Microbiology of Spirochetes and Leptospira
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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?

<p>Outer membrane proteins for adherence (C)</p> Signup and view all the answers

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

<p>It helps in perivascular infiltration (C)</p> Signup and view all the answers

What is the correct characteristic of Leptospira interrogans?

<p>It has characteristic hooked ends like a question mark. (B)</p> Signup and view all the answers

Which treatment is appropriate for Lyme disease?

<p>Cefuroxime (D)</p> Signup and view all the answers

What mainly contributes to tissue destruction and lesions in leptospirosis?

<p>Host’s immune response. (D)</p> Signup and view all the answers

Which of the following is a transmission method for leptospirosis?

<p>Contact with infected soil or water. (B)</p> Signup and view all the answers

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

<p>5-15% (D)</p> Signup and view all the answers

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

<p>Sudden high fever (C)</p> Signup and view all the answers

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

<p>M. pneumoniae lacks a cell wall (A)</p> Signup and view all the answers

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

<p>Meningoencephalitis (A)</p> Signup and view all the answers

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

<p>Mycoplasma hominis (B)</p> Signup and view all the answers

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

<p>Minimizing close contact with others (B)</p> Signup and view all the answers

What is the primary cause of congenital syphilis?

<p>Transplacental infection of T. pallidum (D)</p> Signup and view all the answers

Which treatment protocol is recommended for early-stage syphilis?

<p>7-10 days of penicillin (A)</p> Signup and view all the answers

What is Bejel primarily caused by?

<p>Treponema pallidum subsp. endemicum (A)</p> Signup and view all the answers

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

<p>Cognitive impairment (C)</p> Signup and view all the answers

Pinta is primarily associated with which type of symptoms?

<p>Skin lesions and discoloration (B)</p> Signup and view all the answers

Which method is NOT recommended for the prevention of syphilis?

<p>Vaccination against syphilis (A)</p> Signup and view all the answers

Which type of syphilis is transmitted through contaminated eating utensils?

<p>Bejel (D)</p> Signup and view all the answers

What is a primary characteristic of icteric leptospirosis?

<p>Overwhelming disease with vascular collapse (D)</p> Signup and view all the answers

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

<p>Liver (D)</p> Signup and view all the answers

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

<p>Painless lesions (D)</p> Signup and view all the answers

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

<p>Penicillin (B)</p> Signup and view all the answers

What is the typical incubation period for icteric leptospirosis?

<p>10-12 days (D)</p> Signup and view all the answers

Which species of Mycoplasma is strictly aerobic?

<p>M.pneumoniae (A)</p> Signup and view all the answers

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

<p>Direct invasion and replication in tissues (B)</p> Signup and view all the answers

What type of colonies are characteristic of Mycoplasma species?

<p>Fried-egg-like colonies (A)</p> Signup and view all the answers

Which of the following treatments is effective for icteric leptospirosis?

<p>Penicillin or doxycycline (C)</p> Signup and view all the answers

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

<p>Antigenic shift and immune reactions (D)</p> Signup and view all the answers

Which organism is responsible for epidemic relapsing fever?

<p>B.recurrentis (B)</p> Signup and view all the answers

What is a characteristic feature of Lyme disease?

<p>Unique skin lesion known as erythema migrans (A)</p> Signup and view all the answers

How is epidemic relapsing fever primarily transmitted?

<p>By body lice from infected humans (A)</p> Signup and view all the answers

Which vectors are responsible for tick-borne borreliosis?

<p>Soft-shelled ticks (D)</p> Signup and view all the answers

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

<p>2-14 days (C)</p> Signup and view all the answers

What is a common reservoir for Lyme borreliosis?

<p>Deer and rodents (A)</p> Signup and view all the answers

Which of the following is NOT associated with relapsing fever?

<p>Constant symptoms without recurrence (C)</p> Signup and view all the answers

Flashcards

Spirochete

A type of bacteria that is spiral-shaped and has a thin, flexible structure.

Treponema

Treponema are a type of bacteria in the Spirochaetales order causing various diseases such as syphilis, yaws, and pinta.

How do Spirochetes move?

They use specialized structures called periplasmic flagella, also known as axial fibrils or endoflagella, to move.

Treponema pallidum subspecies

The Treponema pallidum subspecies causes syphilis. The other subspecies are responsible for various diseases like yaws and pinta.

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Why is it difficult to grow Treponema?

These bacteria are difficult to grow in the lab because they don't survive well outside the host.

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Leptospirosis

Infectious disease caused by bacteria of the genus Leptospira, often transmitted through contact with infected animal urine.

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Leptospira interrogans

Gram-negative, spiral-shaped bacteria with characteristic hooked ends, resembling a question mark. It has two periplasmic flagella that help it move.

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Leptospira virulence factors

Direct invasion and replication of Leptospira bacteria into tissues, causing inflammation. This response triggers the body's immune system to fight the infection.

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Epidemiology of Leptospirosis

A zoonotic disease primarily transmitted from animals to humans through contact with infected urine. Common hosts include rats, dogs, and farm animals.

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Anicteric Leptospirosis

A severe form of Leptospirosis characterized by systemic symptoms with aseptic meningitis. This occurs when the bacteria spreads throughout the body.

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Mycoplasma pneumoniae Infection

Mycoplasma pneumoniae is a common cause of atypical pneumonia in children and young adults.

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Symptoms of M. pneumoniae

M. pneumoniae infections are usually mild and can cause a dry cough and low-grade fever, lasting for over two weeks.

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M. pneumoniae Treatment

M. pneumoniae is difficult to treat with typical antibiotics because it lacks a cell wall.

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Complications of M. pneumoniae

M. pneumoniae can cause a wide range of complications, including hemolytic anemia, arthritis, and neurological problems.

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Preventing M. pneumoniae Spread

Preventing the spread of M. pneumoniae involves avoiding close contact with infected individuals.

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Relapsing Fever - Pathogenesis

Characterized by recurring febrile episodes following an initial 2-14 day incubation period. The presence of spirochetes in the blood is a constant feature, worsening during fever episodes.

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Lyme Disease - Stages

Lyme disease is a multistage illness involving a unique skin lesion called Erythema Migrans ('bullseye rash'), followed by neurological, cardiac, and musculoskeletal complications. The rash is not seen in all infected individuals.

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Relapsing fever - Cause

Antigenic shift and immune reactions are the driving force behind relapsing fever. This is due to the ability of the bacteria to change its surface antigens, escaping the immune system.

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Lyme Disease - Discovery and Transmission

Lyme disease, a tick-borne illness, was first recognized in 1975 in Lyme, Connecticut. It is primarily linked to Borrelia burgdorferi and transmitted by Ixodes ticks, especially the black-legged tick.

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Relapsing Fever - Epidemiology

Relapsing fever is a disease associated with poverty and crowding, often occurring during warfare. It is caused by Borrelia species and transmitted by either body lice or soft-shelled ticks.

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Lyme Disease - Reservoirs

Lyme disease has a diverse reservoir of hosts including white-footed deer mice, other rodents, deer, and domesticated pets. This broad reservoir contributes to the disease's spread and persistence.

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Relapsing Fever - Louse-borne Transmission

Louse-borne borreliosis (Epidemic Relapsing Fever) spreads quickly from person to person through the bite of infected lice. It is contracted only when the louse is injured, often while scratching the infected area.

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Relapsing Fever - Tick-borne Transmission

Tick-borne borreliosis (Endemic Relapsing Fever) occurs sporadically through the bite of soft-shelled ticks that feed on small mammals. These infected ticks can multiply and transmit the disease to new hosts.

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What is Icteric Leptospirosis?

A bacterial infection characterized by jaundice, fever, and kidney damage, often leading to death.

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What is Leptospiremia?

The initial stage of Leptospirosis where bacteria multiply in the blood.

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How are Leptospires spread?

Shed in urine and can infect others.

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Describe Mycoplasmas.

The smallest type of bacteria, lacking a cell wall.

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What are Mycoplasmataceae?

A group of bacteria that need sterols and glucose for energy.

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What is unique about Ureaplasma spp.?

Require urea for energy.

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What is M. pneumoniae?

A type of Mycoplasma causing pneumonia.

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What is the role of the P1 pili in M.pneumoniae?

A protein that helps M.pneumoniae attach to the respiratory tract.

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What is syphilis?

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. It can have serious consequences if left untreated, leading to cardiovascular issues, neurological complications, and even death.

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What is congenital syphilis?

Congenital syphilis occurs when a pregnant woman with syphilis passes the infection to her unborn baby. This can lead to serious health problems for the child, including miscarriage, stillbirth, or birth defects.

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How is syphilis treated?

Penicillin is the main treatment for syphilis. It is usually administered as an injection for 7-10 days in the early stages of the disease and for longer periods in later stages.

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What is Bejel?

Bejel, or endemic syphilis, is a non-sexually transmitted form of syphilis caused by Treponema pallidum subsp. endemicum. It is spread through contact with sores and is prevalent in developing countries.

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What is Yaws?

Yaws is a chronic infectious disease caused by Treponema pallidum subsp. pertenue. It is characterized by skin lesions and can lead to bone destruction.

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What is Pinta?

Pinta is a skin infection caused by Treponema carateum. It is characterized by lesions that can cause discoloration and scarring.

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What is Lyme Disease?

Borrelia bacteria cause Lyme disease, a tick-borne illness. It can affect the skin, joints, nervous system, and heart.

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What are Borrelia bacteria known for?

Different Borrelia species cause various diseases, including Lyme disease, relapsing fever, and tick-borne spirochetosis.

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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)

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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.

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