Microbiology of Spirochetes and Leptospira

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary motility mechanism of spirochetes?

Periplasmic flagella (correct)

Cilia

Flagella

Pseudopodia

Which of the following Treponema subspecies is responsible for syphilis?

T.pallidum ssp.pallidum (correct)

T.carateum

T.pallidum ssp.pertenue

T.pallidum ssp.bejel endemicum

Which method is NOT effective for directly observing Treponema under a microscope?

Fluorescent microscopy

Darkfield microscopy

Light microscopy with Giemsa stain (correct)

Light microscopy with Gram stain (correct)

What is a primary virulence factor of T.pallidum that aids in its disease-causing ability?

Outer membrane proteins for adherence Signup and view all the answers

What is the role of hyaluronidase in the virulence of T.pallidum?

It helps in perivascular infiltration Signup and view all the answers

What is the correct characteristic of Leptospira interrogans?

It has characteristic hooked ends like a question mark. Signup and view all the answers

Which treatment is appropriate for Lyme disease?

Cefuroxime Signup and view all the answers

What mainly contributes to tissue destruction and lesions in leptospirosis?

Host’s immune response. Signup and view all the answers

Which of the following is a transmission method for leptospirosis?

Contact with infected soil or water. Signup and view all the answers

What percentage of patients with neurological or cardiac involvement may progress to the subsequent stage of Lyme disease?

5-15% Signup and view all the answers

Which of the following symptoms is NOT typically associated with atypical (walking) pneumonia?

Sudden high fever Signup and view all the answers

What is the primary reason cell wall synthesis inhibitors cannot be used to treat M. pneumoniae infections?

M. pneumoniae lacks a cell wall Signup and view all the answers

Which of the following is a secondary complication that can arise from M. pneumoniae infection?

Meningoencephalitis Signup and view all the answers

Which organism is known to cause postpartum fever and is resistant to erythromycin and tetracycline?

Mycoplasma hominis Signup and view all the answers

What preventive measure is recommended to reduce the risk of M. pneumoniae infection?

Minimizing close contact with others Signup and view all the answers

What is the primary cause of congenital syphilis?

Transplacental infection of T. pallidum Signup and view all the answers

Which treatment protocol is recommended for early-stage syphilis?

7-10 days of penicillin Signup and view all the answers

What is Bejel primarily caused by?

Treponema pallidum subsp. endemicum Signup and view all the answers

What is a common late-stage symptom of congenital syphilis?

Cognitive impairment Signup and view all the answers

Pinta is primarily associated with which type of symptoms?

Skin lesions and discoloration Signup and view all the answers

Which method is NOT recommended for the prevention of syphilis?

Vaccination against syphilis Signup and view all the answers

Which type of syphilis is transmitted through contaminated eating utensils?

Bejel Signup and view all the answers

What is a primary characteristic of icteric leptospirosis?

Overwhelming disease with vascular collapse Signup and view all the answers

What organ is primarily affected in icteric leptospirosis leading to jaundice?

Liver Signup and view all the answers

What type of lesions are associated with Treponema pallidum subsp. pertenue in its early stages?

Painless lesions Signup and view all the answers

Which of the following antibiotics is not effective against Mycoplasmataceae due to their lack of a cell wall?

Penicillin Signup and view all the answers

What is the typical incubation period for icteric leptospirosis?

10-12 days Signup and view all the answers

Which species of Mycoplasma is strictly aerobic?

M.pneumoniae Signup and view all the answers

What is the primary method through which leptospires infect the body?

Direct invasion and replication in tissues Signup and view all the answers

What type of colonies are characteristic of Mycoplasma species?

Fried-egg-like colonies Signup and view all the answers

Which of the following treatments is effective for icteric leptospirosis?

Penicillin or doxycycline Signup and view all the answers

What primarily contributes to the disease caused by gram-negative spirochetes?

Antigenic shift and immune reactions Signup and view all the answers

Which organism is responsible for epidemic relapsing fever?

B.recurrentis Signup and view all the answers

What is a characteristic feature of Lyme disease?

Unique skin lesion known as erythema migrans Signup and view all the answers

How is epidemic relapsing fever primarily transmitted?

By body lice from infected humans Signup and view all the answers

Which vectors are responsible for tick-borne borreliosis?

Soft-shelled ticks Signup and view all the answers

What is the typical incubation period for an acute infection of relapsing fever?

2-14 days Signup and view all the answers

What is a common reservoir for Lyme borreliosis?

Deer and rodents Signup and view all the answers

Which of the following is NOT associated with relapsing fever?

Constant symptoms without recurrence Signup and view all the answers

Study Notes

Spirochaetales

Gram-negative spirochetes
Spirochete comes from Greek for "coiled hair"
Extremely thin and can be very long
Motile by periplasmic flagella (axial fibrils or endoflagella)

Taxonomy

Order: Spirochaetales
Family: Spirochaetaceae
Genus: Treponema, Borrelia
- Family: Leptospiraceae
- Genus: Leptospira

Treponema

Too thin to be seen with light microscopy in specimens stained with Gram or Giemsa stain
Motile spirochetes can be seen with darkfield microscopy
Staining with anti-treponemal antibodies labeled with fluorescent dyes
Intracellular pathogen
Three periplasmic flagella at each end
Does not survive well outside of host and cannot be grown in cell-free cultures in vitro

Treponema and Human Disease

Microorganism	Disease
T. pallidum ssp. pallidum	Syphilis
T. pallidum ssp. endemicum	Bejel
T. pallidum ssp. pertenue	Yaws
T. carateum	Pinta

Virulence Factors of T. pallidum

Outer membrane proteins promote adherence
Hyaluronidase may facilitate perivascular infiltration
Antiphagocytic coating of fibronectin
Tissue destruction and lesions are primarily a consequence of the host's immune response

T. pallidum (Syphilis)

Transmitted through direct sexual contact or from mother to fetus
Not highly contagious (~30% chance of acquiring the disease after single exposure to infected partner)
Transmission rate is dependent on the stage of the disease
Long incubation period, where the host is non-infectious

Syphilis

Tissue destruction and lesions are primarily a consequence of the patient's immune response
Syphilis is a disease of blood vessels and the perivascular areas
Despite the host immune response, organisms can persist for decades
In early stages, there is inhibition of cell-mediated immunity
Inhibition of CMI reduces in late stages, hence late lesions tend to be localized

Primary Syphilis

The primary disease process involves invasion of mucous membranes, rapid multiplication, and wide dissemination through perivascular lymphatic and systemic circulation.
Occurs prior to development of the primary lesion.
Usually 3-4 weeks after initial contact, the host mounts an inflammatory response at the site of inoculation, forming a chancre (usually painless).
Chancre develops into a hardened ulcer with profuse shedding of spirochetes.
Swelling of capillary walls and regional lymph nodes occurs.
Lesion heals spontaneously via fibrotic walling-off within two months.

Secondary Syphilis

Secondary disease occurs 2–10 weeks after the primary lesion.
Characterized by a widely disseminated mucocutaneous rash
Secondary lesions of skin and mucous membranes are highly contagious.
A generalized immunological response follows.

Latent Stage Syphilis

Following secondary disease, the host enters a latent period
First 4 years = early latent
Subsequent period = late latent
About 40% of late latent patients progress to late tertiary syphilitic disease

Tertiary Syphilis

Tertiary syphilis is characterized by localized granulomatous dermal lesions (gummas), with few organisms present
Granulomas reflect containment by the host's immunologic reaction to chronic infection
Late neurosyphilis develops typically more than 5 years after initial infection.
Central nervous system and spinal cord involvement can manifest as dementia, seizures, wasting, etc.
Cardiovascular involvement appears 10-40 years after initial infection, resulting in myocardial insufficiency and death.

Famous People Affected by Syphilis

Friedrich Nietzsche
Schubert
Goya
Van Gogh
Peter I and Catherine of Russia
Al Capone
Mussolini

Congenital Syphilis

Congenital syphilis results from transplacental infection.
T. pallidum septicemia occurs in the developing fetus.
Widespread dissemination frequently leads to
Abortion, neonatal mortality, and late mental or physical problems following scarring.

Prevention and Treatment of Syphilis

Penicillin remains the drug of choice.
WHO monitors treatment recommendations
7-10 days continuously for early stage
At least 21 days continuously beyond the early stage
Prevention with barrier methods
Prophylactic treatment of contacts identified through epidemiological tracing

Treponema pallidum subsp. endemicum

Causes bejel (endemic syphilis)
Initial lesions: oral
Secondary lesions: oral papules and mucosal patches
Late lesions: gummas of skin, bones, and nasopharynx
Transmitted person-to-person through contaminated eating utensils.
Primitive tropical/subtropical areas (Africa, Asia, and Australia).

Treponema pallidum subsp. pertenue

Causes yaws
Early: skin lesions
Late: destructive lesions of skin, lymph nodes, and bones (painless nodules)
Widely distributed over the body with abundant contagious spirochetes.
Transmitted by direct contact with lesions containing abundant spirochetes.
Primitive tropical areas (South America, Central Africa, Southeast Asia)

Treponema carateum

Causes pinta
Primarily restricted to skin
1-3 week incubation period
Initial lesions: small pruritic papules
Secondary: enlarged plaques persist for months to years
Late: disseminated, recurrent hypopigmentation or depigmentation of skin lesions
Scarring and disfigurement frequently occur.
Transmitted through direct contact with skin lesions
Primitive tropical areas (Mexico, Central and South America)

Borrelia spp.

Gram-negative spirochetes
Giemsa stain of blood or phase contrast microscopy can be used
Antigenic shift and immune reactions are responsible for the disease.

Borrelia and Human Disease

Microorganism	Reservoir	Vector	Disease
B. recurrentis	Humans	Body lice	Relapsing fever
B. spp.	Rodents, ticks	Soft-shelled ticks	Relapsing fever
B. burgdorferi	Rodents, ticks	Hard-shelled tick	Lyme disease
	other animals

Relapsing Fever

Associated with poverty, crowding, and warfare
Arthropod vectors
Louse-borne borreliosis = Epidemic Relapsing Fever
- Transmitted person-to-person by human body lice (vectors)
- Infects host when louse is injured
- Lice leave the host and seek a new normal-temperature host
Tick-borne borreliosis = Endemic Relapsing Fever
- Sporadic cases
- Transmitted by soft-body ticks
- Small mammals are the reservoir
- Ticks can multiply and infect new human hosts
Pathogenesis of relapsing fever includes acute infection (2-14 days incubation), recurring febrile episodes, and constant and worsening spirochaetemia during febrile stages.

Epidemiology of Lyme Borreliosis

Lyme disease was recognized in 1975 in Lyme, Connecticut.
Associated to Borrelia burgdorferi.
Transmitted by hard-body ticks (Ixodes spp.).
Common reservoirs include white-footed deer mice, other rodents, deer, domesticated pets, and hard-shelled ticks.

Lyme Disease

Characterized by 3 stages:
- Unique skin lesion (erythema migrans, or bullseye rash) with general malaise. EM not seen in all infected hosts
- Lesions periodically reoccur
- Subsequent stage: seen in 5-15% of patients, with neurological or cardiac involvement.
- Third stage: migrating episodes of non-destructive, but painful arthritis.

Leptospira

Gram-negative spirochete
Characteristic hooked ends, like a question mark
Two periplasmic flagella

Leptospira interrogans

Tissue destruction and lesions are primarily a consequence of host's immune response

Virulence Factors

Able to directly invade and replicate in tissues, inducing inflammatory response

Epidemiology of Leptospirosis

Mainly a zoonotic disease
Transmitted to humans from a variety of wild and domesticated animals (rats, dogs, farm and wild animals).
Transmitted through breaks in the skin or intact mucus membranes.
Indirect contact (soil, water, feed) with infected urine from an animal with leptospiruria.
Occupational disease of animal handling

Clinical Disease: Leptospirosis

1. Mild virus-like syndrome 2. Anicteric leptospirosis: systemic with aseptic meningitis 3. Icteric leptospirosis or Weil's disease: overwhelming disease with vascular collapse, thrombocytopenia, hemorrhage, hepatic, and renal dysfunction

Icteric refers to jaundice (yellowing of skin and mucus membranes) and liver involvement

Pathogenesis of Icteric Leptospirosis

Direct invasion and replication in tissues
Characterized by an acute febrile jaundice and glomerulonephritis
Incubation period usually 10-12 days.
Leptospiremia develops rapidly after infection
Infects the kidneys, organisms shed in the urine (leptospiruria) and renal failure, or death.
Hepatic injury and meningeal irritation are common.

Treatment

Treatment: penicillin or doxycycline
Control of reservoirs and vaccination of animals

Mycoplasma

Smallest (0.1-0.3 µm) bacteria
Grow slowly and require sterols and glucose
Ureaplasma spp. require urea
Facultative anaerobes (except M. pneumoniae, which is strict aerobe)
Lack a cell wall
Resistant to penicillin, cephalosporins, vancomycin, but sensitive to tetracycline, erythromycin
Small, fried-egg-like colonies (except M. pneumoniae)

Mycoplasmataceae and Human Disease

Microorganism	Human Disease
Mycoplasma genitalium	Non-gonococcal urethritis, pelvic inflammatory disease
Mycoplasma hominis	Pelvic inflammatory disease, postpartum fever, systemic infections (in immunocompromised)
Ureaplasma urealyticum	Non-gonococcal urethritis, pyelonephritis, spontaneous abortion, premature birth

M. pneumoniae

Mostly asymptomatic carriage
Acute pharyngitis: low-grade fever, malaise, headache, dry/non-productive cough
Tracheobronchitis with lymphocyte and plasma cell infiltration
Atypical (walking) pneumonia
Secondary complications: hemolytic anemia, arthritis, myocarditis, pericarditis, neurological abnormalities (meningooencephalitis).

Atypical (walking) Pneumonia

Chronic onset and recovery
Flu-like symptoms (generalized aches, discomfort, headache, chills, low-grade fever)
Persistent non-productive cough

(Typical bacterial pneumonia)

Abrupt, rigorous onset
Productive cough, purulent sputum
High fever, chest pain, stiffness in the neck

Treatment and Prevention M. pneumoniae

Treatment: Tetracycline or erythromycin or newer fluoroquinolones
Cannot use cell wall synthesis inhibitors
Prevention: Avoid close contact, no vaccine

Other Mycoplasmataceae

List of additional Mycoplasmataceae species and the associated human diseases (can vary by species)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the microbiology of spirochetes and leptospira, focusing on their motility mechanisms, virulence factors, and treatment options. This quiz covers key aspects of Treponema and Leptospira, including their diseases, characteristics, and transmission methods.