Spirochetes

Spirochaetales

What order do Spirochete organisms belong to?

• Leptospiraceae

• Spirochetaceae

What are the two families under the order Spirochaetales?

• Brachyspira (Serpulina) pilosicoli

• Brachyspira aalborgi

Name two genera under Spirochaetales.

Leptospira

What genus falls under the family Leptospiraceae?

• Borrelia

• Treponema

What genera fall under the family Spirochetaceae?

Spirochetes

Gram-negative bacilli : appear red or pink on Hucker’s method;

Long cell wall, slemder;

Helically curved/coiled

Levaditi method/staining

Tissue specimens

Fontana-Tribondeau

smears

Axial fibrils / Axial filaments/ Periplasmic flagella / Endoflagella;

Outer sheath;

Insertion disks

Morphologic features

Axial fibrils / Axial filaments/ Periplasmic flagella / Endoflagella

Serves as the locomotor/ motility organelle of Spirochete organisms and is covered by periplast (outer membrane). Endoflagella is wrapping the entire body or cell wall.

Outer sheath

Outer membrane / Periplast

Insertion disks

Plate-like structures found towards the end portion of the Spirochete cell wall wherein the endoflagella is attached to. Point of insertion of the endoflagella

An outer membrane (also called the periplast)

What encloses the entire body of the spirochete?

The endoflagella wrapped around the body, creating a corkscrew-like, winding motility.

What gives spirochetes their helical morphology and motility?

Motility: corkscrew-like winding motility

Violet: Outer membrane

Yellow: Cell wall or body of the organism

Thin Dark Red: Endoflagella

Electron Microscopy view of Spirochetes

• Number of axial fibrils

• Number of insertion disks

• Biochemical or metabolic features

What are the 3 main criteria used to differentiate the genera of spirochetes?

Number of axial fibrils

directly proportional to the number of insertion disks present or plate-like structures seen in the cell wall or body of a Spirochete organism.

Number of insertion disk present

depends on the number of endoflagella present, because the endoflagella isalways attached or inserted to an insertion disk.

Treponema

Slender, numerous with tight coils Pointed ends

Borrelia

Thicker, fewer and looser coils (Wave patterns) Pointed ends

Leptospira

Slender, numerous, tighter in appearance Hooked / bent ends; Resembles Borrelia coils

6-10

Trepanoma # of Axial Filaments

30-40

Borrelia # of Axial Filaments

2

Leptospira # of Axial Filaments

1

Treponema # of Insertion Disks

2

Borrelia # of Insertion Disks

3-5

Leptospira # of Insertion Disks

Diaminopimelic acid

Cell wall amino acid content of Leptospira

Treponema and Borrelia

Which genera have Ornithine in their cell walls?

Leptospira

Which spirochete is aerobic?

Borrelia

Which genus is seen under light microscopy?

Treponema and Borrelia

Which genera have overlapping axial fibrils?

Treponema

Which genus has cytoplasmic tubules?

Treponema

Morphology : Tight, regular coils

Motility: Sluggish w/ drifting motion & flexous movements

Axial fibrils/ cell end: 1-8 ; may or may not overlap at the center of the cell

Insertion discs: 1

Borrelis

Morphology : Coarse, irregular coils

Motility: Move in forward waves with a corkskrew-like motion

Axial fibrils/ cell end: 15-20; may or may not overlap

Insertion discs: 2

Leptospira

Morphology : Tight, regular coils with hooked ends

Motility: Undulatory movement & by rapid spinning on the long axis

Axial fibrils/ cell end: 1; Does not overlap at the center of the cell

Insertion discs: 3-5

Tighter coils

What type of coils are present in Treponema organisms?

Regular and angular spirals (4-14)

What is the spiral characteristic of Treponema organisms?

No, they require animal inoculation for growth

Can Treponema organisms be grown in vitro?

Rabbit testes

Which animal is used to grow Treponema pallidum organisms in vitro?

Microaerophilic (small amount of oxygen)

What type of oxygen conditions do Treponema organisms require for growth?

Dark-field or Phase-contrast microscopy

What type of microscopy is used to observe Treponema organisms?

Treponema pallidum subspecies pallidum;

Treponema pallidum subspecies pertenue;

Treponema carateum;

Treponema pallidum subspecies endemicum

4 species of Treponema that can colonize Humans

Treponema pallidum subspecies pallidum

Causative agent of venereal (sexually-transmitted) syphilis

Treponema pallidum subspecies pertenue

Causes yaws / frambesia / pian / buba / buoba.

Infections occurring in most of childhood populations, In warm mild tropical climates

Treponema carateum

Causes pinta / carate / mal de pinto because it causes discoloration in the skin of the infected individual

Treponema pallidum subspecies endemicum

Endemic syphilis, otherwise known as bejel / siti / dichuchwa.

Type of syphilis that is transmitted via non-sexual body contact or by sharing and eating and drinking utensils

T. pallidum subsp. pallidum

Which Treponema species causes Syphilis?

T. pallidum subsp. endemicum

Which Treponema species causes Endemic Syphilis?

T. carateum

Which Treponema species causes Pinta?

T. pallidum subsp. pallidum and T. pallidum subsp. endemicum

Which Treponema species causes cutaneous lesions in rabbits?

T. pallidum subsp. pertenue

Which Treponema species causes cutaneous lesions in hamsters?

None of the species listed cause lesions in guinea pigs

Which Treponema species causes cutaneous lesions in guinea pigs?

T. pallidum subsp. pertenue

Which Treponema species causes Yaws?

T. vincentii,T. pectinovorum, T. denticola,T. macrodentum, T. refringens, T. oralis , T. socranskii

OTHER TREPONEMES THAT ARE PART OF THE NORMAL FLORA

Endarteritis (inflammation of the arteries).

What condition does Treponema cause in the arteries?

It causes tissue destruction

What effect does Treponema have on tissue?

Syphilis or venereal syphilis

Common type of infection that Treponema pallidum subspecie pallidum to cause to humans;

Asexually transmitted disease;

Characterized by 3 stages that each has a prominent feature or manifestation.

Primary stage of Syphilis

Characterized by chancre formation that appears in the dry genital area

chancre

is a small painless ulcer/lesion that grows in the genital area of the infected individual

Secondary stage of Syphilis

Manifested by vague signs and symptoms like fever, sore throat, lymphadenopathy, weight loss, and rash; a unique rash on the palms of the hands and soles of the feet, alopecia, and condylomata lata (painful lesions in moist areas like the vagina and anus). The infection may become latent for 3-30 years with symptoms disappearing temporarily.

Tertiary stage of Syphilis

Involves the CNS and cardiovascular system, potentially lethal. Manifested by gumma formation (generalized lymphadenopathy with swollen lymph nodes) as an aggressive immune response to reactivated syphilis infection.

Congenital syphilis

cause intrauterine death and congenital abnormalities. Prevention involves early serologic testing of pregnant women to detect syphilis, followed by appropriate treatment to prevent transmission to the fetus.

Intrauterine Death

Might cause the infection to be pronounced inside the uterus of the mother, and might cause the demise of the fetus in utero

Congenital abnormalities

If the baby is delivered safely, then the baby will get the congenital syphilis, and the baby will manifest congenital abnormalities

Neurosyphilis

Affects the central nervous system (CNS); Usually in the tertiary stage of the infection

Direct detection (Darkfield Microscopic Examination),

serologic methods

Treponema pallidum Diagnosis

Non-treponemal tests & Treponemal tests

SEROLOGIC METHODS (Treponema)

Non-treponemal tests

It will detect non-treponemal antibodies or non-specific antibodies to Treponema pallidum subspecies pallidum.

Treponemal tests

Detects specific antibodies against Treponema organisms.

• VDRL

• RPR

• Hinton Test

Non-treponemal tests

VDRL

most common non-treponemal test

• FTA-ABS

• MHA-TP

• TPI Test

Treponemal tests

FTA-ABS

Px serum is 1st absorbed with nonpathogenic treponemes Application of fluorecein-labeled anti-human globulin serum

MHA-TP

Utilizes RBC from a turkey coated w/ treponemal antigen

Rapid Reagent

Detects the reagin antibody, non-specific reagin antibody will react to different types of lipids as antigen

Fluorescent Treponemal Antibody Absorption Test (FTA-ABS)

Specimen: Serum

• Procedure:

  1. The serum is treated with non-pathogenic Treponemes to remove nonspecific antibodies.

  2. Fluorescein-labeled anti-human globulin serum is added, which will bind to specific antibodies in the serum.

  3. The mixture is then exposed to Treponema pallidum subspecies pallidum antigen.

  4. If a specific antibody is present, it will bind to the antigen and cause agglutination, visible under UV light as fluorescence.

• Purpose: Fluorescence indicates the presence of specific antibodies against Treponema pallidum.

Micro Hemagglutination Treponema Pallidum (MHA-TP) test

• Procedure:

  1. Uses RBC from turkey coated with Treponema pallidum subspecies pallidum antigen.

  2. Patient serum is added to the coated RBCs.

  3. If the serum contains specific antibodies to Treponema pallidum, hemagglutination occurs.

  4. Hemagglutination indicates a positive result.

• Purpose: The test detects the presence of specific antibodies against Treponema pallidum in the patient’s serum.

Treponema Pallidum Immobilization (TPI)

Its principle is not widely studied but it is a treponemal type of test

Penicillin

Drug of choice for Syphilis

0.004 U

MIC of Penicillin

Jarisch Herxeimer Reaction

the patients will show vague signs and symptoms like fever, myalgia, headache, tachycardia, or increase in respiratory rate 24 hours after the patient is given penicillin due to the release of endotoxins from lysed spirochetes.

looser coils, which are thicker and fewer in number, with pointed ends

What shape do Borrelia organisms have?

3-10 spirals

How many spirals do Borrelia organisms have?

Giemsa and Wright stains

What type of stain is used to demonstrate Borrelia organisms?

bite of an insect vector, usually a tick or louse (arthropod-borne)

How are Borrelia infections transmitted to humans?

Gram-negative, highly flexible spirochete organisms.

What type of organisms are Borrelia?

microaerophilic and require long-chain fatty acids for growth.

What are the growth requirements for Borrelia organisms?

blood smear or using a light microscope.

Where can Borrelia organisms be readily demonstrated?

Borrelia Recurrentis

Causes human relapsing fever manifested by triad of findings (fever, headache, and myalgia)

• Louse (Pediculus humanus humanus louse)

• Tick bite (Ornithodoros tick)

Borrelia Recurrentis Mode of Transmission

• Direct detection methods

• Culture

• Serologic methods

Borrelia Recurrentis Laboratory Diagnosis

At the height of the fever

When is the ideal time to collect blood samples from a patient with relapsing fever?

Because the immune system is actively recognizing the organism’s antigens, making it easier to detect.

Why should blood samples be collected at the height of fever in relapsing fever patients?

Borrelia Burgdorferi

Causative agent of Lyme’s disease or pseudojuvenile rheumatoid arthritis

Tick bite, specifically from Ixodes reduvius

mode of transmission for Borrelia burgdorferi

The organism is injected into the bloodstream and may cause skin lesions or affect the central nervous system.

What happens when a tick carrying Borrelia burgdorferi bites a human host?

Tick-borne meningopolyneuritis, also known as Garin-Bujadoux-Bannwarth syndrome.

What neurological condition is associated with Borrelia burgdorferi infection?

microaerophilic

What is the oxygen requirement classification of Borrelia burgdorferi?

No, it is difficult to isolate in vitro

Is Borrelia burgdorferi easy to isolate in vitro?