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43 Cards in this Set
- Front
- Back
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What is the function of Peptidoglycan? Chemical composition? |
- Gives rigid support and protects against osmotic pressure
- Sugar backbone with peptide side chains cross-linked by transpeptidase |
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What is the function of Cell Wall / Cell Membrane (which kind of bacteria have this)? Chemical composition?
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Gram Positives
- Major surface antigen - Made of peptidoglycan for support - Lipoteichoic acid induces TNF and IL-1 |
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What is the function of Outer Membrane (which kind of bacteria have this)? Chemical composition?
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- Gram Negatives
- Site of endotoxin (LPS) - major surface antigen - Lipid A induces TNF and IL-1 - O-polysaccharide is the antigen |
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What is the function of the Plasma Membrane in bacteria? Chemical composition?
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- Site of oxidative and transport enzymes
- Phospholipid bilayer |
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What is the function of ribosomes? Chemical composition?
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- Protein synthesis
- 50S and 30S subunits |
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What is the function of the Periplasm? Chemical composition?
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- Space between the cytoplasmic membrane and outer membrane in gram-negative bacteria
- Contains many hydrolytic enzymes, including β-lactamases |
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What is the function of the bacterial capsule? Chemical composition?
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- Protects against phagocytosis
- Polysaccharide (except Bacillus anthracis, which contains D-glutamate) |
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What is the function of the pilus/fimbria? Chemical composition?
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- Mediates adherence of bacteria to cell surface
- Sex pilus forms attachment between 2 bacteria during conjugation - Made of glycoprotein |
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What is the function of flagella? Chemical composition?
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- Motility
- Made of proteins |
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What is the function of Spores? Chemical composition?
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- Resistant to dehydration, heat, and chemicals
- Keratin-like coat; dipicolinic acid; peptidoglycan |
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What is the function of Plasmids? Chemical composition?
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- Contains a variety of genes for antibiotic resistance, enzymes, and toxins
- Made of DNA |
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What is the function of Glycocalyx? Chemical composition?
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- Mediates adherence to surfaces, especially foreign surfaces (eg, indwelling catheters)
- Made of polysaccharide |
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What are the different morphologies of bacteria?
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- Circular (coccus)
- Rod (bacillus) - Branching filamentous - Pleomorphic - Spiral - No cell wall |
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What are some G+ cocci? G-?
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G+
- Staphylococcus - Streptococcus G- - Neisseria |
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What are some G+ rods / bacilli?
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- Clostridium
- Corynebacterium - Bacillus - Listeria - Mycobacterium (acid fast) - Gardnerella (gram variable) |
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What are the types of G- rods / bacilli?
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- Enterics
- Respiratory - Zoonotic |
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What are the Enteric G- rods / bacilli?
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- E. coli
- Shigella - Salmonella - Yersinia - Klebsiella - Proteus - Enterobacter - Serratia - Vibrio - Campylobacter - Helicobacter - Pseudomonas - Bacteroides |
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What are the Respiratory G- rods / bacilli?
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- Haemophilus (pleomorphic)
- Legionella (silver) - Bordetella |
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What are the Zoonotic G- rods / bacilli?
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- Francisella
- Brucella - Pasteurella - Bartonella |
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What are the branching filamentous G+?
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- Actinomyces
- Nocardia (weakly acid fast) |
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What are the Pleomorphic G-?
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- Rickettsiae (Giemsa)
- Chlamydiae (Giemsa) |
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What are the Spiral G-?
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Spirochetes:
- Borrelia (Giemsa) - Leptospira - Treponema |
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What are the bacteria with no cell wall (do not gram stain)?
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Mycoplasma
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What is unusual about the cell membranes / walls of Mycoplasma?
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Contain sterols and have no cell wall
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What is unusual about the cell membranes / walls of Mycobacteria?
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Contain mycolic acid; high lipid content
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Which bugs do not gram stain well?
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These Microbes May Lack Real Color:
- Treponema (too thin to be visualized) - Mycobacteria - Mycoplasma (no cell wall) - Legionella pneumophila (primarily intracellular) - Rickettsia (intracellular parasite) - Chlamydia (intracellular parasite, lacks muramic acid in cell wall) |
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How can you visualize Treponema bacteria (causes syphilis)?
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- Use dark-field microscopy and fluorescent antibody staining
- It is too thin to be visualized with Gram stain |
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How can you visualize Mycobacteria (causes TB)?
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- Carbolfuchsin in acid-fast stain detects the high lipid content in cell wall
- Does not Gram stain well |
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How can you visualize Legionella?
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- Silver stain
- Does not Gram stain well |
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Which bacteria can be stained with the Giemsa stain?
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Certain Bugs Really Try my Patience:
- Chlamydia - Borrelia - Rickettsiae - TRYpanosomes - Plasmodium |
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What does the PAS (periodic acid-Schiff) stain, stain? Use?
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PASs the SUGAR:
- Stains glycogen, mucopolysaccharides - Used to diagnose Whipple disease (Tropheryma whipplei) |
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Which bacteria can be stained with the Ziehl-Neelsen (Carbol Fuchsin) stain?
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Acid fast organisms
- Nocardia - Mycobacterium |
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Which microbe can be stained with the India Ink stain?
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Cryptococcus neoformans (mucicarmine can also be used to stain thick polysaccharide capsule red)
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Which microbes can be stained with the Silver stain?
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- Fungi (eg, Pneumocystis)
- Legionella - Helicobacter pylori |
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What are the special culture requirements of H. influenzae?
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Chocolate agar w/ factors V (NAD+) and X (Hematin)
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What are the special culture requirements of N. gonorrhoeae and N. meningitidis?
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Thayer-Martin (or VPN) media
- Vancomycin (inhibits G+ organisms) - Polymyxin (inhibits G- organisms except Neisseria) - Nystatin (inhibits fungi) "To connect to Neisseria, please use your VPN client" |
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What are the special culture requirements of B. pertussis?
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Bordet-Gengou (potato) agar
(Bordet for Bordetella) |
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What are the special culture requirements of C. diphtheriae?
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- Tellurite agar
- Löffler medium |
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What are the special culture requirements of M. tuberculosis?
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Löwenstein-Jensen agar
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What are the special culture requirements of M. pneumoniae?
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- Eaton agar
- Requires cholesterol |
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What are the special culture requirements of Lactose-Fermenting enterics?
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- MacConkey agar (fermentation produces acid, turning the colony PINK)
- E. coli is also grown on eosin-methylene blue (EMB) agar as colonies with green metallic sheen |
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What are the special culture requirements of Legionella?
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Charcoal yeast extract agar buffered with cysteine and iron
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What are the special culture requirements of Fungi?
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SABouraud agar = "SAB's a fun guy"
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