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MIC 205: Case Study 2b: Chapter 9 (Controlling Microbial Growth in the Environment), Chapter 10 (Controlling Microbial Growth in the Body; Antimicrobial Drugs), Reference Chapters 19-24 (Microbial Diseases) Name: __________________________________________________Score: ________ / 20 Typed responses are preferred. Due at my mailbox on or before Friday, October 25th You are working as a scientific consultant for the Institute of Physical & Chemical Control (IPCC). Your job is to apply what you have learned about the microbial growth requirements and methods of physical, chemical and antimicrobial control to formulate a recommendation for each of the client cases listed below. Be sure to include details such as temperature, time, concentration, drug dose, pore size, wavelength, etc needed to effectively treat each microbe. See last page for a list of potential agents. Good luck! Case Study 2b: You Make Me Sick CDC Guidelines for Sterilization in Healthcare Settings Dr. Dee Syntery has been working all night with sick patients in the Emergency Room at Mount Microbius General Hospital. She has just been called in to assist with a surgical procedure on a patient infected with drug-resistant Mycobacterium tuberculosis. She is in a hurry and she needs to know what methods of physical and chemical control she should use to protect both her patient and herself. She calls the Institute of Physical & Chemical Control (IPCC) Hotline (1-800-MICROBE) and asks you for help. There are many different types of physical control methods that can be used to control unwanted microbial growth. Note that sterilization techniques are often needed to effectively destroy Mycobacterium tuberculosis. 1a) Describe 1 physical method that could be used to sterilize the surgical equipment (forceps, scalpels, etc) both before and after the surgery. Be sure to include any relevant units of measure (time, temperature, pore size, wavelength) used in this form of treatment. There are various types of physical methods which are used for sterilization for example sunlight, drying, heat, radiation and filtration. Since mycobaterium is highly resistible organism, the most reliable method is autoclaving (moist heat). Autoclave: Principle: Autoclave work on the basis, that water boils when its vapour pressure is equal to the atmospheric pressure. If pressure is increased then boiling temperature also increases which gives more heat for boiling the same liquid. For effective autoclaving, there are three major requirements: I. Temperature -121 degree C, Pressure - 1 Kpa, and time - A minimum of 20 minutes after reaching full temperature and pressure. Higher temperature and greature pressure shorten the time. For example if temperature is 134-138 and pressure is 30 psi then required time to acheive sterilization is only three minutes. This process has advantage that it can be used for the heat labile substances because here the moist (vapour) of boiling water is used for sterilization purpose under increased pressure. Disadvantage: It is unsuitable for sterilization of powders and oils. It cannot be used for sterilization of injections. 1b) Explain how this physical method works to inactivate the microbe. Identify what part of the bacterial structure will be affected (proteins, DNA, membranes). There are several computers, patient monitors, and digital instruments in the operating room that would be damaged by the use of heat or chemicals. 2a) Describe a physical and/or mechanical method of control that could be used to decontaminate computers, monitors, and other digital instruments without damaging them. Be sure to include details such as time, temperature, wavelength, or pore size required for this method to be effective. 2b) Explain how this method works to inactivate the microbe. Identify what part of the bacterial structure will be affected (proteins, DNA, membranes). There are many different types of chemicals that can be used to regulate microbial growth. Note that chemicals with the ability to sterilize are often needed to effectively destroy Mycobacterium tuberculosis. 3a) Identify 1 type of chemical product they could use to destroy Mycobacterium tuberculosis and decontaminate the surgical instruments in the operating room. 3b) What chemical group does this product belong to? 3c) In this case, is this product a sterilant, disinfectant, antiseptic, or sanitizer? 3d) What concentration (%) and form (gas, solid, liquid) of this product you would recommend. 3e) What part of the microbial structure (proteins, DNA, membranes) does this product target? Dr. Syntery and her staff now must select a chemical to wash their hands before going into the operating room for a long surgery. The hospital has the following 3 chemicals to choose from: Purell alcohol hand sanitizer, antibacterial Soft Soap with triclosan, or Betasept. 4a-c) Identify the chemical group found in each of the 3 products below and state whether these products are residual or non-residual and whether you WOULD or WOULD NOT recommend them as a surgical scrub: 4a) Purell hand sanitizer chemical group – residual or non-residual – Do you recommend this for surgical prep and why? – 4b) Antibacterial Soft Soap with triclosan chemical group - residual or non-residual – Do you recommend this for surgical prep and why? - 4c) Betasept chemical group - residual or non-residual – Do you recommend this for surgical prep and why? - 5) Describe one mechanical method of control hospital workers could use to decontaminate the air within the operating room or that would prevent them from inhaling Mycobacterium tuberculosis. Be sure to include details such as time, temperature, etc required for this method to be effective. You collect a sputum culture from your patient and send it off to the lab for testing. What 2 drug tests should be performed on your patient’s sputum sample to determine: 1) whether penicillin or tetracycline would be effective drugs for this patient and 2) what would be the most effective dose? 6a) DrugTest #1 – to test if it would be effective How is it performed and what does it test for? 6b) DrugTest #2 – to test the effective dose How is it performed and what does it test for? 7. Describe 2 specific mechanisms that bacteria use to block the effects of antibiotics. (You may use a diagram to help illustrate your answer if needed. 7a) Drug-resistance mechanism #1 – 7b) Drug-resistance mechanism #2 – Identify what each of the 3 drugs below targets and state whether or not this type of drug would be recommended for your patient. Be sure to consider any toxic side effects when prescribing drugs. 8a-c) For each of the following drugs, identify what part of bacterial cell it targets (cell wall type, cell membrane, protein synthesis, metabolism, nucleic acid) and whether you would you recommend this drug for a patient with tuberculosis. For help, please visit Merck Manual. 8a) penicillin targets: Explain why you do or do not recommend this drug for treating TB: 8b) ethambutol targets: Explain why you do or do not recommend this drug for treating TB: 8c) isoniazid targets: Explain why you do or do not recommend this drug for treating TB: 8d) Suggested treatment plan (1st vs. 2nd line drugs, dose, duration)? List All Sources Used to Answer this Question Below (Author. Year. Title of webpage or book. Place of publication: Publisher. Pages or URL) List of Potential Physical Methods Boiling (100°C for 10 minutes) Pasteurization (63°C for 30 minutes or 72°C for 15 seconds) Autoclave (121°C for 15 minutes under 15 psi pressure) Sterilization oven (2 hours at 160°C or 1 hour at 171°C) Filtration (pore size of 0.22-0.45 micrometers or 0.01 – 0.22 micrometers) Ultrasonic vibration (20-40 kHz) Ultraviolet radiation (UVC: 260nm) Ionizing radiation (5-50 kiloGrays) List of Potential Chemical Agents Hibiclens (4%) 70 % ethanol 0.07% cetylpyridinium chloride 10% bleach 500-750 ppm of chlorine dioxide gas 0.15% triclosan 2% glutaraldehyde 37% formalin 1% silver nitrate eyedrops 0.1% thimerosal (mercury) 30% hydrogen peroxide 1% benzalkonium chloride 10% betadine 3% hydrogen peroxide Betasept (4%) 5% formaldehyde gas 50% isopropanol