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RUSVM Bacteriology Gram Negatives > Francisella > Flashcards

Flashcards in Francisella Deck (51):
1

What family does Genus Francisella belong to?

Family Francisellaceae (Gammaproteobacteria)

2

What are the three important Francisella species?

F. tularensis F. philomiragia F. noatunensis

3

Francisella Gram _____? Shape?

Gram Negative, small, pleomorphic

4

Francisella Motile/Non-motile?

Non-motile

5

Francisella Oxidase Pos/Neg?

Oxidase negative

6

Francisella Catalase Pos/Neg?

Weakly catalase positive

7

Francisella Aerobe/Non-aerobe?

Obligatory aerobic

8

Francisella Spore/Non-spore forming?

Do NOT produce spores

9

Francisella Is this a fastidious organism? (requires special nutrition to grow)

EXTREMELY FASTIDIOUS!! Glucose-Cysteine blood agar necessary

10

Francisella tularensis

Highly infectious Causes Tularemia REPORTABLE Affects very wide range of species Several different subspecies

11

What are common names for Tularemia?

Rabbit Fever Deer-fly fever Lemming Fever

12

What is the disease also known as Rabbit Fever, Deer-fly fever and Lemming fever?

Tularemia, caused by F. tularensis

13

F. noatunensis

Emergent aquatic animal pathogen

14

Francisella tularensis Pathogenicity and geographical distribution

Most important human pathogens: F. tularensis subsp. tularensis. North America. TYPE A F. tularensis subsp. holarctica. Europe. TYPE B

15

F tularensis subsp. tularensis

Potential Bioweapon! Extreme virulence Low infectious dose Easy aerosol dissemination Severe illness and death 10 CFUs inhaled can cause disease 30-60% untreated infections can be fatal

16

Francisella Virulence factors

Capsule - Mannose Cell wall - LPS Acp - Acid phosphatase Pathogenicity Island

17

What does Mannose on a capsule do?

Mannose receptors in phagocytes Want to be phagocytized by naive-macrophages

18

Francisella Role of Acp

Acid phosphatase Suppresses respiratory burst of phagocytes

19

Francisella Pathogenicity Island Name the components

igl (Intracellular growth locus) Mgl (Macrophage growth locus) Pdp (Pathogenicity determinant proteins)

20

Francisella Products of igl

Intracellular survival in phagocytes T6SS Iron uptake

21

Francisella Mgl role

Many functions Regulatory of igl

22

Francisella Pdp role

Pathogenicity determinant proteins Intracellular survival in phagocytes Virulence

23

Francisella Reservoir

Infected lagomorphs, rodents, amoebae

24

Francisella Transmission

Mainly by *ticks*, mosquitos, deer fly Water Prey Humans- percutaneous, conjunctival, inhalation, ingestion

25

Which tick species transmit Francisella?

Dermacentor variabilis Dermacentor andersoni Amblyomma americanum

26

Name the six forms of Tularemia

**Depends on mode of transmission** *Ulceroglandular* from arthropod vector Oculoglandular Pneumonic Oropharyngeal Gastrointestinal Typhoidal

27

Tularemia presentation in different species

Wide variety of presentations in humans Cats**Most frequent domestic animal Sheep/Horse/Young pigs Dogs fairly resistant

28

Name/describe this lesion

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Ulcer caused by Francisella tularensis on the hand "Ulceroglandular"

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29

Name/describe this lesion

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Oculoglandular tularemia in human

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30

Ulceroglandular tularemia

80% of cases Often from tick bite

31

Pulmonary & Oropharyngeal/Gastrointestinal tularemia

Acquired via inhalation Oral exposure - Water or meat Most dangerous of all (40-60% case fatality)

32

Clinical signs of Tularemia in humans

Depends on mode of infection High fever, headache, signs of toxicity (myalgia, anorexia, prostration) for several days Pneumonia with non-productive cough Liver damage- elevated liver transaminases

33

Francisella Pathogenesis

Infectious event--> Local phagocyte population, uptake, survival and multiplication, survive complement & colonize regional lymph nodes--> Granulomatous inflammation (intracell survival, Mgl, igl, T6SS, apoptosis & necrosis of phagocytes & infection of other cells

34

Francisella Pathology

Irregular microabscesses Pyogranulomatous inflammation (liver, spleen, lymph nodes, necrotizing pneumonia) Highly cytotoxic (damage to inflammatory & parenchymal cells) Local lesions - walled granulomatous structures with central necrosis - Often suggestive of necrosis

35

Francisella Case Report

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Non-human primates in a zoo

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36

Francisella Case Report

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Prairie dog in Texas - Francisellosis

37

Francisella Pathogenesis

Intracellular survival*** Evade phagocytes Macrophage=primary target Eventual host cell death, moves on to neighboring cells

38

Francisella Immunological aspects

Largely Cell Mediated Immunity Live attenuated vaccines for at-risk populations

39

Francisella Lab diagnosis Stain used for Francisella

Giemsa stain exudates

40

Francisella Lab diagnosis Serology tests used

IFA ELISA Agglutination

41

Francisella Lab diagnosis Culture: Agar used

Glucose-cysteine heart agar Chocolate agar Oxidase Negative Does not grow on MacConkey

42

Francisella Lab diagnosis - all tests used

Giemsa stains Serology Culture In vivo infections Molecular - PCR

43

Francisella Name the agar types

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A- Buffered charcoal yeast extract B-Chocolate agar medium C-Sheep's blood agar D-Cysteine heart agar

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44

Francisella Treatment & Control

Antimicrobials Control Ticks Limit access to water/feed Wildlife population control

45

Francisella Antimicrobial treatment

Facultative intracellular organism Aminoglycosides - Gentamycin & Streptomycin Fluoroquinolones Tetracyclines

46

Francisella Type of aquatic organisms

Warm & Cold water Marine & Fresh water Wild & Cultured fish **Tilapia, cod, hybrid striped bass & others***

47

Francisella Describe disease lesions in aquatics

Granulomatous lesions in spleen & head kidney (hematopoetic)

48

What fish cells do Francisella spp. survive in?

Fish macrophages & monocytes

49

What bacteria caused these lesions?

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Francisellosis in fish

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50

What bacteria caused these lesions?

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Francisellosis in fish

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51

What conditions should Francisella be cultured at?

In vitro temperature growth: 20-30C, NO GROWTH at 15 or 37C