Microbiology

Question 1

Which virus does Hepatitis Delta Virus require to be able to be infective?

Answer 1

Hepatitis B because it needs to coat itself with the HBsAg

Question 2

What cell type mediates the reaction seen on a PPD? Hint: It is the same as contact dermatitis.

Answer 2

T Lymphocyte

Question 3

What is the clinical presentation of Listeria in adults?

Answer 3

GPR with tumbling motility that causes meningitis in the immunocompromised (ie. transplant recipients). The source is contaminated food.

Question 4

Which bacteria have a polysaccharide capsule vaccine? How are they administered?

Answer 4

Pneumococcal, HiB, Meningococcal. The polysaccharide is carried by a protein (diphtheria toxin, tetanus toxin or N. Meningitidis outer membrane protein) so it can be presented to T cells.

Question 5

What are the most serious complications of Amphotericin B?

Answer 5

Renal toxicity that causes hypokalemia and hypomagnesemia.

Question 6

What are the signs and symptoms of Measles infection?

Answer 6

Cough, Coryza, Conjunctivitis, and Koplik’s Spots

Question 7

What is the presentation of congenital rubella infections?

Answer 7

PDA, Cataracts and Deafness. Blueberry rash is also possible.

Question 8

What congenital deficiency can lead to increased risk of mycobacterial infections?

Answer 8

INF (specially gamma) deficiencies.

Question 9

What are the side effects of protease inhibitors?

Answer 9

Hyperglycemia, Lipodystrophy (Inc. truncal fat, Dec. peripheral) P-450 inhibitors

Question 10

What is the only DNA hepatitis virus?

Answer 10

Heb B, it’s genome integrates into host genome. It uses a template +RNA for replication.

Question 11

Which hepatitis virus is most often seen in IV drug users?

Answer 11

Hep C

Question 12

What is the treatment for toxoplasma?

Answer 12

Sulfadiazine & Pyrimethamine

Question 13

What is the first line treatment against bacteriodes?

Answer 13

Penicillin G is it has not beta lactamase, if it does use one of the lactmase inhibitor combinations.

Question 14

What are is the major side effect of Daptomycin?

Answer 14

Myopathy and elevation of Creatine Kinase (CPK)

Question 15

What are the features of Endotoxin? Particularly Lipid A, found on gram negatives.

Answer 15

Edema
Nitric oxide
Dic/Death
Outer membrane
TNF-alpha activator
O-antigen
eXtremely heat stable
IL-1
Neutrophil chemotaxis

Question 16

What are the two types of toxin that inhibit protein synthesis? Give examples.

Answer 16

Exotoxin A (P. Aeruginosa) and Diphtheria toxin inhibit EF-2. Shiga toxin and Shiga-like toxin remove adenine from 60S rRNA.

Question 17

Which antibiotic is associated with Serotonin Syndrome?

Answer 17

Linezolid is a slight MOA inhibitor.

Question 18

Which cranial nerve is most likely injured in an uncial herniation?

Answer 18

CN III

Question 19

How can you distinguish MAI/MAC from TB?

Answer 19

MAC/MAI grows better at 41C temp.

Question 20

Which picornavirus cannot colonize the GI because it is acid-labile?

Answer 20

Rhinovirus. All the other ones (Coxsackie A, Echovirus, Polio & HAV) can colonize the GI.

Question 21

What are the three characteristics of HEV?

Answer 21

Epidemic
Expecting mothers
Enteric

Question 22

What makes listeria so virulent?

Answer 22

Tumbling motility at 22C. Growth as low as 4C. Listeriolysin O which allow it to escape phagosomes and live intracellularly.

Question 23

What likely causes loss of vision in HIV patients? What is used to treat it?

Answer 23

CMV can be eradicated with Gancyclovir (first line) & Foscarnet (second line or first line if taking zidovudine)

Question 24

To what does Strep Viridans bind in order to cause endocarditis?

Answer 24

The bacteria produces dextran from sucrose that they use to bind to fibrin. So valvular damage is required.

Question 25

What is responsible for the green color of pus on bacterial infections?

Answer 25

Myeloperoxidase. Heme base molecule within the granules of neutrophils that catalyzes the synthesis of HOCl for respiratory burst.

Question 26

Describe the initial presentation of acute HBV infection.

Answer 26

Serum-sickness like illness. (malaise, fever, urticaria, pruritus, LAD and joint pain) The ALT and AST elevation come after.

Question 27

What is the treatment for S. Epidermidis infection of devices?

Answer 27

Vancomycin plus either Rifampin or Gentamicin or both.

Question 28

Which viral families have segmented genomes?

Answer 28

``` "BORA is a bunch of little islands." Bunyavirus = 3 circular ss(-)RNA Orthomyxovirus = 8 linear ss(-)RNA Reovirus = 10 to 12 linear dsDNA Arenavirus = 2 circular ss(-)RNA ```

Question 29

What is the post-exposure prophylaxis treatment for N. Meningitidis?

Answer 29

Rifampin

Question 30

What electrolyte abnormality can be caused by Legionella?

Answer 30

Hyponatremia

Question 31

Which HIV viral gene is most closely related to HAART resistance?

Answer 31

Mutations in pol can give resistance to either protease inhibitors or reverse transcriptase inhibitors.

Question 32

Roseola versus Rubella?

Answer 32

Roseola is caused by HHV-6 and the maculopapular rash starts at the trunk and moves to the head. Rubella has LAD and the rash moves in the opposite direction.

Question 33

What virulence factor allows E Coli to invade?

Answer 33

K-1 capsular antigen. Allows it to cause neonatal meningitis.

Question 34

What allows S. Epidermidis to create biofilms?

Answer 34

Quorum sensing induces synthesis of an extracellular polysaccharide matrix.

Question 35

What histological finding is useful for distinguishing Tropheruma Whippelii?

Answer 35

Deep pink PAS stain of the Glycoprotein Cell Wall. Unlike Glycogen it is Diastase resistant which makes it even more pink than collagen on PAS.

Question 36

Which bacteria is the most commonly transmitted via deco-oral route from animals to humans in industrialized countries?

Answer 36

Campylobacter. (Puppies, Cattle or contaminated food) Remember the association with Guillain-Barré Syndrome.

Question 37

What vaccine contains Polyribosyl-ribitol-phosphate (PRP)?

Answer 37

HiB

Question 38

What are the catalase positive organisms that are commonly seen in Chronic Granulomatous Disease?

Answer 38

``` Staph A. Pseudomonas Serratia Nocardia Aspergillus ```

Question 39

What is a CNS disease that presents YEARS after apparent recovery from a Measles virus infection?

Answer 39

Subacute Sclerosing Encephalitis

Question 40

What is the complication caused by accidental spilling of contents of a hydatid (Echinococcus) cyst?

Answer 40

Anaphylactic Shock

Question 41

Which cytokine is responsible for septic shock?

Answer 41

TNF-alpha

Question 42

Which type of immunodeficiency allows candida infections to become systemic?

Answer 42

Neutropenia. While loss of CD4+ T Cells from HIV can give you thrush or candidiasis it is loss of neutrophils that can turn it into an invasive infection. (ie. Right Sided Endocarditis, Liver or Kidney abscess, Candidemia)

Question 43

What disease can Parvovirus B19 cause on a healthy adult?

Answer 43

Arthritis

Question 44

What are the first anti-psudomonals that should come to mind?

Answer 44

Piperacillin, Ticarcillin, Ceftazidime, Cefepime and much later ciporfloxacin, levofloxacin, or carbapenems

Question 45

What infection in children can be improved by Vitamin A supplementation?

Answer 45

Measles

Question 46

How do bacteria gain aminoglycoside resistance?

Answer 46

Plasmids that code for proteins that change the drug chemically. Acetyl Adenyl or Phosphate.

Question 47

What are the notable toga viruses?

Answer 47

Rubella EEE WEE

Question 48

Dermatologic findings in Syphilis by stage.

Answer 48

``` Primary = Painless Chancre Secondary = Macular rash of palms and soles plus condylomata lata. Latent = Nothing Tertiary = Gumma ```