Tuberculosis: Transmission and Treatment

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary mode of transmission for Mycobacterium tuberculosis?

Contact with infected surfaces

Consumption of contaminated food

Blood transfusions

Inhalation of aerosol droplet nuclei (correct)

Which demographic is significantly affected by co-infection with M.tuberculosis?

HIV-infected population (correct)

Logistics workers

Elderly individuals

Children under five

What is the initial phase of primary tuberculosis characterized by?

Absence of inflammatory response

Systemic spread of bacteria

Infection through oral ingestion

Lesions in the mid-lung periphery (correct)

What is a defining feature of the cell walls of mycobacteria?

They contain a high percentage of lipids. Signup and view all the answers

What is a common challenge in the treatment of tuberculosis?

Emergence of drug-resistant strains Signup and view all the answers

Which of the following diseases is primarily caused by Mycobacterium tuberculosis?

Tuberculosis Signup and view all the answers

Which of the following is NOT a principal drug used in the treatment of M.tuberculosis?

Metronidazole Signup and view all the answers

What characteristic of mycobacteria makes them resistant to drying?

The composition of their cell walls. Signup and view all the answers

What method is commonly employed for diagnosing active pulmonary tuberculosis?

Nucleic acid amplification PCR Signup and view all the answers

What approach could improve patient compliance during tuberculosis treatment?

Directly observed therapy (DOT) Signup and view all the answers

How long is the generation time for most mycobacterial species?

8 to 24 hours Signup and view all the answers

In which regions has tuberculosis incidence significantly increased?

Asian and sub-Saharan African countries Signup and view all the answers

What is the primary environmental condition required for the growth of mycobacteria?

Oxygen-rich environments Signup and view all the answers

What type of lesions are typically formed due to mycobacterial infections?

Granulomatous lesions Signup and view all the answers

What staining characteristic is associated with mycobacteria?

Acid-fast staining Signup and view all the answers

Which of the following is NOT a feature of mycobacteria?

They can form spores. Signup and view all the answers

What is the primary organism used to produce the vaccine against tuberculosis?

Bacille Calmette-Gurin (BCG) Signup and view all the answers

Which of the following best describes leprosy?

A chronic granulomatous condition of peripheral nerves Signup and view all the answers

What type of bacteria is Actinomycetes classified as?

Filamentous, branching, gram-positive prokaryotes Signup and view all the answers

What is the typical presentation of nocardiosis in humans?

Pneumonia with abscesses and extensive necrosis Signup and view all the answers

Chlamydia trachomatis is primarily responsible for causing which of the following conditions?

Nongonococcal urethritis Signup and view all the answers

What is a key characteristic of Nocardia with respect to transmission?

They cause diseases primarily through environmental exposure. Signup and view all the answers

Which statement correctly describes the nature of Chlamydia as bacteria?

They are obligate intracellular parasites. Signup and view all the answers

Which species of Chlamydia is known to cause atypical pneumonia?

Chlamydia pneumoniae Signup and view all the answers

Which Chlamydia species is known to cause the syndrome non-gonococcal urethritis (NGU)?

Chlamydia Trachomatis Signup and view all the answers

What disease does Chlamydia Psittaci primarily cause in humans?

Psittacosis Signup and view all the answers

What are the possible severe complications of an infection caused by Chlamydia Psittaci?

Hepatitis, encephalitis, or myocarditis Signup and view all the answers

Which Chlamydia species is a significant cause of community-acquired respiratory infection?

Chlamydia Pneumoniae Signup and view all the answers

What is the primary symptom of primary stage syphilis?

Hard genital or oral ulcer Signup and view all the answers

How long after infection does the chancre typically appear?

3 weeks Signup and view all the answers

What symptom is commonly associated with infections caused by Chlamydia Pneumoniae?

Hacking dry cough Signup and view all the answers

What historical significance does trachoma have?

Mentioned in Egyptian writings around 3800 B.C. Signup and view all the answers

What stage of syphilis may cause conditions such as hepatitis or meningitis?

Secondary stage Signup and view all the answers

Which treatment is curative for primary and secondary syphilis?

Penicillin Signup and view all the answers

Which of the following is not a characteristic of mycoplasmas?

Contains peptidoglycan cell walls Signup and view all the answers

Which of the following bacteria is known to cause Q fever?

Coxiella burnetii Signup and view all the answers

What percentage of infected individuals may progress to the tertiary stage of syphilis?

30% to 40% Signup and view all the answers

What is a possible consequence of congenital syphilis for the infant?

CNS and structural abnormalities Signup and view all the answers

What method is usually used for serological diagnosis of syphilis?

Fluorescent treponemal antibody absorption (FTA-ABS) Signup and view all the answers

What can prevent congenital syphilis during pregnancy?

Treatment with appropriate antibiotics Signup and view all the answers

What type of DNA do Borrelia species possess?

Linear plasmid DNA Signup and view all the answers

What is required for transmission of B. burgdorferi to occur via ticks?

The tick must be attached for at least 24 hours Signup and view all the answers

What is the characteristic lesion associated with the first stage of Lyme disease?

Red, circular lesion with a clear center Signup and view all the answers

Which system does L. interrogans primarily affect after initial infection?

Central nervous system Signup and view all the answers

How is leptospirosis primarily transmitted to humans?

By water or food contaminated with animal urine Signup and view all the answers

What condition is NOT typically associated with leptospirosis?

Sepsis Signup and view all the answers

Which of the following statements is correct about Treponema pallidum?

There is no vaccine against T. pallidum. Signup and view all the answers

What primary reservoirs are associated with B. burgdorferi?

Mice and small rodents Signup and view all the answers

Study Notes

Spirochetes, Mycobacteria, and Other Bacteria

Spirochetes, mycobacteria, and other bacteria are key microorganisms studied in microbiology.
Mycobacteria are slender rods with lipid-rich cell walls resistant to chemical dyes, staining poorly but intensely once stained .
The cell wall of mycobacteria prevents removal of the dye after staining.
Mycobacteria are acid-fast, meaning they cannot be decolorized by acidified organic solvents.
Mycobacterial infections often result in slow-growing granulomas, leading to significant tissue destruction.
Examples include Mycobacterium tuberculosis, causing tuberculosis, a chronic bacterial disease and leading cause of death from infection.
Mycobacteria have long slender rods that are non-motile and do not form spores.
They are strictly aerobic, grow slowly with a hydrophobic surface,promoting clumped growth, and resistant to drying but not heat or ultraviolet irradiation.
Important species include: Mycobacterium avium-intracellulare, Mycobacterium bovis, Mycobacterium kansasii, Mycobacterium leprae, Mycobacterium scrofulaceum, Mycobacterium tuberculosis.

Actinomycetes

Actinomycetes are filamentous, branching, gram-positive organisms.
They resemble fungi morphologically but are prokaryotes of bacterial size.
Common in soil, they are related to corynebacteria and mycobacteria, and are sources of important antibiotics.
Notable example is Actinomyces israelii.

Nocardia

Nocardia species are notable aerobic soil organisms.
Infections in humans and domestic animals are opportunistic and not transmitted from person to person.
A significant clinical condition involves pneumonia and a chronic course with abscesses and significant tissue necrosis.
Common Nocardia species: Nocardia asteroides, Nocardia brasiliensis.

Chlamydiae

Chlamydiae are exclusively intracellular parasites depending on the host cell for energy.
They grow in host cell vacuoles.
Important species include: Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae.
Chlamydia trachomatis causes genital and eye infections, such as nongonococcal urethritis (NGU) and trachoma.
Chlamydia psittaci causes psittacosis and respiratory tract infections.
Chlamydia pneumoniae causes atypical pneumonia in humans.
Transmission can occur via sexual contact, respiratory droplets, or inhalation of dried bird feces.

Rickettsia, Ehrlichia, Coxiella, and Bartonella

Rickettsiae, Ehrlichia, Coxiella, and Bartonella are gram-negative intracellular bacteria.
They are causative agents of spotted fevers and related illnesses.
Key species of Rickettsia include: Rickettsia rickettsii causing Rocky Mountain spotted fever, Rickettsia akari causing Rickettsialpox, Rickettsia prowazekii causing Epidemic typhus, Rickettsia typhi causing Endemic typhus, and Rickettsia tsutsugamushi causing Scrub typhus.
Coxiella burnetii causes Q fever
Ehrlichia are distinct from true rickettsiae, have four genera, with Ehrlichia and Anaplasma as important species in humans
Bartonella are similar bacteria but not members of the same taxonomic family.
Transmission often involves arthropods (ticks, lice, fleas, etc.) as vectors.

Mycoplasma

Mycoplasmas are small prokaryotic organisms without cell walls.
They have no peptidoglycan.
Key species are important causes of atypical pneumonia and genitourinary tract diseases including urethritis and pelvic inflammatory disease.
Mycoplasma pneumoniae is responsible for primary atypical pneumonia.
Mycoplasma hominis, Ureaplasma urealyticum are associated with various genitourinary diseases such as urethritis.

Spirochetes

Spirochetes are long, slender, motile, and flexible bacteria with a distinctive spiral shape.
They are gram-negative bacilli.
Some species are aerobic, anaerobic, or facultative anaerobic; others cannot be grown in a lab.
Important species include: Treponema pallidum (syphilis); Borrelia burgdorferi (Lyme disease); Borrelia recurrentis (relapsing fever); and Leptospira interrogans (leptospirosis).
Spirochetes have periplasmic flagella (axial filaments) that propel them in a corkscrew-like manner.
They are capable of penetrating host tissues.

Treponema pallidum (Syphilis)

Causes syphilis, a sexually transmitted disease (STD).
Transmitted through direct contact.
Syphilis is characterized by three stages.
A primary chancre, a painless ulcer, marks the initial stage.
Secondary syphilis is accompanied by systemic involvement including rashes, and various symptoms and is typically followed by a latent period.
Tertiary syphilis may cause degeneration of the nervous system, and cardiovascular damage.
Can be transmitted to the fetus during pregnancy, potentially causing congenital syphilis.
Typically diagnosed using serological assays like FTA-ABS.
Treponema pallidum is fragile, fastidious and requires special laboratory techniques for culture; staining is typically done using immunofluoresence or dark-field microscopy.
Treatment: Usually a single penicillin injection for primary and secondary stages, alternative therapies like erythromycin/tetracycline may be used for patients with penicillin intolerance.

Borrelia Burgdorferi (Lyme Disease)

Causes Lyme Disease, an emerging infection.
Transmitted through the bite of infected ticks.
Characterized by a characteristic circular rash (erythema chronicum migrans) at the site of the tick bite, followed by possible neurological, cardiovascular, musculoskeletal symptoms.
Treated with antibiotics like penicillin, amoxicillin, doxycycline, and ceftriaxone.

Leptospira interrogans (Leptospirosis)

Causes leptospirosis, a zoonotic disease transmitted through water or food contaminated with urine.
Symptoms include fever, jaundice, and sometimes hemorrhage of tissue.
Typically diagnosed serologically.
Treated with antibiotics: penicillin or doxycycline.

Studying That Suits You

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

Description

Test your knowledge on tuberculosis, covering its transmission modes, affected demographics, and key treatment challenges. This quiz includes questions on mycobacterial characteristics and diagnostic methods, providing a comprehensive overview of the disease.