Microbiology exam 3 review

What are the four main characteristics of adaptive immunity?

Memory, Specificity, Antibody Immunity (B-cells), Cellular Immunity (T-cells)

What is an antigen?

A molecule from a pathogen that reacts with antibodies.

Give examples of antigens found on pathogens.

Capsule, Cell wall, Fimbriae, Flagella, Pili, toxins.

What is an antibody?

A protein of the immune system that binds to an antigen and is part of adaptive immunity.

What is an epitope?

The part of the antigen that binds the antibody.

Describe the structure of antibodies.

Antibodies have a variable region and a constant region; the variable region binds to the antigen.

What type of antibody is most abundant in the body?

IgG.

What is the main function of IgA?

Commonly found in secretions like breast milk, tears, and saliva, neutralizes, and traps pathogens in mucus.

What role does IgE play in the immune response?

IgE is involved in allergic reactions, functions against parasites, and stimulates inflammation.

Describe IgM.

A pentamer that is the first antibody produced, functions to opsonize, agglutinate, and neutralize.

What is the function of antibodies during an immune response?

Neutralize pathogens, opsonize for phagocytosis, agglutinate, activate complement, and mediate cytotoxicity.

What are Natural Killer (NK) cells responsible for?

Killing pathogens that are too large and binding with antibodies. Have Fc receptor that binds constant region of Antibody that is attached to a pathogen. Release perforin and granzyme (cytotoxins)

What is the role of antigen-presenting cells?

v  Dendritic cells, Macrophages, B cells

v  Eat bacteria (phagocytosis)

v  Present antigen on MHII (Major Histocompatibility Complex II), which is needed to activate T-helper cells.

                                   

What is the difference between antibody-mediated immunity and T-cell mediated immunity?

Antibody-mediated immunity involves B-cells targeting extracellular pathogens, while T-cell mediated immunity targets intracellular pathogens.

Where do T-cells mature?

In the thymus.

Where do B-cells mature?

In the bone marrow.

What are the functions of Helper T-cells in the immune response?

Activate antibody immunity, T-cytotoxic cells, and enhance killing by macrophages and NK cells.

What do regulatory T-cells do?

Protect against autoimmune diseases.

How do cytotoxic T-cells function in the immune system?

They recognize, target, and kill infected cells.

What is the function of TH1 cells?

Activate cytokines and stimulate cytotoxic T cells, macrophages, and NK cells.

What is the function of TH2 cells in the immune response?

Activate B cells to release/produce antibodies, leading to B cell cloning into plasma cells.

What defines T-helper memory cells?

They live long, remember antigens, and mount secondary immune responses.

What is an allergic reaction?

An immune response to an allergen, which is an antigen not from a pathogen.

What is anaphylaxis?

A severe allergic reaction that can cause drop in blood pressure, swelling, and throat closure. Treated with epinephrine

What is Type I hypersensitivity?

An allergic response activating IgE and treated with antihistamines or steroids.

What are the effects of Type II hypersensitivity?

Blood transfusion reactions, hemolytic disease of the newborn, and transplant rejection.

What happens during Type III hypersensitivity?

IgG/IgM antibodies form immune complexes leading to tissue damage. •       Neutrophils destroy tissues with enzymes trying to destroy complex

•       Activates coagulation  blood clots  Ischemia (low blood supply to tissue)   necrosis (dead tissue)

What is Type IV hypersensitivity characterized by?

Contact dermatitis activated by TH1 cells involving T-cells and macrophages. Asthma

What is celiac disease?

An immune reaction to gluten causing damage to the small intestine.leading to inflammation,  malabsorption and diarrhea.

What are the symptoms of Graves disease?

Bulging eyes, heat intolerance, rapid heart rate, anxiety, fatigue, and goiter(enlarged thyroid).

What is multiple sclerosis?

An autoimmune disorder where the immune system attacks the myelin sheath of nerve fibers.

Symptoms of multiple sclerosis?

Inflammation, muscle weakness, unsteady balance/ gait, blurry/double vision, numbness/ tingling sensation, fatigue, cognitive issues.

What is myasthenia gravis?

An autoimmune disease where antibodies block acetylcholine receptors at neuromuscular junctions.

Symptoms of myasthenia gravis?

• Decreases muscle contraction

• Extreme muscle weakness

• Affects speech, walking, talking, chewing, respiration (breathing)

What is rheumatoid arthritis?

A chronic inflammatory disease that affects joints and other body parts, leading to pain and joint deformity.

RA signs & symptoms?

.Swollen, tender joints

• Stiff Joints

• Fatigue, fever and loss of appetite

  vary in severity and may come and go. Periods of

   increased disease activity (flares), alternate with periods of remission (swelling and pain disappear).

 

What are the symptoms of lupus?

Fatigue, fever, joint pain, butterfly-shaped rash, skin lesions, and shortness of breath.

What is lupus?

Immune System antibodies attack many types of tissues, including the joints, skin, kidneys, 

    blood cells, brain, heart and lungs. Difficult to diagnose because symptoms similar to other conditions.

What is the major role of skin in preventing bacterial infections?

physical barrier, prevent infections, also

•       Sweat (has salts, lysozyme, antimicrobial peptides)

•       Sebum (oil that feed commensal bacteria)

•       Microbiota (commensal bacteria that outcompetes pathogens)

Define skin infections?

many caused by opportunistic microbes (most common: S. aureus, Staph epi,

    Streptococcus). Staph aureus distinguished from Strep infections because S. aureus is catalase positive.

What are common skin infections caused by Staphylococcus aureus?

Folliculitis, furuncles (boils), and carbuncles (deeper abscesses).

Tears have?

•       Lysozyme (destroy bacterial cell wall)

•       Defensins (antimicrobial)

•       Lactoferrin( binds iron some bacteria need to grow)

•       Mucin (hydrates eye)

What is conjunctivitis, and what are its common causes?

An infection of the conjunctiva, commonly caused by Staphylococcus aureus (bacterial) or adenoviruses (viral).

What is staphylococcal scalded skin syndrome?

A superficial infection in young children caused by S. aureus, leading to skin redness and peeling.

What chronic infection is caused by Chlamydia trachomatis?

Ocular Trachoma, a major cause of blindness globally.

What is MRSA?

Methicillin-resistant Staphylococcus aureus, an opportunistic and contagious infection resistant to many antibiotics.

What are some virulence factors of Streptococcus pyogenes?

Streptolysins, hyaluronidase (tissue damage)

streptokinase, (dissolve blood clots)

M protein, capsule (that prevents phagocytosis.)

Describe cellulitis.

A painful red rash on the skin often caused by Streptococcus or Staphylococcus infection.

What is erysipelas?

A large, inflamed patch of skin with clear borders, often due to a Streptococcus infection.

What is erythema nodosum?

inflammation in the fat cells of the hypodermis; characterized by red lumps or nodules, usually on the lower legs Due to streptococcus infection

What is necrotizing fasciitis?

A rare but potentially life-threatening condition caused by Streptococcus pyogenes, leading to rapid tissue destruction (sometimes referred to as flesh-eating bacterial syndrome)

What is the treatment for necrotizing fasciitis?

Debridement or amputation and administration of intravenous antibiotics.

What is Pseudomonas aeruginosa?

A gram-negative bacillus that commonly causes opportunistic infections, especially in wounds and burns.

How does Propionibacterium acnes contribute to acne?

It feeds on sebum and secretes enzymes that damage hair follicles, leading to lesions.

What is anthrax, and what causes it?

A zoonotic infection caused by Bacillus anthracis, primarily affecting herbivorous animals but can infect humans.

What are papilloma warts?

Common skin infections caused by human papillomavirus (HPV), transmitted through direct contact.

What are the two types of herpes simplex virus?

HSV-1 associated with oral herpes and HSV-2 associated with genital herpes.

What is roseola?

A mild viral disease caused by Herpes 6, common in children, characterized by fever and rash.

What condition is caused by Parvovirus?

Fifth disease, a contagious illness primarily affecting children.

What does the Varicella Zoster Virus cause?

Chickenpox and shingles, with reactivation of latent virus causing shingles later in life.

What does the variola virus cause?

Smallpox, a severe disease that has been eradicated but poses a bioterrorism threat.

What is coxsackievirus?

an Enterovirus) Causes Hand, Foot, and Mouth Disease (HFMD)

Most common in babies and children under age 5

What are the symptoms of Coxsackievirus infections?

Fever, sore throat, malaise, and painful blisters, particularly in young children.

What is measles

Also Known as Rubeola, is Caused by the Measles Virus

What are common symptoms associated with measles?

Sore throat, cough, conjunctivitis, fever, and Koplik's spots followed by a characteristic rash.

What are the potential complications of rubella during pregnancy?

Serious congenital defects including deafness, cardiac abnormalities, and ocular lesions.

What are the three categories of fungal infections?

Cutaneous mycoses, subcutaneous mycoses, and systemic mycoses.

What is the most common type of cutaneous mycoses?

Tinea (ringworm) infections.

What is the primary defense mechanism in the respiratory system?

Goblet cells producing mucus and ciliated epithelial cells removing trapped microbes.·       Mucosal Associated Lymphoid Tissue (MALT; release IgA, Lysozyme, surfactant, antimicrobial defensins)

·       Alveolar macrophages

What opportunistic pathogens are found in the respiratory microbiota?

Streptococcus, Corynebacterium, Haemophilus, and Candida.

What is streptococcal pharyngitis?

Commonly known as strep throat, caused by Streptococcus pyogenes.

What is an acute otitis media?

Infection of the middle ear, common in children, causing ear pain and pus accumulation. Can be viral or bacterial, streptococcus pneumonia most common bacteria causing otitis media

What is the causative agent of diphtheria?

Corynebacterium diphtheriae.

What is pneumonia?

A general term for lung infections that can lead to inflammation and fluid accumulation.

What bacteria causes Haemophilus pneumonia?

Haemophilus influenzae, often affecting the elderly.

What bacteria causes Health Care-Associated Pneumonia?

·       Caused by opportunistic bacteria such as Klebsiella pneumoniae, Staph aureus.

·       Risk patients: elderly, persons with preexisting lung conditions, and the immunocompromised.

·       Patients receiving  intubation, antibiotics, and immune suppressing drugs at risk because disruption of the mucocilia and other pulmonary defenses.

·       Medical devices such as catheters, implants, and ventilators can introduce opportunistic  pathogens into the body.

·       Pneumonia caused by K. pneumoniae is characterized by lung necrosis and sputum

·       The sputum is made of clumps of blood, mucus, and debris from the thick polysaccharide capsule produced by the bacterium.

·       K. pneumoniae is often multidrug resistant and can be fatal.

What treatment is often needed for tuberculosis?

Antibiotics, as it is caused by Mycobacterium tuberculosis.

What are the characteristics of a common cold?

·       Mild viral infections of the nasal cavity.

·       More than 200 different viruses cause the common cold.

·       Most common viruses: rhinoviruses, coronaviruses, and adenoviruses.

·       These viruses commonly found in the human population; transmitted through direct contact, coughing and sneezing.

·       Rhinoviruses persist on surfaces for up to a week.

·       Rhinoviruses replicate best between 91.4 °F and 95 °F,  below normal body temperature (98.6 °F) and tend to infect the cooler tissues of the nasal cavities.

·       The absence of high fever is typically used to differentiate common colds from flu.

·       The disease is self-limiting and resolves within 1–2 weeks.

·       There are no effective antiviral treatments for the common cold and antibacterial drugs should not be prescribed.

·        Because of the large number of viruses that cause colds, we don’t develop immunity to all cold viruses.

What distinguishes flu (influenza) from a cold?

Influenza usually involves fever, chills, and body aches, while colds do not typically present with high fever.

Influenza what is it?

 ·       Commonly known as the flu, influenza is viral disease caused by orthomyxovirus.

·       primarily affects the upper respiratory tract but can extend to the lower respiratory tract.

·       Prevalent worldwide and causes up to 50,000 deaths each year in the US.

·       The annual mortality rate can vary greatly depending on the virulence of the strains responsible for seasonal epidemics. 

·       Influenza infections are characterized by fever, chills, and body aches.

What are common urogenital system infections?

Cystitis, urethritis, and pyelonephritis.

What is the role of Lactobacillus in the urogenital system?

Promotes secretion of glycogen, leading to lactic acid production, which helps protect against infections.

What are the signs of pyelonephritis?

Back pain, fever, and nausea or vomiting.

What is Nongonococcal Urethritis typically caused by?

Chlamydia trachomatis.

What organism is gonorrhea caused by?

Neisseria gonorrhoeae.

What are the stages of syphilis?

Primary (painless ulcer), Secondary (rash and fever), Tertiary (serious complications).

What can congenital syphilis lead to in a fetus?

Miscarriage, severe birth defects, and other complications.

Why are expecting mothers screened for syphilis?

To prevent congenital syphilis and its severe complications.

Describe IgG 

most abundant; can cross placenta and tissues; opsonizes, agglutinate, neutralize (viruses, bacteria).

What’s Graves’ disease.?

Hyperthyroid (overactive thyroid); increases Thyroid-stimulating hormone;