Why should the CST possess basic understanding of microbiology (2 reasons)?
(1) Transmission of communicable diseases must be inhibited to protect healthcare providers
(2) Protect patient from contracting healthcare-associated infections (HAI)
Define microbiology.
Term used to describe organisms that cannot be seen without the aid of a microscope.
What is Robert Hooke known for?
Observed fungal growth
What is Anton van Leeuwenhoek known for?
- Created the microscope
- "animalcules" (bacteria, fungi, protozoa)
What is Ferdinand J. Cohn known for?
- Specialty area of Bacteriology
- Contributed to the term "Bacillus"
What is Louis Pasteur known for?
- Created the Germ theory of disease
What is Robert Koch known for?
- Proved the "germ theory" by colonizing the bacteria w/ anthrax & shows that bacilli was the cause
- Koch's postulates
What is the difference between an endemic, epidemic, and pandemic?
- Endemic: outbreaks of infection that is localized
- Epidemic: widespread infectious disease outbreak
- Pandemic: widespread, worldwide outbreak involving a large number of individuals
What viruses are considered global threats?
Ebola, Dengue, Marburg, and Lassa viruses.
What does MDR stand for?
Multidrug-Resistant strain
What does XDR stand for?
Extensively Drug-Resistant strain
What is indigenous microflora?
These can become _______ pathogens.
- Microbes that live on the skin and inside the human body.
- Opportunistic
What does "Opportunistic pathogens" mean?
Under normal circumstances, these microbes are helpful and harmless, but given an "opportunity" to enter the body (through a surgical or traumatic wound", they can become pathogenic.
What is the relationship between human hosts and indigenous microflora called?
Symbiosis
What are the Categories of Symbiosis (definition & example)?
- Mutualism: Both organisms benefit from and depend on one another to a certain extent. (ex. E. coli)
- Commensalism: One organism benefits but second organism neither benefits nor is harmed. (ex. indigenous microflora)
- Parasitism: One organism benefits and the host is harmed. (ex. helminths)
What are microorganisms that cause an infection called?
Pathogens
What microscope uses natural light and consists of a small convex lens that magnifies a small focal area?
What is an example of this microscope?
- Simple Microscope
- Magnifying glass or Eyepiece
What microscope provides detailed, 3D images of the specimen by reflecting light off the surface of the specimen rather than transmitting light through a medium?
Stereo Microscope
Also known as an optical microscope, and uses a light source and a compounding medium a long with a convex lens to provide high-resolution visualization.
What magnification can this microscope go up to>
- Compound Light Microscope
- 1000x
Components of a microscope: What does each part do?
- Base
- Illuminator
- Stage
- Stage Controls
- Objective Lens
- Base: supports the microscope and contains the illuminator
- Illuminator: contains the light-source, usually a low-voltage bulb that is controlled by an on and off switch that is usually located in the base.
- Stage: platform on the base on which the slide with a specimen is placed.
- Stage Controls: knobs that are used to adjust the location/height of the stage to bring the specimen into view and allow for focus.
- Objective Lens:
What is the purpose of a simple stain?
To determine the basic shape and structures of cells.
What is the purpose of a differential stain?
What are the different types of differential staining?
- Employ more than one stain per slide that allows to categorize multiple specimens per slide.
- Gram staining & Acid-fast staining
How is Gram staining performed?
Cells are stained with crystal violet and washed with ethanol that removes the purple stain from bacteria that do not retain the stain. Next, a red dye called safranin is applied and the specimen is rinsed with water.
What color does Gram-positive bacteria stain and what does it indicate?
What color does Gram-negative bacteria stain and what does it indicate?
What is a Gram-variable bacteria? What does it stain as?
- Purple/ thick layer of peptidoglycan (murein).
- Red/ consists of an outer membrane containing lipopolysaccharide that covers a thin peptidoglycan cell wall.
- Does not consistently stain red or purple, will respond to other staining such as acid-fast staining.
What is the purpose of Acid-fast staining?
How is it performed?
- Used to identify bacteria classified in the genus Mycobacterium, such as M. tuberculosis and M. leprae.
- Red dye, Ziehl Neelsen Carbol Fuchsin (ZNCF), is applied to the specimen and counterstained with methylene blue. Red dye is retained by acid-fast bacteria and non-acid-fast bacteria appear blue.
How is a culture and sensitivity test performed?
- A sample is collected into a culture tube usually in an aerobic or anaerobic environment until it can be transported to the lab, then grown so a pure sample of the organism is obtained and identified using one of the staining methods.
- The colonized organism is exposed to various antibiotics to determine sensitivity.
What is the purpose of culture media?
Is designed to allow the sample to multiply/colonize by providing an environment that supplies nutrients to the organism/
What does an Anaerobic Culture media consist of?
An Anaerobic blood agar that is enriched with other substances such as yeast, amino acids, and Vitamin K.
What does a Complex Culture media consist of?
Consists of the exact nutrients and any specific growth factors required for a known organism.
What does a Selective Culture media consist of?
Designed to support growth of a specific organism while inhibiting the growth of other organisms.
What does a Defined Culture media consist of?
Contains a component known to permit growth of a specific bacteria because only that bacteria can utilize the component.
What is the purpose of a Transport Culture media?
To preserve the viability of the specimen from the time of collection to the time of processing without allowing the growth of the organism (often a buffered solution).
What is subculturing?
A method of preservation that involves periodically transferring the organism to a fresh culture medium to maintain viability.
What is Nomenclature?
What what the original classification system called?
- System for naming living organisms, plants, animals, and microorganisms (follows a sequence called taxonomy).
- Linnean System
What is Kingdom referred to?
What is Class referred to?
What is Order referred to?
What is Genus referred to?
- group that is related in some way
- group that shares basic characteristics
- group of organisms that have a large degree of common characteristics
- first grouping of species, represented by a capitalized Latin name
Who was the 3-Domain classification system introduced by?
Carl Woese
What are the 3 Domains?
Archaea, Bacteria, and Eukarya
What does the term Binomial Nomenclature refer to?
A two-term naming system in which the first term represents the genus and the second term represents the species within the genus.
What 2 groups are all living cells classified into?
Which one is more complex, which one is less?
Eukaryotes & Prokaryotes
Eukaryotes is more complex, Prokaryotes is less.
What are characteristics of Eukaryotes versus Prokaryotes?
Eukaryotes: multicellular
- Nucleus: control center of the cell, contains genetic material
- Mitochondria: produces & stores energy (ATP)
Prokaryotes: unicellular
- Nucleoid: region that contains genetic material (no membrane)
- Fagella: long, thin, hairlike structure capable of whip-like movements to allow locomotion of a cell
What are the 2 main types of transport? Define each.
Active Transport: moves against the gradient (low concentration to high concentration)
- Uses ATP
- Phagocytosis: movement of solids
- Pinocytosis: movement of fluids
Passive Transport: move along to gradient (high concentration to low concentration)
- Diffusion: random movement until all particles are evenly distributed
- Filtration: movement of substances through a membrane that allows small substances to pass but prevents passage of larger substances.
What is the abnormal multiplication of organisms in the tissues of a host is called?
An Infection
What is the most transmitted pathogen in the surgical environment?
Staphylococcus aureus
Bacteria divide by the process of _____.
Binary fission
The term _______ is used to describe the study of the form and structure of organisms along with their specific characteristics.
Morphology
What shape are Bacilli?
rod-shaped
What shape are Cocci?
What forms do they come in?
- round-shaped
- Diplococci, Streptococci, & Staphylococci
What are some examples of Bacilli bacteria?
Anthrax, Bactermia/Septicemia, Otitis media, Peritonitis, Pneumonia, and Urinary Tract Infection.
What bacteria causes Tuberculosis (TB)?
How is it transmitted?
Mycobacterium tuberculosis
Transmitted through airborne droplet nuclei.
______ is the study of fungi.
Is fungi prokaryotic or eukaryotic organisms?
- Mycology
- Eukaryotic
______ is the study of invertebrates that cause disease.
Parasitology
What protozoa causes of amebic dysentery, an infection often found in patients who are scheduled to undergo a sigmoidoscopy or colonoscopy?
Entamoeba histolytica
What is the term Prion short for?
proteinaceous infectious particle
Which disease causes a rapidly progressive fatal central nervous disease characterized by dementia and myoclonus?
Creutzfeldt-Jakob Disease (CJD)
What particle does the human body produce that is normally harmless until the Prion makes contact with it?
PrP
What tissues have been identified as high risk for transmission of CJD?
eye tissue, dura mater, brain tissue, and the spinal cord
How are viruses different from bacteria?
Viruses are non-living particles that are reliant on the host cell for survival.
Viruses do not multiply; they are replicated within the host cell.
What does the term virulence refer to?
The severity of a disease and is often measured by the intensity of the patient's symptoms and signs.
What does the Incidence Rate refer to?
What does the Prevalence Rate refer to?
What does the Mortality Rate refer to?
- Incidence Rate: # of new cases of a specific disease that occur within a specific time divided by the population size.
- Prevalence Rate: Frequency by which a specific disease affects a particular population (ie. elderly/ethnic group) during a specific time.
- Mortality Rate: Percentage of the population that dies from a specific disease during a specific time.
What are the 5 stages of the infectious process? What do each mean?
- Incubation: occurs after pathogen enters host & replicates, no symptoms at this time.
- Prodromal: Pathogens multiply & body begins immune response, will experience symptoms.
- Illness: Signs & symptoms are the most severe.
- Decline: # of pathogens is reducing & signs/symptoms are improving.
- Convalescence: Host's functions return to normal.
The term ______ indicates that an individual or surface is soiled w/ gross (visible) debris or microbes (invisible germs).
Contamination
Disease is transmitted by what 3 primary modes?
- Contact (direct & indirect): kissing, shaking hands (direct) or touching an item (fomite) that is infected (indirect)
- Air: spread through the air by droplets (coughing, sneezing, talking)
- Vectors: infection spread by animals, insects, rodents
What is the point at which a microbe enters & exit the body called? What are examples?
Portal of Entry & Portal of Exit
Nonintact skin and the mucous membranes of the respiratory, digestive, and genitourinary tracts.
The major sources of microbes that cause SSIs are divided into 2 groups called ________ and ________.
- Exogenous: perioperative personnel, the environment, and contaminated instrumentation.
- Endogenous: the patient's endogenous microflora.
What are examples of patient-related factors that increase the risk of developing an SSI?
Age, Obesity, General Health, MRSA, Remote infections, Preoperative Hospitalization, Pre-existing illness.
Preoperative hair removal, Type of procedure (Class I, II, III, IV), Duration of procedure.
What are the 3 natural lines of defense against pathogens? Give examples.
- 1st Line of Defense: natural barriers (skin).
- 2nd Line of Defense: nonspecific responses innate to the immune system.
- 3rd Line of Defense: acquired when lymphocytes are produced by antibodies in the response to exposure to the specific pathogens.
When does artificially acquired active immunity occur?
When one is immunized (vaccinated) against a specific pathogen.
What is an Attenuated Vaccine?
Live, weakened organisms are injected. Examples of attenuated vaccines include MMR, varicella, and smallpox.
What is an Inactivated Vaccine?
Killed organisms are injected. Examples of inactivated vaccines include hepatitis A, flu, polio, and rabies.
What is an Recombinant Gene Technology Vaccine?
Pieces of the organism, such as a protein, are extracted and injected
What is an Toxoid Vaccine?
Uses the toxin produced by the organism.