BIO 102: Bacteria Identification and Classification
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Questions and Answers

What are single-celled microorganisms that exist in diverse shapes, sizes, and environments?

Bacteria

Clinical samples can include ______, ______, and ______.

blood, urine, sputum

Which of the following are examples of environmental samples? (Select all that apply)

  • Tissue biopsies
  • Blood
  • Water (correct)
  • Soil (correct)

    • Food samples are used in the food industry to ensure safety and quality.

    <p>True</p> Signup and view all the answers

    What does Gram staining differentiate bacteria based on?

    <p>Cell wall structure</p> Signup and view all the answers

    Name a bacterium that is identified as catalase positive.

    <p>Staphylococcus</p> Signup and view all the answers

    What is the purpose of the Oxidase test?

    <p>Detects the presence of cytochrome c oxidase</p> Signup and view all the answers

    What bacteria is identified as a facultative anaerobe?

    <p>Escherichia coli</p> Signup and view all the answers

    Match the following bacteria with their classification based on oxygen requirement:

    <p>Mycobacterium tuberculosis = Obligate Aerobes Clostridium botulinum = Obligate Anaerobes Escherichia coli = Facultative Anaerobes Helicobacter pylori = Microaerophiles</p> Signup and view all the answers

    What type of bacteria cannot survive in the presence of oxygen?

    <p>Obligate Anaerobes</p> Signup and view all the answers

    What type of medium is MacConkey Agar?

    <p>Selective media</p> Signup and view all the answers

    Which of the following examples are Gram-positive bacteria? (Select all that apply)

    <p>Streptococcus pyogenes</p> Signup and view all the answers

    Name a bacterium that forms nitrogen-fixing nodules on leguminous plants.

    <p>Rhizobium leguminosarum</p> Signup and view all the answers

    Which type of bacteria creates a symbiotic relationship with plants to aid in nitrogen fixation?

    <p>Symbiotic Bacteria</p> Signup and view all the answers

    All strains of Escherichia coli are harmful.

    <p>False</p> Signup and view all the answers

    What is the most potent toxin known, produced by Clostridium botulinum?

    <p>Botulinum toxin</p> Signup and view all the answers

    What is Mpox formerly known as?

    <p>Monkey pox</p> Signup and view all the answers

    What virus causes Mpox?

    <p>Monkey pox virus</p> Signup and view all the answers

    How can Mpox be transmitted to humans?

    <p>Physical contact</p> Signup and view all the answers

    What are common symptoms of Mpox?

    <p>Headache</p> Signup and view all the answers

    What is the laboratory confirmation method for Mpox?

    <p>PCR testing</p> Signup and view all the answers

    Which mosquito is primarily responsible for the transmission of Zika virus?

    <p>Aedes mosquito</p> Signup and view all the answers

    Zika virus transmission can occur through blood transfusion.

    <p>True</p> Signup and view all the answers

    What does hepatitis refer to?

    <p>Inflammatory condition of the liver</p> Signup and view all the answers

    Match the following hepatitis types with their transmission route:

    <p>Hepatitis A = Exposure to contaminated food or water Hepatitis B = Contact with body fluids Hepatitis C = Contact with blood Hepatitis E = Exposure to contaminated food or water</p> Signup and view all the answers

    Which of the following hepatitis types causes both acute and chronic infections?

    <p>Hepatitis B</p> Signup and view all the answers

    How do viruses usually enter the body of their host?

    <p>Through mucous membranes</p> Signup and view all the answers

    Which of the following viruses is classified as a DNA virus?

    <p>Adenovirus</p> Signup and view all the answers

    Viruses cannot replicate without infecting a host cell.

    <p>True</p> Signup and view all the answers

    What is a virion?

    <p>An individual virus particle.</p> Signup and view all the answers

    Which of the following is NOT a common viral infection?

    <p>Asthma</p> Signup and view all the answers

    Which type of virus mainly infects plants?

    <p>Plant viruses</p> Signup and view all the answers

    What is the primary cause of rabies?

    <p>Dog bites</p> Signup and view all the answers

    The virus that causes the flu is known as the _____ virus.

    <p>influenza</p> Signup and view all the answers

    What is one health risk associated with HIV?

    <p>Compromised immune system.</p> Signup and view all the answers

    Which type of virus can be transmitted through sexual contact?

    <p>HIV</p> Signup and view all the answers

    Match the following viral infections with their symptoms:

    <p>Common cold = Stuffy nose, sneezing, sore throat HIV/AIDS = Compromised immune system Chickenpox = Itchy rash with blisters Measles = Fever and red rash</p> Signup and view all the answers

    Which of the following are common sample types for clinical samples? (Select all that apply)

    <p>Blood</p> Signup and view all the answers

    What is a Gram Staining technique used for?

    <p>To differentiate bacteria based on their cell wall structure.</p> Signup and view all the answers

    The _____ Test differentiates bacteria based on their ability to produce the enzyme catalase.

    <p>Catalase</p> Signup and view all the answers

    What characteristic does MacConkey Agar differentiate?

    <p>Lactose fermenters from non-fermenters</p> Signup and view all the answers

    What are autotrophic bacteria?

    <p>Bacteria that can produce their own food using sunlight or chemical energy.</p> Signup and view all the answers

    Facultative anaerobes can only survive in the presence of oxygen.

    <p>False</p> Signup and view all the answers

    Match the following bacterial classifications with their examples:

    <p>Staphylococcus aureus = Gram-positive Bacteria Escherichia coli = Gram-negative Bacteria Rhizobium leguminosarum = Symbiotic Bacteria Salmonella enterica = Pathogenic Bacteria</p> Signup and view all the answers

    What is the function of the capsid in a virus?

    <p>Acts as a protective coating for genetic material</p> Signup and view all the answers

    What type of samples might be used in research studies involving genetically modified organisms?

    <p>Synthetic constructs or model organisms.</p> Signup and view all the answers

    Viruses can replicate independently outside of a host cell.

    <p>False</p> Signup and view all the answers

    Which bacterium is an example of an obligate anaerobe?

    <p>Clostridium botulinum</p> Signup and view all the answers

    Study Notes

    Identification of Bacteria

    • Bacteria are diverse single-celled microorganisms characterized by unique cell wall structures and metabolic processes.
    • Sample collection methods include clinical specimens (blood, urine, tissue), environmental samples (soil, water), food samples, industrial samples, and research samples.
    • Culture-Based Methods involve using selective and differential media to encourage the growth of specific bacterial colonies.

    Examination Methods

    • Macroscopic Examination: Observations of colony morphology such as size, shape, color, texture, and margins can indicate bacterial identity.
    • Microscopic Examination:
      • Gram Staining: Differentiates bacteria into Gram-positive (purple) and Gram-negative (pink) based on cell wall composition.
      • Observations of cell morphology and presence of structures like flagella/capsules.
    • Biochemical Tests: Assess metabolic capabilities, including tests for catalase, oxidase, indole production, citrate utilization, coagulase, and sugar fermentation, with specific bacteria as examples.
    • Molecular Techniques:
      • PCR: Amplifies bacterial DNA for identification.
      • 16S rRNA Sequencing: Analyzes conserved genetic regions for bacterial classification.
      • Whole Genome Sequencing (WGS): Provides extensive genetic information for accurate identification.
    • Serological Methods: Use antibodies to detect bacterial antigens, including ELISA and Western Blotting.
    • Anaerobic Culture Techniques: Specialized methods for bacteria requiring anaerobic conditions.

    Types of Bacterial Isolation Media

    • General Purpose Media: Nutrient Agar supports growth of diverse non-fastidious bacteria.
    • Enriched Media: Blood Agar and Chocolate Agar support fastidious bacteria and differentiate based on hemolytic properties.
    • Selective Media: MacConkey and Mannitol Salt Agar selectively grow certain bacteria and differentiate based on metabolic characteristics.
    • Differential Media: EMB and XLD provide visual differentiation of lactose fermenters and specific pathogens.
    • Specialized Media: TCBS for Vibrio and Lowenstein-Jensen Medium for Mycobacterium species.

    Classification of Bacteria

    • Based on Cell Wall Composition:
      • Gram-positive (e.g., Staphylococcus aureus) versus Gram-negative (e.g., Escherichia coli).
    • Morphological Classification:
      • Cocci: Spherical bacteria (e.g., Micrococcus luteus, Neisseria gonorrhoeae).
      • Bacilli: Rod-shaped bacteria (e.g., Escherichia coli, Haemophilus influenzae).
      • Spirilla: Spiral-shaped (e.g., Spirillum minus).
      • Vibrios: Curved rod-shaped (e.g., Vibrio cholerae).
      • Pleomorphic: Variable shape (e.g., Mycoplasma pneumoniae).

    Oxygen Requirements Classification

    • Obligate Aerobes: Require oxygen (e.g., Mycobacterium tuberculosis).
    • Obligate Anaerobes: Cannot survive in oxygen (e.g., Clostridium botulinum).
    • Facultative Anaerobes: Can utilize both aerobic and anaerobic respiration (e.g., Escherichia coli).
    • Microaerophiles: Require lower than atmospheric oxygen levels (e.g., Helicobacter pylori).
    • Aerotolerant Anaerobes: Can tolerate oxygen but do not use it (e.g., Lactobacillus species).

    Metabolic Characteristics

    • Autotrophic Bacteria: Use inorganic substances (e.g., Nitrosomonas europaea).
    • Heterotrophic Bacteria: Rely on organic compounds (e.g., Pseudomonas aeruginosa).

    Ecological Roles

    • Symbiotic Bacteria: Form relationships with hosts (e.g., Rhizobium leguminosarum).
    • Pathogenic Bacteria: Cause diseases (e.g., Salmonella enterica).

    Systematic Classification of Bacteria

    • Domain: Bacteria
    • Kingdom: Eubacteria
    • Phylum Examples:
      • Firmicutes: Bacillus subtilis (produces antibiotics).
      • Proteobacteria: Includes various classes, each with significant examples (e.g., Neisseria gonorrhoeae in Betaproteobacteria).
      • Actinobacteria: Mycobacterium tuberculosis (common pathogen).
      • Cyanobacteria: Anabaena sp. (nitrogen fixation).
      • Spirochaetes: Borrelia burgdorferi (causes Lyme disease).

    Identification and Classification of Bacteria

    • Bacteria are single-celled microorganisms with diverse shapes and environments.
    • Basic characteristics include cell wall structure, reproduction, and genetic diversity.

    Sample Collection and Preparation

    • Samples collected using sterile techniques from:
      • Clinical sources: blood, urine, sputum, cerebrospinal fluid, tissue biopsies, swabs.
      • Environmental sources: soil, water, air, healthcare surfaces.
      • Food sources: meats, dairy, fruits, processed foods.
      • Industrial sources: biofilms, fermentation products, waste.
      • Research sources: model organisms, genetically modified bacteria, environmental DNA.

    Methods of Examination

    • Culture-Based Methods: Use selective and differential media to promote growth of specific bacteria.
    • Macroscopic Examination: Colony morphology provides initial identification clues based on size, shape, and color.
    • Microscopic Examination:
      • Gram Staining differentiates bacteria into Gram-positive (purple) or Gram-negative (pink).
      • Observes cell shape, arrangement, and specific structures (e.g., flagella).
    • Biochemical Tests assess metabolic capabilities (e.g., catalase test differentiates Staphylococcus from Streptococcus).
    • Molecular Techniques: PCR amplifies bacterial DNA for identification.
    • Serological Methods: Use antibodies to detect bacterial antigens (e.g., ELISA).
    • Anaerobic Culture Techniques: Specialized methods for bacteria requiring low oxygen conditions.

    Types of Bacterial Isolation Media

    • General Purpose Media:
      • Nutrient Agar (NA) supports various non-fastidious bacteria.
    • Enriched Media:
      • Blood Agar (BA) used for fastidious bacteria, identifies hemolytic properties.
      • Chocolate Agar (CHOC) supports growth of respiratory bacteria.
    • Selective Media:
      • MacConkey Agar (MAC) selects for Gram-negative bacteria.
      • Mannitol Salt Agar (MSA) differentiates staphylococci.
    • Differential Media:
      • Eosin Methylene Blue Agar (EMB) differentiates lactose fermenters.
      • Xylose Lysine Deoxycholate Agar (XLD) used for enteric pathogens.
    • Specialized Media:
      • Thiosulfate-Citrate-Bile Salts-Sucrose Agar (TCBS) selects for Vibrio species.
      • Lowenstein-Jensen Medium (LJ) selects for Mycobacterium species.

    Classification of Bacteria

    • Based on Cell Wall Composition:

      • Gram-positive: e.g., Staphylococcus aureus, causes skin infections.
      • Gram-negative: e.g., Escherichia coli, can cause foodborne illness.

    • Based on Morphology:

      • Cocci: spherical shapes (e.g., Streptococcus pyogenes).
      • Bacilli: rod shapes (e.g., Escherichia coli).
      • Spirilla: spiral shapes (e.g., Treponema pallidum).
      • Vibrios: comma-shaped (e.g., Vibrio cholerae).
      • Pleomorphic: variable shapes (e.g., Mycoplasma pneumoniae).

    • Based on Oxygen Requirement:

      • Obligate Aerobes: need oxygen (e.g., Mycobacterium tuberculosis).
      • Obligate Anaerobes: cannot tolerate oxygen (e.g., Clostridium botulinum).
      • Facultative Anaerobes: can use oxygen or ferment (e.g., Escherichia coli).
      • Microaerophiles: need low oxygen levels (e.g., Helicobacter pylori).
      • Aerotolerant Anaerobes: tolerate oxygen, ferment energy (e.g., Lactobacillus).

    • Based on Metabolic Characteristics:

      • Autotrophic: e.g., Nitrosomonas europaea, oxidizes ammonia.
      • Heterotrophic: e.g., Pseudomonas aeruginosa, opportunistic pathogen.

    • Based on Ecological Roles:

      • Symbiotic: e.g., Rhizobium leguminosarum, aids plant nitrogen fixation.
      • Pathogenic: e.g., Salmonella enterica, causes salmonellosis.

    Systematic Classification of Bacteria

    • Bacteria classified into hierarchical categories based on evolutionary relationships.

    • Domain: Bacteria, part of the three life domains: Bacteria, Archaea, Eukarya.

    • Kingdom: Eubacteria.

    • Phylum Examples:

      • Firmicutes (Bacilli): e.g., Bacillus subtilis.
      • Proteobacteria (Gammaproteobacteria): e.g., Escherichia coli.
      • Actinobacteria: e.g., Mycobacterium tuberculosis.
      • Cyanobacteria: e.g., Anabaena sp.
      • Spirochaetes: e.g., Borrelia burgdorferi.

    Virus Overview

    • Viruses are non-cellular infectious agents with genetic material (DNA or RNA) encased in a protein coating (capsid).
    • Require host cells for replication, leading to illnesses like respiratory infections and STIs.
    • Common viral infections include flu, COVID-19, chickenpox, and HIV/AIDS.
    • Smaller than bacteria, viruses range from 20-300 nm.
    • Cannot be classified as living or non-living due to characteristics of both.
    • Enter the host through mucous membranes or breaks in the skin.### Classification of Viruses
    • Classification based on nucleic acid presence: DNA viruses (single-stranded and double-stranded) and RNA viruses (single-stranded and double-stranded).
    • Examples of DNA viruses:
      • Single-stranded: Picornaviruses, Parvovirus.
      • Double-stranded: Adenovirus, Herpes virus.
    • Examples of RNA viruses:
      • Double-stranded: Reovirus.
      • Single-stranded: Poliovirus, Hepatitis A, Rabies virus, Influenza virus.
    • Classification based on replication properties:
      • Replication in cytoplasm: All RNA viruses except Influenza.
      • Replication in nucleus and cytoplasm: Influenza virus, Poxvirus.
      • Replication predominantly in nucleus: All DNA viruses except Poxvirus.
      • Double-stranded DNA intermediate replication: All DNA viruses, retroviruses, some tumor-causing RNA viruses.
      • Single-stranded RNA intermediate: All RNA viruses except Reovirus and tumor-causing RNA viruses.

    Host Range Classification

    • Animal viruses: Infect animal cells; notable examples include Influenza virus, Rabies virus, Herpes virus.
    • Plant viruses: Infect plant cells; examples include Potato virus, Tobacco mosaic virus.

    Transmission Modes

    • Airborne transmission: Through respiratory tract; examples include Swine flu and Rhinovirus.
    • Fecal-oral route: Contaminated food or water transmission; examples include Hepatitis A and Poliovirus.
    • Sexual transmission: Spread through intimate contact; examples include Retrovirus and Human papillomavirus.
    • Transfusion-related transmission: Through blood transfusions; examples include Hepatitis B and HIV.
    • Zoonotic transmission: Spread through animal bites; examples include Rabies virus and Ebola virus.

    Major Virus Types

    • Influenza viruses (Orthomyxoviridae): Cause flu; strains include A (avian flu, swine flu) and B.
    • Human herpesvirus (Herpesviridae): Causes oral/genital herpes, chickenpox, shingles, Epstein-Barr virus.
    • Coronaviruses: Include SARS-CoV-1, SARS-CoV-2 (COVID-19), and MERS; cause respiratory infections with serious outcomes.
    • Human Papillomavirus (HPV): Causes warts and some cancers; casual transmission is primarily sexual.
    • Enteroviruses: Affect intestinal tract; notable for causing polio and hand, foot, and mouth disease.
    • Flaviviruses: Often spread by mosquitoes; examples include Zika, West Nile, dengue, yellow fever.
    • Orthopoxviruses: Cause flu-like symptoms and rashes; examples include Cowpox and Mpox.
    • Hepatitis viruses: Affect the liver, with variants A-E differing in transmission and severity.
    • Oncoviruses: Can lead to cancer; include HPV and Human herpes virus 8 (HHV-8).

    Types of Viral Infections

    • Respiratory infections: Affect respiratory tract; examples include common cold, flu, COVID-19.
    • Digestive system infections: Affect stomach/intestines; examples include Norovirus, Hepatitis viruses.
    • Viral hemorrhagic fevers: Affect blood clotting; examples include Ebola and Yellow fever.
    • Sexually transmitted infections: Spread through sexual contact; examples include HIV, HPV.
    • Exanthematous infections: Cause skin rashes; examples include Measles, Chickenpox, Mpox.
    • Neurological infections: Attack nervous system; examples include Polio, Rabies.
    • Congenital infections: Passed from mother to child; examples include Zika, Rubella.

    Common Viral Diseases

    • Common cold: Caused primarily by Rhinoviruses, with symptoms including nasal congestion and cough.
    • Influenza: Respiratory infection with sudden onset, fever, muscle aches; vaccination is crucial for at-risk groups.
    • COVID-19: Caused by SARS-CoV-2, spread through respiratory droplets; severe cases require hospitalization.
    • Respiratory Syncytial Virus (RSV): Common in children and the elderly, causing cold-like symptoms.
    • Chickenpox: Highly contagious, causing itchy skin rash; preventive vaccines are available.
    • Measles: Airborne disease with symptoms including fever and rash; vaccination provides effective protection.
    • HIV/AIDS: Attacks immune system; transmitted sexually or through body fluids; management through antiretroviral therapy.
    • Human Papillomavirus: Causes warts and can lead to cancer; vaccination and regular check-ups can prevent complications.
    • Herpes infections: Painful blisters on skin, caused by HSV-1 and HSV-2; management is important though no cure exists.
    • Polio: Can cause paralysis; vaccination is essential for prevention.
    • Rabies: Transmitted via animal bites, leading to fatal outcomes without prompt treatment.
    • Mpox: Caused by monkeypox virus, presenting with skin rashes and flu-like symptoms.
    • Zika Virus: Mosquito-borne virus, asymptomatic in many cases but can cause birth defects in pregnancies.
    • Hepatitis: Involves liver inflammation caused by several viruses, differing in transmission routes and disease severity.

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