Spirochaetes

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Spirochaetes

Phenotypic traits and phylogeny

Gram negative

A typical outer membrane

Penicillin generally has effects on all spirochaetes

Unique - helically shaped

Free living / host associated

Flagella run from pole to pole

Sit between inner and outer membrane

Contract to produce motility

Highly motile

Very different genetically

Very different characteristics

Clinical significance

8 genre , only 4 are clinically relevant

Borrelia

Microaerophilic

Host associated

Pathogen

Transmitted to man and animals by arachnid vector

Zoonotic

Brachyspira

Anaerobic

Consume O2 using NADH oxidase

Some species are pathogenic to man and animals

Leptospira

Obligately aerobic

Include free living saprophytes

Host associated

Pathogen

Infect man and animals

Treponema

Aerobic

Host associated

Some of which are pathogenic to man and animal

Brevinema?

Pathogenic

Isolated from blood and tissues of shrews and mice

Only one species in this genus so far

Leptonema?

Obligately aerobic

Non pathogenic

Only one species in this genus thus far

Isolated from bull urine

Spirochaeta?

Facultative / obligate anaerobes

Free living

Found in aquatic /marine environment

Cristispira?

Observed in digestive tract of bivalves

Commensal

Large

Observed but not yet cultures

Only one species recognised

?

Virulence factors

Koch's postulates

Phenotype under investigation should be associated with pathogenic members of a genus or pathogenic strains of a species

Specific inactivation of genes associated with a suspected virulence trait should lead to measurable loss in pathogenicity or virulence

Reactivation of mutated gene should lead to restoration of pathogenicity

Borrelia

Lyme disease (Borreliosis)

Symptoms

Stage 1

Local inflammation

Red rash

Stage 2

Weeks later

Penetration of blood vessels and dissemination

Brain infection , Arthritis , Heart complications

Stage 3

Years later

Persistent chronic disease

Relapse of arthritis , SKIN DISEASES

Borrelia garinii - brain

B burgdorferi sensu strictu - arthritis

B afzelii - skin

B burroferi sensu lato = all 3

Slide 13?

Tick transmission involves both larval + nymph stages

Ixodes ticks can also carry + transmit other parasites which may cause other coinfection

Virulence factors identified

Decorin-binding proteins A + B, Decorin abundant in ECM

Major outer surface protein C - function not identified

??? slide 17

Interchange between OspA and OspC depending on host

Diagnosis + Treatment

In dogs and horses in UK + worldwide

Diagnosis based on symptoms

History of tick exposure/ tick attached

Positive serology

Detection

Serology

PCR methods developed but not widely used

Treatment

Doxycycline

Amoxicilin

Longer treatment for late stages

Infection in dogs, cats and horses normally doesn't cause clinical disease

Prevention

Drop on pesticide

OspA vaccine available for canines

Leptospira

Leptospira biflexa

Free living saprophytes

Dont cause disease

Leptospira interrogans

Host associated

Pathogen

Transmitted in urine

Rodents are primary hosts

Dogs, deer + ruminants carry and transmit disease as secondary hosts

Common sufferers are Humans, dogs and cattle

Liver + kidney most commonly damaged

Slide 28?

Serological methods allows for typing into ?

Serovars? slide 29

Brachyspira

Several species have potential to cause diarrhoea + retarted growth in animals

Most notably pifs

Swine dysentry is worldwide spread

Charracterised by mucohemmorrhagic colitis + rapid weigh loss

Affected herds often suffer devastating production losses

Caused by proliferation of brachyspira hyodysenteriae

Virulence factors

Flg - flagellar protein

Required for motility + therefore tissue invasive capability

??slide 24

Transmission

Faecal -oral route

Spreads from pig to pig

May be spread by flies, mice, birds and dogs

Less evidence

Some pigs may become carriers

Detection

PCR of faeces is generally used for detection

Tylocin + tiamulin are used as treatment

Porcine intestinal Spirochaetosis

Non fatal

Wasting diarrhoea disease

Caused by B pilosicoli

Worldwide spread with high prevalence

Treponema

slide 30

Fastidious

Periodontal disease

Vari?

Spirochaetes and polymicrobial disease