Microbiology

Question 1

What is a septic abortion?

Answer 1

Any type of abortion resulting in infected retained products of conception.

Patients with septic abortion typically have fever, abdominal pain, uterine tenderness, and/or foul smelling vaginal discharge

Question 2

Name the most common causes of septic abortion

Answer 2

Staph Aureus and E. Coli

…Group B strep

Question 3

What is cord factor?

Answer 3

Cord factor is a mycoside found in mycobacterium tuberculosis —> serpentine growth

The presence of cord factor correlates with virulence. It is responsible for inactivating neutrophils, damaging mitochondria, and inducing release of TNF.

Question 4

Symptoms of infant botulism?

Answer 4

Constipation, mild weakness, lethargy and poor feeding

Question 5

Characterize hemolytic uremic syndrome

Answer 5

Microangiopathic hemolytic uremia
Thrombocytopenia
Renal insufficiency

Question 6

Name the test in which the patient’s serum is mixed with cardiolipin, cholesterol and lethicin

Answer 6

Rapid plasma reagin (RPR)

Flocculation (aggregation) suggests the patient’s serum contains antibodies

Question 7

Which fungus contains “spherules packed with endospores”

Answer 7

Coccidioides immitus

Found in SW US

Question 8

What is the major virulence factor for H. Influenzae?

Answer 8

Polyribosylribitol phosphate (PRP): capsule component

Question 9

First line treatment for chlamydia/gonorrhea infections?

Answer 9

Azithromycin/ceftriaxone

Question 10

Other than gas gangrene, what can Clostridium perfringens cause in the GI tract?

Answer 10

Late-onset food poisoning: watery diarrhea and abdominal discomfort

Question 11

What part of the virion life cycle of Hep B requires co-infection with Hep B?

Answer 11

Coating of viral particles

Question 12

Which bacteria requires a notoriously low infectious load to cause problems?

Answer 12

Shigella- as few as 10-500 cells may cause infection

Question 13

Other than blastomycosis, what else appears as “budding yeast?”

Answer 13

Cryptococcus neoformans

Question 14

How does the shiga-like toxin of E.coli have its effect?

Answer 14

Inhibits 60S ribosome

Question 15

People with chronic granulomatous disease have a defect in neutrophil NADPH oxidase required for bacterial killing. What organisms are they susceptible to?

Answer 15

Catalase-positive

Includes: Burkholderia cepacia

Question 16

What is the appearance of histoplasma on light microscopy?

Answer 16

Ovoid bodies within a macrophage- it can survive intracellularly and still cause disease

Question 17

What does disseminated Histoplasmosis look like?

Answer 17

systemic features (fever and weight loss), painful oral ulcers, lymphadenopathy, and heptosplenomegaly

Question 18

What two aspects of the immune system help to clear encapsulated organisms?

Answer 18

Opsonization by compliment/antibody

Spleen

Question 19

Axillary lymphadenopathy is common with which bacterial infection?

Answer 19

Bartonella henselae

It is characterized by low fever, lymphadenopathy and a self-limiting course

Question 20

What type of vaccine is the rabies vaccine?

Answer 20

Inactivated

Question 21

Route of spread of infection of Hep E? Enveloped or unenveloped?

Answer 21

Fecal- oral

It is a naked virus

Question 22

Haemophilus ducreyi causes which venereal disease?

Answer 22

Chancroids- they are usually multiple with deep lesions, base can have a gray to yellow exudate, - they are painful

Question 23

List all of the Herpes viruses

Answer 23

1 and 2- herpes simplex 
3- Varicella/Zoster
4- EBV
5- CMV
6 and 7- Roseola
8- Kaposi

Question 24

What is unique about the h influenza type B capsule?

Answer 24

Type B capsular material consists of a ribosyl and ribitol phosphate polymer called polyribitol phosphate (PRP).

It is the only capsule that contains pentose monosaccharides rather than hexose sugars. This PRP capsule prevents phagocytosis and intracellular killing by neutrophils

Question 25

What is lysogenization?

Answer 25

The process whereby a bacteriophage infects a host bacterium and integrates its genome into the viral genome

Question 26

Path of infection –> meningitis in Neisseria infections?

Answer 26

Pharynx –> blood –> choroid plexus –> meninges

Question 27

Path of infection —> meningitis for H. influenza?

Answer 27

Pharnyx –> lymphatics –> H. influenza

Question 28

Differentiate the two Strep Pneumo vaccines

Answer 28

Pneumococcal polysaccharide vaccine- contains capsular material from 23 different serotypes. Polysaccharides cannot be presented to T cells and therefore produces a T cell independent B cell response that is less effective in the young and elderly
(IgM in adults)

Pneumococcal Conjugate Vaccine- polysaccharides from 13 capsular serotypes conjugated to inactivated diptheria toxoid –> good immunity (IgG in kids)

Question 29

Two ways to treat bacterial vaginosis (gardnerella)?

Answer 29

Metronidazole OR clindamycin

Question 30

Gram stain/shape of bordatella pertussus?

Answer 30

Gram negative cocco bacillli

Question 31

MOA of isoniazid?

Answer 31

Inhibition of mycolic acid synthesis?

Question 32

MOA of rifampin?

Answer 32

Inhibition of bacterial DNA dependent RNA polymeras

Question 33

Describe the gram stain of the causative agent of bacterial vaginosis

Answer 33

Anaerobic gram variable rod

Gardnerella

Question 34

List three drugs we use to treat C. Diff infections

Answer 34

Oral vancomycin, metronidazole or fidoxomicin

Fidoxomicin- macrocyclic antibiotic that inhibits the sigma subunit for RNA polymerase –> bacterocidal.

Question 35

Which antibiotic is used for recurrent C. diff infections?

Answer 35

Fidoxomicin

Question 36

Which is the only pathogenic fungi with a polysaccharide capsule?

Answer 36

Cryptococcus neoformans