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Bact > Test 2- Brucella > Flashcards

Test 2- Brucella Flashcards

1
Q

Brucella

A

 Gram–

 Small

 Non-motile

 Coccobacilli

 Culture: +

 Obligate symbiotic, resistent

 Obligate pathogen

 Facultative intracellular

 Reportable disease

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2
Q

Species

  • Species
A
  • B. melitensis, several animal species, mainly goat and sheep
  • B. abortus, cattle
  • B. suis, swine (hare, reindeer, caribou)
  • B. canis, Dog
  • etc
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3
Q

All of the brucella species have…

A

a high genetic homology, which makes it difficut to distinguish

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4
Q

International epidemiological context

A

 B. melitensis: principal cause of human brucellosis  No vaccines

 Many countries eliminated B. abortus from cattle

 Wildlife reservoirs, including marine-

 B. melitensis: principal cause of human brucellosis  No vaccines

 Many countries eliminated B. abortus from cattle

 Wildlife reservoirs, including marine This is why it has been very hard to get rid of

 Falsepositiveserology(Y.enterocoliticaO9)

 Facultative intracellular: carriers

 Spread mainly by females animals  Abortion

 Fetus and especially placenta contains a huge amount of bacteria

 Can spread via dogs and horses

 False positive serology(Y.enterocoliticaO9)

 Facultative intracellular: carriers

 Spread mainly by females animals

 Abortion- the aborted fetus is full of brucella

 Fetus and especially placenta contains a huge amount of bacteria

 Can spread via dogs and horses

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5
Q

Brucella abortus

Symptoms:

A

Infection
 Mucosae

 Oral
 Wounds (upon handling contaminated meat)

Spread to regional lymphonodus

Further spread to other lymphonods, where it is safe from the immune system and then it goes to the TARGET ORGANS- only when it is in the target organs then the serology will be positive)

No symptoms- spread is via intracellular in macrophages– 1 to 6 weeks Incubation period

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6
Q

Brucella abortus

Pathogenesis

Target organs

A

 Target organs

 Reproductive organs

 Uterus-fetus

 Udder
 Male reproductive organs

 Articulations

 Tendon sheath

 Synovial bursa

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7
Q

Brucella abortus

Pathogenesis: Uterus + fetus

A

 Placentoma & multiplication- Excretion and spread to bovines humans

 Fetus & multiplication-

Abortion
Premature birth
Normal partution but calf is carrier

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8
Q

Pathogenesis: Udder

A

 Subclinical mastitis

 Excretion and spread

Diagnosis on milk samples

———– Antibodies

———–antigens

 Farm status

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9
Q

Symptoms (human infection)

A

 Acute bacteremic phase

 Chronic phase (can take many years)

 Intermittent fever
 Duration: 3-4 weeks
 A febrile period:3-4weeks

 Long term
 Weakness

 Malaise
 Headache
 Jointandmusclepains
 Enlargedlymphonodus
 Enlargedliverandspleen  Eventuallyosteomyelitis

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10
Q

Virulence

A

 No capsule

 No flagella (genetic code deficient)

 Cell wall

Smooth colonies (Higher virulence )

———- Zoonotic more important species B.melitensis,B.abortus,B.suis

————- Not a stable phenotype, dissociation to R (mixed) (unfavorable growth conditions)

—————B. ovis and B. canis

————-Lacking the O-polysaccharide

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11
Q

What is different about the cell wall of brucella?

A

 Cell wall (cont.)

 Thicker PG than other Gr-

 Erythritol
 Responsible for preferential location

 Reproductive organs

 Mammary gland

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12
Q

Immunity

A

 Antibodies
——--Come late

 Cellular immunity

———-Early

Note
Facultative intracellular
Spread intracellular
Only when in organs antibodies are formed

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13
Q

Carriers

A

When cellular Immunity is not capable of killing all intracellular bacteria

———– Bacteria are intracellular
When immunity goes down (Pregnancy)

Bacteria

  • ——– Start multiplication
  • ———-are released from the cells

———–Abortion or transfer to fetus

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14
Q

Vaccination

A

 Need for both humoral and cellular immunity

———- AroC mutants and DnaK mutants

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15
Q

Diagnosis

A

 SAW or SAT: Slow Agglutination Test or Slow Agglutination of Wright.

 Rose Bengal test simple, rapid slide-type agglutination assay, stained B. abortus suspension and plain serum

 CFT- Complement fixation test

 ELISA

 IFN-γ-

 Skin test

 Bacteriology

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16
Q

How to grow B. abortus

A

B. abortus

 Primary growth needs 10-20% CO2

 B. abortus and B. suis produce H2S

 Primary isolation: 4-7 days

 Monoclonal antibodies

 Farrell’s medium/ modified Thayer-Martin’s medium

 Chocolate agar, horse blood (nicotinamide adenine dinucleotide (NAD))

 eventually supplemented with Gr+ spectrum antibiotics and colistin if sample is contaminated like in abortions. Care what species (≠ susceptibility)

 Specific commercial agars (eg. Brucella agar)

17
Q

Brucellosis CMI Skin Test

A

Brucellergen (Skin) Test

  • not an OIE recommended test
  • often slight positive skin reactions - herd test
  • not widely used- very hard to read

•EU regulation
(Proposed by the Scientific Committee)

  • in the context of False Positive Serological Reactions
  • discriminating method between FPSR and True Positive
18
Q

Brucellosis CMI- IFN- gamma

A
  • intrinsic values not known
  • control possible, without any delay - complementary to serology
  • costly
  • need of culture

—— blood test

19
Q

Diagnosis

A

 Test strategy should be adapted to the countries plan for elimination of the agent

 Note that there is a major interference when Yersinia enterocolitica O9 is present

 Note that also B. suis can give false positive infections (contact wild boars)

 Transient positive serology

20
Q

Brucella suis

A

 Small non-motile Gram-negative coccobacilli

 Needs enriched media for growth

 Obligate symbiotic

 Obligate pathogenic

 Resistant in the environment (in organic material) but does not withstand direct sunlight

- REPORTABLE

 Eradicated in domesticated swine (including US, Canada, most EU countries)

 Still present in wildlife

21
Q

Reservoir for b. suis

A

wild boar (Sus scrofa scrofa)

Care: hunters!

22
Q

B. suis General
 5 biovars (based on biochemical testing)

A

5 biovars (based on biochemical testing)

 Biovar1 and 2:
 (reservoir in hares)

 Biovar3:

Most pathogenic for pigs

Biovar4:

 mainly in reindeer, caribou

 Less pathogenic for pigs (seldom found)

Biovar5:

 Brucellosis in mice

 Genetically closer to the marine Brucella species

 VariousB. suis biovarshavebeen reportedoccasionally in cattle, small ruminants, horses, dogs and other spillov er hosts

1-3 Biovars are the most pathogenic of pigs

23
Q

Symptoms of B. suis

A

 Reproduction system: abortion, orchitis, infertility

 Arthritis

 Tendovaginitis

 Bursitis

 Osteomyelitis

 Note: swine can be infected with B. abortus, B. melitensis, B. canis but these infections do not result in clinical symptoms- but they can give false positive reactions

 Has been weaponized

 Zoonotic, hunters!

More pathogenic than B. abortus

 Acute infection; duration couple of months

 Temperature raises and falls intermittent

 Sweating
 Chills
 General malaise

 Weakness  Joint pain

 Complications: osteomyelitis  Chronic

 Localisation
 Necrosis and pus

24
Q

Pathogenesis of B. suis

A

 Introduction  Skin

 M ucosae

 XXX

 1. regional lymph nodes (in leucocytes)

 2. bacteremia after 1-7 weeks (in macrophages and neutrophils), duration 1 wk- 34 mths (mean 5 wks)

 3. localization with abscess formation  Lymphnodes

 Reproductiveorgans  Liver
 Spleen
 joints

25
Q

Immunity to B. suis

A

 Humoral

 Cellular +++ (facultative IC)

 However, carriers

 In macrophages
 Insufficiently activated MF
 Not destroyed by cytotoxic T-lc

26
Q

Diagnosis Brucellosis in wild boar, serology

A

 Care

 Contact with bovines: B. abortus

 Yersinia enterocolitica O9

 Brucella suis, wild boars

 Serological tests only of value at farm level

 Many cross reactions:

 Y. enterocolitica O9 (and others)

 Francisella

 Campylobacter

 Salmonella

 Pasteurella

 E. coli O157

27
Q

Brucella melitensis Brucella ovis

A

 Sheep and goat

 Similar to B. abortus in bovines

 Mainly in subtropical and Mediterranean countries (Malta fever)

 B. melitensis, zoonotic: worse than B. abortus (Malta fever)

 B. ovis: not zoonotic

28
Q

Brucella canis

A

 Need rich media for growth

 Primary isolation up to 4 weeks!

 Do not have O antigens

 Obligate parasitic

 Obligate pathogen

 Resistant in the environment in organic material

 Zoonotic

29
Q

Symptoms of Brucella canis

A

 Long bacteremia, no fever!

 Lymphadenitis

 Late abortion

 Vaginal discharge

 Epididymitis

 Scrotum dermatitis

 Atrophia testicularis

 Prostatitis

 STD

30
Q

Dx and treatment of Brucella canis

A

 Diagnosis
 Bacteriology

 Serology
 Care: many false positive and false negative results

Treatment

 Difficult

 Long antibiotic treatment

 Frequent recurrences after stop of treatment (IC)

 Consider euthanasia (zoonosis!)

Bact (34 decks)

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