Microbiology Quiz on Spirochetes and Chlamydia

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Questions and Answers

Which disease is specifically associated with Borrelia burgdorferi?

Psittacosis

Inclusion conjunctivitis

Syphilis

Lyme disease (correct)

Which of the following correctly describes Chlamydia trachoma?

Can cause genital infections (correct)

Is a Gram-positive bacterium

Is exclusively free-living

Causes respiratory infections

What characteristic differentiates Rickettsiae from Chlamydia?

Rickettsiae are primarily respiratory pathogens

Chlamydia can survive outside a host cell

Chlamydia is exclusively a vector-borne disease

Rickettsiae are Gram-negative intracellular pathogens (correct)

Which structural feature is unique to spirochetes like Treponema pallidum?

Outer sheath with glycosaminoglycan coating Signup and view all the answers

How do endoflagella contribute to the motility of spirochetes?

By flexing and rotating around the protoplasmic cylinder Signup and view all the answers

What is a common complication of B.miyamotoi infection in severely immunocompromised patients?

Meningoencephalitis Signup and view all the answers

Which treatment is recommended for patients with neurologic involvement due to B.miyamotoi infection?

Intravenous ceftriaxone Signup and view all the answers

What is the recommended approach for diagnosing B.miyamotoi infection?

Enzyme immunoassay followed by Western blot Signup and view all the answers

In which months is the nymphal stage of Ixodes ticks most active?

May to July Signup and view all the answers

Which of the following is a characteristic of Rickettsia?

Obligate intracellular parasites Signup and view all the answers

What disease is caused by Epidemic typhus, which is related to Rickettsia?

Rocky Mountain spotted fever Signup and view all the answers

What is a commonly used preventive measure after a tick bite in highly endemic regions?

Prophylactic doxycycline Signup and view all the answers

Which of the following describes the life cycle of Rickettsia?

Requires live cells for cultivation Signup and view all the answers

Which subspecies of Treponema is responsible for causing Pinta?

Treponema carateum Signup and view all the answers

What is the primary method of transmission for leptospirosis?

Contact with contaminated urine Signup and view all the answers

Which of the following is NOT a symptom of leptospirosis?

Skin depigmentation Signup and view all the answers

Which vector is primarily responsible for the transmission of Borrelia hermsii?

Ticks Signup and view all the answers

What characterizes the staining properties of Borrelia species?

They stain readily with bacteriologic dyes Signup and view all the answers

What is a distinctive feature of the antibodies produced after Borrelia infection?

They change over the course of a single infection Signup and view all the answers

Which of the following best describes the structure of Leptospira?

Tightly regular individual coils with bends Signup and view all the answers

What is the common name for the disease caused by Borrelia burgdorferi?

Lyme disease Signup and view all the answers

How is the treatment typically managed for patients with penicillin hypersensitivity?

Doxycycline is used Signup and view all the answers

What is the primary environmental source for leptospirosis outbreaks?

Wildlife urine Signup and view all the answers

What is the primary function of the major outer membrane protein (MOMP) in Chlamydiaceae?

Acts as an immunogenic factor Signup and view all the answers

Which of the following diseases is NOT associated with Bartonella species?

Pneumonia Signup and view all the answers

Which treatment is specifically indicated for cat-scratch disease?

Erythromycin Signup and view all the answers

In the development cycle of Chlamydia, what is the role of the reticulate body (RB)?

Grows within host cell vacuoles Signup and view all the answers

What distinguishes the elementary body (EB) in the life cycle of Chlamydia from the reticulate body (RB)?

EB is the infectious form, while RB is not Signup and view all the answers

Which pathogen requires metabolites from host cells for survival?

Chlamydia trachomatis Signup and view all the answers

What is the mechanism by which Chlamydia establishes infection in host cells?

Induction of its own endocytosis Signup and view all the answers

What is a characteristic of Bartonella species in terms of culturing?

Fastidious, requiring specific culture conditions Signup and view all the answers

How does Chlamydia prevent host cell destruction during its growth phase?

By inhibiting lysosomal fusion Signup and view all the answers

Which of the following statements about Coxiella burnetii is true?

High-temperature short-time pasteurization can destroy it Signup and view all the answers

What is the primary reservoir for Rickettsia pox?

House mouse and semidomestic rodents Signup and view all the answers

Which statement is true about endemic louse-borne typhus fever?

Diagnosis is largely based on serology tests. Signup and view all the answers

What distinguishes Rickettsia typhi from Rickettsia prowazekii in terms of symptom severity?

Rickettsia prowazekii is more severe. Signup and view all the answers

What is the mode of transmission for Q fever caused by Coxiella burnetti?

Inhalation of spores or aerosols Signup and view all the answers

Which of the following is true regarding the treatment of endemic typhus?

Doxycycline should be initiated immediately on suspicion. Signup and view all the answers

What characteristic feature is associated with Rickettsia pox at the site of the mite bite?

Eschar formation Signup and view all the answers

Coxiella burnetti is resistant to what environmental condition?

Drying Signup and view all the answers

Which of the following correctly describes the epidemiological conditions favoring the spread of endemic louse-borne typhus fever?

Disaster situations leading to overcrowding. Signup and view all the answers

What is a unique characteristic of Coxiella burnetti compared to other rickettsiae?

It produces resistant spore-like structures. Signup and view all the answers

In untreated cases of endemic louse-borne typhus fever, which age group experiences the highest fatality rate?

Elderly individuals over 60 Signup and view all the answers

Study Notes

Lecture 12: Microbiology - Spirochetes, Rickettsiae, Chlamydia

This lecture covers the biological characteristics, infection, pathogenesis, immunity, diagnosis, treatment, and prevention of microbial infections caused by spirochetes, rickettsiae, and chlamydia.

Spirochetes

Gram-negative human pathogens
Free-living saprophytes (or commensals) of animals; not considered primary pathogens
Genera include Treponema, Leptospira, Borrelia
T. pallidum has an outer sheath/glyco-aminoglycan coating. The outer membrane within this coating contains peptidoglycan to maintain structural integrity.
Spirochetes are elongated, motile, and flexible bacteria; they are spiral-shaped along their long axis.
Spirochetes contain endoflagella, which are polar flagella wound along the axial filament. They're situated between the outer membrane and cell wall.
Motility involves rotation and flexion of the spiral structure.
Many spirochetes stain poorly with Gram-stains; visualization may involve special staining techniques like dark-field microscopy or immunofluorescence.
T. pallidum, the causative agent of syphilis, is highly fastidious and sensitive, unable to survive long outside the host. It's sexually transmitted and transplacental.
Live cells exhibit characteristic rotating motility and sudden 90-degree angle flexion.
T. pallidum is susceptible to drying and killed by various detergents/disinfectants.
Spirochetes are visualized via immunofluorescent stains or dark-field illumination.
Some are not readily seen under a light microscope.
Genus Treponema: thin, regular, coiled cells; may be aerobic or anaerobic; live in oral cavity, intestinal tract, perigenital regions of humans and animals. Many are part of nasopharyngeal flora. Pathogens are strict parasites with complex growth requirements requiring live cells for cultivation.
Treponema pallidum: humans are the natural host. The spirochete is the causative agent for syphilis.
Spirochaetales Associated Human Diseases: A table listing genera, species, and their associated diseases; includes Syphilis, Bejel, Yaws, Pinta, Lyme disease, Epidemic relapsing fever, Endemic relapsing fever, Leptospirosis.
Spirochetal diseases include Trench mouth; (Vincent infection) caused by overgrowth of spirochetae. The infection correlates with immunocompromise, severe malnutrition, and neglect of basic hygiene. This historically happened to soldiers in trenches during World War I.
Treponema pallidum: the causative agent of syphilis. The great pox was recognized in the 16th century and rapidly spread in Europe.
Syphilis: The current name for the disease. In its explanation comes from a 18th-century poem and was written by Girolamo Fracastoro.
Syphilis pathogenesis and host response: T. pallidum is an exclusively human pathogen; binds to epithelium, and multiplies; penetrates capillaries. Infection rapidly moves into circulation and is established in distant tissues within hours. Untreated syphilis manifests in three clinical stages (primary, secondary, tertiary). Infection is contracted through direct sexual contact or trans-placental route. Tertiary syphilis lacks infectivity.

Rickettsiae

Small, Gram-negative, non-motile, pleomorphic bacteria.
Obligate intracellular parasites that are involved in the life cycle of ticks, fleas, and lice.
Bacteria invade endothelial cells causing necrosis in the vascular linings and lead to vasculitis, vascular leakage, and thrombosis.
Causes rickettsioses, important emerging diseases.
Specific Rickettsioses: Includes diseases like epidemic typhus, endemic typhus, Rocky Mountain spotted fever, scrub typhus, and others.
Rocky Mountain Spotted Fever (RMSF) is commonly found in the Southeast and eastern seaboard of the U.S.
RMSF: Symptoms (rash, fever, myalgia), transmission by ticks, and complications.
Rickettsia pox: Caused by Rickettsia akari transmitted by rodent mites; distinguishing feature is an eschar at the bite site and vascular rash. House mice are the primary reservoirs.
Endemic Louse-Borne Typhus Fever: Caused by R. prowazekii, transmitted by body lice; appears in times of war or famine; highly infectious.
Endemic (Murine) Typhus: Caused by R. typhi, transmitted by rat fleas; resembles typhus, but less severe.

Coxiella Burnetti

Causes Q fever; an intracellular parasite that produces a resistant spore. Q fever is harbored in a wide assortment of vertebrates and arthropods. Infectious material includes urine, feces, milk, and airborne particles.
Q fever often presents as pneumonia, fever, and hepatitis.

Bartonella Species

Bartonella quintana causes Trench Fever.
Bartonella henselae causes cat-scratch disease, a lymphatic infection from a claw injury by cats.
Both are small gram-negative bacteria cultured on blood agar.

Chlamydiaceae

Obligate intracellular parasites that require metabolites from host cells and are small gram-negative. They have a lipopolysaccharide- containing outer membrane and lack peptidoglycan.
Chlamydia trachomatis can infect the mucous membranes of the eyes, genitourinary tract, and lungs, causing conditions like trachoma, inclusion conjunctivitis, and more.
Chlamydophila pneumoniae and psittaci cause diseases like pneumonia and psittacosis (flu-like viral infection) in humans.
Chlamydia alternates between two stages: elementary bodies (EB) are small, metabolically inactive, infectious forms, whereas reticulate bodies (RB) are non-infectious, actively dividing forms growing within host cell vacuoles.
Chlamydia trachomatis: Human reservoir, different strains cause various diseases. Infections includes trachoma (ocular infection, possible blindness), inclusion conjunctivitis (in newborns), and sex-transmitted diseases.
Chlamydophila pneumoniae: Often associated with outbreaks of community-acquired pneumonia. Also causing pharyngitis and laryngitis.
C. psittaci: Causes ornithosis or psittacosis (birds)

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Description

Test your knowledge on key characteristics and diseases associated with spirochetes like Treponema pallidum and Chlamydia trachomatis. This quiz will cover important differentiators and structural features relevant to these microorganisms. Ideal for students studying microbiology or infectious diseases.