Microbiology Exam 4: Chapters 14-18

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Questions and Answers

What was the Chinese procedure called where practitioners blew a powder made from dried scabs of smallpox lesions into a healthy individual’s nose to gain protection from smallpox?

Variolation

What was Edward Jenner’s contribution to science in the field of vaccines?

He created a new method of purposely infecting people with cowpox to spur immunity.

What disease was eradicated in the 20th century and which disease is targeted for eradication next?

Smallpox was eradicated. Polio is targeted for eradication next.

Which study published in The Lancet in 1998 claimed a correlation between the MMR vaccine and the development of autism?

The study with just 12 patients claimed a correlation between the MMR vaccine and autism. Signup and view all the answers

Which disease is showing the strongest reemergence in the US and UK due to declining vaccination rates?

Measles Signup and view all the answers

What type of immunity do vaccines induce?

Artificially acquired active immunity Signup and view all the answers

What is the concept of herd immunity?

Herd immunity occurs when a sufficient percentage of the population is vaccinated, offering protection to nonvaccinated individuals. Signup and view all the answers

What are live attenuated vaccines?

Vaccines containing altered pathogens that do not cause disease but are still infectious. Signup and view all the answers

What are inactivated vaccines?

Vaccines consisting of whole inactivated pathogens or parts of pathogens. Signup and view all the answers

What is an adjuvant in the context of vaccines?

A pharmacological additive that enhances the body’s immune response to an antigen. Signup and view all the answers

What super family of drugs work by blocking cell wall synthesis?

Beta-lactam antimicrobials Signup and view all the answers

What molecule do most bacterial cell walls consist of?

peptidoglycan Signup and view all the answers

What is the function of beta-lactamases?

Enzymes that inactivate beta-lactam drugs Signup and view all the answers

How do beta-lactamase inhibitors such as clavulanate work?

Beta-lactamase inhibitors have a beta-lactam ring structure and bind strongly to beta-lactamase enzymes. This binding blocks beta-lactamase from deactivating the administered antimicrobial. Signup and view all the answers

Which generation of cephalosporin is used to combat MRSA/ORSA strains?

Fifth generation Signup and view all the answers

What drug family is effective against a variety of multidrug-resistant (MDR) bacterial strains, so they are often reserved for strains that are healthcare-acquired?

Carbapenems Signup and view all the answers

What does the abbreviation CRE stand for?

Carbapenem-resistant Enterobacterales (CRE) Signup and view all the answers

What drug family is not a beta-lactam but inhibits cell wall synthesis?

Glycopeptides Signup and view all the answers

What is the etiological agent of the neglected tropical disease called leishmaniasis?

Leishmania species Signup and view all the answers

What is the name of the glycopeptide drug used to treat MRSA and Clostridiodes difficile infections?

vancomycin Signup and view all the answers

What are the differences between cutaneous, mucocutaneous, and visceral leishmaniasis?

All of the above Signup and view all the answers

What antibiotic is the Staphylococcus aureus strain VRSA resistant to?

vancomycin Signup and view all the answers

What was the reason there was so much death during the Spanish Influenza outbreak of 1918?

Cytokine storm Signup and view all the answers

Why is it recommended that individuals get an influenza vaccine every year?

The viral candidates change from year to year. Signup and view all the answers

What is the cornea of the eye?

A transparent layer at the front of the eye that covers the iris Signup and view all the answers

Conjunctivitis is commonly known as 'pink eye'.

True Signup and view all the answers

What type of virus causes Severe Acute Respiratory Syndrome (SARS-CoV-1 and SARS-CoV-2) and Middle Eastern Respiratory Syndrome (MERS-CoV)?

Coronavirus Signup and view all the answers

____ is the leading cause of bacterial blindness in the United States.

Trachoma Signup and view all the answers

What host cell receptor does the SARS-CoV-2 spike protein bind to?

Angiotensin-converting enzyme 2 (ACE2) Signup and view all the answers

List live tissues that express ACE2 receptor.

Kidneys, heart, blood vessels, neurons, lungs Signup and view all the answers

What occurs in the body if a patient develops Acute Respiratory Distress Syndrome (ARDS) in severe cases of COVID-19?

Rapidly progressing inflammatory lung injury leading to a sudden and marked reduction in blood oxygenation Signup and view all the answers

What is the difference between a viral variant and a viral strain?

Viral Variant: genetically distinct virus isolate; Viral Strain: has mutations with physiological consequences Signup and view all the answers

What is Hanta Pulmonary Syndrome (HPS) and how is it contracted?

Acute and potentially fatal respiratory illness contracted by inhaling hantavirus particles in dust from rodent urine or feces. Signup and view all the answers

Define pulmonary edema.

Fluid accumulation in the lungs Signup and view all the answers

What is the outermost, waterproof barrier that protects the inner basal level of cells from intruders?

Epidermis Signup and view all the answers

What cells comprise most of the epidermis? What is the main protein component of these cells?

Keratinocytes; Keratin Signup and view all the answers

What layer of skin is located below the epidermis?

Dermis Signup and view all the answers

What layer associated with the skin is located below the dermis?

Subcutaneous layer Signup and view all the answers

What is melanin and what is its function?

Brown pigment in skin; Provides protection against UV radiation Signup and view all the answers

What enzyme is found in perspiration and what is its function?

Lysozyme; Breaks down peptidoglycan in bacterial cell walls Signup and view all the answers

What is sebum?

An oily or waxy substance produced by the skin's sebaceous glands Signup and view all the answers

Define dermatoses.

Infections and noninfectious skin diseases Signup and view all the answers

What is the difference between a primary and secondary skin lesion?

Primary lesions are directly associated with a disease, while secondary lesions have diverse origins or evolve from primary ones. Signup and view all the answers

What is the etiological agent of chickenpox and how is it typically spread?

Herpesviridae virus varicella-zoster; Through respiratory droplets or direct contact with pox lesions Signup and view all the answers

What is the etiological agent of pneumococcal meningitis? Is it Gram positive or Gram negative? Is it encapsulated or non-encapsulated?

Streptococcus pneumoniae Signup and view all the answers

What bacteria cause most cases of meningitis in the United States?

Streptococcus pneumoniae Signup and view all the answers

What is the danger of S. pneumoniae exotoxin?

The exotoxin stimulates severe inflammation and provokes host tissue damage. Signup and view all the answers

What is the etiological agent of Listeria meningitis? How are the bacteria transmitted to humans?

Listeria monocytogenes. Transmitted as a foodborne illness through tainted cheese, lunchmeats, or even mangos. Signup and view all the answers

What is the advantage of Listeria monocytogenes’ intracellular lifestyle?

The bacteria can grow and divide hidden from antibody-mediated immune responses. Signup and view all the answers

What is the etiological agent of Hansen’s disease?

Mycobacterium leprae Signup and view all the answers

What does a sandwich ELISA detect in a patient’s serum?

specific antigen Signup and view all the answers

What does a positive reaction look like in a sandwich ELISA?

color change in the wells of the microplate Signup and view all the answers

What does a positive reaction indicate in a sandwich ELISA?

specific antigen is present Signup and view all the answers

What is immunoJfluorescence microscopy?

a protocol where fluorescent-tagged antibodies recognizing a specific antigen are incubated with tissue or cell samples Signup and view all the answers

What molecule is fluorescent tagged in immunoJfluorescence microscopy?

antibodies Signup and view all the answers

What is flow cytometry?

a process by which cells can be sorted using a flow cytometer and is useful for enumerating specific cells Signup and view all the answers

What special piece of equipment is required for flow cytometry?

Fluorescence-activated cell sorter (FACS) Signup and view all the answers

What do interferon gamma release assays (IGRAs) detect?

T cells response to Mycobacterium tuberculosis antigens Signup and view all the answers

What molecules do Western blots detect?

specific proteins Signup and view all the answers

What does the abbreviation PCR stand for?

Polymerase Chain Reaction Signup and view all the answers

What is Taq polymerase used for in PCR?

heat resistant DNA polymerase Signup and view all the answers

What is gel electrophoresis used for?

separate molecules based on their size Signup and view all the answers

What does real-time PCR (qPCR) use to visualize DNA copies?

fluorescence imaging Signup and view all the answers

What is reverse transcription PCR (RT-PCR) useful for detecting?

RNA in a sample Signup and view all the answers

Besides Taq polymerase, what additional enzyme is used in RT-PCR?

Reverse transcriptase Signup and view all the answers

Why was the Genetic Information Nondiscrimination Act of 2008 (GINA) passed?

To protect patients from discrimination based on genetic information Signup and view all the answers

What is recombinant DNA (rDNA) generated by?

Combining DNA from different organisms Signup and view all the answers

What are restriction enzymes used for in genetic engineering?

generate compatible ends for constructing recombinant DNA Signup and view all the answers

What is the term for a process by which cells take up DNA from their environment?

transformation Signup and view all the answers

What type of tool is CRISPR-Cas9?

a gene-editing tool Signup and view all the answers

What do microarray assays investigate generally?

differences between healthy and diseased cells Signup and view all the answers

Define antimicrobial drugs.

Therapeutic compounds that kill microbes or inhibit their growth Signup and view all the answers

Who discovered penicillin?

Alexander Fleming Signup and view all the answers

What is selective toxicity of a drug?

Inhibits or kills the targeted microbe without damaging host cells Signup and view all the answers

What is the therapeutic index of a drug?

The ratio of the maximum safe dose to the minimum effective dose Signup and view all the answers

A drug with a high therapeutic index is safer than a drug with a narrow therapeutic index.

True Signup and view all the answers

What is half-life when referring to drugs?

The time it takes for half of a dose to be eliminated or deactivated by the body Signup and view all the answers

Study Notes

Chapter 14: Biomedical, Applications: Vaccines, Diagnostics, Therapeutics, and Molecular Methods

Section 14.1: A Brief History of Vaccines

Variolation: a Chinese procedure that involved blowing a powder made from dried scabs of smallpox lesions into a healthy individual's nose to gain protection from smallpox.
Edward Jenner's contribution: creating a new method of purposely infecting people with pathogens to spur immunity, specifically with cowpox.
Louis Pasteur's contribution: developing an early version of the rabies vaccine to protect humans and a vaccine to protect cattle against anthrax.
Eradication of smallpox: achieved in the 20th century, with polio being the next targeted disease, which may be difficult to achieve due to challenges in maintaining consistent vaccination access in war-torn areas.
The 1998 Lancet study: a flawed study that claimed a correlation between the MMR vaccine and the development of autism, which was later retracted and led to the lead author losing his medical license.

Section 14.2: Overview of Vaccines

Vaccines induce artificially acquired active immunity.
Immunological memory must be stimulated for a vaccine to be effective.
Herd immunity: a concept where a sufficient percentage of the population is vaccinated, protecting non-vaccinated individuals from disease.
Vulnerable populations protected by herd immunity: babies who have not yet been fully vaccinated and immune-compromised individuals.
Shingles is a sequela to chickenpox, meaning it is a consequence that occurs after having chickenpox.
Live attenuated vaccines: contain pathogens that have been altered to not cause disease, but are still infectious.
Benefits of live attenuated vaccines: stimulate potent immunological responses, broader protection, and long-lived memory.
Drawbacks of live attenuated vaccines: can cause disease in immune-compromised hosts, mutate to an infectious form, and potentially transmit other infectious agents.
Inactivated vaccines: consist of whole inactivated pathogens or parts of pathogens.
Advantages of inactivated vaccines: stable at room temperature, safe for immune-compromised patients, and lack of infectivity.
Disadvantage of inactivated vaccines: limited exposure to antigens, requiring booster doses.
Difference between inactivated whole-agent and subunit vaccines: whole-agent vaccines contain the entire pathogen, while subunit vaccines consist of purified parts of the pathogen.
Adjuvants: pharmacological additives that enhance the body's natural immune response to an antigen.
Recombinant subunit vaccines: use genetic engineering to produce antigens.
Toxoid vaccines: use naturally occurring bacterial toxins that have been purified and inactivated.
Conjugate vaccines: link polysaccharides to a protein antigen to stimulate an immune response.
mRNA vaccines: use genetic instructions to build an antigenic protein, triggering an immune response.

Section 14.3: Immunological Diagnostic Testing

Serology: the study of what is in a patient's serum.
Agglutination: a reaction where antibodies bind antigens into a clump.
Plaque reduction neutralization test (PRNT): detects patient antibodies against a specific virus.
ELISA (Enzyme-Linked Immunosorbent Assay): a diagnostic test that detects specific antigens or antibodies in a patient's serum.
Direct ELISA: detects specific antigens in a patient's serum.
Indirect ELISA: detects specific antibodies in a patient's serum.
Sandwich ELISA: detects specific antigens in a patient's serum, but is more sensitive and overcomes the downside of the direct ELISA.
Immunofluorescence microscopy: a protocol that uses fluorescent-tagged antibodies to detect specific antigens in tissue or cell samples.
Flow cytometry: a process that sorts cells using a flow cytometer and is useful for enumerating specific cells.
Interferon Gamma Release Assays (IGRAs): a test that measures how a patient's T cells respond to Mycobacterium tuberculosis antigens.
Western blot: a diagnostic test that detects specific proteins in a sample and reveals the size of the protein being detected.

Section 14.4: Selected Genetic Applications in Medicine

PCR (Polymerase Chain Reaction): a method that creates billions of copies of a target gene in a few hours.
Taq polymerase: a heat-resistant DNA polymerase used in PCR.
Thermocycler: a machine that controls the heat of the reaction, cycling between different temperatures.
Gel electrophoresis: a method used to separate molecules based on their size.
Real-time PCR (quantitative PCR or qPCR): a modified PCR method that uses fluorescence imaging to visualize DNA copies as they are made.
RT-PCR (Reverse Transcription PCR): a method that detects RNA in a sample, such as the genome of an RNA virus.
Reverse transcriptase: an enzyme used in RT-PCR to build DNA that is complementary to RNA molecules.
Genetic Information Nondiscrimination Act of 2008 (GINA): a law that protects patients from discrimination based on genetic information.
Recombinant DNA (rDNA): DNA generated by combining DNA from different organisms.
Restriction enzymes: enzymes used to generate compatible or sticky ends of complementary base pairs between the copied DNA and the plasmid to construct recombinant DNA.
Transformation: a process by which cells take up DNA from their environment.
CRISPR-Cas9: a gene-editing tool that uses a guide RNA to find a specific genetic sequence and a Cas9 enzyme to cut the targeted DNA sequence.
Gene therapy: the process of introducing genetic material that is not a human cell as a treatment.### Broad-Spectrum and Narrow-Spectrum Antimicrobial Drugs
Broad-spectrum drugs: effective against both gram-negative and gram-positive bacterial cells
Narrow-spectrum drugs: target a limited range of bacteria, preferred because they present less disruption to the normal microbiota

Empiric Therapy

Standard, accepted, or typical treatment based on clinical presentation in the absence of definitive or complete clinical data
Used when the exact bacterium causing the issue is unknown

Prolonged Treatment with Broad-Spectrum Antimicrobial Drugs

Can disrupt the normal microbiota, leading to infections such as Clostridioides difficile infection

Bacteriostatic and Bactericidal Antimicrobial Drugs

Bacteriostatic drugs: prevent bacteria from growing
Bactericidal drugs: actively kill bacteria

Antibiotics, Synthetic Antimicrobials, and Semisynthetic Antimicrobials

Antibiotics: naturally occurring antimicrobial compounds
Synthetic antimicrobials: wholly manufactured by chemical processes
Semisynthetic antimicrobials: naturally occurring antibiotics that can be chemically modified to improve their pharmacological actions and/or stability

Selective Toxicity and Therapeutic Index

Selective toxicity: a drug's ability to inhibit or kill the targeted microbe without damaging host cells
Therapeutic index: the ratio of the maximum tolerated or safe dose to the minimum effective or therapeutic dose

Half-Life

The time it takes for half of a dose to be eliminated or deactivated by the body

Super Family of Drugs: Beta-Lactam Antimicrobials

Work by blocking cell wall synthesis
Most bacterial cell walls consist of peptidoglycan

Drug Families

Beta-lactam antibiotics: include penicillins and cephalosporins
Glycopeptides: include vancomycin
Quinolones: target DNA replication enzymes
Rifamycin: targets RNA polymerase
Sulfonamides: target folic acid synthesis
Carbapenems: effective against a variety of multidrug-resistant bacterial strains

Antiviral Drugs

Stimulate an immune response to viruses
Interferons: a category of antiviral drugs that stimulate an immune response

Antifungal Drugs

Target fungal cell walls and plasma membranes
Azoles, allylamines, and polyenes: target fungal plasma membranes, specifically ergosterol

Antiprotozoan Drugs

Antimalarial drugs: used to treat malaria
Non-antimalarial drugs: used to treat other protozoan infections

Antimicrobial Resistance

A situation in which a microbe is not affected by a drug therapy intended to inhibit or eliminate the pathogen
Can be intrinsic or acquired
Can be spread by horizontal gene transfer

Assessing Sensitivity to Antimicrobial Drugs

Antimicrobial susceptibility tests: performed to assess if a pathogen is likely to be treatable with a particular antimicrobial drug
Kirby-Bauer test: used to determine a bacterium's susceptibility to antimicrobial drugs

Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC)

MIC: the lowest concentration of an antimicrobial drug that inhibits the microbe's growth
MBC: the minimum concentration of a drug that kills at least 99.9% of the bacteria present### Bacterial Respiratory System Infections
Gram-positive rod Corynebacterium diphtheriae causes diphtheria
- A bull neck is a swelling in the neck region observed in acute diphtheria infections
- A thickened, leathery structure called a pseudomembrane can form on the throat if left untreated
DTaP vaccine protects against diphtheria, tetanus toxoids, and acellular pertussis
Gram-negative bacterium Bordetella pertussis causes pertussis (whooping cough)
- Paroxysms are sudden or violent attacks of severe coughing associated with pertussis
Tdap booster is necessary to renew immunity to pertussis as DTaP immunity is not long-lived
Mycobacterium tuberculosis; acid-fast, Gram-positive bacteria causes tuberculosis (TB)
- Granulomas are small areas of inflammation due to tissue injury that store infected macrophages to limit spread of infection
- Granulomas form during latent tuberculosis stage
- Latent TB can progress to active TB infection when the center of the granuloma liquefies and the walls break down

Fungal Respiratory System Infections

Fungal infection is called mycosis
Blastomyces dermatitidis causes blastomycosis in the USA, also known as Chicago Disease
Fungus can be dimorphic, existing in two distinct forms
Saprophyte is a mold form that thrives on decomposing plant matter in moist soil
Coccidioides immitis and Coccidioides posadasii cause coccidioidomycosis, also known as Valley fever
Histoplasma capsulatum causes histoplasmosis
Opportunistic fungal pathogens cause most ubiquitous mycoses, affecting immune-compromised patients
Aspergillus fumigatus is the main fungal genus isolated from patients with invasive aspergillosis
Rhizopus arrhizus causes mucormycosis
Pneumocystis jirovecii causes pneumocystis pneumonia (PCP)

Skin and Eye Infections

Overview of Skin Structure, Defenses, and Afflictions

Epidermis is the outermost, waterproof barrier that protects the inner basal level of cells from intruders
Keratinocytes comprise most of the epidermis, containing keratin, a water-prooüng protein
Dermis is the layer of skin below the epidermis
Subcutaneous layer is the layer associated with the skin below the dermis
Melanin is the brown pigment in our skin, having antimicrobial properties and protecting against ultraviolet radiation
Lysozyme is an enzyme found in perspiration, breaking down the peptidoglycan found in bacterial cell walls
Sebum is an oily or waxy substance produced by the skin's sebaceous glands, moisturizing and protecting the skin

Viral Skin Infections

Herpesviridae family virus varicella-zoster causes chickenpox
- Typically spread through respiratory droplets and direct contact with pox lesions
Varicella-zoster virus causes shingles
- Remains dormant in the peripheral nerves
Postherpetic neuralgia (PHN) is a chronic pain condition associated with shingles
Variola major virus causes smallpox
- Had a mortality rate of 30% and was highly contagious
Human Herpes virus 1 (HSV-1) causes oral herpes
- Presents as painful, itchy, vesicular lesions on the lips
- Can cause latency and reactivate in about 2/3rds of patients
Rubeola (measles) virus causes measles
- Associated with Koplik's spots, red spots with white dots in the center on the tongue and in the mouth
Measles is making a comeback due to parents choosing not to vaccinate their children
MMR vaccine protects against measles, mumps, and rubella

Bacterial Infections of the Skin

Propionibacterium acnes bacteria play a major role in certain types of acne
Staphylococcus aureus bacteria cause "staph infections"
Staphylococcus aureus can cause impetigo, erysipelas, cellulitis, and folliculitis
Cellulitis is a deeper Staphylococcus aureus infection of the lower dermal and subcutaneous fat
MRSA stands for Methicillin-resistant Staphylococcus aureus
VRSA stands for Vancomycin-resistant Staphylococcus aureus
Staphylococcus aureus can be differentiated from Streptococcus pyogenes by coagulase and catalase tests
Streptococcus pyogenes is coagulase and catalase negative
Streptococcus pyogenes causes impetigo, cellulitis, and necrotizing fasciitis
Necrotizing fasciitis is also known as "Llesh-eating disease"
Pseudomonas aeruginosa is a common cause of HAIs, an opportunistic pathogen that readily establishes infections in people with weak immune systems
Pyocyanin is a greenish-blue pigment produced by P. aeruginosa, generating reactive forms of oxygen to further damage tissue

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Description

This quiz covers the biomedical applications of microbiology, including vaccines, diagnostics, and therapeutics, as well as molecular methods. Topics include the history of vaccines and smallpox.