Microbio Basic Bacteriology2

Question 1

Ziehl-Neelsen stain

Answer 1

Acid fast bacteria (nocardia, mycobacteria), protozoa (cypto oocytes)

Question 2

India ink stains what?

Answer 2

crypto neoformans (mucicarmine can also be used)

Question 3

Silver stain is good for what?

Answer 3

fungi (pneumocystis), legionella, and h. pylori

Question 4

Best media for H. influenza culture

Answer 4

chocolate agar

Question 5

best media for Neisseria (gonorrhea and meningitidis) cx

Answer 5

thayer-martin agar (vanc, trimethoprim, colisin, and nystatin)

Question 6

best cx for bordatella pertussis cx

Answer 6

Bordet-gengou agar (made of potato)

Question 7

best cx medium for c. diptheriae

Answer 7

tellurite agar, loffler medium

Question 8

best cx for m. tuberculosis

Answer 8

Lowenstein-jensen agar

Question 9

best cx medium for mycloplasma pneumoniae

Answer 9

eaton agar (requires cholesterol)

Question 10

best cx for e coli

Answer 10

EMB agar

Question 11

best cx medium for lactose-fermenting enterics

Answer 11

macconkey agar (ferentaton produces acid, causing colonies to turn pink)

Question 12

best cx for legionella

Answer 12

charcoal yest extract agar buffered with cysteine and iron

Question 13

best cx medium for fungi

Answer 13

sabouraud agar (“Sab’s a fun guy!”)

Question 14

pseudomonas, nocardia, and mycobacterium are all?

Answer 14

aerobes

Question 15

fusobacterium, clostridium, bacteroides, and actinomyces are all what?

Answer 15

anaerobes (generally foul smelling, difficult to cx, and produce gas in tissue)

Question 16

obligate intracellular bugs

Answer 16

rickettsia, chlamydia, coxiella

Question 17

facultative intracellular bugs

Answer 17

salmonella, neisseria, brucella, mycobacterium, listeria, francisella, legionell, yersinia pestis

Question 18

encapsulated bacteria

Answer 18

strep pneumo, HIB, neisseria meningitidis, e. coli, salmonella, klebsiella pneumoniae, and group b strep

Question 19

urease positive organisms

Answer 19

cryptococcus, h. pylori, proteus, ureaplasma, nocardia, klebsiella, s. epidermis, staph saprophyticus; “CHuck norris hates PUNKSS”

Question 20

catalase pos organisms

Answer 20

people with chronic granulomatous disease (NADPH oxidase def) hav recurrent infections w certain catalase pos organisms; nocardia, pseudomonas, listeria, aspergillus, candida, e. coli, staphylococci, seratia; “Cats need PLACESS to hide”

Question 21

pigment producing bacteria

Answer 21

actinomyces israelii is yellow’ staph aureus is yellow; pseudomonas is blue/green; serratia marcescens is red

Question 22

protein A

Answer 22

expressed by staph aureus; bind sthe Fc region of IgG; prevents opsonization an dphagocytosis

Question 23

IgA protease

Answer 23

enzyme that cleaves IgA; secreted by strep pneumo, Hib and Neisseria in order to colonize the respiratory mucosa

Question 24

M protein

Answer 24

helps prevent phagocytosis; expressed by group a strep; possibly underlies the autoimmune response seen in acute rheumatic fever

Question 25

Type III secretion system

Answer 25

aka "injectisome"; needle-like protein appendage facilitating direct delivery of toxins from certain GN bacteria to eukaryotic host cell

Question 26

exo versus endotoxin

Answer 26

endotoxins are expresed on the outer cell membrane of most gram neg bacteria as lipopolysaccharides; exotoxins are secreted by certain gram pos and gram negs;

Question 27

bacteria with exotoxins

Answer 27

corynebacterium diptheriae, pseudomonas, shigella, EHEC, ETEC,, bacillus anthracis, vibrio cholerae, bordatella pertussis, c. tetani,c. botulinum, c. perfringens, strep pyogenes, staph aureus

Question 28

corynebacterium diptheriae exotoxin characteristics

Answer 28

called the "diptheria toxin"; inactivates elongation factor EF-2; causes pharyngitis with pseudomembranes in the throat ad severe lymphadenopathy (bull's neck)

Question 29

pseudomonas exotoxin

Answer 29

called "Exotoxin A"; it inactivates EF-2; causes host cell death

Question 30

shigella exotoxin

Answer 30

"shiga toxin"; inactivates 60S ribosome; causes GI mucosal damage leading to dysentery; the shiga toxin also enhances cytokine release causing HUS

Question 31

EHEC exotoxin

Answer 31

shiga-like toxin; inactivates the 60S ribosome; enhances cytoine release causing HUS, esp serotype EHEC 0157:H7; unlike shigella, EHEC does not invade host cells

Question 32

ETEC exotoxin

Answer 32

there is the heat labile toxin (increaes chloride secretion in gut and water efflux) and heat stable toxin (decreases resorption of NaCl and water in the gut); both toxins cause watery diarrhea

Question 33

b. anthracis toxin

Answer 33

"edema toxin"; likely responsible for characteristic edematous borders of black eschar in cutaneous anthrax

Question 34

vibrio cholera exotoxin

Answer 34

"cholera toxin"; increases secretion in gut and water efflux; causes voluminous rice water diarrhea

Question 35

bordatella pertussis toxin

Answer 35

"pertussis toxin"; impairs phagocytosis to permit survival of the microbe; cause of whooping cough

Question 36

clostridium tetani toxin

Answer 36

tetanospasmin; it is a protease that cleaves SNARE, which is required for neurotransmitter release; causes spasticity, risus sadonicus and lockjaw; toxin prevents release of inhibitory nts from Renshaw cells in spinal cord

Question 37

clostridium botulinum

Answer 37

botulinum toxin; protease that cleaves SNARE; causes flaccid paralysis, floppy baby; toxin prevents release of stimulatory (Ach) signals at NMJs

Question 38

clostridium perfringens exotoxin

Answer 38

"alpha toxin"; phospholipase that degrades tissue and cell membrane; you get gas gangrene and hemolysis ("double zone " of hemolysis on blood agar)

Question 39

strep pyogenes exotoxin

Answer 39

Streptolysin O; protein that degrades the cell membrane; lyses RBCs; contributes to beta hemolysis; host antbodies against toxin (ASO) used to dx rheumatic fever

Question 40

what organisms can produce superantigens causing toxic shock syndrome?

Answer 40

staph aureus (fever, rash, shock, scaeded skin syndrome and food poisoning); strep pyogenes (fever, rash, shock)

Question 41

endotoxin

Answer 41

LPS found on the outer membrane of gram neg bacteria (both cocci and rods)

Question 42

how does the endotoxin work?

Answer 42

activates macrophages (which produce IL-1, TNF-a, nitric oxide); activates complement (C3a, C5a) and activates tissue facto (coag cascade to DIC)

Question 43

transformation

Answer 43

a bacteria's ability to take up naked DNA from the environment (aka "competence"). A feature of many bacteria, esp strep pneumo, HIB and Neisseria

Question 44

Conjugation F+xF-

Answer 44

F+ plasmid contains the genes reqd for sex pilus and conjugation. Bacteria without this plasmid are F-. Sex pilus on F+ contacts the F- and a single strand of plasmid DNA is transferred across theconjugal bridge. No transfer of chromosomal DNA

Question 45

Conjugation Hfr x F-

Answer 45

F+ plasmid can become incorporated into bacterial chromosomal DNA, termed high-freq recombination (Hfr) cell. Transfer of plasmid and chromosomal genes

Question 46

Transposition

Answer 46

segment of DNA (transposon) that can jump from one location to another. Can transfer genes from plasmid to chromosome and vice versa; can include flanking chromosomal DNA that is transferred to another bacterium

Question 47

generalized transduction

Answer 47

lytic phage infects the bacterium and parts of bacteral chromosomal DNA may become packaged in viral capsid. Page infects another bacterium, transferring these genes

Question 48

specialized transduction

Answer 48

an excision event in which phage infect bacterium and viral DNA incorportates into bacterial chrom. When phage DNA is excised, flanking bacterial genes may be excised with it. DNA s packaged into pahage viral capsid and can infect other bacterium

Question 49

Genes for which 5 bacterial toxins are encoded in a lysogenic phage?

Answer 49

ABCDE; ShigA like toxin, botulinum toxins, cholera, diptheria, erythrogenic toxin of strep pyogenes