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What is the primary reason tuberculosis takes a long time to cure?
Which of the following characteristics describes gram-negative bacteria?
What is a common feature of the Enterobacteriaceae family?
Which bacterium is identified as a common cause of urinary tract infections (UTIs)?
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What distinguishes Pseudomonas species from other bacteria?
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The primary method for differentiating closely related Enterobacteriaceae species is through what process?
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What is the toxic component found in the outer membrane of gram-negative bacteria known for having endotoxic effects?
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Which characteristic of bacteria helps them develop resistance to antibiotics?
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What is the primary function of the elementary bodies in Chlamydiae?
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Which statement correctly describes the reticulate body of Chlamydiae?
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What serious condition can persistent infection with C. Trachomatis lead to?
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Chlamydia lacks a classic cage-like structure in its cell wall but has a narrow ring of what?
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What role does the outer membrane of Chlamydiae play?
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Which organism is responsible for causing pneumonia and is linked to cardiovascular disease?
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What happens to the elementary bodies when the host cell lyses?
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What is a potential consequence of untreated pelvic inflammatory disease (PID)?
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What is the primary transmission method of Yersinia pestis to humans?
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Which component of Yersinia pestis aids in its colonization of the flea midgut?
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What is a unique characteristic of the capsule formed by Yersinia pestis?
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What type of bacteria is Pseudomonas aeruginosa primarily classified as?
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Which bacteria is incorrectly identified as the cause of influenza?
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What role does the protease secreted by Yersinia pestis play in its virulence?
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What can Pseudomonas aeruginosa commonly form in the lungs of cystic fibrosis patients?
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What is the main symptom caused by Yersinia pseudotuberculosis?
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Which bacterium is known to cause botulism and is also used in the production of Botox?
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What characteristic do Clostridium spores exhibit when the environment becomes anaerobic?
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What is the primary complication when a patient is treated with antibiotics concerning Clostridiodes difficile?
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Which of the following describes Clostridium tetanus?
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Which property distinguishes non-spore formers from spore formers in bacteria?
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What role do Lactobacillus spp. and Lactococcus spp. play in food production?
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What is the main clinical significance of Enterococcus spp. in a hospital setting?
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What characteristic is observed when colonies of Moraxella catarrhalis are moved on an agar plate?
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What is a common treatment for infections caused by Enterococcus spp.?
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How do the flagella of spirochetes contribute to their movement in viscous environments?
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What is the nature of the cell wall of spirochetes?
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Which species of Treponema is responsible for the sexually transmitted infection syphilis?
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What distinguishes the different subspecies of Treponema pallidum in terms of disease?
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In what stages can syphilis present itself?
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Which of the following statements is true about Treponema pallidum pertenue?
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Which type of organisms are nonpathogenic spirochetes typically associated with?
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Study Notes
Gram-Positive Firmicutes
- Clostridium spores are found in soil and water, ready to germinate and grow in anaerobic environments.
- Bacillus anthracis is a rod-shaped soil bacterium that causes anthrax.
- Clostridiodes difficile is a rod-shaped bacterium with bulging spores that causes intestinal disease in patients whose normal microbiota are diminished by antibiotics, leading to pseudomembranous colitis.
- Clostridium botulinum is a rod-shaped bacterium with bulging spores that causes botulism and produces Botox.
- Clostridium tetanus is a rod-shaped bacterium with bulging spores that causes tetanus, resulting in continuous muscular contraction.
- Enterococcus spp. are cocci found in the intestinal tract and are a common cause of urinary tract infections (UTIs) and bacteremia in immunocompromised patients.
- Lactobacillus spp. and Lactococcus spp. are rods and cocci, respectively, involved in dairy culture.
- Lactobacillus and Lactococcus spp. are obligate fermenters, meaning they can grow in the presence or absence of oxygen, but they don't use oxygen to respire.
Phylum Proteobacteria: A Diverse Superphylum
- Proteobacteria are gram-negative and include heterotrophs, lithotrophs, and photosynthesizers.
- The gram-negative envelope consists of an outer membrane, a peptidoglycan cell wall permeated by the periplasm, and an inner membrane.
- The outer membrane contains receptor proteins, porins, and lipopolysaccharide (LPS), which can have toxic effects on the host and pose an endotoxic shock risk.
- Enterobacteriaceae is a family of proteobacteria, mostly appearing as rods.
- Pseudomonadaceae contain pseudomonas, which are rod-shaped obligate respirers, requiring oxygen as a terminal electron acceptor for energy production.
Escherichia coli
- A rod-shaped bacterium that is a main vehicle for biotechnology and can cause intestinal and bladder infections.
- It is part of the Enterobacteriaceae family and plays a crucial role in the human intestine, producing vitamins.
- E. coli is a major cause of death in children under 5.
- It is also the causative agent of the bubonic plague.
Yersinia spp.
- Gram-negative bacilli that can be transmitted from animals to humans through infected fleas or respiratory droplets.
- Y. Pestis is a variant of Y. Pseudotuberculosis, arising from horizontal gene transfer, and causes the bubonic plague.
- Y. Pseudotuberculosis causes gastrointestinal disease resembling appendicitis.
Pseudomonas aeruginosa
- Obligate aerobic bacilli related to Enterobacteriaceae.
- Commonly found in soil as a decomposer, but in humans, it can infect surgical wounds or form biofilms in the lungs of cystic fibrosis patients.
- Known to cause hospital-acquired infections and can be resistant to many antibiotics.
- Produces a characteristic greenish color on agar plates.
Haemophilus influenzae
- An intracellular symbiont and predator.
- Frequently mistaken for the cause of influenza, which is actually caused by a virus.
- Causes pneumonia.
Moraxella catarrhalis
- Exhibits a "hockey puck" behavior on agar plates, where the colony moves as a single unit when disturbed.
Phylum Spirochaetes: Twisted-Cell Pathogens and Symbionts
- Spirochetes are a distinctive group of bacteria with a long, tight, and flexible spiral shape, resembling a coiled telephone cord.
- They have a thin peptidoglycan cell wall completely separating the sheath from the plasma membrane.
- Most spirochetes are slow-growing heterotrophs and are difficult to culture.
- Many are free-living in soil and water, and some are digestive symbionts in hosts like termites and cattle.
- The cell is surrounded by a thick outer sheath of lipopolysaccharides and proteins.
- One or more flagella extend from each end of the cell and double back within the periplasmic space, propelling the cell in a corkscrewing motion.
Treponema pallidum
- Causes syphilis, a sexually transmitted infection.
- Syphilis is caused by T. pallidum pallidum and progresses in three stages: primary, secondary, and tertiary.
- Can cross the placenta and infect a developing fetus.
Treponema pertenue
- Causes yaws, a multistage disease transmitted through direct skin contact, prevalent in developing countries.
- Unlike syphilis, it cannot cross the placenta and infect a fetus.
Phylum Chlamydiae: Intracellular Pathogens
- Chlamydiae are a group of bacteria with cell walls containing very little peptidoglycan.
- Pathogenic species lack the classic cage-like form of peptidoglycan but have a narrow ring at mid-cell for cell division.
- They are obligate parasites or pathogens and spend their entire life cycle within a host cell.
- They possess an outer membrane cross-linked by disulfide bonds, providing osmotic stability despite lacking a proper cell wall.
- Chlamydia trachomatis is a major cause of sexually transmitted infections in the U.S. and can lead to pelvic inflammatory disease (PID).
- Chlamydia trachomatis also causes trachoma, an eye disease.
- Chlamydophila pneumoniae causes pneumonia and has been implicated in cardiovascular disease.
- Chlamydiae alternate between two developmental stages: elementary bodies and reticulate bodies.
- Elementary bodies are metabolically inert and responsible for transmission.
- Reticulate bodies are metabolically active and multiply rapidly inside the host cell, but lack infectivity and are vulnerable to osmotic shock.
- PID can lead to permanent adhesions and infertility.
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Description
Explore the fascinating world of Gram-positive Firmicutes, including key species like Bacillus anthracis and Clostridium spp. This quiz covers their characteristics, pathogenic potential, and ecological roles. Test your knowledge on these essential bacteria and their impacts on health and environment.
