Tuberculosis and Actinomycetes Quiz

Spirochetes, Mycobacteria, and Other Bacteria

• Spirochetes, mycobacteria, and other bacteria are a group of microorganisms that have various characteristics and cause different diseases.
• Mycobacteria are slender rods with lipid-rich cell walls. They are acid-fast.
• Mycobacteria stain poorly but, once stained, cannot be easily decolorized by treatment with acidified organic solvents.
• Mycobacterial infections are primarily intracellular and result in slow-growing granulomatous lesions causing major tissue destruction. Tuberculosis is an example of a disease caused by mycobacteria.
• Mycobacterium tuberculosis causes tuberculosis, a chronic bacterial disease in humans. It's a leading cause of death globally due to infection.
• Mycobacteria are long, slender rods, non-motile, strictly aerobic, and non-resistant to UV.
• Mycobacteria have cell walls rich in complex lipids and waxes (mycolic acids).
• Mycobacteria are difficult to stain and decolorize and therefore remain acid-fast.
• Mycobacteria are long, slender, nonmotile rods that do not form spores. Mycobacterial cell walls are unusual in that they are approximately sixty percent lipid including a unique class of very long-chained mycolic acids (75 to 90 carbons)

Atypical Bacteria

• A general heading for a group of bacteria that don't fit neatly into typical categories

Mycobacteria and Actinomycetes

• Mycobacteria and actinomycetes are characterized by their resistance to staining, requiring acid-fast staining.
• Their rigid cell walls are resistant to chemical dyes.

Overview

• Mycobacteria are slender rods with lipid-rich cell walls.
• They stain poorly and are acid-fast.
• Mycobacterial infections are typically intracellular and form slow-growing granulomas.

Medically Important Bacteria

• Mycobacteria, Actinomycetes, Rickettsia, Ehrlichia, Coxiella, and Bartonella are medically important.
• This slide shows a classification of these bacteria based on cell wall structure (rigid or lacking).
• Mycobacteria and actinomycetes are filamentous and gram-positive, whereas Rickettsia, Ehrlichia, Coxiella, and Bartonella are of differing types.

Mycobacteria

• Mycobacteria are long slender rods that are nonmotile and do not form spores.
• Mycobacterial cell walls are a significant component of their structure.

Tuberculosis

• Tuberculosis (TB) is a contagious bacterial disease caused by Mycobacterium tuberculosis.
• TB spreads person-to-person frequently via respiratory droplets.
• Prevention of TB is available with vaccination to prevent this and also through treatment of those infected.

Mycobacterium Tuberculosis

• It is currently estimated that about one-third of the world's population is infected with M. tuberculosis.

Epidemiology

• Tuberculosis is a disease with large numbers of organisms shed by coughing.
• The main mode of transmission is person-to-person via inhalation of aerosol droplets.

Range of Rates per 100,000

• A geographic map shows reported rates of tuberculosis per 100,000 across the globe.

Primary Disease Initial Phase

• Primary tuberculosis is usually acquired through the respiratory tract. Initial lesions are in the midlung periphery of the lungs.
• The organisms are engulfed by local mononuclear phagocytes, and their presence triggers an inflammatory response.

Tuberculosis Signs and Symptoms

• Potential symptoms include blood cough, fever, chest pain, chills, long-term cough, weight loss, and night sweats.

Laboratory Identification

• Identifying M. tuberculosis in patient samples is crucial for diagnosis.
• Nucleic acid amplification PCR and culture on specialized agar plates are used for this purpose.

Treatment

• Treating tuberculosis requires a prolonged course of multiple antibiotic therapy. This is due to emerging antibiotic resistance.
• Isoniazid, rifampin, ethambutol, streptomycin, and pyrazinamide are examples of first-line tuberculosis drugs.

Prevention

• BCG vaccine is available and used for the prevention of latent tuberculosis.
• Directly observed therapy (DOT) programs improve patient compliance with multi-drug regimens.

Mycobacterium Leprae

• Mycobacterium leprae is an acid-fast bacterium.
• It causes leprosy.

Leprosy

• Leprosy is a chronic granulomatous condition affecting peripheral nerves and mucocutaneous tissues.
• It occurs in a range of severity from tuberculoid to lepromatous forms.

Actinomycetes

• Actinomycetes are gram-positive, filamentous, branching bacteria often described as opportunistic pathogens.

Nocardia

• Nocardia species are aerobic soil organisms that are usually opportunistic pathogens and not directly transmissible between people.
• They can infect humans, as well as domestic animals.
• Common symptoms/signs are pneumonia, inflammation, abscesses, and necrosis.

Chlamydia

• Chlamydiae are obligate intracellular bacteria.
• They live in cells, require a host cell for energy, and grow in cytoplasmic vacuoles within host cells.
• Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae are different species within this genus.

Chlamydia Trachomatis

• C. trachomatis causes various diseases, including urethritis, conjunctivitis, lymphogranuloma venereum (LGV), and trachoma.
• The most common disease caused by C. trachomatis in the United States is non-gonococcal urethritis (NGU).
• C. trachomatis can cause eye infections, ranging from irritation to blindness.

Chlamydia Psittaci

• C. psittaci causes psittacosis (ornithosis), a zoonotic disease.
• Transmission is through inhalation of dust contaminated with respiratory secretions or feces from infected birds.

Chlamydia Pneumoniae

• C. pneumoniae is a respiratory pathogen that causes pharyngitis, laryngitis, bronchitis, or interstitial pneumonia.

Rickettsia, Ehrlichia, Coxiella, and Bartonella

• These are gram-negative intracellular bacteria, classified into different phyla.
• The different organisms cause symptoms like spotted fevers, typhus, and similar illnesses in humans.
• Each has a unique range of hosts, vectors, pathology, and worldwide distribution.

Mycoplasma

• Mycoplasmas are small prokaryotic organisms with no peptidoglycan cell walls.
• They cause diseases like primary atypical pneumonia, urethritis, pelvic inflammatory disease, and intrapartum infections.

Spirochetes

• Spirochetes are long, slender, motile, flexible, and undulating bacteria.
• They have a corkscrew or helical shape, and the shape is key to diagnosis.
• Some spirochetes are part of normal flora.
• A few genera (Treponema, Borrelia, and Leptospira) are important human pathogens.

Treponema Pallidum

• T. pallidum causes syphilis, a sexually transmitted disease.
• Syphilis progresses through stages, starting with a painless lesion.
• If left untreated, it can cause serious issues with the nervous and cardiovascular systems.

Borrelia Burgdorferi

• This is the spirochete that causes Lyme disease.
• Spirochetes like Treponema and Borrelia are highly motile, have unique structures within their cell walls and are transmitted from ticks to humans.

Leptospira Interrogans

• L. interrogans causes leptospirosis, an infection primarily transmitted via water or food contaminated with animal urine.
• L. interrogans is a slender, tightly coiled, culturable spirochete with a single, thin axial filament.
• The infection affects the liver, kidneys, and the nervous system.

Test your knowledge on tuberculosis, including its transmission, diagnosis, and treatment methods. This quiz covers key concepts related to Mycobacterium tuberculosis and Actinomycetes, as well as their clinical implications. Assess your understanding of these important infectious diseases.