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135 Cards in this Set
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- 3rd side (hint)
Average bacterial diameter
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Small (0.3-2 micrometers)
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Bacterial cellular membranes lack these
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Sterols, with the exception of Mycoplasma, are not a component.
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Mycoplasma cell membranes contain what, making them different from all other bacterial cell membranes?
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Cholesterol
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The bacterial cell wall is composed of what?
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Peptidoglycan
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How bacteria replicate
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binary fission (assexual)
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Bacteria contain mono- and poly-cistronic mRNA. The presence of what allows for this?
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Shine-Dalgarno sites allow for what property of bacteria?
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Normal flora of blood, stomach and internal organs
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These have NO common organisms and are generally sterile
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Important normal flora of cutaneous surfaces, including urethra and outer ear
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Common: Staph epidermidis
Less common: Staph aureus, Corynebacteria (diphtheroids), streptococci, yeasts (Candida spp.) |
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Important normal flora of the nose
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Common: Staph aureus
Less common: S. epidermidis, diphtheroids, assorted streptococci |
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Important normal flora of the oropharynx
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Common: Viridians streptococci, including Strep mutans
Less common: assorted Streptococci, nonpathogenic Neisseria, nontypeable H. flu (unencapsulated) |
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Important normal flora of the gingival crevices
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Common: Anerobes (Prevotella, Fusobacterium, Streptococcus, Actinomyces)
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Important normal flora of the colon (in breastfed babies)
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Common: Bifidobacterium
Less common: Lactobacillus, streptococci |
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Important normal flora of the colon (in adults)
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Common: Bacteriodes (predominant,) Escherichia, Bifidobacterium
Less common: Eubacterium, Fusobacterium, Lactobacillus, gram-negative anaerobic rods, Strep faecalis and other streptococci |
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Important normal flora of the vagina
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Common: Lactobacillus, group B strep in 15-20% of women
Less common: assorted streptococci, gram-negative rods, diphtheroids, yeasts |
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Encapsulated bacteria
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Strep pneumo, Klebsiella pneumo, Haemophilus influenza, Pseudomonas aeruginosa, Neisseria meningitidis, Cryptococcus neoformans
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These bacteria can adhere to inert materials through the creation of biofilms
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Staph epidermidis, Strep mutans
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Responsible for dental plaque
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Strep mutans
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Factors that assist with bacterial adherence
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Pili/fimbriae (in gram negative cells)
Teichoic acids (in gram positive cells) Adhesins (colonizing factor, pertussis toxin, hemagglutinins) IgA proteases (cleaved Fc portion may coat bacteria and bind them to cellular Fc receptors) |
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Antiphagocytic surface component of Strep pyogenes
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M protein
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Antiphagocytic surface component of Neisseria gonorrhoeae
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pili (antiphagocytic in which organism?)
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Antiphagocytic surface component of Staph aureus
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A protein
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These bacteria contain IgA proteases which destroy mucosal IgA
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Haemophilus, Neisseria, S. pneumoniae
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Siderophores
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these chelate ("steal") and import iron into bacteria, effectively obtaining needed nutrients
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M. tuberculosis evades intracellular killing by this mechanism
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this bacteria prevents phagosome-lysosome fusion
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Listeria evades intracellular killing by this mechanism
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this bacteria escapes the phagosome before phagosome-lysosome fusion
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Invasins
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surface proteins that allow an organism to bind to and invade normally non-phagocytic human cells, thus escaping the immune system (such as in Yersinia pseudotuberculosis)
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Another name for endotoxin
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LPS
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Where endotoxin is found
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Gram-negative outer membrane
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Toxic portion of LPS
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Lipid A, generally not released until cell death
Exception: N. meningitidis overproduces outer membrane fragments |
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Mechanism of LPS
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activates macrophages, leading to release of TNF-a, IL-1, and IL-6. This leads to tissue damage. Damage to the endothelium from bradykinin-induced vasodilation leads to shock, and DIC is mediated through the activation of Hageman factor.
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Can LPS be converted to a toxoid?
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No, so LPS remains non-immunogenic and cannot be used for vaccines
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Protein toxins secreted from bacterial cells (both gram positive and gram negative)
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Exotoxins
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Can exotoxin be converted to a toxoid?
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Yes, these are modifiable by heat or chemicals to a nontoxic but immunogenic form useful for vaccination.
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The A and B components of exotoxins have these functions
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B component Binds specific receptors to assist the internalization of A
A component is the Active component (often an enzyme) |
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Toxin, Mode of Action, and Disease Role of Corynebacterium diphtheriae
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Diphtheria toxin
ADP ribosyl transferase inactivates EF-2 Primarily targets heart, nerves and epithelium Inhibits eukaryotic cell protein synthesis |
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Toxin, Mode of Action and Disease Role of Pseudomonas aeruginosa
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Exotoxin A
ADP ribosyl transferase inactivates EF-2 Primary target is the liver Inhibits eukaryotic protein synthesis |
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Toxin, Mode of Action and Disease Role of Shigella
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Shiga toxin
Interferes with 60s ribosomal subunit Inhibits protein synthesis in eukaryotic cells Enterotoxic, cytotoxic and neurotoxic |
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Toxin, Mode of Action and Disease Role of EHEC
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Verotoxin (shiga-like toxin)
Interferes with 60s ribosomal subunit Inhibits protein synthesis in eukaryotic cells |
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Toxin, Mode of Action and Disease Role of Clostridium tetani
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Tetanus toxin
Blocks release of inhibitory transmitters glycine and GABA Inhibits neurotransmission in inhibitory synapses |
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Toxin, Mode of Action and Disease Role of Clostridium botulinum
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Botulinum toxin
Blocks release of ACh Inhibits cholinergic synapses |
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Toxins of Staph aureus
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Toxins: TSST-1 & Alpha toxin
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Mode of Action and Disease Role of TSST-1
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An endotoxin enhancer, this toxin is pyrogenic and decreases liver clearance of LPS and superantigen.
Causes fever, increases susceptibility to LPS, rash, shock and capillary leakage |
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Mode of Action and Disease Role of Alpha toxin
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In Staph aureus, this toxin intercalates and forms pores in the cell membrane of eukaryotic cells
In C. perfringens, this toxin is a lecithinase that damages cell membranes and causes myonecrosis |
One toxin in two different bacteria, causes two different effects
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Toxin, Mode of Action and Disease Role of Strep pyogenes
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Exotoxin A, aka pyrogenic toxin
Similar to TSST-1 Endotoxin enhancer Fever, increased suceptibility to LPS, rash, shock, capillary leakage, cardiotoxicity |
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Toxin, Mode of Action and Disease Role of ETEC
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Heat labile Toxin (LT)
Stimulates adenylate cyclase by ADP ribosylation of GTP binding protein Promotes secretion of fluid and electrolytes from intestinal epithelium A cAMP inducer toxin |
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Toxin, Mode of Action and Disease Role of Vibrio cholerae
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Cholera toxin
similar to E coli LT-- stimulates an adenylate cyclase by ADP ribosylation Profuse, watery diarrhea |
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Toxin, Mode of Action and Disease Role of Bacillus anthracis
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Anthrax toxin (3 proteins, 2 toxins)
EF = edema factor -> adenylate cyclase LF = lethal factor PA = protective antigen (B component for both) Decreases phagocytosis, causes edema, kills cells |
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Toxin, Mode of Action and Disease Role of Bordetella pertussis
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Pertussis toxin
ADP ribosylates Gi, the negative regulator of adenylate cyclase -> increased cAMP Histamine sensitizing Lymphocytosis promotion Islet activation |
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Toxin, Mode of Action and Disease Role of Clostridium perferingens
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Alpha toxin
Lecithinase activity causes myonecrosis |
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Bacterial capsule
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present in many gram positive and gram negative bacteria, composed of polysaccharide gel (except B. anthracis), protects against phagocytosis until opsonized, immunogenic (except S. pyogenes and N. meningitidis.)
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Capsule component of B. anthracis
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polypeptide of poly D-glutamate
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Nonimmunogenic cell capsules
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S. pyogenes (hyaluronic acid)
N. meningitidis (sialic acid) |
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Chemical composition and fuctions of bacterial outer cell membrane
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Gram-negative only
Lipid A & polysaccharide (LPS) LPS = endotoxin Lipid A = toxic moiety PS = immunogenic portion Contains protein porins for passive transport and proteins for attachment and virulence |
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Bacterial cell wall composition and function
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Made of peptidoglycan, net of NAG-NAM
Functions to provide support, cell shape and protection from osmotic damage. Synthesis inhibited by penicillins and cephalosporins. Confers gram reaction |
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Gram positives have this in their cell wall, which gram negative bacteria do not. What is its function?
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Techoic acids
Immunogenic, induce TNF-a, IL-1 |
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Acid-fast bacteria have this in their cell wall, which other bacteria do not. What is its function?
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Mycolic acids
Confers resistance to drying and chemicals |
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Periplasmic space-- location, bacteria and function
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Gram negative bacteria only
Located between inner and outer cell membranes Contains enzymes to break down large molecules, aids regulation of osmolarity |
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Cytoplasmic membrane-- location and function
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Gram positive and gram negative
Phospholipid bilayer with embedded proteins Selective permeability and active transport Carrier enzymes for oxidative metabolism, phosphorylation, phospholipid synthesis, DNA replication, peptidoglycan crosslinking, penicillin binding proteins |
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Pili or fimbria-- type of bacteria, composition and function
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Primarily gram negative
Made of glycoprotein (pilin) Adherence to cell surfaces, attachment to other bacteria during conjugation |
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Flagellum -- type of bacteria, composition and function
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Gram (+) and (-)
Made of protein (flagellin) Used for motility |
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Axial filaments-- type of bacteria, composition and function
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Spirochetes and gram negative bacteria
Made of protein Used for motility |
internal flagellum
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Acid fast bacteria turn this color with methylene blue stain
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Red color after methylene blue staining indicates these bacteria
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Acid fast bacteria
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Mycobacterium
Legionella Nocardia (partially) |
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Bonus: protozoan parasites with acid-fast oocysts
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Cryptosporidium and Isospora
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Corynebacterium diphtheriae have granules of this
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volutin granules are useful for identifying this species
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Endospores-- bacteria, composition and function
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Gram positive only
Made of keratin coat, calcium dipicolinate Confers resistance to heal, chemicals and dehydration (not reproductive) |
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Bacteria that make endospores
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Bacillis and Clostridium
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Special media for anaerobes
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thioglycolate
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Special media for Corynebacterium
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Loffler's coagulated serum medium (selective)
Tellurite agar (differential) |
1 selective and 1 differential
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Special media for enteric bacteria
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Eosin methylene blue (differential)
MacConkeys (differential) |
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Special media for enteric pathogens
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Hektoen enteric agar (differential)
Xylose-lysine-deoxycholate agar |
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Special media for Vibrio cholera
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TCBS (thiosulfate citrate bile salts sucrose agar) (selective)
This organism likes an alkaline growth medium |
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Special media for Legionella
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Charcoal yeast extract agar (selective)
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Special media for Mycobacterium
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Lowenstein-Jensen medium (selective)
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Special media for Neisseria from normally sterile sites, Haemophilus
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Chocolate agar
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Special media for Neisseria from sites with normal flora
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Thayer-Martin selective medium (selective)
This is a chocolate agar with vancomycin, nystatin and colistin to inhibit normal flora |
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Growth requirements of mycoplasma
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cholesterol, purines and pyrimidines
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Bacteria requiring cysteine for growth
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Francisella, Brucella, Legionella, Pasteurella
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The 4 sisters Ella at the Cysteine chapel
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Growth requirements of Haemophilus
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X (protoporphyrin) and V (NAD) are required by what bacteria for growth?
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These bacteria are obligate aerobes
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Mycobacterium
Pseudomonas (Bacillus) |
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Superoxide dismutase
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O2 + 2H ------->H2O2
enzyme contained by most obligate anaerobes |
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Microaerophilic (requires low but not full oxygen tension) bacteria
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Campylobacter
Helicobacter |
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Obligate anaerobes
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Actinomyces
Bacteriodes Clostridium |
ABCs of anaerobes
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DTaP vs DTP
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Diphtheria-- diphtheria toxoid
Tetanus-- tetanus toxoid Pertussis -- killed pertussis cells vs acellular pertusis toxoid, filamentous hemagglutinin and pertacin. |
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Neisseria vaccine is active against these capsular polysaccharides, but not against which one that causes 50% of US cases?
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Active against Y, W-135, C and A
Not active against B (capsule is sialic acid, non-immunogenic) |
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Bacillus anthracis vaccine
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supernatant of partially purified proteins used as vaccine for military or occupational usage
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Salmonella typhi vaccine (ty21)
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attenuated bacterial vaccine for travelers to endemic typhoid areas
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HIB vaccine (H. influenza type B)
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protects against 95% of US cases
capsular polysaccharide conjugated to protein, making a T cell dependent vaccine which infants respond to |
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BCG vaccine
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attenuated strain of mycobacterium bovis
does not prevent pulmonary TB, but does prevent dissemination not used in US |
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Yersinia pestis vaccine
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Killed cellular F-1 antigen vaccine
Used in military in endemic areas and with laboratory workers |
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Gram negative aerobic cocci
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Neisseria & Moraxella
have what shape, respiration and gram stain? |
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Gram negative aerobic rods
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Pseudomonas, Legionella, Brucella, Bordetella, Francisella
have what shape, respiration and gram stain? |
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Gram negative helical microaerophilic bacteria
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Campylobacter & Helicobacter
have what shape, respiration and gram stain? |
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Gram postive cocci
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Staphylococcus & Streptococcus
have what shape and gram stain? |
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Gram positive aerobic or facultative rods
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Bacillus, Listeria, Corynebacterium, Nocardia, Mycobacterium
have what shape, respiration and gram stain? |
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Gram positive anaerobic rods
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Clostridium, Actinomyces, Eubacterium, Propionibacterium, Lactobacillus
have what shape, respiration and gram stain? |
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Spore forming bacteria
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Bacillus & Clostridium
... are capable of what? |
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Non-gram staining bacteria
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Mycoplasma & Ureaplasma
... are not capable of what? |
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Gram negative facultative anaerobic rods
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Esherichia, Shigella, Salmonella, Citrobacter, Klebsiella, Enterobacer, Serratia, Proteus, Yersinia, Vibrio, Pasteurella, Haemophilus
have what shape, respiration and gram stain? |
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Gram negative anaerobic straight or helical rods
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Bacteroides, prevotella, Fusobacterium, spirochetes, Rickettsia, Chlamydia
have what shape, respiration and gram stain? |
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Spirochetes
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Treponema, Borrelia, Leptospira
... are all what? |
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Features of all Staphylococcus species
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Gram positive, cocci arranged in clusters, catalase positive
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Staphylococcus aureus
Description, Virulence factors and Associated Diseases |
Coagulase positive, Beta-hemolytic
Contains protein A, TSST-1, enterotoxins, exfoliatins, cytolysins Causes: osteomyelitis, infective endocarditis in IVDU, abscesses, TSS, gastroenteritis and suppurative lesions |
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Staphylococcus epidermidis
Description, Virulence factors and Associated Diseases |
coagulase negative, no hemolysis, susceptible to novobiocin
Part of normal skin flora, can form a biofilm Causes: catheter and device infections, endocarditis in IVDU |
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Staphylococcus saphrophyticus
Description, Virulence factors and Associated Diseases |
coagulase negative, non-hemolytic, resistant to novobiocin
Causes: UTIs in newly sexually active women |
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What color on blood agar is associated with beta hemolysis?
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"Clear" color on blood agar is indicative of this type of hemolysis
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What color on blood agar is associated with alpha hemolysis?
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Green color on blood agar is indicative of this type of hemolysis
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What color on blood agar is associated with gamma hemolysis?
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Red color on blood agar is indicative of this type of hemolysis
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Common features of all Streptococcus
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gram positive cocci in chains or pairs, catalase negative
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This streptococcus is serotyped by capsular antibodies
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Strep pneumo
... is serotyped by what? |
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This streptococcus is serotyped by the M protein
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Strep pyogenes
... is serotyped by what? |
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Lancefields' groups A-O refer to what?
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Streptococci are serotyped by what, using known antigens to cell wall carbohydrates?
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S. pyogenes
Lancefield group, hemolysis, and important lab characteristics |
Lancefield Group: A
Hemolysis: beta Bacitracin-sensitive, PYR test positive |
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S. agalactiae
Lancefield group, hemolysis, and important lab characteristics |
Lancefield Group: B
Hemolysis: beta Bacitracin resistant, hippurate utilized, cAMP test positive |
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Enterococcus faecalis
Lancefield group, hemolysis, and important lab characteristics |
Lancefield Group: D
Hemolysis: alpha, beta or none Growth in 6.5% NaCl, PYR test positive |
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S. bovis
Lancefield group, hemolysis, and important lab characteristics |
Lancefield Group: D
Hemolysis: alpha or none No growth in 6.5% NaCl |
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S. pneumonia
Lancefield group, hemolysis, and important lab characteristics |
Lancefield Group: not groupable
Hemolysis: alpha bile-soluble, inhibited by optochin |
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S. viridans
Lancefield group, hemolysis, and important lab characteristics |
Lancefield Group: not groubable
Hemolysis: beta not bile-soluble, not inhibited by optochin |
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Diseases caused by S. pyogenes
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pharyngitis, scarlet fever, pyoderma, impetigo
... can all be caused by what? |
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Rheumatic fever occurs after this, and manifests through this mechanism
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post-streptococcal pharyngitis with group A strep
antibodies to heart tissue (mean 19 days) fever, joint inflammation, carditis |
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post-streptococcal glomerulonephritis occurs after this infection, and manifests in this manner.
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post-strep pharyngitis, immune complexes bind to glomeruli, leading to pulmonary edema, hypertension and dark urine.
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Group B Strep = Strep agalactiae
commonly causes what? |
Neonatal septicemia and meningitis
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Treatment for group B strep
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ampicillin with cefotaxime or gentamicin
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used to treat which Strep infection?
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Predisposing conditions for strep pneumoniae pneumonia
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antecedent influeza or measles infection, COPD, congestive heart failure, alcoholism, asplenia
... predispose to what infection? |
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Pathogenic factors in Strep pneumo
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IgA protease aids colonization
Teichoic acids aid attachment and are highly inflammatory in CNS Polysaccharide capsule, major virulence factor, inhibits phagocytosis pneumolysin O is a hemolysin |
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postive Quelling reaction
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this test demonstrates capsular swelling with type-specific antiserum in Strep pneumo
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Quelling = Swelling
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positive latex particle agglutination test
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this test for capsular antigen in spinal fluid is diagnostic for S. pneumo meningitis
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Actions of pneumolysin O
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This hemolysin/cytolysin in S. pneumo causes:
damage to respiratory epithelium inhibition of classical complement fixation inhibition of leukocyte respiratory burst |
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Most common cause of adult meningitis
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S. pneumo-- most common cause of what in adults?
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Most common cause of otitis media and sinusitis in children
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S. pneumo-- most common cause of what in children?
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Reason for S. pneumo resistance to penicillin
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chromosomal-- altered penicillin binding proteins
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treatment of S. viridans infective endocarditis
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penicillin G with aminoglycoside useful for treatment of this Strep infection
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Pathogenesis of enterococcus endocarditis
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medical procedures in GI or GU tract --> bloodstream --> previously damaged heart valves --> endocarditis
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Disease associated with group D Gram-positive cocci in chains, PYR test +, with variable hemolysis
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urinary and biliary tract infections
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Enterococcus faecalis
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vancomycin resistance in enterococcus faecalis
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resistant strains of this have D-alanyl D-lactate as terminal of the UDP-N-acetylmuramyl pentapeptide, which functions in cell wall synthesis but is not inhibited by the drug in question
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