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PCMS 2007

DR JEANNETTE WADULADR JEANNETTE WADULA

Consultant MicrobiologistConsultant Microbiologist

CMID/NHLSCMID/NHLS

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SPIROCHETES

OBJECTIVESOBJECTIVES Describe the characteristics and classification of Describe the characteristics and classification of

SpirochetesSpirochetes Discuss the etiology and epidemiology of Discuss the etiology and epidemiology of

spirochetal diseasesspirochetal diseases Identify the pathogenic and clinical similarities of Identify the pathogenic and clinical similarities of

spirochetesspirochetes Discuss briefly the principles of diagnosis and Discuss briefly the principles of diagnosis and

managementmanagement

SPIROCHETES

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Characteristics of Spirochetes

Spirochetes are unusual gram-negative, Spirochetes are unusual gram-negative, helically curved bacteria with a complex helically curved bacteria with a complex peptidoglycan-cytoplasmic peptidoglycan-cytoplasmic membrane,referred to as protoplasmic membrane,referred to as protoplasmic cylinder surrounded by an outer cylinder surrounded by an outer membrane(lipid bilayer sheath) membrane(lipid bilayer sheath)

Free-living or host associated (colonize) Free-living or host associated (colonize) bacteria widespread in naturebacteria widespread in nature

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Their motility differs from other bacteria owing to the unique structure

(presence of periplasmic flagella (presence of periplasmic flagella within the periplasma)within the periplasma)

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Periplasmic fibrils, are responsible for their cockscrew movement

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CLASSIFICATION

L e pto sp ira ce aeL e pto sp ira (Zo on os is)

S p iroch ae ta ce aeT rep on e m a (h um an -h u m a n con tac t)

B or re lia (Zo o no sis)

O th er

C la ss S p iroch ae tesO rde r sp iro ch e ta les

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Of the six genera, three- Treponema, Borrelia and Leptospira

contain organisms pathogenic for contain organisms pathogenic for humanshumans

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Human Spirochetal diseases and their etiologic agents

Infecting organismInfecting organism

TreponemaTreponema T. carateumT. carateum T. pallidumT. pallidum subspecies subspecies

pertenuepertenue T. pallidumT. pallidum subspecies subspecies

endemicumendemicum T. pallidumT. pallidum subspecies subspecies

pallidumpallidum

DiseaseDisease

PintaPinta

YawsYaws Bejel, Endemic Bejel, Endemic

syphilissyphilis SyphilisSyphilis

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Human spirochetal diseases and their etiologic agents

Leptospira interogansLeptospira interogans

BorreliaBorrelia spp spp ( ( recurrentis, hermsii, recurrentis, hermsii, turicatae)turicatae)

Borrelia burgdoferiBorrelia burgdoferi

LeptospirosisLeptospirosis

Relapsing feversRelapsing fevers

(epidemic or)(epidemic or)

sporadicsporadic

Lyme diseaseLyme disease

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Epidemiology

Treponemes- except for Treponemes- except for congenital syphilis congenital syphilis (transplacental), syphilis is (transplacental), syphilis is transmitted through sexual transmitted through sexual contactcontact

Pinta, Yaws and endemic Pinta, Yaws and endemic syphilis – nonvenereal syphilis – nonvenereal trepomatoses are not spread by trepomatoses are not spread by sexual contact but bysexual contact but by

close skin-skin contact close skin-skin contact between humans and therebetween humans and there

is no known animal is no known animal reservoir.reservoir.

Leptospira and Borrelia Leptospira and Borrelia are zoonotic i.e., animal are zoonotic i.e., animal reservoirs exist and infect reservoirs exist and infect humans via direct or humans via direct or indirect contact.indirect contact.

Human leptospirosis is Human leptospirosis is acquired by direct contact acquired by direct contact with contaminated urine with contaminated urine from rats, pigs, dogs, from rats, pigs, dogs, cats...cats...

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Epidemiology

Many animals are Many animals are asymptomatic carriers of asymptomatic carriers of L. interrogansL. interrogans in their in their kidneys –no arthropod or kidneys –no arthropod or insect vectorinsect vector

Relapsing fever is Relapsing fever is transmitted by either transmitted by either infected human infected human louse(louse(LBRFLBRF)/tick()/tick(TBRFTBRF))

((B.B. recurrentis- recurrentis- transovarial transovarial passage doesn’t occur ) by passage doesn’t occur ) by bites-epidemic formbites-epidemic form

Ticks (ornithodoros) are Ticks (ornithodoros) are vectors of sporadic casesvectors of sporadic casesof relapsing feverof relapsing fever

These infected ticks These infected ticks transmit infection transmit infection transovarily for transovarily for generations and remain generations and remain infective for many years infective for many years without feedingwithout feedingLyme disease is Lyme disease is transmitted to humans by a transmitted to humans by a minute tick (ixodes) minute tick (ixodes)

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Pathogenic features

Spirochetes invade Spirochetes invade host tissue at mucus or host tissue at mucus or skin membranes skin membranes (portal of entry), cause (portal of entry), cause infection and gain infection and gain access to the lymph access to the lymph systems and bloodsystems and blood

Spirochetemia early in Spirochetemia early in the course, the course, wide wide

dissemination dissemination throughout tissues, throughout tissues, and body fluids, and body fluids, one/more stages of one/more stages of disease, often disease, often intervening latent intervening latent periods (1periods (1oo22oo33o)o)

Such illness suggests Such illness suggests that pathogenic that pathogenic spirochetesspirochetes

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Pathogenic features

share unique virulence characteristicsshare unique virulence characteristics Once pathogen has entered host, it is Once pathogen has entered host, it is

successful at evading defense mechanisms successful at evading defense mechanisms by not being immunogenicby not being immunogenic

In most cases, spirochetes persist in host for In most cases, spirochetes persist in host for extended periods, extended periods, late presentation of late presentation of disease appears to be due to the presence of disease appears to be due to the presence of viable organismsviable organisms

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Clinical similarities

common tropism for the skin, bone, and common tropism for the skin, bone, and central nervous systemcentral nervous system

Myocardial disease is found in Myocardial disease is found in leptospirosis, relapsing fever, possibly leptospirosis, relapsing fever, possibly syphilis and Lyme diseasesyphilis and Lyme disease

Chronic arthritis uniquely occurs in Lyme Chronic arthritis uniquely occurs in Lyme disease, but can occur in syphilis alsodisease, but can occur in syphilis also

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Principles of diagnosis and management Based on recognition of Based on recognition of

clinical features of patient clinical features of patient illness with a history of illness with a history of possible exposure to the possible exposure to the causative organism causative organism

Based on either direct Based on either direct detection (dark-field detection (dark-field microscopy /culture) or microscopy /culture) or serology(IFA/ELISA). serology(IFA/ELISA).

TreponemaTreponema spp have not spp have not been cultured, do not take been cultured, do not take up aniline stains up aniline stains gram gram stain not effective. Dark stain not effective. Dark field illumination allowsfield illumination allows

visualisation, visualisation, nontreponemal (RPR, nontreponemal (RPR, VDRL-) and treponemal VDRL-) and treponemal tests (fluorescently labeled tests (fluorescently labeled antibody..) can be usedantibody..) can be used

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Principles of diagnosis and management L.interrogansL.interrogans can be can be

grown on artificial culture grown on artificial culture media media can be isolated can be isolated from patients blood. from patients blood. Serologic diagnosis is Serologic diagnosis is made using convalescent made using convalescent serum serum

Borrelia relapsing fevers – Borrelia relapsing fevers – blood smears with typical blood smears with typical spirochetes, blood cultures spirochetes, blood cultures possible but serologic possible but serologic diagnosis difficultdiagnosis difficult

Borreliae stain well with Borreliae stain well with aniline dyes and can be aniline dyes and can be observed with the ordinary observed with the ordinary light microscope!!!light microscope!!!

Lyme disease – culture of Lyme disease – culture of B. burgdoferiB. burgdoferi from from patients blood is definitive patients blood is definitive but rare except from skin but rare except from skin biopsy samples. biopsy samples. Determination of specific Determination of specific antibody titers – most antibody titers – most helpfulhelpful

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References

Manual of Clinical Microbiology seventh Manual of Clinical Microbiology seventh edition, Murray.edition, Murray.

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Frambesia- T. pertenue

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Bone disfiguration-tertiary T. pertenue infection