USMLE Bacteria

Question 1

Glycocalyx - use?

Answer 1

Adherence onto foreign surfaces, loosely organized polysaccharides

Question 2

Microbes that don’t stain well?

Answer 2

Treponema (too thin)
Mycobacteria (high lipid content in cell wall)
Mycoplasma (no cell wall)
Legionella (IC)
Rickettsia (IC)
Chlamydia (IC)
"These Microbes May Lack Real Colour"

Question 3

Giemsa stain

Answer 3

Chlamydia (certain)
Borrelia (bugs)
Rickettsia (really)
Trypanosomes (try my)
Plasmodium (patience)

Question 4

Obligate intracellular microbes

Answer 4

Really CHilly and COld
Rickettsia
Chlamydia
Coxiella

Question 5

Facultative intracellular microbes

Answer 5

FRANCIS “NEISS”LY invited LISTER to the LEGION in YERSINIA for MY SALMON and BRUCELL sprouts

Salmonella
Neisseria
Brucella
Mycobacterium
Listeria
Francisella
Legionella
Yersinia

Some Nasty Bugs May Live FacultativeLY

Question 6

Urease-positive organisms

Answer 6

yoUR SAPpy PRO boNO KLEB is an EPIc HPoCRYPT.

Cryptococcus
H. pylori
Proteus
Ureaplasma
Nocardia
Klebsiella
Saprophyticus
S. Epidermis

CHuck Norris hates PUNKSS

Question 7

Encapsulated organisms

Answer 7

SHiNE SKiS

Strep Pneumo
Haemophilus Influenza B
Neisseria
E. Coli

Salmonella
Klebsiella (i)
Strep (Group B)

Question 8

Catalase positive organisms

Answer 8

Cat positively said “NO, PSEUDOwoodo, ASPER CANDIDlE LISTed a SERRATed STAPH

Nocardia
Pseudomonas
Aspergillus
Candida
E Coli
Listeria
Serratia
Staph

Question 9

High neutrophil content with intracellular organisms. Microbe?

Answer 9

N. gonorrhea

Question 10

If everyone was vaccinated with recombinant HbsAg, what disease would be eliminated?

Answer 10

Delta agent infection

Question 11

What diseases are caused by Staph A exotoxin?

Answer 11

Scalded skin syndrome
Toxic shock syndrome
Gastroenteritis

Question 12

Febrile maculopapular rash that starts on the face and spreads to the trunk and extremities with postauricular LAD points towards?

Answer 12

Rubella, caused by togavirus

Question 13

What do you use to treat a C Diff infection?

Answer 13

Oral metronidazole, vancomycin, fidaxomicin

Question 14

What do you use to prophylax vs C Diff?

Answer 14

Fidaxomicin

Question 15

What do you use to treat toxoplasmosis?

Answer 15

Pyrimethamine and sulfadiazine

Question 16

Person returns from trip with many white spots on tanned skin…dx and pathologic agent?

Answer 16

Pityriasis versicolor from malassezia furfur

Question 17

What predisposes a person to a cholera infection?

Answer 17

Achlorhydria (from, for e.g., omeprazole tx, b/c cholera is acid sensitive)

Question 18

What does H.Flu need to grow in media?

Answer 18

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

Question 19

Hx of viral esophagitis and pneumocystis pneumonia = ?

Answer 19

HIV

Question 20

CNS infection in HIV patient is most likely caused by?

Answer 20

Cryptococcus neoformans

Question 21

How do you dx a cryptococcus neoformans brain infection?

Answer 21

Positive latex agglutination of CSF

Question 22

Headache, retro-orbital pain, high-grade fever, joint and muscle pains w/ epistaxis. Dx?

Answer 22

Dengue fever

Question 23

What has a similar transmission to dengue fever?

Answer 23

Chikungunya fever

Question 24

Spherules that contain endospores with fever, mild tachy, lung auscultation. Dx and region?

Answer 24

C. immitis in Arizona

Question 25

The presence of ____ would prevent death from Diptheria infection?

Answer 25

IgG against circulating proteins

Question 26

What virus replicates by generating several functional viral proteins from a single, large, virally coded precursor polypeptide?

Answer 26

Echovirus

Question 27

What part of a RNA virus determines its ability to infect humans?

Answer 27

Surface glycoprotein

Question 28

What is the main source of rabies in the USA?

Answer 28

Bats

Question 29

Restlessness, agitation, dysphagia progressing to coma within weeks of exploring a bat cave = suspect?

Answer 29

Rabies

Question 30

What kind of vaccine is used for rabies?

Answer 30

Various inactivated rhabdovirus strains

Question 31

Where is the primary bodily site for cryptococcus neoformans and where is it found?

Answer 31

Lungs; soil & pigeon droppings

Question 32

Gram positive rod with tumbling motility at room temperature. Microbe?

Answer 32

Listeria

Question 33

Infection with what microbe results in the formation of cold agglutinins?

Answer 33

Mycoplasma pneumoniae | EBV, too

Question 34

What is the major virulence factor for S. pneumo?

Answer 34

Polysaccharide capsule

Question 35

Ab against Polyribosyl-ribitol-phosphate (PRP) protects against what microbe?

Answer 35

H. influenzae type B

Question 36

What prevents infection with oral inoculation with C. diff?

Answer 36

Intestinal biomass prevents overgrowth of C Diff.

Question 37

What diseases do you think of from the Northeast USA?

Answer 37

Babesiosis, Lyme disease, both by Ixodes tick

Question 38

Immunosuppressed patient with fever, chills, multiple skin patches with ulcerated appearance, and occasional necrotic center. Dx and microbe?

Answer 38

Ecthyma gangrenosum, pseudomonas

Question 39

What is the essential pathogenic mechanism for Shigella?

Answer 39

Mucosal invasion (NOT SHIGA TOXIN)

Question 40

What do you use to prevent perinatal transmission of HIV?

Answer 40

Viral enzyme inhibitor drug (zidovudine, (ZDV, AZT))

Question 41

What is the cause of positive monospot with heterophile antibody-negative mononucleosis-like syndrome?

Answer 41

CMV

Question 42

Sputum cultures grow budding yeast that form germ tubes at 37C. Dx?

Answer 42

Candida albicans

Question 43

What might you see after impetigo infection?

Answer 43

Glomerulonephritis (more common than rheumatic fever!)

Question 44

What kind of vaccine is the vaccine for rubella?

Answer 44

In the MMR, live attenuated vaccine

Question 45

What viruses are capable of genetic shifts through reassortment?

Answer 45

Rotaviruses, orthomyxoviruses.

Question 46

What is the most common cause of aseptic meningitis?

Answer 46

Enterovirus (fecal oral route transmission)

Question 47

Patient from central/South America presents with achalasia. Suspect?

Answer 47

Trypanosoma cruzi

Question 48

Spherule filled with endospores - suspect?

Answer 48

Coccidioidomycosis

Question 49

How do you prophylax vs M. avium?

Answer 49

Azithromycin

Question 50

CD4 count > 50 prophylaxis?

Answer 50

TMP-SMX vs pneumocystis pneumonia and toxoplasmosis

Question 51

CD4 count

Answer 51

Azithro/clarithromycin vs M. avium complex

Question 52

Prevention of postsurgical infxn due to S. aureus?

Answer 52

Cefazolin

Question 53

Exposure to meningococcal infection prophylaxis?

Answer 53

Ceftriaxone, ciprofloxacin, rifampin

Question 54

Prophylaxis of strep pharyngitis in child with prior rheumatic fever?

Answer 54

Benzathine penicillin G

Question 55

PYR+?

Answer 55

S. pyogenes

Question 56

Hippurate test +?

Answer 56

GBS (S. agalactiae)

Question 57

The only bacteria with a polypeptide capsule?

Answer 57

B. anthracis

Question 58

G+ that produces endotoxin?

Answer 58

Listeria monocytogenes

Question 59

All replication of DNA viruses are in the _____ except ____.

Answer 59

Nucleus, poxvirus

Question 60

All replication of RNA viruses are in the ______ except ______.

Answer 60

Cytoplasm, retrovirus, influenza

Question 61

Where does herpesvirus get its membrane?

Answer 61

Nuclear membrane

Question 62

Calf myalgias in surfers in tropics. Dx and source?

Answer 62

Leptospirosis, water w/ animal urine

Question 63

What is the natural reservoir of Borrelia burgdorferi?

Answer 63

Mouse

Question 64

Broad based ataxia, Charcot joints, + Romberg sign, stroke w/out HTN

Answer 64

3 syphilis

Question 65

Spiking fevers, HSM, pancytopenia. Dx?

Answer 65

Visceral leishmania