MICR20010 Agricultural Microbiology Exam Schedule PDF

MICR20010 Agricultural Microbiology Dr. Tadhg Ó Cróinín  MICR20010 – Exam Schedule Practical Exam – 2-3pm November 22nd – 30 MCQ Questions over 1 hours – Only on Practical material (manual/online material) – Worth 15% of grade Final Exam – 9.30-11.30...

MICR20010 Agricultural Microbiology Dr. Tadhg Ó Cróinín  MICR20010 – Exam Schedule Practical Exam – 2-3pm November 22nd – 30 MCQ Questions over 1 hours – Only on Practical material (manual/online material) – Worth 15% of grade Final Exam – 9.30-11.30pm Thursday 12th December – Confirm on Exam timetable – 60 MCQ Questions over 2 hours – On Lecture Material – Worth 70% of grade Practice for Practical Exam under Quiz on Brightspace. Sample questions Final Exam on Brightspace  MICR20010 - remaining lectures Lecture 10 – Microorganisms and Disease Lecture 11 – The Immune System Lecture 12 - Pathogenic Bacteria Lecture 13 – Pathogenic Fungi and Viruses Lecture 14 – Antibiotic Resistant Microorganisms Lecture 15 – Microbiology in the Food Industry – The Fungi Lecture 16 – Microbiology in the Food Industry - Fermentations Lecture 17 – The Nitrogen Cycle Antibiotic Discovery and Resistance  What are Antibiotics? Compounds produced by microorganisms that kill or inhibit the growth of other microorganisms. 70% are produced by Streptomyces bacteria Penicillin was first and produced by Penicillium notatum Approx 8000 known antibiotics. Discovery of Penicillin 192 8 Alexander Fleming first discovered that colonies of the bacterium Staphylococcus aureus failed to grow in the area of a culture that had been contaminated by the green mold Penicillium notatum 1940 Howard Florey and Ernst Chain purified the penicillin mold, injected it in live mice, and initiated human trials  1942 Pfizer successfully achieved mass production of Penicillin using deep-tank fermentation techniques 1945 Nobel Prize in Physiology & Medicine was awarded jointly Penicillin was to Fleming, Florey and Chain available orally to the public without 195 for the discovery of Penicillin prescription 0 Antibiotic producing organisms  Development of strains Original Penicillium mould (notatum) produced less than 10 units per ml of broth (1943) Penicillium chrysogenum found to produce 100 times more. Strain development then continues for the next 30 years Industrial evolution of penicillin production Date Yield (units/mL) Development 1929 2-20 Wild-type (P. notatum) 1941 40-80 Better WT 1943 80-100 New WT (P. chrysogenum) 1944 100-200 Colony selection 1944 300-500 X-irradiation 1945 800-1000 UV-irradiation 1949 1500-2000 Chemical mutagenesis 1951 2400 Chemical mutagenesis 1953 2700 Strain selection 1960 5000 Strain selection 1970 10000 Strain selection Drug Discovery Figure 20.1  Initial screening for strains Select for Streptomyces colonies Overlay with a test strain Check for colonies with zones of inhibition  Check antibiotic spectrum Initial streak of new organisms Look for inhibition zones against multiple organisms  The Disk-Diffusion Method- Identifying suitable antibiotics Figure 20.17  Testing a Strain Staphylococcus albus Micrococcus luteus The Action of Antimicrobial Drugs Bactericidal – Kill microbes directly Bacteriostatic – Prevent microbes from growing Effects of Combinations of Drugs Synergism occurs when the effect of two drugs together is greater than the effect of either alone Antagonism occurs when the effect of two drugs together is less than the effect of either alone – Combination of penicillin with potassium clavulanate (an inhibitor of penicillinase) Combined with broad spectrum penicillin- ammoxicillin – Augmentin Synergism between Two Different Antibiotics Figure 20.23 The Action of Antimicrobial Drugs Microbiology and introduction Figure 20.2 Figure 20.3 Bacterial infection  Inhibitors of Cell Wall Synthesis Penicillin – Natural penicillins – Semisynthetic penicillins- overcome problems with natural – Extended-spectrum penicillins- broader range However….  Antibiotic Resistance Misuse of antibiotics selects for resistance mutants. Misuse includes – Using outdated or weakened antibiotics – Using antibiotics for the common cold and other inappropriate conditions – Using antibiotics in animal feed – the growth effect! – Failing to complete the prescribed regimen – Using someone else's leftover prescription  Antibiotics and Animal Feed Microbiology an introduction, Clinical Resistance to Flouroquinolone (FQ)– Campylobacter jejuni USA Focus, p. 577 Resistance to Penicillin emerged – Gene for beta-lactamase-plasmid borne – Methicillin- introduced as relatively resistant to beta-lactamase But --- methicillin resistant Staphylococcus aureus (MRSA) Beta Lactam ring is broken The Evolution of Drug-Resistant Bacteria The bacterium Staphylococcus aureus is commonly found on people One strain, methicillin-resistant S. aureus (MRSA) is a dangerous pathogen S. aureus became resistant to penicillin in 1945, two years after it was first widely used S. aureus became resistant to methicillin in 1961, two years after it was first widely used  Methicillin works by inhibiting a protein used by bacteria in their cell walls MRSA bacteria use a different protein in their cell walls When exposed to methicillin, MRSA strains are more likely to survive and reproduce than nonresistant S. aureus strains MRSA strains are now resistant to many antibiotics and do produce β-lactamase  Figure 22.14 2,750,000 1 250,000 base pairs 2,500,000 Chromosome map of S. aureus clone USA300 500,000 2,250,000 Key to adaptations Methicillin resistance Ability to colonize hosts 750,000 Increased disease severity 2,000,000 Increased gene exchange (within species) and toxin production 1,000,000 1,750,000 1,250,000 1,500,000 Resistance to Antibiotics: 4 main sites Figure 20.20  Finding new Antibiotics Teixobactin discovery signals a new class of Antibiotics Perhaps more important is the use of the ichip… Opening new environments  Next Time on MICR20010 Microbiology and the food industry Part 1 – The Fungi