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MICROBIOLOGY PART 1 303 > Spirochaetes > Flashcards

Spirochaetes Flashcards

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Biology 101 flashcards
1
Q

Features of spirochaetes

A 
Very unusual bacteria:
Gram-negative
Very thin- viewed by dark-field microscopy or EM
-Spiral shape
Varied genome size
Many plasmids (large)
Virulence factors poorly understood
Unique method of motility via internal flagella
Anaerobic
Slow growing
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2
Q

How to diagnose spirochaetes via a lab?

A

Relies on serological or immunofluoresence tests

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3
Q

Spirochaete taxonomy?

A

Recognised by cell shape

Identification by sequence analysis of 16s rRNA gene

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4
Q

What makes spirochaetes different?

A

Internal flagella = axial filaments

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5
Q

What occurs when deletion of flagella assembly genes occurs?

A

Aflagellate non-motile strains
No longer corkscrew like = straight rod shaped cells
Occurs for Treponema denticola and Borrelia burgdoferei

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6
Q

How to spirochaetes swim?

A

Counter-rotation of the internal flagella filament bundles = rotation of cell body = burrowing motility of spirochaetes

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7
Q

What is located on the spirochaete cell surface?

A

Cell wall components = can modulate immune response, known as major sheath proteins
No LPS - glycolipids

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8
Q

What diseases can spirochaetes cause?

A 
Leptospira = Weils disease
Borrelia = Lyme disease, relapsing fever
Treponema = ANUG, periodontitis
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9
Q

Zoonotic infections examples?

What do zoonotic infecs have?

A

Lyme and Weil’s disease

Have an animal reservoir of infec that can under certain circumstances infect humans via a zoonotic vector

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10
Q

Lyme disease cause?

A

Caused by Borrelia burgdoferi and related sub-species

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11
Q

Features of lyme disease?

A

Most common zoonootic bacterial infec in europe

Nutritionally fastidious anaerobe

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12
Q

Zoonotic reservoir?

A

Transmission via lxodes spp. ticks
Ectoparasites of many vertebrate species; rodents, deer, birds
3 life-cycle stages;
- Fed once in each stage; 3-5 days per feed
Bac live and multiply in midgut of ticks
Transmitted via saliva after biting humans

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13
Q

Stages of infec - acute of lyme disease?

A

Flu-like symptoms
Localised rash
Bulls-eye rash

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14
Q

Stages of infec - later of lyme disease?

A

Seen from 1 week to 2 years post-infection:

  • Neurologic: Meningitis, encephalitis, peripheral neuropathy, cranial-nerve (facial) palsies, vision impairment (chronic)
  • Cardiac: myocarditis, blockages
  • Athralgia and arthiritis- may persist for months or years - often debilitating- possible autoimmune component – reactivity to surface proteins (OspA)
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15
Q

What causes the later symptoms?

A

When bac enter sites other than the bloodstream - neurons, joints

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16
Q

Borrelia burgdoferi feautres?

A

Motility considered a major virulence factor
Invades epithelial cells
Capable of invading many tissue types
No LPS, but numerous Outer membrane lipoproteins OspA-D, expressed at different points in infection cycle. Vls proteins- variable suface proteins- antigenic shift
DbpA- Decorin binding protein, host mimicry?
Copes with low-iron levels by using Manganese instead of iron as an enzyme co-factor

17
Q

How to prevent lyme disease?

A

Antibiotics - doxycycline - chronic infecs hard to treat since bac metabolically inert and resides in sites refractory to treatment

Vaccine - to OspA only partly effective (OspA expressed in tick, not humans)

Prevention - avoid endemic areas, clothing, DEEP based repellants

18
Q

Relapsing fever?

A

Borrelia recurrentis
Transmitted via ticks and human body louse
Repeated febrile illness
Initial infection cleared, but antigenic variation by the bacterium starts a new set of symptoms
3-10 episodes
Can infect liver/ spleen

19
Q

How could it relapse?

A

Antigenic variation- surface protein OspC multiple copies- expressed variably in recurring infecitons

20
Q

How to prevent and control relapse?

A

CDC; check for mice/rodents

21
Q

Leptospirosis and Weils disease?

A 
Caused by Leptospira interrogans
- Leptos (Gr) – ununusually thin spira (la) -   colied, spiral
Two terminal Periplasmic flagella
Present in stagnant water and rivers
Infects many mammals
Dogs and Rats most important zoonotic reservoir (urine)
Enter via broken skin
40- 60 cases/ year in England
Outbreaks in walkers, triathlon runners!
22
Q

Symptoms of leptospirosis (weils disease)?

A

1-2 week incubation in blood
Leptospirosis: Febrile, flu-like illness with muscle pain, reddening of eyes, and other symptoms such as diarhoea and in some cases meningitis and Hemorrhage in Aqueous humour of eye and CSF

23
Q

What does weil’s disease cause?

A

Kidney failure, jaundice and liver failure

Most symptoms due to BV damage

24
Q

How to prevent and treat leptospirosis?

A

Rodent controlled
Doxycline
Avoid swimming in infected rivers

25
Q

What spirohoates cause issues in the mouth? Treatment?

A

Treponema vincentii = acute necrotising ulcerative gingivitis
Treatment = metronidazole or H202 washes

26
Q

What organisms are commonly found in periodontal cases?

A

Treponema denticola
Red complex organisms - (Porphyromonas gingivalis
Tannerella forsythia, Treponema denticola)

27
Q

Treponema denticola: virulence?

A

Adherence to basement membrane proteins via 53 Kda Msp : fibronectin, laminin, fibrinogen, type IV collagen and gelatin

Proteases: in-keeping with other periodontal pathogens
CTLP- Chymotrypsin like Protease (Dentilisin), surface exposed in outer membrane: Cleaves transferrin, fibrinogen, fibronectin, IgA, IgG, gelatin
Sialidases:- cleaves surface sialic acid from human cells/ saliva- mutant reduced infection in mice
Motility: tissue invasion and disease progression
Co-adherence with other oral bacteria in mixed biofilm also important (i.e. Pg, Tf, and Fuso’s)

28
Q

Syphilis: Treponema pallidum treatment?

A

Treatment with mercury

29
Q

Name other treponemal diseases and their features

A 
Yaws: T. pertenue 
- early skin lesions that clear
- later destructive lymph
- south america and central africa
Pinta: T. carateum 
- again early skin lesions
- these progress to chronic disfiguring lesions over time
- south and central america
30
Q

How are treponemal diseases spread?

A

Skin to skin transmission

31
Q

How to treat treponemal diseases?

A

Treatable with penicillin

MICROBIOLOGY PART 1 303 (12 decks)

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