March 30 - Micro

Question 1

P fimbriae

Answer 1

E coli virulence factor. Allows for adhesion to uroepithelium in UTIs

Question 2

Bacillus anthracis morphology

Answer 2

Large gram positive rods that form medusa head colonies. Antiphagocytic capsule composed of D glutamate.

Question 3

Diphtheria morphology

Answer 3

Nonmotile gram pos rods, often in clumps or V or Y shaped chains. Granules stain with aniline dyes (i.e. methylene blud)

Question 4

Thayer martin medium

Answer 4

Selective chocolate agar with multiple antiboitics used to isolate N gonorrhea

Question 5

Chocolate agar

Answer 5

Lysed red cells that release NAD (factor V) and hemin (factor X). Used to culture H flu

Question 6

Bordet-Gengou agar

Answer 6

Used for pertussis

Question 7

Loffler’s media

Answer 7

Selective for diphtheria

Question 8

Tellurite plate

Answer 8

Differential for diphtheria

Question 9

Lowenstein Jensen agar

Answer 9

Used to grow TB

Question 10

Eaton’s agar

Answer 10

Grows mycoplasma, high in cholesterol

Question 11

Eosin-methylene blue

Answer 11

Selective for gram negatives. Differential for lactose fermenters which turn a green metallic sheen.

Question 12

Sorbitol macconkey

Answer 12

used to isolate 0157 e coli

Question 13

buffered charcoal yeast

Answer 13

used for legionella

Question 14

Sabouaud’s agar

Answer 14

used to grow fungi

Question 15

N meningitidis prophylaxis

Answer 15

Done for close contacts. options are rifampin, ciprofloxacin (Adults), and IM ceftriaxone

Question 16

Daptomycin

Answer 16

Antibioitic used to treat MRSA. Creates transmembrane channels, depolarizing cell membranes.

ADRs: myopathy, elevation of CPK.

Inactivated by surfactant so can’t be used to treat pulmonary infections.

Question 17

Linezolid

Answer 17

Antibiotic used to treat MRSA. Inhibits 50s ribosome. ADRs: thrombocytopenia, optic neuritis, serotonin syndrome.

Question 18

INH: MOA and MOR

Answer 18

MOA: activated by mycobacterial catalase peroxidase. Then inhibits mycolic acid synthesis.

Resistance: mutated binding site on mycolic acid synthesis enzyme results in decreased expression of catalase peroxidase

Question 19

Oseltamavir

Answer 19

Neuraminidase inhibitor used to treat influenza A and B. Prevents release of virus from infected cells

Question 20

Amantadine

Answer 20

Impairs uncoating and disassembly of influenza A. Increases dopamine release in PD

Question 21

Aminoglycoside resistance

Answer 21

Bacteria produce enzymes that transfer different chemical groups to drug, decreasing ability to bind ribosomes

Question 22

Waterhouse-Friderichson syndrome

Answer 22

Complication of meningococcemia, either in presence or absence of meningitis. Adrenal gland destruction, DIC, and shock

Question 23

Alcohol as disinfectant

Answer 23

Disrupt cell membranes and denatures proteins. Not sporicidal

Question 24

Chlorhexidine as disinfectant

Answer 24

Disrupts cell membranes and coagulates cytoplasm. Not sporicidal

Question 25

H2O2 as disinfectant

Answer 25

Produces free radicals. Sporicidal

Question 26

Iodine as disinfectant

Answer 26

Halogenates proteins and nucleic acids. Sporicidal

Question 27

Proteus lab characteristics

Answer 27

Gram neg rod, lactose non-fermenter, H2S producer (same as salmonella)

Question 28

Lactose fermenting gram neg rods

Answer 28

Fast fermenters: E coli, Klebsiella, enterobacter Slow fermenters: Citrobacter, serratia E coli and enterobacer distingushed by ecoli indole pos and enterobacter indole neg

Question 29

GAS vs GBS

Answer 29

GAS is PYR positive | GBS is PYR negative

Question 30

Bacillary angiomatosis

Answer 30

Caused by Bartonella henselae infection in immunocompromised. Red-purple papular lesion that mimics Kaposi sarcoma

Question 31

Adenovirus presentation

Answer 31

Fever, congestion, conjunctivits, pharyngitis | Year round outbreaks

Question 32

Bacterial vaginitis vs trichomonas vaginalis

Answer 32

Gardnerella vaginalis - off white discharge iwth fishy odor - clue cells: epitheilial cells covered with gram variable rods Trichomonas -thin yellow-green malodorous frothy discharge

Question 33

Chlamydia trachomatis presentation

Answer 33

Small shallow painless ulcers initially. Followed by large painful inguinal nods

Question 34

Roseola

Answer 34

Caused by HHV-6. Occurs in kids less than 2. High fever for 3-7 days that stops abruptly and is followed by blanching maculopapular rash

Question 35

Aspiration syndromes

Answer 35

1. Aspiration of gastric contents: acid injury and inflammation (not infection) of lung hours later 2. Aspiration of oropharyngeal contents: pneumonia days later

Question 36

Enterococcal endocarditis

Answer 36

Seen followiong cystoscopy, colonoscopy, obstetric procetures

Question 37

Q fever

Answer 37

Caused by inhalation of Coxiella burnetii in air contaminated by animal waste. Acute: fever for over 10 days, retroorbital HA, pneumonia, elevated LFTs, low platelets Chronic: endocarditis in patients with valve disease

Question 38

Bacteria causing lyme disease

Answer 38

Borrelia burgdorfei

Question 39

Vi antigen

Answer 39

Salmonella virulence factor. Capsule that protects against opsonization adn phagocytosis