Microbio – PostMidterm A SGU 2013 – Flashcards
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| HIV 1 and HIV 2 probably came from what animals ? |
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| HIV-1 from chimpanzees HIV-2 from sooty mangabey |
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| What subtype of HIV-1 is in USA ? |
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| Subtype B |
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| What is the first pathogenic human retrovirus ? |
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| Human T-cell leukemia virus |
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| What sub-family do HIV-1 and HIV-2 belong in ? |
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| Lentivirinae |
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| Reverse transcriptase is what ? |
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| RNA dependent DNA polymerase Converts ss HIV RNA to ds HIV DNA |
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| GP120 and GP41 make up ? |
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| GP160 |
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| What enzyme helps HIV insert its DNA into host cell's DNA ? |
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| HIV integrase |
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| What does HIV need to bind CD4 and co-receptors, allowing them to move on and infect other cells ? |
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| HIV glycoproteins |
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| 2 reasons HIV is hard to stop ? |
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| 1) Reverse transcriptase has low fidelity so can make a lot of errors, and HIV keeps evlovling 2) Heterodimers increase variability of HIV genomes so cell can be co-infected by more than 1 HIV protein |
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| HIV enters the body via what cells ? |
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| Infected macrophages |
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| HIV encephalopathy is due to ? |
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| Synctial fusion of HIV-infected macrophages and macroglia |
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| HIV therapy starts when CD4 + cells fall below ? |
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| 350 cells / ul |
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| Seroconversion means what ? |
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| When you can detect antibodies |
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| What is window period for HIV ? |
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| Negative HIV test (primary infection to seroconversion) Viral load very high, increase high transmission risk |
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| Final stage of HIV infection ? |
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| AIDS |
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| Progression of AIDS ? |
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| A S L L O 1) Acute infection 2) Strong anti-HIV immune defense 3) Latent resorvior 4) Loss of CD4+ cells and loss of immune response 5) Onset of AIDS |
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| What bacteria causes bacterial pneumonia in AIDS pts ? |
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| Strep Pneumoniae |
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| AIDS pts can get Mycobacterium Avium Complex under what circumstances ? |
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| Advanced HIV infection and a CD4 lymphocyte count < 50 MAC presents as night sweats, weight loss, abdominal pain, anemia, etc... |
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| What is leading cause of death for those living with AIDS ? |
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| TB |
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| Infections associated with AIDS ? |
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| Bacterial Pneumonia MAC TB Salmoneliosis Bacillary Angiomatosis Viral Hepatitis (Hep B and Hep C) CMV HHV-1, HHV-2 HPV Progressive Multifocal Leukoencephalopathy (PML) - caused by JC virus A lot of other infections |
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| PML is a serious brain infection in AIDS pts. caused by what ? |
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| JC virus |
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| Cryptosporidium Parvum becomes self-limiting in individuals with CD4 counts greater than ? |
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| 200 |
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| Most common microorganism that causes infectious pharyngitis ? |
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| Strep. Pyogenes |
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| Lower Resp. tract (37 degrees celsius) has no normal flora why ? |
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| It is usually sterile Particles should be less than 5 microns to get through. Nonciliated epithelium IgG and IgA |
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| What droplet tends to remain suspended in the air the longest and can cause infection ? |
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| Dried droplet nuclei |
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| Another name for professional invader in a respiratory infection ? |
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| Frank pathogen |
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| 3 Diseases of lower respiratory tract infections ? |
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| Bronchitis Bronchiolitis Pneumonias |
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| Bordet-Gengou growth media can culture what organism ? |
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| Bordetella Pertussis |
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| Tinsdale Agar can culture what organism ? |
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| C. Diptheriae |
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| T or F : Some resp. viruses do not exert their main pathology in resp. tract ? |
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| True They are transported by respiratory droplets |
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| Influenza virus has what type of nucleic acid ? |
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| Segmented RNA |
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| Adenoviruses have what type of nucleic acid ? |
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| Linear ds DNA (Class 1) |
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| Some adenoviral components that interfere with host immune response ? |
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| E1A E1B E3 E4 VA RNAs |
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| Adenovirus Pathogenesis ? |
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| Fiber protein : enables attachment to host cell receptor Receptor varies with viral serotype Penton base has toxic activity (inhibition of cellular mRNA synthesis, cell rounding, tissue damage) |
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| What virus causes phayngitis and conjunctivitis ? |
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| Adenovirus |
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| Antigenic drift allows rhinoviruses to have ? |
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| High number of viral serotypes |
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| What virus can cause common cold and SARS ? |
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| Coronaviruses ss (+) RNA enveloped helical nucleocapsid have "spike" proteins or peplomers Transmission mostly via droplets, fecal/oral also possible Replicate in ** ciliated nasal epithelium ** |
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| Etiologic agent for SARS ? |
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| New Coronavirus (SARS-CoV) |
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| What viruses cause laryngotrachobronchitis and bronchitis ? |
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| HPIV (Human Parainfluenza viruses) Family is Paramyxoviridae Divided into 2 sub-famalies Enveloped Glycoprotein with HN (Hemagglutinin-Neuraminidase) activity Fusion Factor (F) protein involved in viral entry, and against which antibodies can neutralize virus |
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| Which HPIV virus causes Croup (or laryngotrachobronchitis) ? |
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| HPIV-1 |
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| Paramyoxovirinae subfamily of viruses evades immune response how ? |
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| Via V proteins (fusion proteins) Which prevent apoptosis, prevent interferon synthesis, etc... |
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| RSV belongs to what virus subfamily ? |
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| Pneumovirinae |
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| Pathogenesis of RSV ? |
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| 1) Entry is via epithelia nose and eye 2) F & G proteins mediate attachment ; F mediates membrane fusion 3) Primary site of replication is nasopharyngeal epithelium Direct CPE is loss of function |
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| Do not give what as trt of RSV ? |
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| Heat-killed vaccine, b/c it enhances RSV disease...may due to CD8 T cells (immunopathology) |
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| Based on symptoms, how to differentiate b/w cold and flu ? |
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| Flu has fever, headache, vomiting/diarrhea, and severe malaise |
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| 3 types of influenza virus ? |
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| A (found in birds like ducks, only one classified by HN system, can cause epidemic and pandemic) B (also in seals, two lineages: Victoria-like and Yamagata-like) C (no epidemic or pandemic) |
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| Influenza / flu is a zoonotic disease ? |
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| Yes |
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| Antigenic Shift and Influenza ? |
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| Is a sudden rearrangement of 8 genetic subunits of influenza virus, usually due to co-infection of two diff. influenza A strains. Only affects influenza A |
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| How do the following Anti-Flu drugs work ? |
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| Amantadine and Rimantadine - Inhibit uncoating of Influenza A only Target M2 protein Zanamivir and Oseltamvir (Tamiflu) - Inhibit neuraminidase by blocking its release, only works on influenza A and B |
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| What does not work against flu / influenza ? |
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| Post-exposure trt Excessive use of antimicrobials builds up drug-resistance |
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| How to distinguish Strep. Pyogenes from all other Beta-hemolytic streptococci ? |
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| Strep. Pyogenes is Bacitracin sensitive |
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| How to distinguish Strep. Pneumoniae from all other alpah-hemolytic Strep such as Strep. Viridans ? |
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| Strep. Pneumoniae is optochin sensitive |
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| Pneumolysin is one of the virulence factors of what bacteria ? |
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| Strep. Pneumoniae Is a pore-former inhibits ciliated epithelial activity decreases PMN effectiveness etc... |
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| What test is used for determining toxicity of Cornyebacterium Diptheriae ? |
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| Elek test Lines of precipitin on plate indicates toxigenic |
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| How is diptheria exotoxin produced ? |
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| Via lysogenic bacteriophage conversion |
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| What bacteria most common cause of epiglottitis ? |
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| Hemophilus influenzae (is a Gram - rod) **Does not cause influenza** |
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| Pathogenesis of H. Influenzae ? |
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| Pili Non-pilus adhesins LPS PRP (Poplyribose Ribitol Phosphate) - antiphagocytic capsule made of this |
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| Culture of H. Influenzae requires what ? |
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| Chocolate agar with X factor (hemin) and V factor (NAD) |
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| What bacteria causes whooping cough (chronic bronchitis) ? |
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| BOrdetella Pertussis |
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| Why not use cotton swab or throat swab to culture Bordetella Pertussis ? |
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| B/c the bacteria is very susceptible to drying But can culture with nasopharyngeal swab or secretions |
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| Characteristics of Klebsiella Pneumoniae ? |
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| Non-spore forming Gram - rod (bacillus) **Necrotizing Pneumonia** Bronchopneumonia, lung abscesses Two iron uptake systems: aerobactin and enterochelin (are siderophores) "Red currant jelly" sputum |
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| Characteristics of Legionella Pneumophila ? |
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| Causes Legionnaire's disease (pneumonia) and Pontiac fever (self-limiting) Gram - rod, motile, non-spore forming 80% of infections due to serogroup 1 Cannot gram stain b/c bacteria does not take up the counter stain Detect via serology for agglutination or fluorescent antibodies, or with ELISA |
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| What bacteria is a Gram - rod, non-hemolytic, ** smells like grapes ** , is found in fresh water and sea water, stains green on media due to pyocyanin and fluorescein pigments, whose most common infection is otitis externa (swimmer's ear), and is dangerous for people who are burn victims or have cystic fibrosis ? |
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| Pseudomonas |
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| What two bacteria can cause necrotizing pneumonia ? |
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| Klebsiella Pneumoniae and Pseudomonas |
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| Two methods to culture M. tuberculosis ? |
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| Lowenstein-Jensen agar Oleic acid - albumin broth |
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| What is a positive result for TB on Tuberculin test ? |
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| Induration > 10 mm diameter |
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| Two ways to prevent TB ? |
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| Prophylactic antimycotics BCG (Bacillus Calmette-Guerin) vaccine - attenuated M. bovis strain |
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| Know TB first line and second line trts and TB Drug Resistance categories |
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| Two clinically significant varieties of Histoplasma Capsulatum (causes Histoplasmosis) ? |
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| H. capsulatum var capsulatum H. capsulatum var duboisii |
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| Most virulent of all human mycotic pathogens ? |
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| Coccidioides species |
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| Most common fungal infection seen in AIDS patients ? |
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| Cryptococcosis |
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| Two forms of Aspergillosis ? |
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| 1) Allergic 2) Invasive: hyphae invade tissue Gan get "fungal ball" (Aspergilloma) Can get acute pneumonia in severly immunocompromised persons (neutropenia) |
