Microbiology: Spirochetes and Mycobacteria

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What pathogen is used to produce the tuberculosis vaccine?

Chlamydia trachomatis

Nocardia asteroides

Mycobacterium leprae

Bacille Calmette-Gurin (correct)

What is the primary mode of transmission for leprosy?

Ingestion of contaminated food

Prolonged contact with skin lesions (correct)

Direct contact with mucous membranes

Airborne droplets

Which statement best describes Actinomycetes?

They are prokaryotes that resemble yeast morphologically.

They are obligate intracellular parasites.

They are a group of filamentous, branching, gram-positive organisms. (correct)

They are exclusively found in aquatic environments.

Which of the following is a clinical presentation of Nocardia infections?

Chronic pneumonia with abscesses Signup and view all the answers

What is a characteristic of Chlamydia bacteria?

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

Which Chlamydia species is known to cause ocular infections?

Chlamydia trachomatis Signup and view all the answers

What describes the pathogenicity of Mycobacterium leprae?

Requires contact with infected exudates Signup and view all the answers

What type of environment do Nocardia organisms thrive in?

Aerobic soil environments Signup and view all the answers

What is the primary mode of transmission for M.tuberculosis?

Inhalation of aerosolized droplets Signup and view all the answers

What percentage of the HIV-infected population in some regions is co-infected with M.tuberculosis?

50% Signup and view all the answers

What initial site is affected by primary tuberculosis when contracted via the respiratory tract?

Bronchiole or alveolus Signup and view all the answers

Which of the following is NOT a first-line drug used in the treatment of M.tuberculosis?

Amoxicillin Signup and view all the answers

Why is multiple drug therapy employed in the treatment of M.tuberculosis?

To prevent resistance development Signup and view all the answers

What diagnostic method is commonly used for identifying active pulmonary tuberculosis?

Nucleic acid amplification PCR Signup and view all the answers

What strategy is recommended for individuals who test positive for TB but show no symptoms?

Latent TB chemotherapy Signup and view all the answers

What phenomenon occurs when an infected person can pass M.tuberculosis to multiple individuals?

Aerosol transmission Signup and view all the answers

What characteristic distinguishes mycobacteria in terms of their cell wall composition?

They have a high lipid content. Signup and view all the answers

What term is used to describe the staining characteristic of mycobacteria?

Acid-fast Signup and view all the answers

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

Tuberculosis Signup and view all the answers

What is the primary growth characteristic of most mycobacterial species?

Slow growth with generation times of 8 to 24 hours. Signup and view all the answers

What does the hydrophobic surface of mycobacteria contribute to their growth?

Promotes clumped growth. Signup and view all the answers

In what way are mycobacterial infections generally characterized?

They often result in the formation of granulomatous lesions. Signup and view all the answers

Which statement about mycobacteria is TRUE?

They are strictly aerobic and nonmotile. Signup and view all the answers

What is a major consequence of mycobacterial infections in humans?

Major tissue destruction due to granulomatous lesions. Signup and view all the answers

What type of DNA do members of the genus Borrelia possess?

Linear chromosomal DNA Signup and view all the answers

What is the primary reservoir for the spirochete B.burgdorferi?

Mice and small rodents Signup and view all the answers

How long must an Ixodes tick be attached for transmission of Lyme disease to occur?

At least 24 hours Signup and view all the answers

Which of the following symptoms is characteristic of the first stage of Lyme disease?

Erythema chronicum migrans Signup and view all the answers

How is leptospirosis primarily transmitted to humans?

Consumption of infected food or water Signup and view all the answers

What organ systems can be affected by L.interrogans during an infection?

Liver, kidneys, and CNS Signup and view all the answers

What appearance does L.interrogans have under a microscope?

Slender and tightly coiled Signup and view all the answers

What is the most common arthropod-transmitted disease in the United States?

Lyme disease Signup and view all the answers

Which species is primarily associated with the causation of primary atypical pneumonia?

Mycoplasma pneumoniae Signup and view all the answers

Which genera of spirochetes is responsible for causing relapsing fever?

Borrelia Signup and view all the answers

What structural feature of spirochetes aids in their motility?

Endoflagella oriented axially Signup and view all the answers

What is the primary transmission route for Treponema pallidum, the causative agent of syphilis?

Sexual contact Signup and view all the answers

Which disease associated with Ureaplasma urealyticum can lead to serious complications if left untreated?

Pelvic inflammatory disease Signup and view all the answers

Which of the following statements about Treponema pallidum is true?

It is sensitive to disinfectants and heat. Signup and view all the answers

What characterizes the shape of spirochetes?

Corkscrew or helical Signup and view all the answers

Which spirochete is known to cause Lyme disease?

Borrelia burgdorferi Signup and view all the answers

What is the primary clinical syndrome caused by Chlamydia trachomatis?

Non-gonococcal urethritis Signup and view all the answers

Which of the following diseases is caused by Chlamydia psittaci?

Psittacosis Signup and view all the answers

What is a common complication of psittacosis in humans?

Encephalitis Signup and view all the answers

What class of bacteria do Rickettsia belong to?

Gram-negative intracellular bacteria Signup and view all the answers

Which disease is specifically caused by Coxiella burnetii?

Q fever Signup and view all the answers

Which of the following characteristics describes Mycoplasmas?

Lack a peptidoglycan cell wall Signup and view all the answers

Which type of Chlamydia is a significant cause of lower respiratory tract infections in humans?

Chlamydia pneumoniae Signup and view all the answers

What is a prevalent characteristic of community-acquired infections caused by C. pneumoniae?

Significant frequency of epidemic outbreaks Signup and view all the answers

Study Notes

Spirochetes, Mycobacteria, and Other Bacteria

Spirochetes, mycobacteria, and other bacteria are diverse groups of microorganisms
Mycobacteria are slender rods with lipid-rich cell walls
They are acid-fast, meaning they do not easily lose the stain once stained
Mycobacterial infections are intracellular and result in granulomatous lesions
Mycobacterium tuberculosis is a significant cause of chronic bacterial disease
Mycobacteria are long, slender rods, non-motile, and strictly aerobic
They have unique lipid-rich cell walls
Resistant to drying, but not heat or UV irradiation
Mycobacterium tuberculosis (causes TB) is a major cause of death globally
Mycoplasmas are small prokaryotic organisms, lacking cell walls

Atypical Bacteria

Characteristics of Rickettsia species
Characteristics of Ehrlichia species
Characteristics of Coxiella species
Characteristics of Bartonella species

Mycobacteria and Actinomycetes

Mycobacteria are slender rods with a waxy lipid-rich cell wall
Resist staining/difficult to decolorize
Mycobacteria are acid fast
Mycobacteria reproduce slowly ( 8 - 24 hours)
Acid fast example: Mycobacteria Tuberculosis species

Overview

Mycobacteria are acid-fast, rod-shaped bacteria
They are characterized by their thick, waxy cell walls
Mycobacteria cause significant human diseases like TB
Mycobacteria infections result in slow-growing granulomatous lesions
Actinomycetes are filamentous, gram-positive bacteria
They are opportunistic pathogens
Nocardia is a significant example of the actinomycetes

Chlamydiae

Chlamydiae are obligate intracellular bacteria
They require host cells for energy
Divided into three species: C. trachomatis, C. psittaci, and C. pneumoniae
C. trachomatis causes diseases of the genitourinary tract and eyes
C. psittaci causes psittacosis
C. pneumoniae causes atypical pneumonia

Epidemiology of Mycobacterium Tuberculosis

TB is frequently found in developing nations
People affected with HIV are more likely to have TB
Transmission is primarily person-to-person
Patients with active TB can transmit the disease through the aerosolized material
A single patient may transfer the bacterium to many people

Primary Disease Initial Phase

Primary tuberculosis is acquired through the respiratory tract
Bacteria enter a bronchiole or alveolus
Phagocytes engulf the bacteria
The phagocytosis begins an inflammatory response

Tuberculosis

Signs and symptoms include blood cough, fever, chest pain, chills, long-term cough, weight loss, and night sweats
Diagnostic methods include identifying the bacteria in specimens, Nucleic acid amplification PCR, and culture on special agar

Treatment (TB)

Treatment generally takes 8-12 months due to drug resistance
Multiple drug therapy is standard
Common first-line drugs include Isoniazid, Rifampin, Ethambutol, Streptomycin, and Pyrazinamide

Prevention (TB)

Vaccination and latent TB chemotherapy are frequently used preventative measures
Directly observed therapy (DOT) is used for compliance in some cases

Mycoplasma

Mycoplasmas are prokaryotes lacking cell walls
They cause respiratory infections and genitourinary diseases (ex: urethritis, pelvic inflammatory disease, and intrapartum infections)

Spirochetes

Spirochetes are long, slender, and motile
They are gram-negative bacteria
They have a corkscrew or helical shape resulting from the periplasmic flagella
Spirochetes can be aerobic, anaerobic, or facultatively anaerobic
Some are part of the normal human/animal flora

Medically Important Spirochetes

Treponema pallidum causes syphilis
Borrelia burgdorferi causes Lyme disease
Leptospira interrogans causes leptospirosis

Treponema Pallidum, Syphilis (Pathology)

Primary syphilis: sores (chancres) develop
Secondary syphilis: rash, fever, mucous membrane sores
Tertiary syphilis: cardiovascular and nervous system damage
Fastidious: requires very specific cultivation
Diagnosis: dark field microscopy/ immunofluorescence
Treatment: penicillin (other antibiotics sometimes used)

Borrelia Burgdorferi, Lyme Disease (Pathology)

Primarily transmitted by tick bite
Stage one: erythema migrans (bullseye rash)
Stage two: joint related issues , nervous system, cardiac issues
Stage three: chronic illness
Diagnosed via tests for antibodies
Treatment: antibiotics (doxycycline or amoxicillin)

Leptospira Interrogans, Leptospirosis (Pathology)

Transmitted via food or water containing animal urine
Early sign: fever
Secondary symptoms: liver, kidney, and CNS effects: jaundice, hemorrhage, and meningitis
Treatment: penicillinsor doxycycline

Studying That Suits You

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

Description

Explore the fascinating world of spirochetes, mycobacteria, and atypical bacteria in this comprehensive quiz. Learn about the unique characteristics, pathogenicity, and clinical significance of these microorganisms, with a focus on Mycobacterium tuberculosis. Test your knowledge on various bacteria such as Rickettsia and Ehrlichia as well.