Microbiology Class: Normal Flora Quiz

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Questions and Answers

Which type of bacteria play a role in protecting the human body?

Opportunistic bacteria

Normal flora (correct)

Pathogenic bacteria

Microbial pathogens

What is the relationship between normal microbiota and the host classified as?

Commensalism

Neutralism

Competition

Symbiosis (correct)

What term describes microorganisms that are present for a limited time and then disappear?

Pathogenic bacteria

Normal flora

Perennial microbiota

Transient microbiota (correct)

Which of the following body parts does NOT typically contain normal flora?

Central nervous system Signup and view all the answers

What is the primary benefit the host receives from normal flora?

Protection against pathogens Signup and view all the answers

Which of the following is NOT a characteristic of normal microbiota?

Produces disease in healthy individuals Signup and view all the answers

What type of bacteria can emerge as a threat when the immune system is compromised?

Opportunistic bacteria Signup and view all the answers

In which section of the body is normal flora NOT mentioned as present?

Lungs Signup and view all the answers

What is one of the major roles of normal flora in human health?

Facilitating nutrient absorption Signup and view all the answers

Which of the following defines the permanent inhabitants of the body's surfaces?

Normal flora Signup and view all the answers

Which of the following clinical diseases is caused by Streptococcus pyogenes?

Scarlet fever Signup and view all the answers

What unique structural feature is associated with Streptococcus pneumoniae?

Polysaccharide capsule Signup and view all the answers

Which feature is NOT found in Corynebacterium diphtheriae?

Intracellular growth Signup and view all the answers

What type of anthrax is associated with inhalation and poses a significant concern for biological weapons?

Inhalation anthrax Signup and view all the answers

What distinguishing characteristic helps identify Mycobacterium tuberculosis?

It possesses a lipid-rich cell wall Signup and view all the answers

Which bacteria are known to be pleomorphic and can survive in aquatic environments?

Legionella pneumophila Signup and view all the answers

Which factor contributes to the virulence of Bacillus anthracis?

Poly-D-glutamic acid capsule Signup and view all the answers

What is one of the primary clinical diseases caused by Bacillus anthracis?

Anthrax Signup and view all the answers

Which characteristic is true for Streptococcus pneumoniae?

Alpha-hemolytic Signup and view all the answers

What form of tuberculosis is specifically characterized by cavity formation in the lungs?

Pulmonary TB Signup and view all the answers

Which bacterium is associated with severe cases of pneumonia?

Legionella pneumophila Signup and view all the answers

What is a key characteristic of Clostridium botulinum?

Causes lack of muscle contraction Signup and view all the answers

Which of the following bacteria cannot be stained with Gram stain?

Chlamydia trachomatis Signup and view all the answers

What type of clinical disease is associated with Bordetella pertussis?

Whooping cough Signup and view all the answers

Which of the following statements about Pseudomonas aeruginosa is true?

It is associated with infections in cystic fibrosis patients Signup and view all the answers

What common environmental condition can Vibrio cholerae tolerate?

High pH Signup and view all the answers

Which bacterium is known for producing a polysaccharide capsule?

Neisseria meningitidis Signup and view all the answers

Which of the following is a characteristic of Helicobacter pylori?

Produces urease and thrives in acidic environments Signup and view all the answers

Which bacterium is associated with undulant fever?

Brucella species Signup and view all the answers

What is a common symptom of botulism caused by Clostridium botulinum?

Lack of muscle contraction Signup and view all the answers

Which of the following features is true about Staphylococcus epidermidis?

Non-hemolytic cocci that are part of the normal flora of the skin Signup and view all the answers

What type of bacteria are Enterobacteriaceae, such as Escherichia coli, primarily classified as?

Gram-negative bacilli that are facultative anaerobic Signup and view all the answers

Which method can be categorized under the transmission routes for pathogenic bacteria?

Inhalation of contaminated droplets Signup and view all the answers

What characteristic distinguishes pathogenic bacteria from opportunistic bacteria?

Opportunistic bacteria can only cause disease when the host's immune system is compromised Signup and view all the answers

Which statement is true regarding Staphylococcus aureus?

It can cause skin infections and is β-hemolytic Signup and view all the answers

Which of the following bacteria is associated with tooth decay?

Streptococcus mutans Signup and view all the answers

What is a distinguishing characteristic of Streptococcus pyogenes?

It produces exotoxins and forms chains of cocci Signup and view all the answers

Which of the following accurately describes the normal flora of the vagina?

It mainly consists of Lactobacillus species Signup and view all the answers

What best defines an infectious disease?

It is a clinically evident illness resulting from infection Signup and view all the answers

In which of the following situations would an opportunistic bacterium likely cause an infection?

In a person undergoing chemotherapy Signup and view all the answers

Study Notes

Bacteria Important in Human Health

Bacteria play a significant role in human health, both positively and negatively.
They can be protective, causing disease, or opportunistic.

Role of Bacteria in Human Health

Protective: Microbiota (normal flora) protects the body.
Disease-causing: Pathogenic bacteria cause disease.
Opportunistic: These bacteria cause disease only when the host's immune system is compromised.

Microbiota (Normal Flora of Human Body)

Microorganisms colonize the body's surfaces soon after birth.
Permanent microbiota are microorganisms that create permanent colonies without causing disease.
Transient microbiota are microbes present for varying periods before disappearing.
The relationship between the normal microbiota and the host is symbiotic (mutualism).
Beneficial microorganisms derive nutrients and protection from the host, while the host receives protection from pathogens.

Parts of the Human Body Containing Normal Flora

Skin
Eyes (conjunctiva)
Nose and throat (upper respiratory system)
Mouth
Gastrointestinal tract
Genitourinary tract

Normal Flora

Consists of many microorganisms.
Key members are summarized in the following sections.

Skin Microbiota

Staphylococcus epidermidis is a common species.
Staphylococcus epidermidis is gram-positive cocci.
Staphylococcus epidermidis is facultative anaerobic.

Mouth Microbiota

Streptococcus mutans is a common species.
Streptococcus mutans is gram-positive cocci.
Streptococcus mutans are facultative anaerobic.
Streptococcus mutans contribute to tooth decay.

Gastrointestinal Tract Microbiota

Enterobacteriaceae (enteric bacteria like Escherichia coli) are common.
Enterobacteriaceae are gram-negative bacilli.
Enterobacteriaceae are facultative anaerobic.

Genitourinary Tract Microbiota

Lactobacillus in the vagina is a key species.
Lactobacillus is gram-positive bacilli.
Lactobacillus is facultative or strictly anaerobic.
The acidic pH of the vagina creates an inhibiting environment for pathogens.

Disease-Causing Bacteria

Pathogenic bacteria: Can cause disease directly.
Opportunistic bacteria: Cause disease only when the host's immune system is compromised.
Examples can include bacteria introduced through medical procedures like catheters.

Infection and Infectious Disease

Infection: The multiplication of an infectious agent within the body.
Infectious disease: A clinically evident illness with characteristic signs and/or symptoms resulting from the infection.

Transmission of Pathogenic Bacteria

Portals of entry: Respiratory, gastrointestinal, genital, urinary, capillary, skin, eyes, and ears.
Routes of entry: Ingestion, inhalation, trauma, needlestick, arthropod bites, and sexual transmission.

Bacterial Diseases (Specific Examples)

Staphylococcus aureus:
- Gram-positive cocci
- Forms grape-like clusters
- Facultative anaerobic
- Beta-hemolytic
- Toxin production (positive)
- Important clinical diseases: skin and soft tissue infections, gastroenteritis, toxic shock syndrome
Staphylococcus epidermidis:
- Gram positive cocci
- Forms grape-like clusters
- Facultative anaerobic
- Non-hemolytic
- Normal skin flora
- Important clinical diseases: Wound infections and infections related to implants/catheters
Streptococcus pyogenes:
- Gram-positive cocci
- Forms chains
- Group A Beta-hemolytic streptococci (GABHS)
- Facultative anaerobic
- Beta-hemolytic
- Toxin production (positive)
- Important clinical diseases: skin and soft tissue infections, streptococcal sore throat (pharyngitis), scarlet fever
Streptococcus pneumoniae:
- Gram-positive diplococci
- Alpha-hemolytic
- Polysaccharide capsule (positive)
- Important clinical diseases: pneumonia, sinusitis, otitis media, meningitis
Corynebacterium diphtheriae:
- Gram-positive bacilli
- Metachromatic granules (positive)
- Toxin production (positive)
- Important clinical disease: Diphtheria
Bacillus anthracis:
- Gram-positive bacilli
- Centrally located spores (+)
- Capsule (+)
- Polypeptide (poly-D-glutamic acid)
- Toxin production (+)
- Important clinical disease: Anthrax
Mycobacterium tuberculosis:
- Gram-positive cell wall
- Aerobic rods
- Cannot be stained with Gram stain
- Lipid-rich cell wall
- Contain mycolic acids
- Intracellular
- Important clinical diseases: Tuberculosis (TB)
Legionella pneumophila:
- Pleomorphic
- Gram-negative, aerobic rods
- Intracellular
- Important clinical diseases: Pontiac fever, Legionnaires' disease
Clostridium tetani:
- Gram-positive rods
- Anaerobic
- Terminal spores (+)
- Toxin production (+)
- Important clinical disease: Tetanus
Clostridium botulinum:
- Gram-positive rods
- Anaerobic
- Subterminal spores (+)
- Toxin production (+)
- Important clinical disease: Botulism
Pseudomonas aeruginosa:
- Gram-negative bacilli
- Aerobic
- Toxin production (+)
- Diffusible pigments (+)
- Important clinical diseases: pulmonary infections, infections of burn wounds
Bordetella pertussis:
- Gram-negative coccobacilli
- Aerobic
- Toxin production (+)
- Important clinical disease: Pertussis (whooping cough)
Neisseria species:
- Gram-negative diplococci
- Aerobic
- Intracellular
- Important clinical diseases: Neisseria meningitidis: meningitis
Neisseria gonorrhoeae*: urogenital infections
Treponema pallidum:
- Gram-negative spiral bacilli
- Spirochetes
- Cannot be stained with Gram stain
- Dark-field microscopy is needed
- Cannot be cultured
- Important clinical disease: Syphilis
Chlamydia trachomatis:
- Gram-negative bacteria
- Lack rigid peptidoglycan
- Cannot be stained with Gram stain
- Cultivated only in cell cultures
- Important clinical diseases: ocular infections, urogenital infections
Rickettsia species:
- Gram-negative rods
- Aerobic
- Intracellular
- Cannot be stained with Gram stain
- Cultivated only in cell cultures
- Transmitted by arthropod vectors
- Important clinical diseases: spotted fever, typhus
Enterobacteriaceae:
- Gram-negative bacilli
- Facultative anaerobic
  - Some are normal flora, but some cause disease
  - Some produce toxins (exotoxins)
  - Endotoxin is an important virulence factor
  - Identification requires special growth media & biochemical tests
Vibrio cholerae:
- Gram negative curved rods
- Vibrio shaped bacilli
- Halotolerant
- Can grow at high pH
- Toxin production (+)
- Important clinical disease: Cholera
Helicobacter pylori:
- Gram-negative spiral rods
- Multiple flagella at one pole
- Microaerophilic
- Urease (+)
- Important clinical diseases: gastritis, ulcers, stomach cancers
Brucella species:
- Gram-negative coccobacilli
- Aerobic
- Intracellular
- Important clinical disease: Brucellosis.

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Description

Test your knowledge on the role of normal microbiota in human health with this quiz. Explore the relationship between these microorganisms and the host, their characteristics, and the benefits they provide. Perfect for microbiology students looking to deepen their understanding of human-associated bacteria.