugs taken for 2 yrs (traditional TB tx= take antibiotics for 6 months)

2. Why is directly observed therapy so important?

- to make sure patients continue to take medication once they start feeling better bc that promotes resistance

New Drug Development

1. Why do drug companies not want to develop new antibiotics?

- high cost to develop- takes up to 10 years, hard to find 

- chance of resistance

-also, daily drugs like for cholesterol give more profits

2. Give an example of a new antibiotic. 

Tigecycline- derivative of tetracycline 

The Vaccine War Study Guide

The Vaccine War Study Guide

1. What are some reasons why parents don’t get their children vaccinated?

-Complacency- people don’t think they’re at risk bc the disease is not in their area

- fear side effects ex. autism

- they want kid to fight disease naturally

2. What can happen in communities where children are unvaccinated?

- outbreaks of disease from people who have disease

-no herd immunity in community

3. What are some documented potential side-effects from vaccines?

- common=mild fevers, swelling, pain for ~1hr-day at site of injection

-rare= allergic rxn

-very rare= severe rxn ex. deafness, coma- so rare, not even sure if vaccine caused it

4. What did the large epidemiological studies conclude about the MMR vaccine and autism? Thimerosal and autism?

MMR vaccine and autism= no causation-kids who got MMR shot were NOT more likely to develop autism

Thimerosal and autism= no causation- thimerosal does NOT increase incidence of autism

5. Discuss the problems with the following arguments made in the video:

a. A baby should not be vaccinated against hepatitis B bc this disease is a sexually transmitted disease

- there are other ways to transmit Hepatitis B

ex. through blood, mother to baby (mom has and baby gives to mom)

-some people with Hep B don’t get symptoms and may not know

b. A child should be allowed to go through disease processes naturally as has occurred for thousands of years.

- kid could have long term side effects or die from disease 

c. The polio vaccine requirement should be discontinued in the US bc there is no more polio in this country.

- bc their is polio outside of the country and we are a global community= exposure through travel

6. How has the Internet changed the way society approaches medical issues?

a. Web helps perpetuate controversies over vaccinations

-people more likely to believe things on internet then from CDC

- lots of bad info

b. However, it does give people access to lots of medical info

7. How does herd immunity protect vulnerable individuals?

-if a certain number of the population (critical number) are vaccinated then it prevents spread of disease- this protects the very young/old bc they are most at risk

-protects vulnerable people-> people who cannot get vaccinated

ie. infants, pregnant, HIV

-break through disease= people can get sick even with vaccine even when they are vaccinated... if enough people are getting sick 

8. How do you feel about an individual’s responsibility to public health with regard to vaccines? (this will be important for you to think about as a future health care provider)

Lab 18: Enterotube

Enterotube test is only for suspected Entero- (intestinal) bacteria