Shared Flashcard Set

Details

microbio test 1
n/a
160
Microbiology
Graduate
09/23/2009

Additional Microbiology Flashcards

 


 

Cards

Term
sterilization
Definition
Kills everything
Term
disinfection
Definition
does not kill endospores
Term
sanitation
Definition
Cleansing technique that mechanically removes micro-organisms – not sterile but decreases number of microbes
Term
degermation
Definition
reducing the number of microbes on human skin
Term
What is the difference between a microbicide and a microbistatic agent?
Definition
A microbicide kills microbes, but a microstatic agent only temporarily prevents multiplication
Term
microbial death
Definition
The permanent loss of reproductive capability even in optimal conditions
Term
What factors affect the death rate?
Definition
Factors that influence action of antimicrobial agents:

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, also cold temp. and dessication
Term
Which type of heat is the most effective and what method uses this type of heat?
Definition
moist heat is most effective, an autoclave uses this type of heat
Term
What is the thermal death point?
Definition
Lowest temperature required to kill ALL microbes in 10 minutes
Term
pasteurization
Definition
Heat applied to liquids to kill potential agents of infection and spoilage
Term
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 spore, 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
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
chemotherapy
Definition
Any chemical used in the treatment, relief or prophylaxis
Term
prophylaxis
Definition
Any chemical used to treat or prevent disease – meds used to prevent disease
Term
antibiotics
Definition
Natural substances produced by micro-organisms that can inhibit or destroy other microbes.
Term
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
-selectively toxic to microbe but nontoxic to host cells
-microbicidal rather than microbistatic
-relatively soluble
-not broken down or excreted prematurely
-doesn't lead to development of antimicrob. resistance
-complements or assists the activities of the host's defenses
-remains active in tissues and body fluids
-readily delivered to the site of infection
-reasonably priced
-does not disrupt the host's health by causing allergies or predisposing the host to other infection
Term
What are the mechanisms of action of antimicrobials?
Definition
Inhibition of cell wall, DNA/RNA function, protein synthesis and interference with cell membrane 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
Antibiotics that affect the cell wall:
Definition
Penicillins, Cephalosporins, beta-lactam antibiotics
Term
Antibiotics that damage the cell membrane:
Definition
polymyxins
Term
Antibiotics that interfere with protein synthesis:
Definition
Aminoglycosides, Tetracycline antibiotics, Chloramphenicol, Macrolides
Term
Antibiotics that block metabolic pathways:
Definition
Sulfonamides
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
There are 4 generations, 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
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
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, 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.

A Sequale is Long-term permanent damage from the pathogen
Term
What is prevalence? What is incidence?
Definition
Prevalence= The number of existing cases in certain population.

Incidence= The number of new cases compared to the general healthy population.
Term
What is the mortality rate? Morbidity rate?
Definition
Mortality= Total number of deaths in a population due to a certain disease.

Morbidity= Total number of cases afflicting members of the population.
Term
What is endemic? Epidemic? Pandemic?
Definition
Endemic= The frequency of the disease is stable in a certain geographical area

Epidemic= The frequency is increased in a certain area

Pandemic= the disease has spread across continents
Term
What is disease carrier? What is a vector? What is a fomite?
Definition
Disease carrier =An asymptomatic person who carries the pathogen and is able to transmit it.

A vector is infected and transmits it between people (tick, mosquito).

Fomite= Inanimate object that harbors and transmits pathogens.
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
Genetic defenses – 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

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
Agranulocytes:Lymphocytes, monocytes
Granulocytes: Neutrophils, Basophils, eosinophils
Term
Which cells are the largest phagocytes and what is their origin?
Definition
Macrophages – differentiated from monocytes
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 immunity
Term
Which cells are involved in humoral immunity?
Definition
B-cells
Term
what kind of cells are involved in cell mediated immunity?
Definition
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?
Definition
Ability to migrate out of the bloodstream into tissues
Term
What is chemotaxis?
Definition
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
The inflammatory response is a reaction to any traumatic event in the tissues.

Classic signs and symptoms:

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)

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

Examples:
langerhans=skin
kupffers=liver
alveolar=lungs etc
Term
What are the functions of phagocytes?
Definition
Survey tissues for microbes
remove damaged tissue
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 proteinsThe different types of interferon’s are:

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
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.

Functions are 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

The 3 types of MHC receptors are:

Class I – markers that display unique characteristics of self molecules & regulation of immune reactions. Required for T lymphocytes

Class II – receptors that recognize & react with foreign antigens. Located primarily on macrophages & B cells. Involved in presenting antigen to T cells

Class III – 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

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?
Definition
Antigens become coated with specific antibodies so that they will be more readily recognized by phagocytes to dispose of them
Term
neutralization
Definition
antibodies fill the surface receptors on a microorganism to prevent it from functioning normally.
Term
What is agglutination?
Definition
Cross-linking cells into larger clumps
Term
what is Complement fixation?
Definition
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 is the most prevalent
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 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 (TB test).
Term
What is natural immunity?
Definition
Acquired as part of normal life experiences
Term
Artificial immunity
Definition
acquired through a medical procedure such as a vaccine
Term
What is active immunity?
Definition
Results when a person is challenged with Ag that stimulates production of Ab
Term
Passive immunity
Definition
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
Supporting users have an ad free experience!