Quizlet - Bacteria Flashcards
1
Q
Bacterial Structures: Peptidoglycan
A
Gives rigid support, protects against osmotic pressure; Sugar backbone w/ cross-linked peptide side chains. (function; chemical composition)
2
Q
Bacterial Structures: Cell wall / cell membrane (G+’s)
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Major surface Ag; Peptidoglycan for support. Teichoic acid induces TNF and IL-1. (function; chemical composition)
3
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Bacterial Structures: Outer membrane (G-)
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Site of endotoxin (LPS), major surface Ag; Lipid A induces TNF and IL-1 Polysaccharide is the Ag (function; chemical composition)
4
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Bacterial Structures: Plasma membrane
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Site of oxidative and transport enzymes; Lipoprotein bilayer (function; chemical composition)
5
Q
Bacterial Structures: Ribosome
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Protein synthesis; 50S and 30S subunits (function; chemical composition)
6
Q
Bacterial Structures: Periplasm
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Space btw the cytoplasmic membrane and the outer membrane in G- bacteria; Contains may hydrolytic enzymes, including beta-lactamases (function; chemical composition)
7
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Bacterial Structures: Capsule Function? Structure? (… and exception?)
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Protects against phagocytosis; Polysaccharide (except in Bacillus anthracis , which contains D-glutamate) (function; chemical composition)
8
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Bacterial Structures: Pilus/fimbria
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Mediate adherence of bacteria to cell surface, sex pilus forms attachment btw 2 bacteria during conjugation; Glycoprotein (function; chemical composition)
9
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Bacterial Structures: Flagellum
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Motility; Protein (function; chemical composition)
10
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Bacterial Structures: Spore
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Provides resistance to dehydration, heat, and chemicals; Keratin-like coat, dipiclonic acid (function; chemical composition)
11
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Bacterial Structures: Plasmid
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Contains a variety of genes for ABX resistance, enzymes, toxins; DNA (function; chemical composition)
12
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Bacterial Structures: Glycocalyx
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Mediates adherence to surfaces, especially foreign surfaces (e.g. indwelling catheters); Polysaccharide (function; chemical composition)
13
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Structures unique to gram (+) organisms
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Teichoic acid Cell wall
14
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Structures common to Gram +/- organisms
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Flagellum, pilus, capsule, PDG, cytoplasmic membrane
15
Q
Features unique to G(-) organisms
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Endotoxin/LPS (outer membrane) Periplasmic space (location of many beta-lactamases)
16
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Bacteria w/ unusual cell membranes/walls
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Mycoplasma: contain sterols and have no cell wall Mycobacteria: Contain mycolic acid. High lipid content.
17
Q
G(+) cocci
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Staphylococcus Streptococcus
18
Q
G(-) cocci
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Neisseria
19
Q
G(+) Rods
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My cobacterium (acid-fast) List eria B acillus C lostridium C orynebacterium What happened when you were sending that email to Gram + Rod ? My List B ecame CC ‘d
20
Q
My cobacterium (acid-fast) List eria B acillus C lostridium C orynebacterium What happened when you were sending that email to Gram + Rod ? My List B ecame CC ‘d
A
G(+) Rods
21
Q
G(-) Rods
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H ave Y ou E ver L istened to GNR (Guns n’ Roses = Gram (-) Rods)? I like B oy B ands. B esides, Fran kly, I P refer Garden s to jungles. Haemophilus Yersinia Enterics (separate card) Legionella (silver stain) Bordatella Brucella Bartonella Francisella Pasteurella Gardnerella (gram variable)
22
Q
H ave Y ou E ver L istened to GNR (Guns n’ Roses = Gram (-) Rods)? I like B oy B ands. B esides, Fran kly, I P refer Garden s to jungles. Haemophilus Yersinia Enterics (separate card) Legionella (silver stain) Bordatella Brucella Bartonella Francisella Pasteurella Gardnerella (gram variable)
A
G(-) Rods
23
Q
Branching Filamentous bacteria (G+)
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Actinomyces Nocardia (weakly acid-fast)
24
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Actinomyces Nocardia (weakly acid-fast)
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Branching Filamentous bacteria (G+)
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Pleomorphic (G-) bacteria
Rickettsiae Chlamydiae (Giemsa stain)
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Rickettsiae Chlamydiae (Giemsa stain)
Pleomorphic (G-) bacteria
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Spirochetes (G-)
Leptospira Borrelia (Giemsa stain) Treponema
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Leptospira Borrelia (Giemsa stain) Treponema
Spirochetes (G-)
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Neither G+ nor G- (b/c no cell wall)
Mycoplasma
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Bugs that won't Gram stain
These Rascals May Microscopically Lack Color Treponema (too thin to be visualized) Rickettsia (intracellular parasite) Mycobacteria (high-lipid-content cell wall requires acid-fast stain) Mycoplasma (no cell wall) Legionella pneumophilia (primarily intracellular) Chlamydia (intracellular parasite; lacks muramic acid cell wall)
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Visualizing Treponemes
Darkfield microscopy and fluorescent Ab staining
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Visualizing Mycobacteria
Acid-fast stain
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Visualizing Legionella
Silver stain
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Giemsa's stain is used to visualize...?
use for: Borrelia Plasmodium Trypanosomes Chlamydia
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PAS (periodic acid-Schiff) stain
stains glycogen, mucopolysaccharides*; Used to diagnose Whipple's dz (*PASs the sugar)
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Ziehl-Neelsen stain
Use to stain Acid-fast bacteria
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India ink
used to visualize Cryptococcus neoformans
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Silver stain
used to visualize: fungi, Legionella
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Media/Special culture requirements for: H. influenzae
Chocolate agar w/ factors V (NAD) and X (hematin) (Media used for isolation)
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Chocolate agar w/ factors V (NAD) and X (hematin)
H. influenzae
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Media/Special culture requirements for: N. gonorrheae
Thayer-Martin media (Chocolate agar based, w/ various ABX) (Media used for isolation)
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Thayer-Martin media (Chocolate agar based, w/ various ABX)
N. gonorrheae
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Media/Special culture requirements for: B. pertussis
Bordet-Gengou (potato) agar (Media used for isolation)
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Bordet-Gengou (potato) agar
B. pertussis
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Media/Special culture requirements for: C. diphtheriae
Tellurite plate, Loffler's media (Media used for isolation)
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Tellurite plate, Loffler's media
C. diphtheriae
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Media/Special culture requirements for: M. tuberculosis
Lowenstein-Jensen agar (Media used for isolation)
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Lowenstein-Jensen agar
M. tuberculosis
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Media/Special culture requirements for: M. pneumoniae
Eaton's agar (Media used for isolation)
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Eaton's agar
M. pneumoniae
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Media/Special culture requirements for: E. coli
Eosin-methylene Blue (EMB) agar (blue-black colonies w/ metallic sheen) (Media used for isolation)
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Eosin-methylene Blue (EMB) agar (blue-black colonies w/ metallic sheen)
E. coli
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Media/Special culture requirements for: Lactose-fermenting enterics
Pink colonies on MacConkey's agar (Media used for isolation)
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Pink colonies on MacConkey's agar
Lactose-fermenting enterics
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Media/Special culture requirements for: Legionella
Charcoal yeast extract agar buffered w/ increased iron and cysteine (Media used for isolation)
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Charcoal yeast extract agar buffered w/ increased iron and cysteine
Legionella
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Media/Special culture requirements for: Fungi
Sabouraud's agar (Media used for isolation)
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Sabouraud's agar
Fungi
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G(-) Enterics (rod-shaped)
E. coli Shigella Salmonella Yersinia Klebsiella Proteus Enterobacter Serratia Vibrio Campylobacter Helicobacter Pseudomonas Bacteroides
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Obligate aerobes
Use an O2-dependent system to generate ATP Examples: (Nagging Pests Must Breathe) Nocardia Pseudomonas Mycobacterium tuberculosis (w/ prediliction for apices of lungs, where PO2 is highest) Bacillus Also: to help remember Pseudomonas aeruginosa - AERuginosa is an AERobe
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Pseudomonas aeruginosa O2 tolerance? Where does it show up?
P. AERuginosa is an AERobe seen in burn wounds, nosocomial pneumonia, and pneumonias in cystic fibrosis pts.
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Obligate Anaerobes
Lack catalase and/or superoxide dismutase, and thus are susceptible to oxidative damage. Generally foul-smelling (short-chain FA's), are difficult to culture, and produce gas in tissue (CO2 and H2). Normal flora in GI tract, pathogenic elsewhere. Examples: (anaerobes Can't Breathe Air) Clostridium Bacteroides Actinomyces
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Aminoglycosides and anaerobes
AminO2 glycosides are ineffective against anaerobes b/c these ABX require O2 to enter into the bacterial cell.
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Obligate intracellular bugs
Rickettsia, Chlamydia (Stay inside [cells] when it's R eally C old) *Can't make their own ATP
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Facultatively intracellular bugs
Some Nasty Bugs May Live FacultativeLY Salmonella Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia
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Quellung Reaction
Postive quellung: If encapsulated bug is present, the capsule swells when specific anti-capsular antisera are added (Quellung = capsular swellung)
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Capsule and vaccines
Capsule is Ag for vaccines (e.g. Pneumovax, H. influenzae B, meningococcal vaccines) Conjugation w/ protein increases immunogenicity and T-cell dependent response
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Quellung (+) Bacteria
Encapsulated (Some Nasties Have Kapsules) Streptococcus pneumoniae Neisseria meningitidis Haemophilus influenzae (esp. type B) Klebsiella pneumoniae Polysaccharide capsule is an antiphagocytic virulence factor for above bacteria.
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Urease (+) bugs
Particular Kinds Have Urease Proteus Klebsiella H. pylori Ureaplasma
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Pigment-producing bacteria
S. aureus --> yellow pigment (Auerus is Latin for gold) Pseudomonas aeruginosa --> blue-green pigment (AERUGula is green) Serratia marcescens --> red pigment (Think of red maraschino cherries)
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Virulence factors
Promote evasion of host immune response
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Important virulence factors in S. aureus
protein A: Binds Fc region of Ig, disrupts opsonization and phagocytosis. IgA protease: Enzyme that cleaves IgA. Polysaccharide capsules also inhibit phagocytosis. [*also TSST-1, but I don't think it's technically a virulence factor]
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protein A: Binds Fc region of Ig, disrupts opsonization and phagocytosis. IgA protease: Enzyme that cleaves IgA.
Polysaccharide capsules also inhibit phagocytosis. [*also TSST-1, but I don't think it's technically a virulence factor] Important virulence factors in S. aureus
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IgA protease Who secretes it?
Secreted by S. pneumoniae, H. influenzae, and Neisseria to prevent phagocytosis
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Secreted by S. pneumoniae, H. influenzae, and Neisseria to prevent phagocytosis
IgA protease Who secretes it?
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Group A streptococcus virulence factors
M protein: Helps prevent phagocytosis
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M protein: Helps prevent phagocytosis
Group A streptococcus virulence factors
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Exotoxin vs. Endotoxin: Source
Certain species of some G(+) and G(-) organisms; Outer cell membrane of most G(-) bacteria and Listeria (Exo ; Endo)
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Exotoxin vs. Endotoxin: Secreted from cell?
Yes; No (Exo ; Endo)
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Exotoxin vs. Endotoxin: Chemistry
Polypeptide; Lipopolysaccharide (structural part of the bacteria. Released when lysed) (Exo ; Endo)
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Exotoxin vs. Endotoxin: Location of genes
Plasmid or bacteriophage; bacterial chromosome (Exo ; Endo)
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Exotoxin vs. Endotoxin: Toxicity
High (fatal dose on the order of 1 microgram); Low (fatal dose on the order of hundreds of micrograms) (Exo ; Endo)
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Exotoxin vs. Endotoxin: Clinical effects
Various; Fever, shock (Exo ; Endo)
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Exotoxin vs. Endotoxin: Mode of action
Various; Includes TNF and IL-1 (Exo ; Endo)
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Exotoxin vs. Endotoxin: Antigenicity
Induces high-titer Abs called antitoxins ; Poorly antigenic (Exo ; Endo)
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Exotoxin vs. Endotoxin: Vaccines
Toxoids useful as vaccines; No toxoids formed and no vaccine available (Exo ; Endo)
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Exotoxin vs. Endotoxin: Heat stability
Destroyed rapidly at 60C (except staphylococcal enterotoxin); Stable at 100C for 1 hour (Exo ; Endo)
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Exotoxin vs. Endotoxin: Typical diseases
Tetanus, botulism, diphtheria; Meningococcemia, sepsis by G(-) rods (Exo ; Endo)
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Superantigens
Bind directly to MHCII and T-cell receptor simultaneously, activating large numbers of T-cells to stimulate release of IFN-gamma and IL-2
90
Toxins: TSST-1
Organism, toxin function: S. aureus SuperAg that causes toxic shock syndrome (fever, rash, shock).
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S. aureus SuperAg that causes toxic shock syndrome (fever, rash, shock).
TSST-1
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Toxins: Exfoliatin
Organism, toxin function: S. aureus Causes staphylococcal scalded skin syndrome
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S. aureus Causes staphylococcal scalded skin syndrome
Exfoliatin
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Toxins: Enterotoxins
Organism, toxin function: S. aureus (and others) Cause food poisoning
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S. aureus (and others) Cause food poisoning
Enterotoxins
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Toxins: Scarlet fever-erythrogenic toxin
Organism, toxin function: S. pyogenes SuperAg that causes toxic shock-like syndrome
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S. pyogenes SuperAg that causes toxic shock-like syndrome
Scarlet fever-erythrogenic toxin
98
ADP ribosylating exotoxins
Interfere w/ host cell function. B (binding) component binds to a receptor on the surface of the host cell, enabling endocytosis. A (active) component then attaches an ADP-ribosyl to a host cell protein (ADP ribosylation), altering protein function.
99
Toxins: Diphtheria exotoxin
Organism, toxin function: Corynebacterium diphtheriae ADP-ribosylating A-B exotoxin that inactivates EF-2 (similar to Psudomonas exotoxin A) Causes pharyngitis and pseudomembrane in throat.
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Corynebacterium diphtheriae ADP-ribosylating A-B exotoxin that inactivates EF-2 (similar to Psudomonas exotoxin A) Causes pharyngitis and pseudomembrane in throat.
Diphtheria exotoxin
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Toxins: Cholera toxin
Organism, toxin function: Vibrio Cholerae ADP ribosylation of G-protein stimulates adenylyl cyclase Increased pumping of Cl- into gut and decreased Na+ absorption Water moves into gut lumen Causes voluminous rice-water diarrhea
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Vibrio Cholerae ADP ribosylation of G-protein stimulates adenylyl cyclase Increased pumping of Cl- into gut and decreased Na+ absorption Water moves into gut lumen Causes voluminous rice-water diarrhea
Cholera toxin
103
Toxins: Heat-labile toxin, Heat-stabile toxin
Organism, toxin function: E. coli ADP-ribosylating A-B toxins Heat-labile: stimulates Adenylyl cyclase Heat-stabile: stimulates Guanylate cyclase Both: cause watery diarrhea Labile like the A ir, Stable like the G round
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Toxins: Pertussis toxin (PT)
Organism, toxin function: Bordetella pertussis ADP-ribosylating A-B toxin that increases cAMP by inhibiting G-alpha1 Causes whooping cough Inhibits chemokine receptor --> causes lymphocytosis
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Toxins: alpha toxin
Organism, toxin function: Clostridium perfringens Causes gas gangrene Get double zone of hemolysis on blood agar
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Clostridium perfringens Causes gas gangrene Get double zone of hemolysis on blood agar
alpha toxin
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Toxins: Tetanus toxin (tetanospasmin)
Organism, toxin function: C. tetani Blocks the release of inhibitory neurotransmitters GABA and glycine Causes lockjaw
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C. tetani Blocks the release of inhibitory neurotransmitters GABA and glycine Causes lockjaw
Tetanus toxin (tetanospasmin)
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Toxins: Botulinum toxin (aka Botox)
Organism, toxin function: C. botulinum Blocks release of ACh Causes anticholinergic symptoms, CNS paralysis (especially cranial nerves) Spores found in canned food, honey (causes floppy baby)
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C. botulinum Blocks release of ACh Causes anticholinergic symptoms, CNS paralysis (especially cranial nerves) Spores found in canned food, honey (causes floppy baby)
Botulinum toxin (aka Botox)
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Toxins: Anthrax toxin
Organism, toxin function: Bacillus anthracis Edema factor, part of the toxin complex, is an adenylate cyclase
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Toxins: Shiga toxin
Organism, toxin function: Shigella, and E. coli O157:H7 Cleaves host cell rRNA (inactivates 60S ribosome) Enhances cytokine release, causing HUS
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Shigella, and E. coli O157:H7 Cleaves host cell rRNA (inactivates 60S ribosome) Enhances cytokine release, causing HUS
Shiga toxin
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Toxins: Streptolysin O
Organism, toxin function: S. pyogenes a hemolysin. Ag for ASO Ab, which is used in Dx of rheumatic fever
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S. pyogenes a hemolysin. Ag for ASO Ab, which is used in Dx of rheumatic fever
Streptolysin O
116
cAMP inducers (list)
Vibrio cholerae B. pertussis E. coli Bacillus anthracis* *Cholera, pertussis, and E. coli toxins act via ADP ribosylation to permanently activate endogenous adenylate cyclase (increasing cAMP), While anthrax edema factor is itself an adenylate cyclase
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Vibrio Cholerae toxin and cAMP
Toxin permanently activates Gs, Causing rice-water diarrhea (Cholera turns the on on)
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B. pertussis and cAMP
Pertussis toxin permanently disables Gi, causing whooping cough (Pertussis toxin turns the off off) *Pertussis toxin also promotes lymphocytosis by inhibiting chemokine receptors.
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E. coli and cAMP
Heat-labile toxin stimulates adenylyl cyclase
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Bacillus anthracis and cAMP
Anthrax toxin includes edema factor, a bacterial adenylate cyclase (increases cAMP)
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Endotoxin
A Lipopolysaccharide found in the cell wall of G(-) bacteria N-dotoxin is an integral part of the gram-Negative cell wall *Endotoxin is heat stable
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Endotoxin and Macrophages
Activates Macs: IL-1 causes fever TNF causes fever, hemorrhagic tissue necrosis NO causes hypotension (shock)
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Endotoxin and complement
Activates the complement (alternative pathway): C3a causes hypotension, edema C5a causes PMN chemotaxis
124
Endotoxin and Hageman factor (factor XII)
Activates Hageman factor This activates coagulation cascade, causing DIC
125
Bacterial growth curve
Lag phase: metabolic activity w/o division Log phase: rapid cell division Stationary phase: nutrient depletion slows growth. Spore formation in some bacteria. Death phase: prolonged nutrient depletion and buildup of waste products leads to death.
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Transformation
DNA taken up directly from environment by competent prokaryotic and eukaryotic cells. Any DNA can be used
127
F+ x F- Conjugation
F+ plasmid contains genes for conjugation process. Bacteria w/o this are termed F-. Plasmid is replicated and transferred through pilus from the F+ cell. Plasmid DNA only, no transfer of chromosomal genes.
128
Hfr x F- Conjugation
F+ plasmid can become incorporated into bacterial chromosomal DNA, now termed Hfr cell. Replication of incoporated plasmid DNA may include some flanking chromosomal DNA. Transfer of plasmid and chromosomal genes.
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Generalized transduction
Lytic phage infects bacterium, leading to cleavage of bacterial DNA and synthesis of viral proteins. Parts of bacterial chromosomal DNA may become packaged in viral capsid. Phage infects another bacterium, transferring these genes.
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Specialized transduction
Lysogenic phage infects bacterium; viral DNA incorporated into bacterial chromosome. When phage DNA is excised, flanking bacterial gnees may be excised w/ it. DNA is packaged into phage viral capsid and can infect another bacterium.
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Transposition (transposons)
Segment of DNA can jump (excision and reincorporation) from one location to another, can transfer genes from plasmid to choromosome and vice versa. When excision occurs, may include some flanking chromosomal DNA, which can be incorporated into a plasmid and transferred to another bacterium.
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5 bacterial toxins encoded in a lysogenic phage
ABCDE ShigA -like toxin B otulinum toxin (certain strains) C holera toxin D iphtheria toxin E rythrogenic toxin of Streptococcus pyogenes
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Gram (+) | Rods | ?
Clostridium (anaerobe) Corynebacterium Listeria Bacillus
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Gram (+) | Cocci | Catalase (+), in clusters (Staphylococcus) | Coagulase (+) | ?
Staphylococcus aureus
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Gram (+) | Cocci | Catalase (+), in clusters (Staphylococcus) | Coagulase (-) | ?
Novobiocin sensitive: Staphylococcus epidermidis Nobobiocin resistant: Staphylococcus saprophyticus
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Gram (+) | Cocci | Catalase (-), in chains (Streptococcus) | partial hemolysis (green - alpha hemolysis) | ?
(+) Quellung (has capsule), Optochin sensitive, Bile soluble: Streptococcus pneumoniae (-) Quellung (no capsule), Optochin resistant, not bile soluble: Streptococcus viridans
137
Gram (+) | Cocci | Catalase (-), in chains (Streptococcus) | Complete hemolysis (clear, beta-hemolysis) | ?
Bacitracin sensitive: Group A Strep (GAS) aka Streptoccus pyogenes Bacitracin resistant: Group B strep aka Streptococcus agalactiae
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Gram (+) | Cocci | Catalase (-), in chains (Streptococcus) | No hemolysis (gamma hemolysis) | ?
Enterococcus (E. faecalis) Peptostreptococcus (anaerobe)
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Identifying Staphylococci w/ Novobiocin (once you know it's a G(+)/catalase(+) coccus in clusters)
NO vobiocin - S aprophyticus is R esistant; E pidermidis is S ensitive On the office's staph retreat, there was NO S tRES
140
Identifying Streptococci (once you know it's a G(+)/catalase(-) coccus in chains)
O ptochin: V iridans is R esistant P neumoniae is S ensitive (OVRPS = overpass) B acitracin: group B strep are R esistant group A strep are S ensitive (B-BRAS )
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alpha-hemolytic bacteria
Form a green ring around colonies on blood agar. Include: 1.) Streptococcus pneumoniae (catalase (-) and optochin sensitive) 2.) viridans streptococci (catalase (-), optochin resistant)
142
Beta-hemolytic bacteria
Form a clear area of hemolysis on blood agar. Include: 1.) Staphylococcus aureus (catalase and coagulase positive) 2.) Streptococcus pyogenes - GAS (catalase negative and bacitracin sensitive) 3.) Streptococcus agalactiae - GBS (catalase negative and bacitracin resistant) 4.) Listeria monocytogenes (tumbling motility, meningitis in newborns, unpasteurized milk)
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Catalase
Catalase degrades H2O2, an antimicrobial product of PMNs. H2O2 is a substrate for myeloperoxidase.
144
Catalase/Coagulase in G(+) cocci
Staphylococci make catalase, whereas Streptococci do not S. aureus makes coagulase, whereas S. epidermidis and S. saprophyticus do not. (Staph make catalase b/c they have more staff. Bad staph (aureus, b/c epidermidis is skin flora) make coagulase and toxins.)
145
Protein A (virulence factor)
Virulence factor of Staphylococcus aureus Binds Fc-IgG, inhibiting complement fixation and phagocytosis
146
TSST (@ molecular level)
In Staph aureus A superAg that binds MHCII and the TCR, resulting in polyclonal T-cell activation
147
Dzs caused by Staphylococcus aureus
1.) Inflammatory Dz - skin infxns, organ abcesses, pneumonia 2.) Toxin-mediated dz - Toxic shock syndrome (TSST-1), scalded skin syndrome (exfoliative toxin), rapid-onset food poisoning (pre-formed enterotoxins) 3.) MRSA (methicillin-resistant S. aureus) infxn: important cause of serious nosocomial and community-acquired infxns. Resistant to beta-lactams due to altered penicillin-binding proteins. 4.) Misc. - acute bacterial endocarditis, osteomyelitis
148
Staphylococcus epidermidis
Infects prosthetic devices and catheters. Component of normal skin flora. Contaminates blood cultures.
149
Streptococcus pneumoniae (the pneumococcus)
Encapsulated. Has IgA protease. Most common cause of: Meningitis Otitis media (in children) Pneumonia Sinusitis (S. pneumoniae MOPS are M ost OP tochin S ensitive) Associated w/ rusty sputum, sepsis in sickle cell anemia and splenectomy.
150
Viridans group Streptococci
Alpha-hemolytic. Normal flora of the oropharynx. Cause dental caries (S. mutans) and subacute bacterial endocarditis (S. sanguis). Resistant to optochin, differentiating them from S. pneumoniae, which is alpha-hemolytic but optochin sensitive. (Viridans group strep live in the mouth b/c they are not afraid of-the-chin <--op-to-chin resistant)
151
Diseases caused by Streptococcus pyogenes (GAS)
1.) Pyogenic - pharyngitis, cellulitis, impetigo 2.) Toxigenic - Scarlet fever, toxic shock syndrome 3.) Immunologic - rheumatic fever, acute glomerulonephritis PH aryngitis gives you rheumatic PH ever and glomerulonePH ritis No rheum for SPECCulation: Subcutaneous nodules, Polyarthritis Erythema marginatum Chorea Carditis
152
Ab's and Streptococcus pyogenes (GAS)
Ab's to M protein enhance host defenses againt GAS but can give rise to rheumatic fever. ASO titer detects recent GAS infxn.
153
Streptococcus agalactiae (GBS)
Bacitracin resistant Beta-hemolytic Causes: Pneumonia meningitis Sepsis (mainly in babies) B is for Babies!
154
Enterococci
include Enterococus faecalis and E. faecium) Penicillin G resistant. Cause UTI and subacute endocarditis. Enterococci are hardier than nonenterococcal group D, thus can grow in 6.5% NaCl. Variable hemolysis.
155
Lancefield group D
Includes enterococci and nonenterococcal group D streptococci. Lancefield grouping is based on differences in the C carbohydrate on the bacterial cell wall.
156
VRE
Vancomycin-resistant Enterococci: an important cause of nosocomial infxn.
157
Streptococcus bovis
Highly associated w/ colon cancer. One of the group D streptococci.
158
Diphtheria
Caused by Corynebacterium diphtheriae via an exotoxin encoded by beta-prophage. Potent exotoxin inhibits protein synthesis via ADP ribosylation of EF-2. Sx include: pseudomembranous pharyngitis (grayish-white membrane) w/ lymphadenopathy. Lab Dx based on G(+) rods w/ metachromatic granules. Corynebacterium diphtheriae grows on tellurite agar. ABCDEFG ADP ribosylation Beta-prophage Corynebacterium Diphtheriae Elongation Factor 2 Granules
159
Bacterial spores
Certain G(+) rods form spores when nutrients are limited (@ the end of stationary phase) Spores are highly resistant to destruction by heat and chemicals. Have dipiclonic acid in their core. Have no metabolic activity. Must autoclave to kill spores.
160
Important spore-forming bacteria
G (+) spores found in soil: Bacillus anthracis Clostridium perfringens C. tetani Other spore formers: B. cerus C. botulinum
161
Clostridia (generally)
G(+) Spore-forming Obligate anaerobic Bacilli
162
Clostridium tetani
produces the exotoxin that causes tetanus TETanus is TETanic paralysis (blocks glycine release [an inhibitory NT]) from Renshaw cells in spinal cord
163
Clostridium botulinum
produces preformed, heat-labile toxin that inhibits ACh release at the NMJ, causing botulism (flaccid paralysis). In adults, dz is caused by ingestion of preformed toxin. In babies, ingestion of bacterial spores in honey causes dz (floppy baby syndrome). BOTulinum is from bad BOTtles of food and honey.
164
Clostridium perfringens
Produces alpha-toxin (lecithinase) that can cause myonecrosis (gas gangrene) and hemolysis PERFringens PERForates a gangrenous leg
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Clostridium dificile
Produces a cytotoxin, an exotoxin that kills enterocytes, causing pseudomembranous colitis. Often 2' to ABX use, especially clindamycin or ampicillin. DI fficile causes DI arrhea Tx: metronidazole
166
Anthrax
Caused by Bacillus anthracis: Gram (+), spore-forming rod that produces anthrax toxin. Only bacterium w/ a protein capsule (contains D-glutamate)
167
Anthrax infxn via contact
Malignant pustules (painless ulcer) Can progress to bacteremia and death Black skin lesions - vesicular papules covered by black eschar *[I think these only occur via contact route of infxn]
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Anthrax via inhalation of spores
Flulike Sx that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, and shock
169
Woolsorter's dz
Anthrax caused by inhalation of spores from contaminated wool
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Listeria monocytogenes route of transmission
Acquired by ingestion of unpasteurized milk/cheese and deli meats, or by vaginal transmission during birth.
171
Listeria monocytogenes motility
Form actin rockets by which they move from cell to cell. Characteristic tumbling motility.
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Listeria monocytogenes Diseases
Can cause: amnionitis septicemia spontaneous abortion granulomatosis infantiseptica neonatal meningitis meningitis in the immunocompromised mild gastroenteritis (healthy individuals) *Note: is the only G(+) organism w/ endotoxin*
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Actinomyces and Nocardia
Both are G(+) rods forming long branching filaments, resembling fungi SNAP: S ulfa for N ocardia, A ctinomyces use P CN
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Actinomyces israelii
G(+) anaerobe Causes oral/facial abscesses that may drain thru sinus tracts in skin. Forms yellow sulfur granules in sinus tracts. Normal oral flora.
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Nocardia asteroides
G(+) and also weakly acid-fast aerobe found in soil. Causes pulmonary infxn in immunocompromised pts.
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Primary TB
Mycobacterium infects nonimmune host (usu. child). 1' TB causes hilar nodes and Ghon focus (usu. in lower lobes) -> together = Ghon Complex Several outcomes: Heals by fibrosis Progressive lung dz Severe bacteremia Preallergic lymphatic or hematogenous dissemination
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Primary TB (Heals by fibrosis)
Immunity and hypersensitivity | Tuberculin (+)
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Primary TB | Progressive Lung dz
(Seen in HIV, malnutrition) | Death (rare)
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Primary TB (severe bacteremia)
| Miliary TB | Death
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Primary TB Preallergic lymphatic or hematogenous dissemination
| Dormant tubercle bacilli in several organs | Reactivation in adult life | Extrapulmonary TB or Reactivation of TB in lungs
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Extrapulmonary TB
CNS (parenchymal tuberculoma or meningitis) Vertebral body (Pott's dz) Lymphadenitis Renal GI
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Secondary TB
Due to re-infxn of partially immune hypersensitized host (usu. adult) or reactivation of dormant TB in the lungs Causes Fibrocaseous cavitary lesion (usu. in upper lobes)
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PPD test and TB
PPD (+) w/ current infxn, past exposure, or BCG vaccinated PPD (-) if no infxn or anergic (steroids, malnutrition, immunocompromise, sarcoidosis)
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Ghon complex
TB granulomas (Ghon focus) w/ lobar and perihilar lymph node involvement. Reflects primary infxn or exposure.
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Mycobacterium tuberculosis
Causes TB (Sx: fever, night sweats, weight loss, and hemoptysis) Often resistant to multiple drugs
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Mycobacterium kansasii
pulmonary TB-like Sx
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Mycobacterium avium-intracellulare
Often resistant to multiple drugs Causes disseminated dz in AIDS
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Leprosy (Hansen's dz)
Caused by Mycobacterium leprae, an acid-fast bacillus that likes cool temperatures (thus infects skin and superficial nerves), and cannot be grown in vitro. See common Sx below:
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Reservoir for leprosy in the USA
armadillos
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Tx for Leprosy
long-term oral dapsone Toxicity is hemolysis and methemoglobinemia Alternative Tx's: Rifampin Combination of clofazimine and dapsone
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2 Forms of Hansen's dz
Lepromatous: and Tuberculoid Lepromatous is worse (failed cell-mediated immunity); tuberculoid is self-limited LEpromatous is LEthal
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Classifying G(-) Cocci
Maltose fermenter: Neisseria meningitidis Maltose non-fermenter: Neisseria gonorrhoeae
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G(-) Coccoid rods
Haemophilus influenzae Pasteurella - (animal bites) Brucella - (brucellosis) Bordetella pertusis
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G(-) Rods | Lactose fermenters | ?
Fast fermenters: Klebsiella E. coli Enterobacter Slow fermenters : Citrobacter Serratia (others)
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G(-) Rods | Lactose non-fermenters | ?
Oxidase (-): Shigella Salmonella Proteus Oxidase (+): Pseudomonas
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Lactose-fermenting enteric bacteria
Grow pink colonies on MacConkey's agar. Examples: C itrobacter, K lebsiella, E . coli, E nterobacter, S erratia (Lactose is KEE, so test w/ MacC onKEE'S agar
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PCN and Gram(-) bugs
G(-) bugs are resistant to benzylpenicillin G but may be susceptible to PCN derivatives such as ampicillin. The G(-) outer membrane inhibits entry of PCN-G and Vancomycin
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Neisseria (generally)
Both are: Gram(-) cocci Ferment glucose and produce IgA proteases.
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Neisseria gonorrheae (Gonococci)
No polysaccharide capsule No maltose fermentation (Gonococci ferment Glucose) No vaccine Sexually transmitted Causes gonorrhea, septic arthritis, neonatal conjunctivitis, PID
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Neisseria meningitidis (Meningococci)
Polysaccharide capsule Maltose fermentation (MeninGococci ferments Maltose and Glucose) Vaccine available Transmitted by respiratory and oral secretions Causes meningococcemia and meningitis, Waterhouse-Friderichsen syndrome
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Haemophilus influenzae Causes...? Produces what? Mode of transmission?
HaEMOP hilus causes: Epiglottitis, Meningitis, Otitis media, and Pneumonia. (Most invasive dz caused by capsular type B) Does NOT cause flu (influenza virus does) Produces IgA Protease Aerosol transmission
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Tx for Haemophilus influenzae
Ceftriaxone. Rifampin prophylaxis in close contacts.
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Culturing H. influenzae
Chocalate agar w/ factors V (NAD) and X (hematin) When a child has 'flu'*, mom goes to the five (V ) and dime (X ) store to buy some chocolate [*remember that H. influenzae does not cause flu]
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Haemophilus influenzae vaccine
Contains type B capsular polysaccharide conjugated to diphtheria toxoid or other protein to improve immune system recognition of polysaccharide and promote class switching. Given btw 2 and 18 months of age.
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Legionella pneumophila
Gram (-) rod Gram stains poorly --> silver stain Grow on charcoal yeast extract culture w/ iron and cysteine. Think of a French legionnaire (soldier) with his silver helmet, sitting around a campfire (charcoal ) w/ his iron dagger -- he is no sissy (cysteine )
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Transmission of Legionella pneumophilia
Aerosol transmission from environmental water souce habitat. no person-to-person transmission.
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Dz's caused by Legionella pneumophila Tx?
Legionnaires' dz (severe pneumonia) Pontiac fever (mild influenza) Tx: erythromycin
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Pseudomonas aeruginosa Diseases?
Associated w/ wound and burn infxn PSEDUO Pneumonia (esp. in CF) Sepsis (black lesions on skin) Exteral otitis (swimmer's ear) UTI Drug use Diabetic Osteomyelitis (+ hot tub folliculitis) *Think Pseudomonas in burn victims
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Pseudomonas aeruginosa classification and idenification
AERobic (AERuginosa) G(-) rod Non-lactose fermenting Oxidase (+) Produces pyocyanin (blue-green pigment) Has a grapelike odor Comes from water source
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Pseudomonas aeruginosa products
Endotoxin (fever, shock) Exotoxin A (inactivates EF-2)
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Pseudomonas aeruginosa Tx?
Aminoglycoside + extended-spectrum PCN (e.g., piperacillin, ticarcillin)
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Members of Enterobacteriacea
Diverse family including: E. coli Salmonella Shigella Klebsiella Enterobacter Serratia Proteus
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Commonalities among Enterobacteriaceae
All species have somatic (O) Ag (which is the polysaccharide of endotoxin). The capsular (K) Ag is related to the virulence of the bug. The flagellar (H) Ag is found in motile species. All ferment glucose and are oxidase (-) COFFEe Capsular (K) O Ag Flagellar Ag (H) Ferment glucose Enterobacteriaceae
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Klebsiella causes...
Pneumonia in alcoholics and diabetics (red currant jelly sputum) Also a cause of nosocomial UTIs relates to the 4 A's: Aspiration pneumonia Abscess in lungs Alcoholics di-A-betics
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Salmonella typhi
Causes typhoid fever: diarrhea, HA, rose spots on abdomen. Can remain in gallbladder chronically.
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Salmonella vs. Shigella
Both: Lactose non-fermenters Invade the intestinal mucosa and can cause bloody diarrhea Only Salmonella: Has flagella, and can spread hematogenously (like how Salmon swim), Produces H2S. Shigella: Do not have flagella, but can propel themselves while inside cells by actin polymerization Spread by 4 F's: Food, Fingers, Feces, and Flies Is more virulent (10 organisms infective vs. Salmonella: 100,000)
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Salmonellosis
Sx may be prolonged w/ ABX treatments There is typically a monocytic response
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Yersinia enterocolitica
Usually transmitted from pet feses (e.g., puppies), contaminated milk, or pork. Outbreaks are common in day-care centers. Sx can mimic Crohn's or appendicitis.
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Helicobacter pylori Causes...? Is a risk factor for...?
Causes: Gastritis and up to 90% of duodenal ulcers Risk factor for: peptic ulcer, gastric adenocarcinoma, and lymphoma
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Helicobacter pylori Classification/identification
G(-) Rod. Urease (+) --> creates alkaline environment.
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Helicobacter pylori Tx?
Triple-therapy (two regimens): 1.) Bismuth (Pepto-bismol), metronidazole, and either TCN or amoxicillin 2.) Metronidale, omeprazole, and clarithromycin (*more costly option)
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Spirochetes
Spiral-shaped w/ axial filaments. Include: Borellia (big size) Leptospira Treponema (BLT. B is Big) Only Borrelia can be vizualized w/ aniline dyes (Wright's or Giemsa). Treponema is vizualized w/ dark-field microscopy.
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Leptospira interrogans
Question mark-shaped bacteria found in water contaminated w/ animal urine. Causes: Leptospirosis - (flu-like Sx, fever, HA, abdominal pain, jaundice. Most prevalent in tropics) Weil's dz (ictohemorrhagic leptospirosis) - severe form w/ jaundice and azotemia from liver and kidney dysfxn; fever, hemorrhage, and anemia
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Treponemal diseases
Treponemes are spirochetes. Treponema pallidum: Causes syphilis Treponema pertenue: Causes yaws; Infxn of skin, bone, and joints --> healing w/ keloids --> severe limb deformities Dz of the tropics. Not an STD, but VDRL positive.
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Syphilis Cause? Tx?
Caused by Treponema pallidum Tx w/ PCN G
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Primary syphilis
Presents w/ painless chancre (localized dz) Many treponemes present in chancre.
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Secondary syphilis
Disseminated dz w/ constitutional Sx's, macupapular rash (palms and soles), condylomata lata. Many terponemes are present in condylomata lata. S econdary Sy philis = Sy stemic
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Tertiary syphilis
gummas (chronic granulomas), arotitis (vasa vasorum destruction), neurosyphilis (tabes dorsalis), Argyll Robertson pupil (small pupils that accomodate but do not constrict/react [according to wikipedia, known as prostitutes pupils b/c they accomodate, but don't react - not sure what that means) Signs: Broad-based axilla Positive Romberg Charcot joints Stroke w/o HTN
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Congenital syphilis
CN VIII deafness Saber shins (outward curve like a saber) Saddle nose Hutchinson's teeth (smaller and more widely spaced)
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Argyll Robertson Pupil
Constricts w/ accomodation but is not reactive to light. Associated w/ tertiary syphilus. Prostitute's Pupil - accomodates but does not react (???)
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VDRL vs. FTA-ABS
FTA-ABS is specfifc for treponemes, turns (+) earlies in dz, and remains (+) longest. VDRL and FTA-ABS: (+) result means active infxn (+) VDRL: Probably a false positive (+) FTA: Successfully treated FTA-ABS = Find The Ab ABSolutely: 1.) Most specific 2.) Earliest (+) 3.) Remains (+) longest
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VDRL False Positives
VDRL detects nonspecifc Ab that reacts w/ beef cardiolipin. Used for Dx of syphilis, but many biologic false positivies. Sources of false positives --> VDRL V iruses (mono, hepatitis) D rugs R heumatic fever L upus and L eprosy
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List of zoonotic bacteria
Big Bad Bugs From Your Pet named Ella B artonella henselae B orrelia burgdorferi B rucella spp. F rancisella tularensis Y ersinia pestis P asteurella multocida
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Bartonella henselae Disease? Transmission?
Causes: cat scratch fever Transmission: cat scratch
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Borrelia burgdorferi Disease? Transmission?
Causes: Lyme disease transmission: Tick bite; Ixodes ticks that live on deer and mice
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Brucella spp. Disease? Transmission?
Causes: Brucellosis / undulant fever Transmission: Dairy products, contact w/ animals Un pasteurized dairy gives you Un dulant fever.
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Francisella tularensis Disease? Transmission?
Causes: Tularemia Transmission: Tick bite; rabbits, deer
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Yersinina pestis Causes? Transmission?
Causes: Plague Transmission: Flea bite; rodents (esp. prairie dogs)
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Pasteurella multocida Disease? Transmission?
Causes: Cellulitis Transmission: Animal bit; cats, dogs
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Gardnerella vaginalis Microscopic appearance? Causes ....? Tx?
Pleomorphic, gram-variable rod. Causes vaginosis (off-white/gray vaginal discharge w/ fishy smell; nonpainful) Mobiluncus (an anaerobe) is also involved. Vaginosis is associated w/ sexual activity, but is not an STD. Bacterial vaginosis is characterized by overgrowth of certain bacteria in vagina. Clue cells seen. Tx for vaginosis: metronidazole
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Clue cells
Seen in bacterial vaginosis Vaginal epithelial cells covered w/ bacteria
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Rickettsiae Metabolism? Disease? Tx?
Obligate intracellular organisms Need CoA and NAD All except Coxiella are transmitted by an arthropod vector and cause HA, fever, and rash. Coxiella is an atypical rickettsia b/c it is transmitted by aerosol and causes pneumonia. Tx for most rickettsial infxns: TCN
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Classic triad for rickettsial infxns
HA, fever, rash (vasculitis)
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Rickettsia rickettsii Disease? Transmission? Tx?
Causes Rocky Mountain spotted fever Transmission via tick Tx: TCN
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Ricketsia typhus dz? transmission? Tx?
Causes endemic typhus Transmission via fleas Tx: TCN
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Rickettsia prowazekii Dz? Transmission? Tx?
Causes epidemic typhus Transmission via human body louse Tx: TCN
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Ehrlichia Dz? Transmission? Tx?
Causes Ehrlichiosis Transmission via tick Tx: TCN
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Coxiella burnetti Dz? Transmission? Tx?
Causes Q fever Q fever is Queer b/c it has no rash, no vector, and has negative Weil-felix, its causative roganism can survive outside for a long time, and does not have Rickettsia as its genus name. Transmission via inhaled aerosols Tx: TCN
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Rickettsial rash vs. Typhus rash
Rickettsial rash starts on hands and feet; Typhus rash starts centrally and spreads out: R ickettisa on the wR ists, T yphus on the T runk.
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Rocky Mountain Spotted Fever
Caused by Rickettsia rickettsii Sx: rash on palms and soles (migrating to wrists, ankles, then trunk), HA, fever. Endemic to East Coast (in spite of its name).
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Palm and sole rash
Seen in: C oxsackievirus A infxn (hand, foot, and mouth dz) R ocky Mountain spotted fever S yphilis (You drive CARS using your palms and soles)
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Weil-Felix Reaction
Assays for anti-rickettsial Abs, which cross-react w/ Proteus Ag. Weil-Felix is usually positive for typhus and Rocky Mountain spotted fever, but negative for Q fever.
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Chlamydiae
Cannot make their own ATP --> obligate intracellular organisms Cause mucosal infxns Chlamydial cell wall is unusual in that it lacks muramic acid Cell cycle w/ 2 forms: elementary body and initial/reticulate body
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Lab Dx, Tx for Chlamydiae infxns
Dx: cytoplasmic inclusions seen on Giemsa or fluorescent Ab-stained smear Tx: erythromycin or TCN
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Chlamydiae: Elementary body
Small, dense. E lementery E nters cells via endocytosis.
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Chlamydiae: Initial or Reticulate body
R eticulate body R eplicates in cell by fission
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Chlamydia trachomatis Causes...? Tx?
Causes: reactive arthritis conjunctivitisd nongonococcal urethritis pelic inflammatory dz (PID) As with all Clamydiae, Tx w/ erythromycin or TCN
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Chlamydia pneumoniae Disease? Transmission?
Causes atypical pneumonia Transmitted by aerosol As w/ all Chlamydiae, Tx w/ erythromycin or TCN
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Chlamydia psittaci Disease? Transmission?
Causes atypical pneumonia Transmission by aerosol *notable for avian reservoir As w/ all Chlamydiae, Tx w/ erythromycin or TCN
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Chlamydia trachomatis serotypes A, B, and C
Chronic infxn, cause blindness in Africa (ABC = Africa / Blindness / Chronic Infxn)
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Chlamydia trachomatis types D-K
Urethritis/PID Ectopic pregnancy Neonatal pneumonia Neonatal conjunctivitis* Neonatal dz can be acquired during passage thru infected birth canal Tx: oral erythromycin
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Chlamydia trachomatis serotypes L1, L2, and L3
Lymphogranuloma venerum (Acute lymphadenitis - positive Frei test) L 1-3 = L ymphogranuloma venerum
