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MICR 130 - Exam 4
Terms in this set (87)
What are the 4 mechanisms by which bacteria become resistant to antibiotics?
1) Acquisition of a gene to produce an enzyme to destroy the drug
2) Acquisition of a gene to make a MDR pump to pump the drug out
3) Change in the structure of the drug binding site so it can't bind
4) Change in the structure of the cell membrane permeability
What are the 5 different modes of action of antibiotics (how the drugs kill bacteria)? Know one specific example of an antibiotic in each of the 5 groups of antibiotics
1) Inhibition of Cell Wall Synthesis; Penicillin
2) Inhibition of Protein Synthesis; Tetracycline
3) Inhibition of Enzyme Activity; Trimethoprim
4) Injury to Cell Membrane; Polymyxins
5) Inhibition of DNA Synthesis; Ciprofloxacin
What are the "superbugs" we discussed and to which drugs are they resistant to?
CPE: Carbapenem-resistant (makes enzyme "Carbapenemase")
TB: MDRTB is multiple drug resistant, XDRTB is extensively drug resistant
a disease that develops rapidly and only lasts for a short time.
a disease that develops slowly, with less significant reaction (lower grade disease), and tends to last for a long time. (patient may have lower grade symptoms for a long time).
a disease in which the causative agent (etiologic agent) causes an infection, then appears to go away, but remains inactive in the body for a long time before the disease symptoms re-appear.
the infection that is causing the disease is limited to a certain (small) part of the body (only one of the body's systems is actually infected by the organism). Symptoms may or may not be limited to that location.
Generalized (systemic) infection
the infection that is causing the disease has spread throughout the body via the blood or lymph.
the growth of bacteria in the blood, diagnosed with blood cultures.
an acute infection that causes an initial disease.
usually caused by an opportunistic pathogen after the primary infection has weakened the host's immune system.
is an infection where no symptoms are present, but the organism may potentially be transmitted to others. If the person is a source of infection, but is not obviously ill, they are called a "carrier".
the period of time between when the infection begins and when the first symptoms are apparent. Many diseases are contagious during this period.
an infectious disease that is transmissible from one human to another.
an infectious disease that is easily transmissible from one human to another.
an infectious disease that humans acquire from an animal source.
the number of new cases of a particular disease in a particular population over a given period of time. (aka Morbidity rate)
the number of deaths due to a particular disease in a particular population over a given period of time.
a disease that occurs occasionally within a specific population, in a particular geographic location.
a disease that is always present within a particular population in a specific geographic area.
a greater than usual number of cases of a given disease in a relatively short period of time.
a disease that is occurring in epidemic proportions in many countries simultaneously.
A reservoir of infection
is a person or thing which acts as a source of infection
Direct contact transmission
spread of disease directly from one host to the next via direct contact.
Indirect contact transmission
when an infection is transmitted from it's reservoir to the new host by a non-living object or fomite (handkerchief, cups, syringe, etc.,).
small droplets of mucous and infectious organism are liberated into the air and surfaces from coughing and sneezing, laughing, talking.
the insect or arthropod that passes a disease to a human.
What are the 6 steps in pathogenesis of infectious disease?
1) Entry: pathogen enters host
2) Attachment: Pathogen must hold onto host tissue to avoid being flushed away
3) Multiplication: Pathogen finds food/energy and multiplies
4) Invasion/Spread: Spreads from original spot to avoid over-mining resources of original entry point
5) Evasion of Host Defenses: hide/fight WBCs
6) Damage: damage host tissue
What is virulence?
how good an organism is at creating disease
What are virulence factors?
traits that allow the organism to cause disease
What are the mechanisms of attachment discussed in class - know the species and mechanism of attachment of the examples given in class.
Know how attachment, pathogens inside cells (intracellular pathogens), and capsules, allow bacteria to better infect a host, and examples of species that use each.
Know how each of the exoenzymes discussed in class allow the organism to be more virulent.
Know which exoenzymes Staph aureus makes and which Strep pyogenes makes.
Staph aureus makes most of the exoenzymes, including coagulase.
Strep pyogenes makes necrotizing (flesh-eating) enzymes
What are toxins? What are the 2 main types of toxins produced by bacteria?
Exotoxins and Endotoxins are the two main types.
What is endotoxin, where does it come from, what disease symptoms does it cause?
Endotoxins are released from dying bacteria cells;
Know what each of the exotoxins given in class does and the species that produce each (diphtheria toxin, erythrogenic toxin, botulinum toxin, tetanus toxin, staphylococcal enterotoxin, exfoliative toxin, leukocidins, TSST-1), and how they cause disease.
What are the 3 types of exotoxins? Know which of the 3 categories each of exotoxins given fall into.
Regarding food poisoning toxins - what does it mean to be heat stable?
Heat-stable toxins are not killed from being cooked
Know the exotoxins produced by Staph aureus and Strep pyogenes.
Know what Strep pyogenes is called in a clinical setting and why there is a different naming system.
Group A Strep (G.A.S)
Why do endotoxins cause more problems when the organism is being controlled (killed), rather than when the infection is active?
Endotoxin (LPS) is released from bacteria cell membrane when it dies
Be able to recognize the names of the organisms given in class and which can cause endotoxin poisoning.
Salmonella typhi: typhoid fever
Neisseria meningiditis: meningitis
Vibrio cholerae: cholera
E. coli O157:H7 - Food Poisoning
Know which of the"6 steps of pathogenesis" each of the virulence factors discussed in class supports-in other words how is a particular characteristic helpful to the bacteria that possess it?
Know the "factors" (pathogen, host, and environmental factors) that influence whether a particular pathogen is able to cause disease in a particular area.
1) Organism's virulence (how infectious the pathogen is)
2) # of organisms that gain access to the host
3) The health and nutritional status of host (host's immune ability)
4) Availability to potable drinking water and separate sewage treatment
5) Availability of reservoirs (source) of infection and vectors
Know the "chain of infection" - the sequence of events that must occur in order for an infection to be spread to a new host.
1) Reservoir of infection; sick animal or human carries pathogen
2) Pathogen leaves reservoir at host's port of exit
3) Pathogen is transmitted to new host by mode of transmission; direct contact, inhalation, waterborne, etc.
4) Pathogen enters new host through portal of entry
5) New host must be susceptible to pathogen; Susceptible host
What is the portal of entry and exit?
1) entry: point where pathogen enters new host; eyes/nose/mouth, orifices, etc.
2) exit: point of escape from reservoir; aerosols/sneezing/coughing, fecal, etc.
What is a reservoir? Know the different reservoirs discussed in class. Know the different types of carriers. Know the examples of reservoirs and their infections given in class.
Reservoir is a source of the pathogen;
2 types: Living and Non-living
Living reservoirs of infection
Humans, animals, arthropods
Know the modes of transmission given in class - be able to describe each and know the examples given in class.
Be able to match a given disease example to it probable reservoir, portal of entry, portal of exit, mode of transmission.
What is a nosocomial infection?
hospital acquired infection
What is a Community-acquired infection?
infections acquired before being admitted to a health care agency/facility
Know the 4 major factors contributing to nosocomial infections.
What are the 6 species most commonly involved - given in class?
What are the sites of the most common nosocomial infections on/in patients?
Be able to match the nosocomial bacterial species discussed in class with the most common infection site for that species.
What does MDRTB stand for?
What does XDRTB stand for?
Extensively drug resistant tuberculosis
What does MRSA stand for?
methicillin resistant staph aureus
What does MRSE stand for?
methicillin resistant staph epidermidis
What does VRE stand for?
vancomycin resistant enterococcus
What does KPC stand for?
Klebsiella pneumoniae carbapenemase
Know the different levels of Public Health and what Notifiable Diseases are and at least 3 examples
What are the 3 lines of host defense? Which ones are non-specific in nature, which are specific in nature?
The three lines of HD are: surface, interior non-specific, and specific; the first two are non-specific, and the last is specific.
Know surfaces defenses given in class? Know how each, in general, works to protect the host from infection.
skin and mucous membranes work as barriers; mucous traps invaders and cilia or peristalsis (muscle movement) moves them out; molecules in mucous do chemical warfare (lysozyme, sebum, antimicrobial peptides, microbial antagonism)
What is phagocytosis? Which blood cells can do this and why is phagocytosis important to a person's general health?
WBC engulfs and destroys invaders and damaged host cells. Macrophages, Neutrophils, and Eosinophils can do phagocytosis. Phagocytosis is important to destroying invading cells and cleaning up damaged host cells.
Which of the following are phagocytes: polymorphonucleocyte (PMN) or neutrophils, bands, basophils or mast cells, eosinophils, monocytes or macrophages, and lymphocytes. Which are involved in specific host defenses?
PMN, Macrophages, and Eosinophils are phagocytes; Lymphocytes are involved in specific host defenses.
What does a high PMN count indicate? What are "bands" and what does an elevated number of them indicate?
High PMN count indicates that the body is fighting off an infection; "bands" are newly formed WBCs, and indicate the body is fighting off an active infection.
What are "bands" in terms of neutrophils?
What is a basophil/mast-cell?
Involved in allergic reactions; mast-cell while in tissue.
What is an eosinophil?
The Parasite Destroyer
What is a macrophage? What is a monocyte?
Monocytes while in blood vessels, Macrophages in tissue; Phagocytic
What is a lymphocyte?
T-cells and B-cells; involved in specific HD
What are polymorphonucleocyte (PMN) or neutrophils?
WBC's that ingest and destroy microbes in a process called phagocytosis.
What are the symptoms of inflammation, and what are the causes of inflammation?
Symptoms are redness, swelling, heat; cause is infection
What are the primary functions of inflammation?
Serves as beacon that body needs help over in that area.
What are the specific steps involved in inflammation?
Vasodilation, Increased vascular permeability, Chemotaxis
Know where each of the following come from and what they do during inflammation, and how they create the symptoms of inflammation: Prostaglandins, leukotrienes, histamines, and interleukins.
During inflammation, interleukins:
are produced by WBCs after a WBC has ingested an endotoxin; interleukins stimulate the hypothalamus to create prostaglandins, which induce fever.
During inflammation, prostaglandins:
are made by interleuken-1 stimulating the hypothalamus; make the body feel chills and shiver; constricts blood vessels
During inflammation, leukotrienes:
During inflammation, histamines:
What causes fever to occur? How are "chills" related to the fever response?
Prostaglandins constrict blood vessels to up body temperature; vasoconstriction makes body feel chills.
Know specifically how endotoxin (external pyrogen), WBC's, interleukin-1, the hypothalamus, and prostaglandins all act to cause fever.
WBC eats endotoxin; WBC releases IL-1 in response to endotoxin; IL-1 stimulates hypothalamus to release prostaglandins; prostaglandins constrict blood vessels, cause "chills" and fever.
What is the function of fever?
To kill or inhibit pathogen growth
Know how aspirin, ibuprofen, and Tylenol (acetaminophen) work to reduce inflammation and /or fever.
NSAIDS (Aspirin & Ibuprofen) are anti-inflammatory and work at the site of infection to inhibit prostaglandins. Tylenol inhibits prostaglandins at the CNS and brain, and are not anti-inflammatory.
Recommended textbook explanations
Microbiology: An Introduction
Berdell R. Funke, Gerard J. Tortora
Alton Biggs, Hagins
MasteringMicrobiology with Pearson eText -- Standalone Access Card -- for Brock Biology of Microorganisms
David A. Stahl, John M Martinko, Michael T. Madigan
Brock Biology of Microorganisms
Daniel H. Buckley, David A. Stahl, Kelly S. Bender, Michael T. Madigan, W. Matthew Sattley
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