Spirochaetes 2006 07 Med

Spirochetes • Treponema • Borrelia • Leptospira

Objectives • To know primary, secondary, and tertiary clinical manifestations of syphilis • To know the diagnostic test to identify T. pallidum in clinical laboratory • To know the clinical picture of infection caused by Leptospira organisms and to identify them in the laboratory • To know the clinical picture of infection caused by Borrelia organisms and to identify them in the laboratory • Antimicrobial therapy

Spirochete s •Are spiral flexible organisms that move without flagella •Multiply by transverse binary fission

Treponema : Many narrow regular coils

Borrelia : Few wide, irregular coils

Leptospira : Many very narrow coils with hooked ends

Treponema pallidum • • • •

Causative agent of syphilis : A STD Actively motile with an axial filament Are not stained with ordinary stains Are weakly refractile Not seen with ordinary microscope • Require dark-field microscopy to be seen in fresh preparation

Growth requirements • Microaerophilic • Cannot be cultured on artificial media OR tissue culture • Cultured by inoculation of rabbit testes

Treponema pallidum

Treponema Pallidum Antigen • Outer-membrane protein (OMP) Ag

Antibodies : Two types • Specific anti-treponemal Abs (IgM & IgG) o Induced by OMP Ag

• Non-specific Abs (Reagin Abs-IgE) o Stimulating Ag is not known

• Antibodies appear 2-3 weeks after infection

Syphilis Source of Infection • Patient with Primary or Secondary syphilis

Modes of Transmission 1. Venereal : Sexual contact 2. Non-venereal A) Direct Contact • With mucous membranes (kissing) • Blood Transfusion

B) Mother to Child – Congenital syphilis

Syphilis : stages Primary Stage : Incubation period 2-4 weeks Entry of organisms at site of contact

Go to regional LN (inflammed LN)

Bacteremia

Chancre Formation at site of contact After 3 weeks (A flat dull ulcer)

Chancre is painless & Heals spontaneously After 4-6 weeks Chancre & LN Contain a large no. of organisms

Syphilis : stages Secondary Syphilis : • 6-12 weeks after chancre in untreated cases • Generalized non-itchy, coppery-red rashes on skin & MM especially on palms & soles • Snail-track ulcers in oral cavity in 1/3rd of patients • The lesions contain many organisms • Enlarged, painless, rubbery LN Outcome in untreated cases • 25% • 25% • 50%

- Complete recovery - Latent for life (Sero-positive) - Tertiary syphilis

SYPHILIS : stages Tertiary Syphilis

• 3-10 years after primary lesion • Chronic granuloma in skin, MM, bones or any organ (gummas) • Granuloma breakdown to form shallow ulcers • Few treponemes in granuloma • 10-20 years after primary lesion o Neurosyphilis : • Tabes dorsalis • Cranial Nerve palsies

o CVS Changes : Aortic aneurysms, aortitis

Syphilis : stages Latent Syphilis • Dormant for years • Positive serology

Congenital Syphilis • Trans-placental transmission from mother with Pri. OR Sec. syphilis • Fetal death OR Fetus borne with abnormalities • Skin rashes, saddle nose, hepatitis, meningitis

Treatment • Penicillin

SYPHILIS : Lab Diagnosis Specimens • Primary Stage : Chancre & LN • Secondary Stage : Skin rash & mucous patches

Microscopy • Dark-field Microscopy o To see motile treponemes

• Immunofluorescence

Serodiagnosis

Syphilis : Lab Diagnosis Serodiagnosis Non-treponemal non-specific tests : To detect non-specific Abs

• Extracts of normal mammalian tissues ( cardiolipin from beef heart) react with anticardiolipin antibody (Ab) in patient’s serum called Reagin

VDRL (Venereal Diseases research Lab) Test • Slide agglutination test • Rapid screening test • Read microscopically

Rapid plasma reagin (RPR) Test • Read with naked eyes

SYPHILIS : Lab Diagnosis VDRL & RPR Are positive in majority of Pri syphilis Almost always positive in Sec syphilis Are sensitive but non-specific False positive in TB, Malaria, Autoimmune diseases • Have good prognostic value • Titer is used to follow therapy • • • • •

Syphilis : Lab Diagnosis Serodiagnosis Specific tests

• Detect specific Abs • FTA-Abs (Fluorescent treponemal antibody Absorption) Test • MHA-TP (MicroHaemAgglutination test for T. pallidum, is an indirect hemagglutination test using T. pallidum antigens absorbed to erthrocytes.  A titre of non-specific Abs decreases with effective treatment while specific Abs remain for life

Syphilis : Treatment • Penicillin

• Some patients with Sec syphilis, experience fever with chills & myalgias, a few hours after penicillin. • This response (Jarisch-Hexheimer) is due to lysis of treponemes and release of endotoxin-like substances.

Nonvenereal Treponemes  Bejel; caused by T. pallidum spp. Endemicum • •

Common in middle east, causes granulomatous lesion of skin, bone and joint

 Yaws: Caused by T. pallidum spp. pertenue • this disease occurs in tropical equatorial regions. • causes granulomatous lesion of skin, bone and joint.

 Pinta: Caused by T. carateum • Affect the skin with papules on the hands, feet and scalp. These lesions heal slowly after treatment (unlike syphilis, yaws).

LEPTOSPIRA INTERROGANS Leptospira : Many very narrow coils with hooked ends

• Causative agent of Leptospirosis : A zoonotic disease • Habitat : Infected domestic live-stock & pets • The organism settles in the kidney and excreted in urine

LEPTOSPIRA INTERROGANS Mode of Infection

• Direct Contact with:

o Urine of infected animal o Water & soil recently contaminated with infected urine

• The organism enters body through: o Skin lesions o Conjunctival mucus membrane o Ingestion

• High-Risk Groups o Farmers o Sewer workers

Leptospirosis Pathogenesis

• Incubation period : 2 day- 28 days • Bacteremia : organisms multiply in liver, spleen, kidney, meninges, conjunctiva

Clinical Features

• Influenza-like followed by hepatitis & meningitis • Weil’s Disease (severe leptospirosis) o Jaundice, hemorrhage, renal failure

Lab Diagnosis

• Dark field Microscopy of blood & CSF • Sero-diagnosis

Leptospira sp

LEPTOSPIROSIS Treatment & Prevention • Penicillin • Animal immunization • Proper treatment and disposal of contaminated water

Borrelia Recurrentis Borrelia : Few wide, irregular coils

• Can be stained with Giemsa stain in blood film • Can grow in media containing serum & tissue extracts • High frequency of antigenic variation in major surface protein and is responsible for : o Organism can escape immune system o Relapses of disease • Disease : Relapsing Fever

Borrelia

Relapsing Fever Transmission : • Tick-borne Relapsing Fever o From infected rodents to human

• Louse-borne Relapsing Fever o From infected human to human

Clinical Features Bacteremia : Infect various organs A non-pruritic rash at bite site Fever, rigors and headache for weeks to months Weeks to months later : Cardiac and neurological symptoms like Bell’s Palsy, peripheral neuropathies o Predominant arthritis o One of the causes of PUO o o o o

BORRELIA RECURRENTIS Lab Diagnosis • Giemsa staining of blood smear • Detection of IgM OR rising titre of IgG • PCR

Treatment & Prevention • Amoxycillin • Louse, tick & rodent control • Hygienic measures

Borrelia Burgdorferi • Cause lyme disease • Fever, migratory skin rash • Lyme disease rash called erythema migrans. This rash often takes a bull's-eye appearances and is observed in about 80% of Lyme disease • patients muscle and joint pain • Evidence of meningeal irritaion • In chronic cases, meningoencephalitis, myocarditis and arthritis • Transmitted to human by ticks

Tick

Louse

Lab Diagnosis

• Detection of IgM OR rising titre of IgG • PCR

Treatment & Prevention

• Doxycycline and beta-lactms • Tick & rodent control • Hygienic measures

Features of Spirochetal Diseases Organism

Transmission

Diagnosis Microscopy

Serology VDLR RPR, FTA-ABS MHA-TP

Disease

T.pallidum

Sexual, Transplacental Transfusion

Dark field of chancre or sec. lesion

L.interrgans

Ingestion of contaminated water

Not recommended Microagglutination (MAT)

Fever , meningitis hepatitis

B. recurrentis

lice

Gemisa of blood smear

Relapsing fever

B. burgdorferi

ticks

Not recommended EIA

None

Syphilis

Lyme disease

Case #1 A farmer was admitted to hospital. He gave a history of being unwell a week before admission with fever and head ache. These symptoms resolved, but the day before admission he become pyrexial again and on examination was found to be jaundiced and to have elevated blood urea. Urine was collected and inoculated into semisolid agar medium, which after 2 days become turbid and was examined by dark ground microscopy (see figure) Serum was also collected for serology

Questions • What is your clinical suspicion of the diagnosis? • What further investigations would you perform? • How would you manage the patient?

Case # 2 • A 24-year old Saudi student arrived from New york, USA, at a local medical clinic complaining of fever , fatigue and muscle ache. It was mid September, and he had been having symptoms for about 2 weeks. He reported that he had removed numerous insects, he assumed that some of them had escaped detection for several days. On examination the doctor noticed a circular erythematous lesion on hid ankle, he said this had followed an insect bite.

Questions • What is the insect and what relevance does it have to his illness? • What are the tests of choices for Lab diagnosis of the disease? • How should you treat this patient?

Case # 3 A male patient presented at a dermatology department with a history of malaise and scaling, papular rash on palms of his hands and an ulcer on his hard palate. Further examination revealed a generalized non-tender lymphadenopathy. Dark ground microscopy of scrapings of the mucous ulcer revealed the organisms shown in figure.

Questions • What was your diagnosis? • How is the illness transmitted • How should the patient treated?