Random Micro Things that are annoying Flashcards

1
Q

Media used for H. influenzae culture

A

Chocolate agar

-Requires Factors V (NAD) and X (Hematin)

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2
Q

Media used for N. gonorrhoeae and N. meningitidis culture

A

Thayer-Martin agar (VCN)

  • Vancomycin: inhibits gram pos organisms
  • Colistin: inhibits gram neg except Neisseria
  • Nystatin: inhibits fungi
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3
Q

Media used for B. pertussis culture

A

Bordet-Gengou agar (Bordet for Bordetella)

Regan-Lowe medium (contains charcoal, blood, Abx)

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4
Q

Media used for C. diptheriae culture

A

Cystine-Tellurite agar

Loffler medium

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5
Q

Media used for M. tuberculosis culture

A

Lowenstein-Jensen agar

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6
Q

Media used for M. pneumoniae culture

A

Eaton agar (requires cholesterol)

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7
Q

Media used for Lactose-fermenting enterics culture)

A

MacConkey agar (colonies turn pink)

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8
Q

Media used for E. coli culture

A

Eosin-methylene blue (EMB) agar

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9
Q

Media used for Legionella culture

A

Charcoal yeast extract agar buffered with cysteine and iron

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10
Q

Media used for Fungi culture

A

Sabouraud agar (Sab’s a fun guy)

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11
Q

Spirochetes

A

Borrelia
Leptospira
Treponema

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12
Q

No cell wall

A

Mycoplasma

Ureaplasma

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13
Q

Pleomorphic

A

Chlamydiae

Rickettsiae

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14
Q

Which bugs don’t gram stain well and why?

A

Treponema - too thin to be seen
Mycobacteria - high lipid content; mycelia acids in cell wall detected by carbolfuchsin in acid fast stan
Mycoplasma - no cell wall
Legionella - primarily intracellular
Rickettsia - intracellular parasite
Chalmydia - intracellular parasite; lacks classic peptidoglycan because of low muramic acid

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15
Q

Silver stain

A

Legionella, Fungi (pneumocystis), Helicobacter pylori

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16
Q

India ink

A

Cryptococcus neoformans

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17
Q

Ziehl-Neelsen (carbol fuchsin) stain

A

Acid-fast bacteria (Nocardia, Mycobacteria)

Protozoa (Cryptosporidium oocysts)

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18
Q

Alternative to Ziehl-Neelsen stain

A

Auramine-Rhodamine stain

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19
Q

PAS (periodic acid Schiff stain)

A

Stains glycogen, mucopolysaccharides, used to diagnose Whipple disease (Tropheryma whipplei)

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20
Q

Giemsa stain (Certain Bugs Really Try my Patience)

A
Chlamydia
Borrelia
Rickettsia
Trypanosomes
Plasmodium
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21
Q

Which bacteria has the following?

a. Antiphagocytic capsule
b. Hypervariable pili
c. IgG binding outer membrane protein
d. Intracellular polyphosphate granules

A

a. Strep pneumo, H. influenzae, Neisseria
b. Neisseria meningitidis AND gonorrhea
c. Staph aureus (Protein A)
d. Corynebacterium diptheriae (evident with methylene blue stain)

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22
Q

Obligate Aerobes (Naggy Pests Must Breathe)

A
Nocardia
Pseudomonas
MycoBacterium tb (predilection for apices of lung which have highest pO2)
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23
Q

Obligate Anaerobes (Frankly Can’t Breathe Air)

A

Fusobacterium
Clostridium
Bacteroides
Actinomyces

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24
Q

Properties of Anaerobes

A

Lack catalase and/or superoxide disputes so they are susceptible to oxidative damage

  • Generally foul smelling (short chain fatty acids) and difficult to culture
  • Produce gas in tissue (CO2 and H2)
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25
Q

Which antibiotic is ineffective against anaerobes? Why?

A

AminOglycOsides –> they require O2 to enter into bacterial cell

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26
Q

Obligate intracellular bugs (stay inside, it’s Really CHilly COld)

A

Rickettsia
Chalmydia
Coxiella
-ALL rely on host ATP

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27
Q

Facultative intracellular bugs

A

Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis

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28
Q

Encapsulated bacteria (SHiNE SKiS) + P

A
Strep pneumo
H. influenzae
Neisseria
E. coli
Salmonella
Klebsiella
Group B strep
AND PSEUDOMONAS
29
Q

How are encapsulated bacteria cleared?

A

Opsonized and cleared by spleen

30
Q

Which bacteria have conjugate vaccines?

A

PCV (pneumococcal conjugate)
H influenzae type B
Meningococcal

31
Q

Urease positive (CHubby PUNKSS)

A
Cryptococcus
H pylori
Proteus
Ureaplasma
Nocardia
Klebsiella
S. epidermidis
S. saprophyticus
32
Q

Catalase positive organisms (Cats Need PLACESS)

A
Nocardia
Pseudomonas 
Listeria
Aspergillus
Candida
E. coli
Staphylococci
Serratia
33
Q

Abscesses commonly caused by?

A

Catalase + organisms

34
Q

Bacteria that produce yellow sulfur granules

A

Actinomyces

35
Q

Bacteria with yellow pigment

A

Staph aureus

36
Q

Bacteria with blue green pigment

A

Pseudomonas

37
Q

Bacteria with red pigment

A

Serratia marcescens

38
Q

Which organisms have IgA protease and what does it do?

A

Strep pneumo, H influenzae and Neisseria –> cleaves IgA so that they can colonize respiratory mucosa

39
Q

Which bacteria have type III secretion system?

A

Pseudomonas
Salmonella
Shigella
E. coli

40
Q

Toxin produced by bacteria and released

A

Exotoxin (gram + and -)

41
Q

Location of exotoxin genes

A

Plasmid or bacteriophage

42
Q

Are exotoxins and endotoxins heat stable?

A

Exotoxin - destroyed rapidly at 60 degrees celsius (except staph enterotoxin)
Endotoxin - stable at 100 degrees celsius for 1 hour

43
Q

Corynebacterium diphtheria toxin

A

Exotoxin that inactivates elongation factor 2 –> pharyngitis with pseudomembranes in throat and severe lymphadenopathy (bull neck)
-Similar to Pseudomonas toxin

44
Q

Pseudomonas aeruginosa toxin

A

Exotoxin A –> inactivates EF2 –> host cell death

-Similar to C. diphtheria toxin

45
Q

Shigella toxin

A

Shiga toxin –> inactivates 60s ribosome by removing adenine from rRNA–> inhibits protein synthesis –> GI mucosal damage causes dysentery and ST also enhances cytokine release causing HUS

46
Q

E. coli (EHEC) toxin

A

Shiga-like toxin (SLT) –> inactivates 60s ribosome by removing adenine from rRNA –> stops protein synthesis –> enhances cytokine release causing HUS (DOES NOT INVADE HOST CELLS LIKE SHIGELLA)

47
Q

E. coli (ETEC) toxin

A
  1. Heat labile (LT) –> overactivates adenylate cyclase to increase cAMP –> increase Cl secretion in gut and water efflux
  2. Heat stable (ST) –> overactivates guanylate cyclase to increase cGMP –> decrease resorption of NaCl and H20 in gut
48
Q

Bacillus anthracis toxin

A

Edema toxin –> mimics adenylate cyclase enzyme to increase cAMP and causes edematous borders of black eschar in cutaneous anthrax

49
Q

Vibrio cholerae toxin

A

Cholera toxin –> overactivates adenylate cyclase to increase cAMP by permanently activating Gs –> increases Cl secretion in gut and water efflux –> rice water diarrhea

50
Q

Bordetella pertussis toxin

A

Overactivates adenylate cyclase (increases cAMP) by disabling Gi –> impairing phagocytosis to permit survival of microbe –> whooping cough

51
Q

Clostridium tetani toxin

A

Tetanospasmin –> protease that cleaves SNARE –> prevents release of inhibitory (GABA and glycine) neurotransmitters from Renshaw cells in spinal cord

52
Q

Clostridium botulinum toxin

A

–> protease the cleaves SNARE to prevent release of stimulatory Ach signals at neuromuscular junction –> flaccid paralysis

53
Q

Clostridium perfringens toxin

A

Alpha toxin –> phospholipase (lecithinase) that degrades tissue and cell membranes –> degradation of phospholipids –> myonecrosis and hemolysis

54
Q

Streptococcus pyogenes toxin

A

Streptolysin O –>protein that degrades cell membrane –> lyses RBCs (host antibodies against toxin can be used to diagnose acute rheumatic fever)

55
Q

Staph aureus toxin

A

Toxic shock syndrome toxin (TSST1) –> binds to MHCII and TCR outside of antigen binding site to cause overwhelming release of IL1, IL2, IFNy and TNFalpha –> shock

56
Q

Strep pyogenes toxin

A

Exotoxin A –> binds to MHC II and TCR outside of antigen binding site to cause overwhelming release of IL1, IL2, IFNy and TNFalpha –> shock

57
Q

Actions of endotoxin (esp Lipid A)

A
Edema (C3a)
Nitric oxide (hypotension)
DIC/Death (activates tissue factor)
Outer membrane 
TNF-alpha (fever and hypotension)
O-antigen
eXtremely heat stable
IL-1 (fever)
Neutrophil chemotaxis (C5a)
58
Q

What is transformation?

A

Ability to take up NAKED DNA from environment (also known as competence)

59
Q

Which bacteria can undergo transformation?

A

Strep pneumo
H. influenzae type B
Neisseria

60
Q

How does adding deoxyribonuclease to environment affect transformation?

A

Deoxyribonucleases degrade DNA and there is no transformation

61
Q

What are F+ bacteria?

A

F+ plasmid contains genes required for sex pilus and conjugation

62
Q

What are F- bacteria?

A

Bacteria without the plasmid (conjugation)

63
Q

What is F+ x F- conjugation?

A

The sex pilus on the F+ bacterium contacts the F- bacterium and a single strand of plasmid DNA is transferred across the conjugal bridge
NO TRANSFER OF CHROMOSOMAL DNA

64
Q

What is Hfr x F- conjugation?

A

F+ plasmid can become incorporated into bacterial chromosome (high frequency recombination = Hfr) –> replication of incorporated plasmid DNA may include some flanking chromosomal DNA so there is transfer of plasmid AND chromosomal DNA (unlike F+ x F-)

65
Q

What is transposition?

A

Segment of DNA (transposon) that can jump from one location to another and transfer genes from plasmid to chromosome and vice versa

66
Q

What is generalized transduction?

A

A packaging event –> a lytic phage (virus) infects bacterium leading to cleavage of bacterial DNA –> parts of the bacterial chromosomal DNA may become packaged in viral capsid –> phage infects another bacterium and transfers these genes

67
Q

What is specialized transduction?

A

Excision event where lysogenic phage infects bacterium and viral DNA incorporates into bacterial chromosome –> when phage DNA is excised the flanking bacterial genes may be excised with it –> the DNA is packaged into phage viral capsid and can infect another bacterium

68
Q

Which bacterial toxin genes are encoded as lysogenic phage? (ABCDE)

A
shiga A like toxin
Botulinum toxin 
Cholera toxin
Diptheria toxin
Erythrogenic toxin of Streptococcus pyogenes