Micro Yersinia, Francisella, Brucella, And Pasteurella

Front 1

Yersinia, Francisella, brucella, and Pasteurella have what in common?

Back 1

Are gram-negative bacilli; all are zoonotic; are very virulent and are able to penetrate any body area they touch; on skin contact, they are phagocytosed by macrophages, but are facultative intracellular organisms; common treatment is aminoglycoside and/or doxycycline; Pasteurella only applies to the first two premises.

Front 2

Who harbors Yersinia pestis and who is the vector of it as well?

Back 2

Rodents (rats during the Bubonic Plague; squirrels and prairie dogs in the southwestern US) harbor the disease while fleas are the vectors.

Front 3

What are the antigens that enable Yersinia Pestis to resist destruction after phagocytosis?

Back 3

Fraction 1 (F1): allows for survival in phagocytosis and multiplication in phagocytes)

V and W antigens: unknown actions, but are specific to Yersinia pestis

Front 4

What kind of staining pattern does Yersinia pestis have?

Back 4

Bipolar

Front 5

During interepidemic periods, how does one contact Y. pestis?

Back 5

During camping, hunting, or hiking when the person either touches a dead infected rodent or is bitten.

Front 6

Once within the macrophage, what does Y. pestis do?

Back 6

Reproduce intracellularly, move to a nearest lymph node (usually inguinal nodes), leaving the nodes to swell like egg, becoming hot, red, and painful--"buboes." Fever and headaches follow.

Monocytes facilitate hematogenous dissemination of the organisms to the lungs and cause pneumonia. This allows aerosol transmission, resulting in pneumonic plague

Note: not all PTs have swollen lymph nodes

Front 7

As Y. pestis follows course, what happens to the skin?

Back 7

The bacilli invades the bloodstream, liver, lungs, and other organs. Hemorrhages under the skin causes a blackish discoloration.

Endotoxin causes DIC

Front 8

Yersinia enterocolitica is related to?

Back 8

E. coli, it infects the colon.

Front 9

Treatment of Y. petsis?

Back 9

Streptomycin and/or doxycycline (as as a prophylactic to those with exposure)

Exposed PTs should be isolated.

Front 10

What causes Tularemia?

Back 10

Francisella tularensis

Front 11

What closely resembles the bubonic plaguqe and must be considered as part of its differential diagnosis?

Back 11

Tularemia

Front 12

How does tularemia infection usually occur by?

Back 12

Infected rabbits, and bites of ticks, lice, and deerflies.

Front 13

Do you perform a culture of Francisella tularensis?

Back 13

No, because it is highly virulent. Nor, should you drain the infected lymph nodes.

Front 14

How do you diagnosis F. tularensis?

Back 14

Skin test (DTH response), serology titers.

Diagnosis is made clinically. This pathogen is not cultured due to high virulence.

Front 15

How do you diagnosis Y. pestis?

Back 15

Culture of bubo fluid: gram negative bacilli, with bipolar staining resembling safety pins.

Front 16

What is tularemia? What is it a risk for?

Back 16

Site-specific infection of F. tularensis plus lymphadenopathy.

Bioterrorism due to extreme infectivity, ease of dissemination and substantial capacity for causing pneumonitis and death.

Front 17

What are the clinical presentation of tularemia, and what are the two major diseases?

Back 17

Ulceroglandular tularemia: A well-demarcated, "punched out" hole in the skin with a black base develops. Ulcer is erythematous. Fever and systemic symptoms develop. Lymph nodes become swollen, red, and painful (sometimes draining pus)--similar to the plaque, but skin ulcer is usually absent in the plaque.

Pneumonic tularemia: occurs during skinng of infected rabbit.

Can also cause oculoglandular tularemia and typhoidal tularemia (GI tract)

Front 18

After being bite from the vector (ticks, deerfly lice, mites) from an infected rabbit, how does ulceroglandular tularemia present itself?

Back 18

Well-demarcated hole in the skin with black base develops. Fever, with systemic symptoms develop, and local lymph nodes swell, become red and painful. F. tularensis may spread to blood and other organs by monocytes. Hematogenous spread results in pneumonia (as in pneumonic plaque)

Front 19

How does pneumonic tularemia occur?

Back 19

Aerosolization of F. tularensis occurs during skinning and evisceration of an infected rabbit or hematogenous spread from skin (ulceroglandular tularemia) to the lungs.

Front 20

How do you diagnosis Brucella?

Back 20

Bone marrow or blood culture: Gram --, coccobacilli, facultative intracellular, skin test (DTH response)(indicates current OR previous exposure)

Front 21

What is the treatment of F. tularensis?

Back 21

Streptomycin.

Alternatives: gentamicin or doxycycline

Front 22

How is Brucella named?

Back 22

Based on the species that they infect: melitensis (goats), abortus (causes abortions in cows), suis (pigs), and canis (dogs)

Front 23

How will you most likely encounter a PT with Brucellosis?

Back 23

Worker in a meat-packing industry (beef), a veterinarian, farmer, or traveler consuming unpasteurized diary (cow or goat) products outside of the US (Rare in US because cattle are immunized and milk is pasteurized).

Also, those handling placentas, discharges, and fetuses from aborted animals.

Front 24

Like Francisella tularensis, and Yersinia pestis, Brucella also penetrates the skin, conjuctiva, lungs, and GI tract; however, does it also cause buboes or primary skin ulcers?

Back 24

Nope

Penetration is followed by lymphatic spread, facultative intracellular growth in macrophages, and blood and organ invasion (liver, spleen, bones, kidneys, lymph nodes, heart valves, nervous system, and testes).

Front 25

How is the fever associated with Brucella? What else is associated with Brucella?

Back 25

Undulant fever: fever peaks in the evening and slowly returns to normal by morning.

LPS, with cytokines IL-1 and TNF causing weight loss.

Osteoarticular complications (particularly the sacroiliac joint).

Sometimes can last for months to years, but rarely fatal.

Front 26

How do you treat Brucella?

Back 26

Doxycycline + one other drug (gentamicin, streptomycin, or rifampin)

Front 27

Is Pasteurella multocida a facultative intracellular organism?

Back 27

It is not.

Front 28

What does P. multocida colonize?

Back 28

Colonizes the mouth of cats, the same way Streptoccoccus viridans colonizes the human nasopharynx.

Front 29

If a PT is bitten by a dog or a cat, what should you NOT do and why?

Back 29

You should not close the wound with sutures, because this will become a pleasant environment for P. multocida growth, resulting in local invasion of joints and bones.

Front 30

How do you treat P. multocida?

Back 30

Penicillin G or doxycycline

Front 31

How do you diagnosis P. multocida?

Back 31

Gram -- coccobacilli, with bipolar staining.

Front 32

What is the clinical presentation of P. multocida?

Back 32

Cellulitis, osteomyelitis (if the cat's teeth directly implants bacteria in the periosteum), tenosynovitis (into the tendon sheath) and can progress to septicemia

Front 33

How can Francisella tularenisis be confused as the plaque?

Back 33

Because of bubo (suppurative lymphadenopathy), and following hematogenous dissemination, and subsequent pneumonia.

Unlike the plaque though, secondary cases of P2P transmission of pneumonic tularemia rarely occurs.