All about those microbes

Question 1

What enzyme is responsible for the greenish color of pus?

Answer 1

Myeloperoxidase from azurphilic granules

Produced by neutrophils

Question 2

Black eschar in nares of diabetic patient

Answer 2

Mucormycosis caused by mucor & rhizopus spp.

Question 3

Partial circular, double-stranded DNA virus

Answer 3

Hepadnavirus
*Hepatitis B

Contains reverse transcriptase

Question 4

Dane particle

Answer 4

Hepatitis B

Virion capable of infecting hepatocytes

Question 5

Single stranded, linear DNA virus

Answer 5

Parvovirus

Question 6

Viruses that acquire envelopes by budding from nuclear membrane

Answer 6

Herpesviruses

Question 7

Lancet-shaped gram positive cocci in pairs

Answer 7

Strep pneumonia

*Most common cause of bacterial meningitis in adults!

Question 8

Positive quellung reaction

Answer 8

Encapsulated organisms

Strep pneumo
Neisseria meningitidis
Klebsiella pneumonia
Haemaphilus influenzae
Salmonella typhi
Cryptococcus neoformans
Pseudomonas aeruginosa
Group B strep

Some nasty killers have some capsular protection. Go!

Question 9

Bean-shaped gram negative cocci

Answer 9

Neisseria menigitidis

Question 10

Chocolate agar with factors V (NAD+) and X (hematin)

Answer 10

H. influenzae

Question 11

Thayer-Martin media

Answer 11

Neisseria gonorrhoeae

aka VPN- Vancomycin (inhibit gram positives), Polymyxin (inhibit gram negatives), & Nystatin (inhibits fungi)

Question 12

Bordet-Gengou

Answer 12

Potato agar!

Bordetella pertussis

Question 13

Tellurite plate

Answer 13

Corynebacterium diptheriae

Question 14

Loffler’s media

Answer 14

Corynebacterium diptheriae

Question 15

Eaton’s agar

Answer 15

M. pneumonia

Question 16

Lowenstein-Jensen Agar

Answer 16

M. tuberculosis

Question 17

Charcoal yeast extract agar buffered w/ cysteine & iron

Answer 17

Legionella

Question 18

Sabouraud’s agar

Answer 18

Fungi

Question 19

Eosin-methylene blue

Answer 19

E. coli

Question 20

Pink colonies on MacConkey’s agar

Answer 20

Lactose-fermenting enterics

Question 21

Biofilm-producing organisms

Answer 21

Staph epidermidis- prosthetic devices, IV catheters

Strep mutans & strep sanguinis- dental plaques

Pseudomonas aeruginosa- cystic fibrosis pneumonia, contact lenses

Viridans group strep- endcarditis

Nontypable H. influenzae- otitis media

Question 22

Abdominal rose spots

Answer 22

Salmonella typhi

Question 23

Comma-shaped, oxidase positive, gram negative organism that grows at 42 degrees C

Answer 23

Campylobacter jejuni

Question 24

Comma-shaped, oxidase positive, gram negative, grows in alkaline media

Answer 24

Vibrio cholerae

Question 25

Gram-positive rod w/ tumbling motility

Answer 25

Listeria

Question 26

These viruses lose infectivity after being exposed to ether

Answer 26

Enveloped viruses

Question 27

Spherules packed with endospores

Answer 27

Coccidioides

Question 28

Hepatocytes w/ ground glass appearance

Answer 28

Hepatitis B

Question 29

Capsule composed of D-glutamate

Answer 29

Bacillus anthracis

Question 30

Fungal ball

Answer 30

Aspergillus

Grows in pre-existing lung cavities in immunocompromised pts

Question 31

Agent of malignant otitis externa

Answer 31

Pseudomonas aeruginosa

Question 32

Gram positive rod w/ metachromatic granules

Answer 32

Corynebacterium diphtheriae; contains AB exotoxin

B= binding subunit

A= active subunit (inhibits cell protein synthesis by inactivating EF2)

Question 33

In response to injury, local neutrophils & macrophages release:

Answer 33

TNF-alpha, IL-1, & IL-6

Question 34

Fever + productive cough + diarrhea

Answer 34

Legionella!

Question 35

Evades host immune response by binding Fc region of Ig

Answer 35

S. aureus (Protein A)

Prevents opsonization & phagocytosis

Question 36

Bacteria w/ red pigment

Answer 36

Serratia marcescens

Question 37

Virulence factor of group A strep

Answer 37

M protein- helps prevent phagocytosis

Question 38

Which bacteria secrete IgA protease?

Answer 38

S. pneumonia
H. influenzae
Neisseria

*enzyme that cleaves IgA * allows colonization of respiratory mucosa

Question 39

Endotoxin induces the production of:

Answer 39

TNF & IL-1

Question 40

Which bacteria inactivate elongation factor (EF-2)?

Answer 40

Corynebacterium diptheriae (Diptheria toxin)

Pseudomonas aeruginosa (Exotoxin A)

Question 41

Voluminous ‘rice-water’ diarrhea

Answer 41

Vibrio cholerae

Caused by cholera toxin, which overactivates adenylate cyclase by permanently activating Gs :. increasing Cl- secretion in gut & H2O efflux

Question 42

Which bacteria cleave SNARE protein?

Answer 42

Clostridium tetani (Tetanospasmin toxin)- prevents release of inhibitory (GABA & glycine) neurotransmitters in spinal cord :. muscle rigidity

Clostridium botulinum (Botulinum toxin)- prevents release of stimulatory (Ach) signals @ musculoskeletal junction :. flaccid paralysis

Question 43

Which organisms cause toxic shock syndrome & how?

Answer 43

MOA: Bring MHC II & TCR together to cause massive release of IFN-gamma & IL-2

Strep pyogenes (Exotoxin A)

Staph aureus (Toxic shock syndrome toxin-1)

Question 44

Associated w/ rusty sputum, sepsis in sickl cell anemia, & splenectomy

Answer 44

Strep pneumoniae (aka pneumococcus)

Question 45

Actin rockets

Answer 45

Formed by listeria to allow movement from cell to cell

Question 46

Weil-felix reaction tests for. . .

Answer 46

Rickettsial infection (BUT it’s negative for coxiella- Q fever)

Question 47

Describe 2 forms of chlamydia

Answer 47

Elementary body- small dense, infections (Enfectious), enters cell via endocytosis

Reticulate body replicates in cell by fission; seen on tissue on culture

Question 48

Treatment for local vs systemic dimorphic fungi infections

Answer 48

Local- Fluconazole or ketoconazole

Systemic- Amphotericin B