Microbiology Exam 3 Study Guide

Lecture 11: Lab Diagnostics Favorite Movie Aliens or Breakfast Club Acapella for why she is not there in Kingston Ontario •Define sensitivity and specificity - Both measures of ability to test to correctly classify a person having a disease or not having a disease - Sensitivity: Refers test ability designate individuals with disease as positive. Highly sensitive test= few false negative results fewer cases of disease of disease missed - Specificity: Refers ability to designate an individual who does not have the disease as negative. Highly specific test-few false positive results few incorrect diagnoses •Describe immunological methods including: agglutination tests,EIAs/ELISAs, ICAs - Agglutination tests: Antibodies have 2 antigone binding sites Can attach to one or more antigens Antibody binds antigen in a clump Testing either antigen or antibody patient sample Tiny synthetic beads coated antigens EIAs/ELISAs: Uses enzyme bound antibody to detect presence of antigen Enzyme labeled antibody added to sample Variable region binds specific antigen Addition substrate allows detection substrates: chromogen, alkaline phosphatase, horseradish peroxidase ICAs Simple device detect presence/absence antigen or antibody Combination of chromatography Separation of components sample based on difference to movement through sorbent And immunological reactions (antibody-antigen) •Define POCT and state the pro/cons - Medical diagnostic testing at or near the point of care - Performed by clinicians - POCTS for infection often based ICAs - Pros: Efficiency, Speed/diagnose of treatment, portable, relatively easy to use - Cons: cost, processing errors, sample shortage/collection sensitivity (less sensitivity than lab methods) Reliability (higher margin of error) •Describe polymerase chain reaction (PCR) - DNA template Sensitive enough detect DNA of single cell/virion in sample Creates billions copies genes few hours Highly specific: only DNA that is exact match primers amplified Applications: gene sequencing genetic disorders diagnosing infections •Describe DNA microarrays and explain how they are used in clinical diagnostics - Based ability of ssDNA to hybridize (bond) to complementary ssDNA - Short ssDNA molecules (oligos) bound glass slide microscopic array - If complementary DNA molecules they will bind and can be visualized by detector - Useful for: panel test, blood culture panels/specific GP bacteria GN bacteria or yeast species, Respiratory panels (respiratory viruses) •Compare and contrast common diagnostic methods for infectious disease - Culture show morphology fungi and bacteria but can take a long time for growth - Microscopy show morphology bacteria and fungi do not work for viruses - Immunological methods are able to use antibodies to identify specific proteins - Molecular methods: Detection of DNA/RNA used to diagnose viruses Lecture12: Antimicrobials and AMR •Define: empiric therapy and prophylaxis - Empiric therapy is commonly started protect patient - Prophylaxis: process that prevents infection or disease in a person at risk •For each drug class, identify: cellular target (mode of action) and whether they are bacteriostatic or bactericidal - See note cards •Identify the 3 drug classes that are considered beta- lactam drugs - Penicillins - Cephalosporins - Carapemens •Explain the significance of MRSA, VRSA, and CRE - They are among resistant microbes of greatest concern •Define the spread of AMR describe the 3 methods of HGT that occur in bacteria HGT - Transformation- take up new DNA from environment - Transduction- genes transported between bacterial cells by bacteriophages (viruses) - Conjugation- sharing DNA through physical connection (sex pilus) •Describe the three mechanisms by which antibiotic resistance may develop AMR - Target Alteration- bacterial protein changes (mutates) drug is no longer effective - Drug inactivation- acquire new proteins (acquire new genes) - Drug reducing considerations inside the cell- Limited drug entry or pumping drugs out Lecture 13:Respiratory Infections- viral •Define:sinusitis, pharyngitis, epiglottitis, laryngitis, bronchitis, croup,stridor, pneumonia, dyspnea, viral variant, viral strain - Sinusitis is inflammation of the sinuses and nasal membranes - Pharyngitis is the Inflammation of the pharynx at the back of the throat - Epiglottitis is inflammation or swelling of the epiglottis which can be life threatening - Laryngitis is the inflammation of the larynx or the voice box that causes hoarse sounding voice - Bronchitis is the when the bronchi become inflamed resulting coughing and other symptoms - Coup is an infection upper respiratory system making it hard to breathe - Stridor is a high pitched breathing sound (partial obstruction of the upper airway) - Pneumonia is a Lung infection where air sacs fill with fluid making it hard to breathe - Dyspnea is the medical term for shortness of breath - Viral variant is a mutation of the virus compared to the original strain - Viral strain is if the mutations are enough to causes new function of the virus compared to the original •Describe the factors that limit infection of the respiratory system - Mucus membrane Goblet cells and mucus Ciliated epithelial cells Muscolalitary escalator MALT Adenoids and tonsils Alveolar macrophages