MICRO Exam 4 Flashcards
Antifungals
Attack fungal infections
Antiprotozoals
Attack protozoans
Quinine
Extracted from the bark of a cinchona tree used for 100s of years but now largely replaced by synthesized quinolines like chloroquine to reduce parasite resistance.
Azole
broad-spectrum antifungal agents with complex ringed structure that inhibit ergosterol and cell membrane synthesis
Contains 2 ph groups, a ph group with a Cl and a pentane with two N
Antibacterials
Bacterial infection that is treated with an enormous diversity of compounds.
Antivirals
Selective toxicity is almost impossible due to the obligate intracellular parasitic nature of viruses
1. Block penetration into the cell
2. Block replication, transcription, or translation of genetic material aka Acyclovir
3. Prevent maturation of viral particles
MIC
Minimum inhibitory concentration
Minimum amount of antibiotic needed
Antibiotic resistance
Microbes become resistant to certain treatments of antibiotics
Intrinsic resistance
cells have an innate or natural resistance to a drug
Tolerance or situational resistance
A usually susceptible cell is in a environmental situation where it is no longer susceptible to the drug
Acquired resistance
permanent, genetically encoded resistance to an antimicrobial drug
Human opportunistic pathogen
Can cause disease by penetrating a break in the skin or through mucous membranes
Nosocomial
Hospital acquired infection
Mech of resistance to beta lactams
- Alternative Enzymes (PBP2A)
- Beta-Lactamases
PBP2A
A new transpeptidase that helps form the bacterial cell wall
Beta-Lactamases
Enzymes produced and secreted by bacteria that degrade all beta-lactam structures.
Clavulanate
Inhibitor of beta-lactamases
Summary of Resistance Mech for Acquired resistance
- Inactivating enzymes (Inactivates AB)
- Alternative enzyme (Diff enzyme used)
- Target Alteration (Changes binding site)
- Decrease uptake (lBlocks entry)
- Increase flux (Flushes AB out)
Human microbiota
All the microbes that can naturally reside on or within human tissue or fluids
Microbiome
Describes the collective genomes of the microbes that reside in an ecological niche
Sites that harbor microbes
Skin and mucous membranes
Upper respiratory tract
GI Tract
outer opening of the urethra
External genitalia
Vagina
External ear and canal
External eye
Sites that don’t harbor micorbes
All internal tissues and organs
Heart
Liver
Kidneys and bladder
Brain and spinal cord
Muscles
Bones
Ovaries/Testes
Glands
Middle and Inner Ear
Internal Eye
Fluids within an organ or Tissue
Blood
Urine in kidneys, ureters, and bladder
cerebrospinal fluid
Saliva prior to entering the oral cavity
Semen prior to entering the urethra
Axenic Condition
Germ-free animals as a way to investigate how essential the microbiota are to human life
Importance of the Microbiota
- Microbiota provide essential nutrient
- Lead to development of health immune system
- Microbiota can protect against pathogens
Course of infection
- Contact- Microbe adheres to body surface
- Colonization with microbiota
- Invasion of microbe cross lines of defense toxins or virulence factors can assist
- Infection- Microbe growing in what should be sterile tissue/fluids which leads to a disease state
- Treatment or human defenses fail
Alternatively
Infection clears
Infection
Microbe penetrates host defenses, and invades sterile tissues/organs and multiplies to cause disease
Disease
Defined as any deviation from health
Infectious disease
Infection causes damage/disruption to tissues/organs by microbes or their products
Pathogens
Organism capable of causing disease in healthy personas with normal immune defenses
Opportunistic pathogens
Not pathogenic to a normal health person, also organisms causing disease when the host’s defenses are compromised or when they grow in a part of the body not natural to them
pathogenicity
Ability of microbe to establish itself in the host and cause damage/disease
Virulence
The degree to which an organism is pathogenic. It determines a microbe’s ability to establish itself and cause damage
Virulence factor
Genetically-encoded, structures, characteristics or products of the microbe that contribute to the infection or disease state
Examples:
Invasin, BI antigen, endotoxin, exoenzymes, excreted enzymes
Toxin
Also known as exotoxins, a specific chemical products of microbes, promote infection and disease by directly damaging host tissues and disabling the immune system
Exotoxins
Proteins with a strong specificity for a target cell and extremely powerful, sometimes deadly effects, generally by damaging the cell membrane and initiating lysis or disrupting intracellular function
Symptom
Subjective evidence of disease as sensed by the patient
Asymptomatic
Infections that do not produce overt indications, no noticeable symptoms even though the microbe is active in the host tissue
Syndrome
When a disease can be identified or described by a defined collection of signs and symptoms
Signs
Evidence of disease by an observer
Incubation period
Time from initial contact with the infectious agent to the appearance of the first symptoms; the agent is multiplying but the damage is insufficient to cause symptoms; several hours to several years
Prodromal stage
vague feelings of discomfort; nonspecific complaints
Period of invasion
Multiplies at high levels, becomes well-established; more specific signs and symptoms
Convalescent period
As person begins to respond to the infection, symptoms decline. In the event that the patient does not recover and dies the infection is considered terminal.
Communicable
Capable of spreading person to person
Contagious
How “easy” a infectious disease spreads from person to person
Acute infection
Rapid onset with severe but short-lived effects (hours, days, weeks)
Chronic infection
Infections that progress and persist over long periods of time (months, years, lifetime)
Latent infection
The casual pathogen goes dormant for extended periods of time with no active replication and therefore no host symptoms and signs.
Portal of entry
Where the microbe must enter or there is a lesser chance of infection
(Respiratory is the greatest portal of entry)
Infectious does
Minimum number of microbes to cause disease
Adhesion
Microbes gain a stable foothold at the portal of entry; dependent on binding between specific molecules on the host and pathogen
Phagocytes
Engulf pathogens and destroy them by means of enzymes and antimicrobial chemicals.
Local
Localized on a spot
Systemic
Throughout the body
Focal
Growing in one location, causes an infection elsewhere (breaks loose and disseminates)
Polymicrobial
Many microbes causing infections
Primary/Secondary
First infection was followed by a second infection of different microbes
Latency
After the intial symptoms in certain chronic disases, the microbe can periodically become active and produce a recurrent disease; person may or not may shed it during the latent stage
Carrier
An individual who inconspicuously shelters a pathogen and spreads it to others.
Asymptomatic carrier
Shows no symptoms of the infection and carries the infection
Incubation carrier
spread during the incubation period
Convalescent carrier
Recuperating without symptoms
Chronic carrier
Individual who shelters the infectious agent for a long period
Passive carrier
A person is infected with a microbe, shows no signs of infection and passes the microbe to a susceptible host
Epidemiology
Study of the frequency and distribution of disease and other health-related factors in defined human populations, the science that underlies public health
Primary functions of the immune system
Surveillance
Recognize self from non-self
Destroy the non self material
Innate immunity
Inborn(innate), genetically encoded, non specific defenses
Physical barriers
Skin
Mucous membranes (Thick + slimy)
Flushing (tear production, saliva)
Chemical barriers
Lysozyme (Cleaves Peptidoglycan resulting in lysis)
Defensins (Break up cell/wall membrane of microbes in a non specific way)
Cytokines
Signaling proteins for the immune system
Types of cytokines
- Interleukins (modulate almost every function of the immune system)
- Chemokines (Recruit leukocytes to the site of infection, tissue damage, and inflammation)
- Interferons (Interfere with viral replication)
Leukocytes
Also known as White blood cells; the body’s main internal immune response
Bacteremia
bacteria in the blood
Viremia
Viruses in the blood
Septicemia
Bacteria reproducing in the blood as they spread
Toxemia
Microbial toxins in the blood
Red Blood Cells
Carry o2 and Co2
Plasmodium Falciparum
Also known as Malaria, and it is one of the most infectious diseases in the world today. (carried by arthropods)
Stages of infection:
1. Carried in Arthropod’s saliva which is then injected into the host blood
2. The parasites then circulate to the hosts liver where they develop and release merozoites
3. The merozoites move to the bloodstream where they infect RBC
4. The RBC release merozoites which are taken up by Vectors
Vector
An animal or instinct that transmits a pathogen from host to host
Hematopoiesis
Formation of blood cells and stem cell differentiation
Cell Differentiation Flowchart
Stem cell–> RBC->Leukocytes->Platelets
Leukocytes
1. Most cells (innate immunity)
2. Monocytes —> Macrophages and Dendritic cells
3. Neutrophils
4. Immune cells involved in adaptive immunity (T cells, B cells, and NK cells)
Monocytes
Phagocytes that rapidly leave circulation to mature into other cell types
macrophages
Largest phagocyte which is matured from monocytes; Ingest and kill foreign cells, required for specific immune reactions
(Is an Antigen Presenting Cell)
Dendritic cell
related to macrophages; involved in early immune reactions with foreign matter
(Is an Antigen Presenting Cell)
Neutrophils
Phagocytes that are active engulfers and killers of bacteria (die plus turn into pus)
Platelets
Involved in blood clotting and inflammation
Phagocytes
perform phagocytosis to recognize self from nonself. Then, Attack and ingest microbes in a non-specific matter
PRRS
Pattern Recognition Receptors; Displayed by leukocytes on their membranes. Encoded in the germline of the host, aka Toll-like receptors (TLR)
Can recognize a range of pathogens + molecule types
PAMPS
Pathogen Associated Molecular Patterns; Recognized by PRR on Leukocytes which causes it to target the pathogen for destruction.
Phagocytosis
Ingestion and Destruction by WBC
- Chemotoxis- Phagocyte recognizes pathogen
- PRR recognizes PAMP
- Ingest pathogen; Phagolysosome formation
- Destroy pathogen; Neutrophils expel or die plus turns to pus; Exocytosis of cellular debris
- Macrophages plus dendritic cells become antigen-presenting cells (APC)
Lymphatic system
Part of circulatory system with vessels, cells, and accessory organs.
Lymph
A plasmalike liquid carried by the lymphatic circulation
Thymus gland
Two lobes in the pharyngeal region near the tip of the sternum, required in children for proper WBC development (specifically T cells) which help your body fight disease and infections
Lymph nodes
small, encapsulated, bean-shaped at various locations in the body, specialized for filtering our materials in the lymph and contains WBC to fight infections. Contain macrophages and dendritic cells for antigen presentation
Spleen
The lymphoid organ in the upper portion of the abdominal cavity below the diaphragm serves as a filter for blood and worn-out RBCs, and also filters pathogens from the blood to be phagocytosed by macrophages. Contains specialized macrophages and dendritic cells crucial for antigen presentation
Mast cells
Detect injury to nearby cells and release histamine, initiating an inflammatory response
Histamine
Increases blood flow to the wound site, and increased vascular permeability allows fluid, proteins, phagocytes, and other immune cells to enter infected tissue.
SHARP
Swelling
Heat
Altered Function
Redness
Pain
Inflammation
A reaction to traumatic events in the tissues that attempts to restore homeostasis
Acute inflammation
Resolves in days/weeks and results in tissue repair
Chronic inflammation
Leads to changes where leukocytes are repeatedly deposited in new connective tissue at the site of inflammation, causing permanent damage.
Shock
Collapse of circulatory and respiratory systems
Fever
An inflammatory response that extends beyond the site of infection; abnormally high body temp
Benefits:
An increase in Body temp makes it harder for microbe to survive
Stimulates immune system further
Pyrogen
Causes the hypothalamus to reset which increases body temperature; signals muscles to increase heat production and vasoconstriction
Immunocompetence
Ability of human to mount a “normal” immune response
Adaptive immunity
Extremely specific immune response of humans for resisting infectious agents
Two features that differentiate it from innate immunity:
Memory and Specificity
-Discriminates well between self and nonself
-Enormous diversity (receptors and antibodies) that can recognize trillions of antigens
-Specific, unique response to each pathogen and/or antigen
-remembers previous exposures to antigens to mount stronger subsequent response
Specificity
Antibodies produced, function only against the antigen that they were produced in response to
Memory
Lymphocytes are programmed to “recall” their first encounter with an antigen and respond rapidly to subsequent encounters
Antigen
Molecules that are recognized by Tcells or Bcells; very specific interactions
Epitopes
Complex with multiple chemical features
Antigenicity
How good or bad a Antigen is
Poor antigens are
Small simple molecules not attached to a carrier molecule and simple large molecules (repetitive chains of monomers)
B cells
Production and actions of antibodies in response to the antigen.
-Matured in bone marrow
-Stored in Lymph node until needed
-Reacts with only one antigen
T cells
responses to the APCs.
-Matured in Thymus
-Stored in Lymph node until needed
-Reacts with only one antigen
Clonal Selection Theory
Undifferentiated lymphocytes in embryo and fetus undergo a continuous series of divisions and genetic changes that generate millions of different cell types, each with a particular/unique receptor specificity.
- Clone that recognizes self is eliminated
- Clone that “fits” with the antigen is selected and triggers clonal expansion plus cytokines are released
- A monoclonal population is created
Clone
A pool of cells all with a unique cell surfacer receptor
Monoclonal
A population deriving from a single progenitor cell
B cells: Plasma and memory cells
T cells: CD8 Cytotoxic T cells, CD4 T helper cells, T memory cells
Major histocompatibility complex (MHC)
Cell surface proteins encoded in the DNA region
-Encodes a set of cell surface proteins (receptors) essential for the acquired immune system in the recognition of self and in rejection of foreign molecules.
- Found on all cells except RBCs
-Also known as the Human Leukocyte antigen (HLA) system
Class I MHC
Genes code for markers that display unique characteristics of self and allow recognition of self molecules and regulation of immune reactions
Class II MHC
Genes code for immune regulatory receptors found on antigen-presenting cells (macrophages, dendritic cells and B cells)
B cells (or B lymphocytes)
The production and actions of antibodies in response to the antigen
T lymphocyte (T cells)
Respond to the APCs.
-Release cytokines, which can induce lysis or apoptosis, can stimulate B-cell maturation.
-Target abnormal cells (cancer cells, damaged, transplanted, cells infected with the pathogen)
-T cell receptors are formed in a similar manner to B cells with genetic modification, having variable and constant regions, much smaller
-Unlike B-cell receptors, T cell receptors are small, not secreted.
Plasma cells
Antibody factories
Memory cells
long-lived cells capable of quickly producing more effector cells
MHC II receptor pathway
- Clonal Selection and Antigen binding
- B cells independently recognize microbes and their foreign antigens - Antigen processing and presentation
- Once the microbe is attached, the B cell endocytoses it, processes it into smaller protein units, and displays these in the MHC II complex - B cell/T helper cell cooperation and recognition
- For most B cells to become functional, they must interact with a T helper cell that bears receptors for antigens from the same microbe - B-Cell Activation
- The T cell gives off additional signals in the form of interleukins and B cell growth factors
5-6 Clonal Expansion/Memory Cells
- The activated B cell undergoes numerous mitotic divisions, which expand the clone of cells bearing this specificity and produce memory + plasma cells - Plasma Cells/Antibody Synthesis
- The plasma cells are short-lived, active secretory cells that synthesize and release antibodies.
Antiserum
Serum of blood containing specific antibodies
Primary response
A latent period with no measurable antibody occurs early on. The first antibody to appear is IgM, followed later by IgG arising from the activation of the first memory cells. Within weeks, the titer tapers back to low levels.
Secondary response
A latent period is lacking because other memory lymphocytes from the earlier response are immediately ready to react. A rapid rise in antibody tier, mainly of IgG, is sustained for several weeks. A smaller amount of IgM is also produced by naive B cells
Advantage:
faster response and higher titer of antibodies to antigen
Principle activity of antibodies
Unite with, immobilize, call attention to, or neutralize the Ag for which it was formed
Viral Inhibition
Antibodies react with molecules at the viral surface and prevent the viral attachment to cells
Neutralization
Antibodies combine specifically with toxins (or microbes), thereby neutralizing them, and preventing attachment to cells
Opsonization
Antibodies (called opsonins)
coat bacterial cells, preventing bacterial attachment to cells.
Agglutination
Antibodies combine with antigens on the cell wall surface and bind the cells together or restrict their movement
Precipitation
Antibodies combine with dissolved antigens to form lattice-like arrangements that precipitate out of solution
T helper cells (CD4)
Recognize MHC II + antigen to trigger cytokine production
Killer T Cells (CD8)
Recognize MHC-1 + antigen and target the cell for destruction
Antigen Presenting cell (APC)
Dendritic cells, T helper cells, B cells
T memory cells (CD4)
Stored in lymph nodes and protect against future encounters with same antigen
Interleukins
released by the activated T cell which assists other lymphocytes in their functions
Interleukin I - cytokine released by APC to activate T helper cells
Interleukin II - cytokine produced by T helper cells to activate B and other T cells
Clonal expansion
A period of meiotic division which causes effector T cells, memory T cells and other T cell types
Natural immunity
Acquired as part of normal life expierences
Artificial immunity
Acquired through medical procedures like a vaccine (also called immunization)
Active immunity
Results when a person develops their own immune response to an antigen that stimulates the production of antibodies; creates memory cells, takes time, and is lasting
Passive immunity
Pre-formed antibodies are by one individual and donated to another individual; does not create memory, acts immediately, and is short term
Immunization
Providing immunity through medical procedure
Vaccines
A killed or weakened form of a virus or bacteria, which trains our bodies to recognize and fight the disease if we encounter it in the future
Can be administered orally, injected, or nasal
Recombinant vaccines
Plasmid with gene for surface antigen is cloned in a vector which produces Recombinant antigens that stimulate immune response without direct contact with the virus
Attenuated Vaccine
Live virus has its virulence eliminated or reduced, which is then introduced to the patient who forms immunity without gaining the disease
Killed Vaccine
A killed microbe has retained its antigenicity, which is then introduced to a patient who forms a immune response without getting sick
A cellular vaccine
The antigenic surface molecules are separated from the virus and used to create a vaccine with no intact pathogen present.
Adjuvant
A compound to enhance immunogenicity and prolong retention of antigen
Herd Immunity
Occurs when a large portion of the community becomes immune to a disease. The spread of disease from person to person becomes unlikely when herd immunity is achieved.
Drug resistance
An adaptive response in which microorganisms begin to tolerate an amount of drug that would normally be inhibitory
Transformation
Transfer of free DNA
Conjugation
Plasmid Transfer
Transduction
Transfer by viral delivery
