Basic Bacteriology Flashcards

Question

Special culture requirements: N.gonorrhoeae, N.meningitidis

Answer 1

Media: Thayer-Martin Selectively favors growth by Neisseria by inhibiting growth of gram + organisms with Vancomycin, gram - organisms (except Neisseria) with Trimethoprim and Colistin and fungi with Nystatin *Very Typically Cultures Neisseria*

Answer 2

Media: Bordet-gengou agar (*Bordet for bordatella*); Regan-Lowe medium Potato; charcoal, blood, antibiotic

Answer 3

Media: Tellurite agar; loffler medium

Answer 4

Media: Lowenstein-Jensen agar

Answer 5

Media: Eaton agar | Requires cholesterol

Answer 6

Media: MacConkey agar | Fermentation produces acid, causing colonies to turn pink

Answer 7

Media: Eosin-methylene blue (EMB) agar | Colonies with green metallic sheen

Answer 8

Media: charcoal yeast extract agar buffered with cysteine and iron

Answer 9

Media: Sabouraud agar | *Sab's a FUN-guy*

Answer 10

Use an O2-dependent system to generate ATP Examples: Nocarida, pseudomonas aeruginosa, mycobacterium tuberculosis (*Nagging Pests Must Breath*) Reactivation of M.tuberculosis has predilection for the apices of the lungs

Answer 11

Examples: Clostridium, bacteriodes, fuse bacterium, Actinomyces (*anaerobes Can't Breathe Fresh Air*) They lack catalase and/or superoxide dismutase and are thus susceptible to oxidative damage (foul smelling, difficult to culture, produce gas in tissue) Anaerobes are normal flora in the GI tract and typically pathogenic elsewhere. Aminoglycosides are ineffective against anaerobes because the antibiotics require O2 to enter into bacterial cell

Answer 12

Rickettsiae, CHlamydia, COxiella - rely on host ATP | *stay inside cells when it's Really CHilly and COld*

Answer 13

Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis *Some Nasty Bugs May Live FacultativeLY*

Answer 14

Pseudomonas aeruginosa, Streptococcus pneumoniae, Haemophilius influenzae type B, Neisseria meningitidis, E.coli, Salmonella, Klebsiella pneumoniae and group B Strep *Please SHINE my SKiS* Capsules serve as an anti phagocytic virulence factor --> then are opposites and cleared by the spleen instead. Asplenic pts have decreased opsonizing ability and thus increased risk for severe infections (give S.pneumo, HiB, & N.menigitidis vaccines) Capsular polysaccharide + protein conjugate serves as Ag in vaccines

Answer 15

``` Some vaccines containing polysaccharide capsule Ag are conjugated to a carrier protein, enhancing immunogenicity by promoting TC activation and subsequent class switching A polysaccharide Ag alone cannot be presented to TCs PCV, PPSV, HiB, Meningococcal vaccine ```

Answer 16

``` Proteus, Cryptococcus, H pylori, Ureaplasma, Nocardia, Klebsiella, S epidermis is, S saprophyticus (*Pee CHUNKS*) Potentiates struvite (ammonium magnesium phosphate) stones, urease hydrolyzes urea to release ammonia and CO2 --> increases pH ```

Answer 17

Catalase degrades H2O2 into H2O and bubbles of O2 before it can be converted into microbicidal products by the enzyme myeloperoxidase People with chronic granulomatous disease (NADPH oxidase deficiency) have recurrent infections with certain catalase + organisms Examples: Nocardia, Pseudomonas, Listeria, Aspergillus, Candida, E.coli, Staphylococci, Serratia, B.cepacia, H.pylori (*Cats Need PLACESS to Belch their Hairballs*)

Answer 18

Actinomyces israelii - yellow suffer granules (comprised of filaments of bacteria) S.aureus - yellow pigment P.aeruginosa - blue-green pigment Serratia marcescens - red pigment

Answer 19

S.epidermidis - catheter and prosthetic device infections Veridans streptococci (mutans, sanguinis) - dental plaques, infective endocarditis P.aeruginosa - respiratory tree colonization in CF pts, contact lens-associated keratitis Nontypeable (unencapsulated) H.influenzae - otitis media

Answer 20

Binds Fc region of IgG. Prevents opsonization and phagocytosis Expressed by S.aureus

Answer 21

Enzyme that cleaves IgA | Secreted by S.pneumoniae, H.influenzae type B, Neisseria (SHiN) in order to colonize respiratory mucosa

Answer 22

Helps prevent phagocytosis Expressed by group A streptococci Shares similar epitope to human cellular proteins (molecular mimicry) possibly underlies the autoimmune response seen in acute rheumatic fever

Answer 23

Also known as "injectisome" - needle like protein appendage facilitating direct delivery of toxins from certain gram (-) bacteria Pseudomonas, Salmonella, Shigella, E.coli) to eukaryotic host cell

Answer 24

Flagellum: made of proteins, function for motility Pilus/fimbria: made of glycoproteins, function to mediate adherence of bacteria to cell surface, sex pilus forms during conjugation

Answer 25

Ability to take up naked DNA (i.e. From cell lysis) from environment (AKA competence) A feature of many bacteria - S.pneumoniae, HiB, Neisseria (SHiN) Any DNA can be used. Adding deoxyribonuclease to environment will degrade backed DNA in medium thus no transformation is seen

Answer 26

F+ plasmid contains genes required for sex pilus and conjugation. Bacteria without this plasmid are termed F-. Sex pilus on F+ bacterium contains F- bacterium. A single strand of plasmid DNA is transferred across the conjugal bridge ("mating bridge") No transfer of chromosomal DNA

Answer 27

F+ plasmid can become incorporated into bacterial chromosomal DNA, termed high frequency recombination (Hfr) cell. Replication of incorporated plasmid DNA may include some flanking chromosomal DNA. Transfer of plasmid and chromosomal genes

Answer 28

Segment of DNA (eg transposon) that can "jump" (excision and reintegration) from one location to another, can transfer genes from plasmid to chromosome and vice versa. When excision occurs, may include some flanking chromosomal DNA, which can be incorporated into a plasmid and transferred to another bacterium. e.g. VanA gene from vancomycin resistant enterococcus to S.aureus

Answer 29

A "packaging" event. Lytic phage infects bacterium, leading to cleavage of bacterial DNA. Parts of other bacterial chromosomal DNA may become packaged in phage capsid. Phage infects another bacterium, transferring these genes

Answer 30

An "excision" event. Lysogenic phage infects bacterium; viral DNA incorporates into bacterial chromosome. When phage DNA is excised, flanking bacterial genes may be excised with it. DNA is packaged into phage capsid and can infect other bacterium

Answer 31

``` *ABCDs* group A strep erythogenic toxin Botulinum toxin Cholera toxin Diphtheria toxin Shiga toxin ```

Answer 32

``` Some bacteria forms spores at end of the stationary phase when nutrients are limited. Spores are highly resistant to heat and chemicals. Have dipicolinic acid in their core, have no metabolic activity. Must autoclave to potentially kill spores (as is done with surgical equipment) by steaming at 121 degrees C for 15 minutes Bacillus anthracis (Anthrax), Bacillus cereus (Food poisoning), Clostridium botulinum (botulism), clostridium difficle (pseudomembranous colitis), clostridium perfringens (gas gangrene), clostridium tetani (tetanus) ```

Answer 33

Source: certain gram + and gram - bacteria Secreted from cell Polypeptide Location of genes: plasmid or bacteriophage High amounts of adverse effects Antigenicity: induced high-tiger Abs called antitoxins Vaccines: toxoids used Heat stability: destroyed rapidly at 60 degrees C (except staph enterotoxin) Typical diseases: tetanus, botulism, diphtheria

Answer 34

Source: outer cell membrane of most gram - bacteria Not secreted from cell Lipid A component of LPS (structural part of bacteria; released when lysed) Location of genes: bacterial chromosome Low amount of adverse effects Clinical effects: fever, shock (hypotension), DIC MOA: inducing TNF, IL-1 & IL-6 Poorly antigenic Vaccines: none - no toxoid formed Heat stability: stable at 100 degrees C for 1 hr Typical diseases: meningococcemia; sepsis by gram - rods

Answer 35

Toxin: diphtheria toxin (AB toxin) MOA: inactivation of elongation factor (EF-2) Manifestation: pharyngitis with pseudomembranes in throat and severe lymphadenopathy (bull neck)

Answer 36

Toxin: exotoxins A (AB toxin) MOA: Inactivation of EF-2 Manifestation: host cell death

Answer 37

Toxin: Shiga toxin (ST - AB toxin) MOA: inactivate 60S ribosome by removing adenine from rRNA Manifestation: GI mucosal damage --> dysentery; ST also enhances cytokine release, causing hemolytic uremic syndrome (HUS)

Answer 38

Toxin: Shiga-like toxin (SLT - AB toxin) MOA: inactivation of 60S ribosome by removing adenine from rRNA Manifestation: SLT enhances cytokine release, causing HUS (stereotype O157:H7), but does not invade host cells

Answer 39

Toxin: Heat Labile toxin (LT - AB toxin) MOA: over activates adenylate cyclase (increased cAMP) --> increase Cl- secretion in gut and H2O efflux Manifestation: watery diarrhea (*Labile in the Air (Adenylate cyclase)*)

Answer 40

Toxin: Heat-stable toxin (ST - AB toxin) MOA: over activates guanylate cyclase (increased cGMP) - decreased reabsorption of NaCl and H20 I the gut Manifestations: watery diarrhea (*stable on the Ground (guanylate cyclase)*)

Answer 41

Toxin: edema toxin (AB toxin) MOA: mimic the adenylate cyclase enzyme (increased cAMP) Manifestations: likely responsible for characteristic edematous borders of black Escher in cutaneous anthrax

Answer 42

Toxin: Cholera toxin (AB toxin) MOA: over activates adenylate cyclase (increased cAMP) by permanently activating Gs --> increased Cl- secretion in gut and H2O efflux

Answer 43

Toxin: pertussis toxin (AB toxin) MOA: over activates adenylate cyclase (increased cAMP) by disabling Gi impairing phagocytosis to permit survival of microbe Manifestation: Whooping cough - child cough on expiration and "whoops" on inspiration (toxin may not actually be the cause of coughs; can cause "100-day cough" in adults)

Answer 44

Toxin: Tetanospasmin (AB toxin) MOA: protease that cleave SNARE, a set of proteins required for neurotransmitter release via vesicular fusion Manifestation: spastic paralysis, risks sardonicus and lockjaw, toxin prevents release of INHIBITORY (GABA and glycine) NTs from Renshaw cells in spinal cord

Answer 45

Toxin: Botulinum toxin (AB toxin) MOA: protease that cleaves SNARE, a set of proteins required for NT release via vesicular fusion Manifestation: flaccid paralysis, floppy baby; toxin prevents release of STIMULATORY (ACh) signals at the neuromuscular junction --> flaccid paralysis

Answer 46

Toxin: alpha toxin MOA: phospholipase (lecithin are) that degrades tissue and cell membrane Manifestation: degradation of phospholipids --> myonecrosis (gas gangrene) and hemolysis (double zone of hemolysis on blood agar)

Answer 47

Toxin: Streptolysin O MOA: protein that degrades cell membrane Manifestations: Lyses RBCs; contributes to Beta-hemolysis; host Abs against toxin (ASO) used to diagnose rheumatic fever (do not confuse with immune complexes of poststreptococcal glomerulornephritis)

Answer 48

Toxin: toxic shock syndrome toxin (TSST-1) MOA: binds to MHC II and TCR outside of Ag binding site to cause overwhelming release of IL-1, IL-2, IFN-gamma, and TNF-alpha --> shock Manifestation: toxic shock syndrome - fever, rash, shock; other toxins cause scalded skin syndrome (exfoliating toxin) and food poisoning (enterotoxin)

Answer 49

Toxin: Exotoxin A MOA: binds to MHC II and TCR outside the Ag binding site to cause overwhelming release of IL-1, IL-2, IFN-gamma, TNF-alpha --> shock Manifestation: Toxic shock syndrome: fever, rash, shock

Answer 50

LPS found in outer membrane of gram - bacteria (cocci and rods). Composed of O Ag + core polysaccharide + lipid A (toxic component) Released upon cell lysis or by living cells by blebs detaching from outer surface of membrane (vs. Exotoxin which is actively secreted) Three main effects: MP activation (TLR4), complement activation and tissue factor activation

Answer 51

``` *ENDOTOXINS* Edema Nitric Oxide DIC/Death Outer membrane TNF-alpha O-Ag + core polysaccharide + Lipid A eXtremely heat stable IL-1 and IL-6 Neutrophil chemotaxis Shock ```

Basic Bacteriology Flashcards

(75 cards)