Clinical Micro - Musculoskeletal

Front 1

In an established bone infection, the local inflammatory response and pus (under pressure) cause impaired blood circulation leading to avascular necrosis of the affected part; thus a _ is formed

Back 1

sequestrum

Front 2

Osteomyelitis infection affecting Sickle cell pts?

Back 2

Salmonella

Front 3

What is the most common microbe causing osteomyelitis in newborns?

Back 3

Group B strep

Front 4

What is the most common microbe causing osteomyelitis following a puncture wound?

Back 4

Pseudomonas

Front 5

A 10-year-old boy who recently migrated from Sri Lanka with his family presents with a bump at the T12-L1 region. He also complaints of severe pain while picking something from the ground. The boy has history of cough and low grade fever for several months. Which of the following is likely involved in this case?

Back 5

M. tuberculosis

Front 6

An adjuvant does which of the following?

Back 6

Increases inflammation regardless of the antigen

Front 7

Viral vectors are used to transmit what type of vaccine?

Back 7

Subunit vaccine

Front 8

Which of the following would be a good example of passive immunization?

Back 8

Injection of antibodies to a bacterial toxin

Front 9

Which of the following would confirm the diagnosis of Enterococcus infection

Back 9

growth on bile esculin agar

Front 10

A 55 year-old man with a titanium knee from previous arthroplasty presents with pain, redness and swelling around the prosthetic joint following lower GI endoscopy. The organism involved in this case very likely is

Back 10

Enterococcus species

Front 11

The synovial fluid aspirate from a painful knee reveals clear and highly viscous fluid. The cell count is 500/mm3 with 30% PMN. The glucose content is nearly equal to the blood glucose level. The patient is suffering from

Back 11

Degenerative arthritis

Front 12

A 28-year-old man presents with swollen, red and tender right knee joint that started about a week ago. The cause of this suspected arthritis is very likely

Back 12

N. gonorrhea

infectious arthritis in sexually active age group

Front 13

Culture of a synovial aspirate grows S. aureus which is Methicillin reseistant. The patient has severe renal impairment that limits the use of Vancomycin. Which of the following would be your preferable choice of medication for this patient?

Back 13

Levofloxacin (quinolone)

Front 14

Sequestrum is formed due to

Back 14

avascular necrosis of the affected part

Front 15

Newborns and infants have most difficulty with what type of vaccine composition?

Back 15

Polysaccharide subunit vaccine

Front 16

Toxoid is what type of vaccine?

Back 16

Subunit Vaccine

Front 17

Most common causative organism for osteomyelitis?

Back 17

staphylococcus

staph aureus
coag (-): staph epidermidis

Front 18

MC agents in osteomyelitis following trauma or surgery?

Back 18

s aureus, group A strep (strep pyogenes)

Front 19

Puncture wound by a dirty nail?

Back 19

Clostridium

Front 20

Bite wound involves what pathogens?

Back 20

Eikenella or Kingella

Front 21

Evidence of osteomyelitis as indicated by _ and _

Back 21

erosion of bone and subperiosteal bone deposition

Front 22

Sequestrum is formed due to

Back 22

AVASCULAR NECROSIS OF THE AFFECTED PART

Front 23

What are the two most common organisms that cause osteomyelitis via hematogenous spread?

Back 23

Staph aurues and strep pneumoniae

Front 24

_ and _ cause hematogoneous osteomyelitis in IV drug abusers

Back 24

Candida and Pseudomonas

Front 25

Eikenella corrodons causes _ osteomyelitis

Back 25

"needle licker"

Front 26

28 yo female presents with pain the pelvic region. She gave birth 3 weeks ago to a baby boy, and states it was a very complicated delivery. Bone scan shows increased radioisotope uptake in the pubic bone. What organisms are likely to cause this? (3)

Back 26

S. aureus, Enterococcus sp, E Coli,

Osteitis pubis - requires a hx of trauma, surgery or complicated delivery.

Front 27

Pt develops a unilateral sacroiliac joint infection. What is the probable organism?

Back 27

Brucella spp

Front 28

Subacute bacterial endocarditis in IV drug abusers is likely to be caused by _

Back 28

Staph epidermidis

Front 29

An urban homeless alcoholic presents with sx of pneumonia. He also has lower back pain and pain in his right arm. MIcroscopy on silver staining reveals.....

Back 29

(extracutaneous) sporthrix


(Rose Gardener’s disease, can also cause pneumonia in urban, alcoholic homeless, osteomyelitis)

Front 30

Budding yeast with wide neck?

budding yeast with a narrow neck

Back 30

blastomycosis

histoplasma

Front 31

Patient has all the clinical features of osteomyelitis. However, you cannot isolate an organism (ie. Brodie's abscess, gaucher's disease, etc). What should you treat with initially

Back 31

Go based off of clinical findings and most commonly encountered organisms. .

Front 32

What would the synovial fluid look like in osteoarthritis?

Back 32

Clear yellow, hgh viscosity, 200-2000 WBCs, 25-50 % PMNs

Front 33

What would the synovial fluid look like in rhuematoid arthritis or gout

Back 33

Translucent yellow or opaque. Low viscosity. 2000-20000 WBC. > 50% PMNs

Front 34

What would the synovial fluid look like in septic arthritis

Back 34

WBC 25000-100000 with predominant PMNs very low glucose. Opaque and yellow or green

Front 35

In olecranon bursitis, pain increases with _
In septic arthritis of elbow, pain increases with _

Back 35

flexion

extension

Front 36

Exfoliatin: disrupt intercellular junctions (intracellular splitting of epidermis between _ and _

Back 36

stratum spinosum and stratum granulosum)

Front 37

Superantigen binds to the _ and to the outer surface of _molecule

It induces a _ response

Back 37

Vb region of TCR

MHC class II

polyclonal T cell response (resulting in a large release of cytokine

Front 38

S aureus obtained penicillin resistance via what mechanism?

Back 38

Conjugation

(Plasmid mediated)

--chromosome mediated coding of beta lactamase
They obtained DNA that encodes for penicillinase.

Front 39

Methicillin targets the _ which is essential for the bacteria to do what

Back 39

PBP peptidoglycan transpeptidase

cross link the peptidoglycan

Front 40

MRSA encodes for a protein that _

It is mediated by _

Back 40

reduces the affinity for the beta lactam antibiotics - changes the shape of PBP

It is plasmid mediated trasdunction!!

Front 41

How does vancomycin work?

Back 41

Directly binds to the amino acid side chain of the peptidoglycan.

Front 42

What organism turns black when grown on bile esculin agar?

Back 42

Enterococcus (E. faecalis, E faecium)

Front 43

Lactose fermenting Enterobacteria

Back 43

e coli, klebsiella

CEEK

Front 44

Non lactose fermenting enterobacteria

Back 44

SHY PS

Shigella, Yersina, Proteus Salmonella

Front 45

Salmonella is a (non/lactose fermenter) and a (non/H2S producer)

Back 45

non lactose

+ H2S producer

Front 46

On radiologic exam, you see osteomyelitis with a gas bubble surrounding it. Immediately, you have narrowed down the possible pathogens to three, what are they?

Back 46

E coli,

bacterioides

Clostridium perfringes

Front 47

What strain of E coli is associated with causing osteomyelitis?

Back 47

Extraintestinal pathogenic E Coli


All others cause gastroenteritis

Front 48

Urease producing pathogens?

Back 48

PUNCH
Proteus
Ureaplasma
Nocardia
Crytococcus
Helicobacter

Front 49

2 organisms that use inactivation of EF2 by ADP ribosylation as their mechanism of pathogenesis?

Back 49

Diptheria and Pseudomonas

Front 50

exotoxin A expression is influenced by _


What organism uses this toxin?

Back 50

O2, temperature and iron regulated genes


This is pseudomonas

Front 51

Lyme Disease is difficult to diagnose after stage _ has passed

Back 51

1

Front 52

The trypomastigote of trypnosomiasis is found where?

What about the amastigote?

Back 52

Human blood

Tissue cells

This is talking about Chagas disease and how it has multiple morphologies depending on where it is located. IMPORTANT for diagnoses! Blood culture shows Trypomastigote with UNDULATING MEMRANE, while tissue biopsy shows circular amastigote

Front 53

Regarding the diagnosis of Chaga's disease:

Blood culture shows _
while tissue biopsy shows _

Back 53

Trypomastigote with UNDULATING MEMRANE,

circular amastigote

Front 54

Gram positive cocci arranged in clusters

Back 54

Staphylococci

Front 55

Gram Positive cocci that Contains ribitol-teichoic acid in wall. Mannitol fermenting

Back 55

S. Aureus

Front 56

gram (+) cocci => catalase (+) => coagulase (-) => Novobiobin Sensitive. OR Non hemolytic growth on blood agar, (-) fermentation on mannitol => Novobiocin sensitive

Back 56

S. epidermidis

Front 57

gram (+) cocci => catalase (+) => coagulase (-) => Novobiobin Resistant. OR Non hemolytic growth on blood agar, (-) fermentation on mannitol => Novobiocin resistant

Back 57

S. saprophyticus

Front 58

Gram positive cocci that grow in chains, alpha hemolytic. What test is next and what are the possible results?

Back 58

Optochin test

Strep Pneumonia is sensitive and Strep viridans are resistant.

You could also do bile test: Pneumonia is (+) and viridans are (-)

Front 59

Dental procedures are often assoicated with what type of infection

Back 59

strep viridans

Front 60

Bile esculin agar (black colonies),

Back 60

Enterococci

Front 61

CT needle aspiration shows gram neg rods --> black colonies on hektoen enteric agar

Back 61

Salmonella

Front 62

Often seen in a sickle cell patient, or patient with a pet reptile

Back 62

Salmonella

Front 63

Salmonella ferments _, and is H2S (producing/non producing)

Back 63

glucose; (+) H2S producing (thus it's black colony on hektoen enteric agar)

Front 64

What are the two possibilities for the colorless colony on Hektoen Enteric Agar?

Back 64

Yersinia or Shigella

Non lactose fermenting, non H2S producing

Front 65

What enterobacteria is highly motile, and looks like a brown film covering the agar?

Back 65

Proteus

Front 66

What are the virulence factors of E coli

Back 66

O antigen (outer membrane), K antigen (capsular), H antigen (flagella

Front 67

A gram negative, lactose fermenting bacteria should be grown on what agar?

Back 67

MacConkey

Front 68

What is the differentiating characteristic of E coli?

Back 68

Indole producing

Gram neg, lactose fermenter --> Indole

Front 69

gram negative rod --> beta hemolysis --> oxidase (+).

Back 69

Pseudomonas


Characteristic because it is a gram negative rod that is oxidase POSITIVE, all others are negative

Front 70

Why is pseudomonas resistant to beta lactams?

Back 70

Mutated porin proteins

Front 71

Who is at particular risk for developing osteomyelitis due to pseudomonas?

Back 71

IVDA and neonates.


Typically, this organism causes infection in CF and burn pts. But with regards to osteomyelitis, Iv drug abusers and neonates are at risk

Front 72

What is the morphology of Kingella Kingae?

Back 72

gram (-) rods with square ends, arranged in pairs or chains.

Front 73

Colonies are 1-2 mm in diameter, pit the agar, smell like bleach

Back 73

E corrodens

Front 74

Mycobacterium tuberculosis grows best on _ agar, and has a characteristic colony morphology:

Back 74

Lowenstein Jensen: granular, waxy pattern of growth

Front 75

Needle licker osteomyelitis:

Back 75

E corrodens

Front 76

What organism has ornithine decarboxylase and lysine decarboxylase

Back 76

E corrodens

Front 77

Gram Negative rod that is beta hemolytic

Back 77

Kingella Kingae

Human bite wounds --> osteomyelitis

Front 78

What is the pathogenesis of the bacteria that contains ribitol teichoic acid?

Back 78

(Staph Aureus)

protein A binds to Fc portion of Ig interfering with opsonization, produce a number of toxins: alpha toxin creates holes, Superantigen producing (bypasses T cell receptor).

Front 79

B. burgdoferi is a _ that causes _.

What is the main vector of transmission?

Back 79

spirochete; Lyme Disease

Ixodes Scapularis - a tick

Front 80

There are 3 stages of Lyme Disease, what are they?

Back 80

3 stages: 1. Acute illness: concentric erythematous rash (bulls eye) 2. Disseminations: CNS and cardiac 3. Late: arthritis, diffuse atrophy of skin, neuropathy (immune)

Front 81

Trichinosis is a _ .

How do humans obtain a trichinilla infection?

What are the two big lab results for diagnosis?

Back 81

nematode (round worm)

eating undercooked meat (that contains the larva, larva hatch in stomach and can get into blood and deposit elsewhere)

Elevated LDH and CK-MM

Front 82

Toxoplamosis is most commonly transmitted by _. What other activity is is associated with?

Back 82

eating undercooked pork

cleaning cat litter box

Front 83

obligate intracellualar sporozoan?

Back 83

Toxoplasma gondii - causes toxoplasmosis which presents similar to mono

Front 84

Patient presents with fever, ST, rash, lymphadenopathy. You have narrowed down the differential diagnosis to Infectious mononucleosis and Toxoplasmosis. What test do you want to run to tell the difference?

Back 84

Heterophile antibody test. If it is (+) then it is caused by EBV and it mononucleosis.

Otherwise, both of these present the same way

Front 85

WHo is the definitive host of toxoplasma?

Back 85

felines

Front 86

How do you diagnose cystercyosis?

Back 86

Proglodditids and eggs are found in stool.

Front 87

Amastigotes in tissue cells is diagnostic for _.

What are other sx?

Back 87

chagas disease

Early - Romana's sign