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Mmicro Test #1
Review
155
Microbiology
Graduate
09/23/2009

Additional Microbiology Flashcards

 


 

Cards

Term
What is sterilization
Definition
Kills everything
Term
What is disinfection
Definition
does not kill endospores
Term
What is sanitization
Definition
Cleansing technique that mechanically removes micro-organisms – not sterile but decreases number of microbes
Term
What is degermation
Definition
reducing the number of microbes on human skin
Term
What is a microbicide
Definition
Kills microbes
Term
What is a microbistatic agent
Definition
temporarily prevents multiplication
Term
What is microbial death
Definition
The permanent loss of reproductive capability even in optimal conditions
Term
What factors affect the death rate
Definition
Number of microbes
Nature of microbes in the population
Temperature & pH of environment
Concentration or dosage of agent
Mode of action of the agent
Presence of solvents, organic matter, or inhibitors
Term
Physical control of microbes is accomplished by which methods
Definition
Heat and radiation
Term
Which type of heat is the most effective and what method uses this type of heat
Definition
-Moist heat under pressure
-autoclave
Term
What is pasteurization
Definition
Heat applied to liquids to kill potential agents of infection and spoilage
Term
What is cold sterilization
Definition
Sterilizing using radiation instead of heat
Term
What is the difference between ionizing and non-ionizing radiation
Definition
Ionizing radiation penetrates much deeper, non-ionizing radiation is UV light and doesn’t penetrate past the surface
Term
What method is used to sterilize the air in hospital isolation rooms
Definition
Filtration
Term
What are the four cellular targets of antimicrobials
Definition
Cell walls, cell membranes, DNA or RNA synthesis, protein function
Term
What types of microbes are the least resistant? Most resistant?
Definition
Highest resistance=Bacterial endospores
Moderate resistance=Pseudomonas sp.,
Mycobacterium tuberculosis, Staphylococcus aureus,
Protozoan cysts
Least resistance
Most bacterial vegetative cells
Fungal spores
Enveloped viruses
Yeast
Protozoan trophozoites
Term
Which chemical agents are the closest to ideal agents
Definition
Glutaraldehyde and hydrogen peroxide
Term
What class of chemical agents does chlorine and iodine belong to
Definition
Halogens
Term
What class of chemical agents does Lysol belong to
Definition
Phenolics
Term
What is the mechanism of action of alcohols
Definition
Dissolve membrane lipids, disrupt cell surface tension and denatures proteins
Term
What is a chemiclave
Definition
Automatic ethylene oxide sterilizer
Term
What is the mechanism of action of hydrogen peroxide
Definition
Germicidal effects are due to the direct and indirect actions of oxygen which forms free radicals that are highly toxic to microbes.
Term
Detergents are useful for which level of antimicrobial effects
Definition
Low level disinfection only
Term
What types of heavy metals have been used for microbial control
Definition
Silver and mercury
Term
What class of chemical agents does Cidex belong to? What is it used for?
Definition
Aldehydes – glutaraldehyde; sterilize equipment that cannot tolerate high heat
Term
What is chemotherapy? What is prophylaxis
Definition
Any chemical used to treat or prevent disease – meds used to prevent disease
Term
What are antibiotics
Definition
Natural substances produced by micro-organisms that can inhibit or destroy other microbes.
Term
What is selective toxicity
Definition
Kills microbial cells without damaging host cells
Term
What are narrow and broad spectrum
Definition
Narrow=limited range of microbes affected by the drug, broad=large range of microbes affected by the drug
Term
What are some of the characteristics of the ideal antimicrobial drug?
Definition
selective toxicity,microcidal instead of microbistatic,rather soluble, remains potent even in low concentration, does not lead to antimicrobial resistance, complements/assists host own defenses,
readily delivered to infection site, cost.
Term
What are the mechanisms of action of antimicrobials
Definition
Inhibition of cell wall, DNA/RNA function, protein synthesis an structure or function.
Term
Which classes of drugs affect the bacterial cell wall
Definition
Penicillins and cephalosporins
Term
Which classes of drugs affect DNA/RNA synthesis
Definition
Fluoroquinolones, Rifampin, antiviral drugs
Term
Which classes of drugs affect protein synthesis
Definition
tetracyclines, aminoglycosides, erythromycin
Term
Which classes of drugs affect cell membranes
Definition
Polymyxins, antifungals
Term
What is unique about the structure of penicillins? How do microbes become resistant to penicillins
Definition
Beta lactam ring – develop enzymes to break the ring
Term
Penicillins are effective against what types of microbes
Definition
Gram positive cooci – streptococcus, staphylococcus, syphilis, some gram positive rods
Term
What is clavulanic acid? What drug is it found in
Definition
Chemical that inhibits beta-lactamase enzymes – augmentin
Term
What group of antibiotics account for the majority of all antibiotics administered
Definition
cephalosporins
Term
How many generations of cephalosporins are there and what is significant about these generations
Definition
4, first gen=gram pos organisms; second, third, & fourth gen=increasing effectiveness against gram negs
Term
What are 2 examples of aminoglycocides
Definition
Streptomycin and gentamicin
Term
What are the limiting factors of tetracyclines
Definition
GI disruption of normal flora and staining of teeth
Term
Which drugs are synthetic rather than natural antibiotics
Definition
Sulfonamides, fluoroquinolones, trimethoprim, dapsone
Term
Which drugs are used to treat fungal infections
Definition
Amphoteracin B, nystatins, and azoles
Term
Which drugs are classified as macrolides
Definition
Erythromycin, clindamycin, vancomycin, rifampin, clarithomycin, azithromycin
Term
Which drugs are used for protozoan infections
Definition
Quinines, metronidazole
Term
What is the mechanism of action of drugs used for helminth infections
Definition
Interfer with their metabolism so they are weakened and able to be excreted from the body
Term
What is the mechanism of action of antivirals
Definition
Inhibit viral penetration, multiplication or assembly
Term
How is drug resistance acquired? (4 ways)
Definition
Drug inactivation, decreased permeability/increased elimination, change of metabolic pattern, change in drug receptors
Term
What is natural selection and how does it effect drug resistance
Definition
The resistance microbes survive and replicate
Term
What are the 3 categories of adverse host-drug reactions
Definition
Direct toxicity to organs, allergic responses, changes to the normal flora/superinfection
Term
Most important considerations in selecting a medication
Definition
The nature of the microbe, the susceptibility of the microbe, overall medical condition of the patient, toxicity of the drug
Term
What is the MIC
Definition
Minimum inhibitory concentration – smallest effective dose of a drug against a specific microbe
Term
What is the therapeutic index
Definition
The ratio of the toxic dose to the effective dose – the smaller the TI the more risk of toxicity to the patient
Term
What is the difference between a true pathogen and an opportunistic pathogen
Definition
True pathogen (adequate infectious dose) will cause disease in an otherwise healthy person, opportunistic only causes disease when the immune system is compromised.
Term
What is normal flora and where does it occur
Definition
Beneficial bacteria that are present on the skin, in the GI tract, upper respiratory tract and GU tracts
Term
Where are staphylococcus spp found
Definition
Skin, mouth, upper resp tract, GU
Term
Where are coliforms found
Definition
GI tract mostly and small amt on urinary tract
Term
What are the primary events in the infectious process
Definition
Portal of entry, invasion of tissue and portal of exit
Term
What is an infectious dose
Definition
The amount of pathogen required to cause disease in the host
Term
What are the mechanisms of adhesion of pathogens
Definition
Fimbriae, capsules, spikes, hooks or flagella
Term
What are exoenzymes
Definition
Enzymes secreted by the pathogens that damage tissues and promote invasion
Term
What are endotoxins and exotoxins
Definition
Endotoxins are chemicals secreted when the pathogenic cells lyses/dies; exotoxins are secreted by active/live pathogens
Term
What is the difference between localized, systemic and focal infections
Definition
Localized=infection stays in portal of entry; systemic=infection spreads to several areas; focal=infection stays in portal of entry but releases toxins that effect other organs.
Term
What is the difference between and sign and a symptom
Definition
Signs=objective finding noted by the observer; symptoms=subjective findings reported by the patient
Term
What does the acronym STORCH stand for
Definition
These are diseases that can infect the fetus from the mother – syphilis, toxoplasmosis, others (Hep B, HIV, chlamydia), rubella, cytomegalovirus and herpes simplex virus
Term
What are some common portals of exit? Is the portal of exit the same as the portal of entry
Definition
The pathogen may leave the body by a different portal than used for the entry – respiratory and salivary, skin scales, fecal, urogenital tract, blood.
Term
What is latency? What are sequelae
Definition
The pathogen remains in the body in a dormant state – it may still be shed and the person is a chronic carrier. Long-term permanent damage from the pathogen
Term
What is prevalence? What is incidence
Definition
The number of existing cases in certain population. The number of new cases compared to the general healthy population
Term
What is the mortality rate? Morbidity rate
Definition
Total number of deaths in a population due to a certain disease. Total number of cases afflicting members of the population
Term
What is endemic? Epidemic? Pandemic
Definition
The frequency of the disease is stable in a certain geographical area, the frequency is increased in a certain area, the disease has spread across continents
Term
What is disease carrier? What is a vector? What is a fomite
Definition
An asymptomatic person who carries the pathogen and is able to transmit it. A vector is infected and transmits it between people (tick, mosquito). Inanimate object that harbors and transmits pathogens
Term
What is Koch’s postulate
Definition
A theory to prove a certain microbe caused the disease
Term
What is a nosocomial infection? What are the most common sites of a nosocomial infection
Definition
Disease acquired during a hospital stay – respiratory tract, urinary tract, surgical incisions
Term
What are the 3 lines of host defenses
Definition
First line – physical, chemical and genetic barriers; Second line – inflammatory response, Interferons, Phagocytosis; Third line – acquired/specific immunity
Term
Which lines of defense are inborn/innate
Definition
Only the first 2 lines of defense are inborn/innate – the third line is acquired
Term
What are some examples of physical barriers
Definition
Skin, rapid regeneration of mucous membranes, nasal hairs, ciliary defense in the respiratory tract, flushing by saliva, tears, sweat, vomiting, defecation, urination
Term
What are some examples of chemical barriers
Definition
Sebaceous secretions are antimicrobial, stomach acid, lysozyme in tears, lactic acid in sweat
Term
What are genetic defenses
Definition
some pathogens can only infect certain species – some genetic mutations make people immune to disease
Term
What 3 functions is the immune system responsible for
Definition
Surveillance of the body, recognition of foreign material, and destruction of foreign material
Term
What are markers and why are they important
Definition
Markers are proteins and/or carbohydrates that enable the immune system to identify a foreign particle
Term
Which body compartments are involved in the immune function
Definition
Reticuloendothelial system, extracellular fluid, bloodstream, lymphatic system
Term
What 2 systems are included in the circulatory system
Definition
Blood stream and lymphatic system
Term
Which type of blood cells are the most responsible for immune functions
Definition
Leukocytes – WBCs
Term
Which cells are agranulocytes? Granulocytes
Definition
Lymphocytes, monocytes; neutrophils, basophils, eosinophils
Term
Which cells are the largest phagocytes and what is their origin
Definition
Macrophages – differentiated from monocyte
Term
What types of cells do lymphocytes differentiate into
Definition
B-cells, T-cells
Term
What role does the eosinophil play in the immune system
Definition
Destroy eucaryotic pathogens especially helminth worms and fungi
Term
What role do lymphocytes play in the immune system
Definition
The third line of defense – specific/acquired immunit
Term
Which cells are involved in humoral immunity? Cell mediated immunity
Definition
B-cell, T-cells
Term
What functions are macrophages responsible for
Definition
Phagocytic and killing functions, processing foreign material and presenting them to lymphocytes, secreting substances that activate other cells of the immune system (cytokines, interleukins)
Term
What is diapedesis? What is chemotaxis
Definition
Ability to migrate out of the bloodstream into tissues; leukocytes migrate to the site of inflammation by following chemical stimuli
Term
What are the major functions of the lymphatic system
Definition
Provides an auxiliary route for return of extracellular fluid to the circulatory system; Acts as a drain-off system for the inflammatory response; Renders surveillance, recognition, and protection against foreign material through the use of lymphocytes, phagocytes and antibodies.
Term
Where does lymph come from? How is it circulated
Definition
From plasma; by skeletal muscle contraction
Term
Where in the body is lymphoid tissue
Definition
Lymph nodes, thymus, spleen, GI tract (GALT), tonsils etc
Term
What are the functions of the inflammatory response
Definition
Mobilize and attract immune components to the site of injury; Set in motion mechanisms to repair tissue damage and localize and clear away harmful substances; Destroy microbes and block their further invasion.
Term
What is the inflammatory response
Definition
a reaction to any traumatic event in the tissues.
Term
What are the classic signs and symptoms of the inflammatory response
Definition
Rubor – redness
Calor – warmth
Tumor – swelling
Dolor – pain
Term
What substance initiates a fever? What are some examples of these
Definition
Pyrogens – exogenous (pathogens, blood, vaccines) or endogenous (liberated by wbc’s during phagocytosis – interleukin 1 and tumor necrosis factor)
Term
What are some benefits of a fever
Definition
Inhibits multiplication of pathogens, impedes nutrition of bacteria, increases host’s metabolism and stimulates immune reactions
Term
Which cells are considered phagocytes
Definition
Neutrophils and macrophages (which have a larger role in the immune system than the neutrophils)
Term
What are histiocytes
Definition
Specialized macrophages that remain in certain tissues – langerhans=skin, kupffers=liver, alveolar=lungs etc
Term
What are the functions of phagocytes
Definition
Survey tissues for microbes, damaged tissue; remove these; extract antigens from foreign material
Term
What is interferon? What are the different types
Definition
family of proteins produced by leukocytes and fibroblasts that inhibit the reproduction of viruses by degrading viral RNA or blocking the synthesis of viral proteins; alpha, beta, gamma
Term
What is the complement system? How does it function
Definition
Complement is a complex defense system with multiple proteins involved that produces a cascade reaction
Term
What are the 3 stages of the complement cascade
Definition
Initiation, amplification and cascade, membrane attack
Term
What is the final result of the complement system
Definition
Formation of a membrane attack complex to make holes in the cell membrane of bacteria, cells and enveloped viruses
Term
What is the difference between the 3 complement pathways
Definition
The major difference is the substance that initiated the cascade reaction.
Term
All classes of interferon are produced in response to
Definition
viruses, RNA, immune products and other antigens.
Term
Interferons
Definition
Bind to cell surfaces and induce changes in genetic expression
Inhibit the expression of cancer genes and have tumor suppressor effects.
Alpha & beta IFN stimulate phagocytes and gamma IFN is an immune regulator of macrophages, T and B-cells.
Term
What is the third line of host defense? What are the two features that most characterize this defense
Definition
Acquired specific immunity; specificity to the antigen and memory
Term
What are the stages of acquired specific immunity
Definition
Development of the lymphocyte system; Processing of Antigens and Clonal Selection; Activation of lymphocytes and Clonal Expansion; Antibody production; Cell-Mediated Immunity
Term
What are receptors? What are their functions
Definition
Protein or carbohydrate markers on the surface of cells - to perceive & attach to foreign molecules, recognition of self molecules, to receive & transmit chemical messages, to aid in cellular development
Term
What is the clonal selection theory and what does it result in
Definition
It is preprogrammed lymphocyte specificity, existing in the genetic makeup before an antigen has ever entered the system; Each genetically different type of lymphocyte expresses a single specificity - Undifferentiated lymphocytes undergo a continuous series of divisions and genetic changes that generate hundreds of millions of different cell types.
Term
What is immune tolerance
Definition
The elimination of any clones that may be specific for self cells
Term
What is the specific B-cell receptor
Definition
Immunoglobulins – large glycoprotein molecules that serve as the specific receptors of B-cells and as antibodies
Term
How are immunoglobulins synthesized
Definition
A heavy chain is bound with a light chain then the 2 heavy chains are bound together forming a Y structure
Term
What are antigen binding sites
Definition
Highly variable in shape to fit very specific antigens – at the ends of the Y structure of the Ig
Term
What are MHC receptors? What do the 3 groups of receptors react with
Definition
Receptors found on all cells except RBCs
Term
Functions of Class I MHC
Definition
markers that display unique characteristics of self molecules & regulation of immune reactions
Required for T lymphocytes
Term
Functions of Class II MHC
Definition
receptors that recognize & react with foreign antigens. Located primarily on macrophages & B cells
Term
Functions of Class III MHC
Definition
secreted complement components, C2 and C4
Term
How are lymphocytes differentiated initially
Definition
Maturation occurs differently for B and T cells – b cells in the bone marrow and t cells in the thymus
Term
What are the different classes of T-cell receptors called and why are they significant
Definition
CD receptors (cluster of differentiation) - Type of receptors dictates what is recognized by the T-cell
Term
What are the characteristics of an antigen
Definition
Provokes an immune reaction, perceived as foreign by the immune system, large enough to provoke an immune reaction
Term
What is an antigenic determinant
Definition
Small molecular group that is recognized by lymphocytes. It is the primary signal that the molecule is foreign. An antigen has many antigenic determinants
Term
What is a hapten
Definition
Are small molecules that are usually not antigenic unless attached to a larger carrier
Term
What is an allergan
Definition
Antigen that provokes allergic reactions
Term
Are most antigens t-cell dependant or do they react directly with b-cells
Definition
Most are t-cell dependant – only a few can interact with b-cells directly
Term
How is an antigen processed and presented
Definition
Must be processed by phagocytes (dendrites) called antigen presenting cells (APC). An APC/dendrite alters the antigen and attaches it to its MHC receptor where it can be presented to the b and t-cells
Term
What are interleukins? How are they involved in antigen processing & presentation
Definition
Interleukins are peptides that carry signals between leukocytes; Interleukin-1 is secreted by APC to activate TH cells; Interleukin-2 is produced by TH to activate B & other T-cells
Term
What happens to the b-cell once it is activated
Definition
They enter the cell cycle in preparation for mitosis and clonal expansion. Divisions give rise to plasma cells that secrete antibodies and memory cells that can react to the same antigen later.
Term
What 2 fragments make up the structure of the antibody? What do they attach to
Definition
Fab – antigen binding fragement binds the antigen and Fc - crystallizable fragment binds to various cells and molecules of the immune system.
Term
What are the functions of antibodies
Definition
To unite with, immobilize, call attention to, or neutralize the antigen; specifically opsonization, neutralization, agglutination and complement fixation
Term
What is opsonization? Neutralization?
Definition
Antigens become coated with specific antibodies so that they will be more readily recognized by phagocytes to dispose of them; antibodies fill the surface receptors on a microorganism to prevent it from functioning normally.
Term
What is agglutination? Complement fixation?
Definition
Cross-linking cells into larger clumps; The interaction of an antibody with complement can result in the specific rupturing of cells and some viruses.
Term
How many classes of immunoglobulins are there? Which class is the most prevalent
Definition
Five, IgG
Term
Which class of Ig’s is the first responder with an initial antigen encounter
Definition
IgM
Term
Which class of Ig’s is in many secretions of the body and is present in breast milk
Definition
IgA
Term
Which class of Ig’s has the largest molecules
Definition
IgM
Term
Which class of Ig’s are produced by memory b-cells in a second exposure
Definition
IgG
Term
Which class of Ig’s interact with mast cells and basophils and is involved with allergic responses?
Definition
IgE
Term
What is cell mediated immunity? What cells are involved with CMI
Definition
Rather than making antibodies to control foreign antigens, the T-cells act directly against antigens and foreign cells.
Term
What are the 3 types of t-cells? How are they differentiated?
Definition
Helper, suppressor, cytotoxic and delayed hypersensitivity T-cells. The functions of T-cells vary in their CD receptors and sensitivity to cytokines.
Term
Which receptor is common to all t-cells? Which t-cells have CD4? CD8?
Definition
Cd2 is common to all t-cells; t-helper cells have only CD4 receptors; t-cytotoxic cells have only CD8 receptors
Term
What is the most prevalent t-cell? What is significant about it?
Definition
T-helper cells – the conductor of the immune response by assisting other T and B-cells. Reacts directly by receptor contact and indirectly by releasing cytokines such as interleukin-2.
Term
How does a patient with an HIV infection become immunosuppressed
Definition
HIV depresses and destroys the t-helper cells
Term
What is the function of t-cytotoxic cells
Definition
Foreign receptors are presented to it and it mounts a direct attack against the target cell by secreting perforins that lyse cells by creating pores in the target cell membrane.
Term
What is the function of t-suppressor cells
Definition
Inhibit the actions of other T-cells and B-cells and regulate the immune response by producing protein inhibitors that prevent lymphocytes and macrophages from reacting with antigens
Term
What is the function of t-delayed hypersensitivity cells
Definition
Responsible for allergies occurring several hours or days after contact such as the tuberculin reaction
Term
What is natural immunity? Artificial immunity?
Definition
Acquired as part of normal life experiences; acquired through a medical procedure such as a vaccine
Term
What is active immunity? Passive immunity?
Definition
Results when a person is challenged with Ag that stimulates production of Ab; preformed Ab are donated to an individual
Term
What type of immunity is the result of an infection and recovery
Definition
Natural active immunity
Term
What type of immunity is the result of pregnancy and lactation
Definition
Natural passive immunity
Term
What type of immunity is the result of a vaccination?
Definition
Artificial active immunity
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