11 Bacteria & Antibiotics - Info.pdf - haspi

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11 Bacteria & Antibiotics - Info.pdf - haspi

HASPI Medical Biology Lab 11Bacteria & AntibioticsTeacher InformationDescriptionThere has been a recent influx of complaints that the normally prescribed ampicillin antibiotic forsalmonella infections has been ineffective, and a few individuals have actually died from the infection.A question has arisen as to whether the local pharmaceutical company is producing an ineffectiveantibiotic, or whether a new strain of salmonella that is antibiotic resistant is the problem. Studentswill act as medical lab technicians who have been asked to determine whether salmonella samplescollected from patients have actually become antibiotic resistant. The concept of how antibioticresistance occurs, as well as current antibiotic resistant strains will be reviewed in the analysis. Theactual organism used for this lab is a harmless strain of antibiotic resistant E. coli (MM294).Objectives1. Understand how antibiotics work to defend against bacterial infections, and why they are noteffective in viral infections.2. Understand how natural selection has allowed antibiotic resistant bacteria to develop.3. Identify why it is important for the full prescription of antibiotics to be taken.4. Identify recent strains of antibiotic resistant bacteria, and the risks associated with possibleinfection by these organisms.5. Understand the importance of proper collection, handling, and disposal when dealing withpossibly pathogenic organisms.CA Biology State Standards1c. Students know how prokaryotic cells, eukaryotic cells (including those from plants and animals),and viruses differ in complexity and general structure.7c. Students know new mutations are constantly being generated in a gene pool.7d. Students know variation within a species increases the likelihood that at least some members of aspecies will survive under changed environmental conditions.10c. Students know how vaccination protects an individual from infectious diseases.10d. Students know there are important differences between bacteria and viruses with respect to theirrequirements for growth and replication, the body’s primary defenses against bacterial and viralinfections, and effective treatments of these infections.Time: 35-45 minutes over 1-3 daysPlan on calling in the order for the E.coli strain 2-3 weeks before the lab. This lab requires theteacher to make 10 Luria broth agar plates before the lab. Follow the directions on the packet. Youmay consider having the students make their own plates. Wait to add the sterile distilled water to theampicillin until right before the lab, and keep the ampicillin bottle on an ice pack or coldwater bathuntil use. If the ampicillin has not been kept cold, it may be ineffective (in which case you can blamethe “pharmaceutical company” for the negative results).Labeling and inoculating the LB plates, as well as adding the antibiotic will take the students 15-20minutes. There will only be one “patient culture” plate so it may take a bit more time for the studentsto inoculate their plates. The plates will then either need to be placed in an incubator for students tolook at the following day, or can be kept at room temperature and observed 2-3 days later.Observation and analysis will take 20-25 minutes.163


Materials Supplies needed for 10 lab groupsSupplyProvided (P) orNeeded (N)QuantityPetri plates P 10Luria broth agar (20 ml per plate) – 200 ml P 200 mlPatient bacteria culture – MM294 strain of E. coli P 1 plateInoculating loops P 10Ampicillin solution P 20 mg bagPlastic pipette P 2Small beaker (to mix ampicillin) N 1Sharpie N 1Ice bath N 1IMPORTANT: Check the MSDS for safety information on unfamiliar chemicalsAdditional Information• AMPICILLIN MUST BE KEPT IN THE FREEZER UNTIL USE!• Ampicillin solution can be created adding 50 ml of distilled water to the 20 mg of ampicillin inthe small beaker. Students will be adding drops of the ampicillin solution to their plates.• This lab can be previewed or followed-up with the DVD 2000 and Beyond: Confronting theMicrobe Menace. Obtain the free resource through the Howard Hughes Medical Institute(HHMI). http://www.hhmi.org/catalog/main?action=getCategoryListing&catId=2Kit Replenishment Instructions- HASPI Supported Sites OnlyFunds permitting, HASPI will replace annually:• Petri plates• Bacteria culture A – MM294• Inoculating loops• Luria broth agar (MUST return bag for refill)• Ampicillin (MUST return bottle for refill)Resources and References• NIH. 2008. Antimicrobial (Drug) Resistance. National Institute of Allergy and InfectiousDiseases.http://www.niaid.nih.gov/topics/antimicrobialResistance/Understanding/Pages/default.aspx• NIH. 2011. Bacterial Infections. National Institute of Allergy and Infectious Diseases.http://www.niaid.nih.gov/topics/bacterialInfections/Pages/default.aspx• Heather Peterson, HASPI Curriculum Coordinator. www.haspi.org• Edited by Janet Hoff-Kneier, HASPI Program Manager. www.haspi.orgImages (in order of appearance)• http://www.textbookofbacteriology.net/MTBCDC.jpg• http://findmeacure.com/wp-content/uploads/2009/01/streptococcus-bacteria.jpg• http://www.foodsafetynews.com/Salmonella%20bacteria.jp• http://media1.corbisimages.com/CorbisImage/170/23/59/4304/23594304/42-23594304.jpg• http://www.turingfoundation.nl/img/foto_lepra2010.jpg• http://ecx.images-amazon.com/images/I/51HLj2SznDL._SL500_AA300_.jpg• http://www.gadgetscience.com/wp-content/uploads/bacteria-300x223.jpg• http://www.allbacteria.com/images/bacteria-colonies.jpgHASPI Medical Biology Lab 11, Bacteria & Antibiotics, Teacher Info; Revised July 2011 164

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