Overview Microbiology Flashcards
What is microbiology?
Study of microorganisms or minute living bodies not perceptible to the naked eye.
What are the microorganisms?
Bacteria, Viruses, Protozoa Rickettsiae, Algae
Robert Hooke 1665
An English man
.1st to report on cell theory - that all living things are composed of cells
What is a cell?
The basic functional unit of all living organisms. The human body is made up of 50-100 trillion cells. Cells combine to form tissue & organs. The cell contains the genetic material, DNA (Deoxyribonucleic Acid.)
Anton Van Leeuwenhoek 1673
A Dutch scientist
. 1st to observe and record Bacteria & Protozoa;
Protozoa
One-celled animal
Edward Jenner 1798
English physician
- Developed the 1st vaccine against smallpox
Ignaz Semmelweis 1840
Advocated frequent hand washing between treatment of patients to prevent the spread of infection
Louis Pasteur 1857
Discovered that heating can kill bacteria (pasteurization)
Joseph Lister (1860)
English surgeon
. 1st to advocate aseptic technique to be used in the operating room
. Used phenol as an antiseptic agent
Robert Koch 1876
German physician, proved that bacteria are the cause of disease
. Discovered the organisms causing tuberculosis, anthrax and cholera
. Developed techniques to culture bacteria
. Urged the sterilization of surgical instruments using heat
Hans Gram 1884
Danish physician, developed the Gram staining method that differentiates between gram-positive and gram-negative bacteria
Microscopy
The use of light to magnify objects
Microscope
Is an instrument used to see objects that are too small for the naked eye
Simple Microscope
With a single magnifying lens, capable of approximately 300x magnification
Compound Microscope
Uses a series of lenses for greater magnification; can magnify 1,000-2,000x
Dark Field Microscope
Useful for examining pale or colorless cells; specimen appears light against a dark ground
Fluorescent Microscope
Uses UV light to fluoresce objects
Electron Microscope
Can magnify objects 10,000-100,000x
What are the differences in Eukaryotic & Prokaryotic cells?
. Presence of membrane-bound compartments (such as the nucleus) in eukaryotes
. Prokaryotes - less complex organisms ex. Bacteria
. Eukaryotes - more complex organisms ex. Plant & Animal cells, Protozoa, fungi, algae, human cells
Eukaryotic - Structure
- Cell Membrane (plasma membrane) - the thin membrane that forms the outer boundary of the cell
- Nucleus - the membrane-bound structure inside the cell that contains the genetic material DNA (deoxyribonucleic acid)
- Cytoplasm - the gel-like living fluid in the cell between the cell membrane & nucleus
What contains organelles & define each organelle
The cytoplasm
1. Ribosomes- tiny particles that serve as “protein factories” of the cell making enzymes & other protein compounds
2. Mitochondria- “power plant” of the cell containing enzymes and substances whose reactions release energy to recharge the cells “battery” - the ATP (adenosine triphosphate)
3. Lysosomes - the “digestive bags” of the cell containing enzymes that break apart large food molecules through hydrolysis. Lysosomes digest & destroy microbes that invade the cell.
4. Centrioles- are paired rod-shaped structures that play an important role for moving the chromosomes during cell division.
Eukaryotic- Cell Membrane
The cell membrane is the gateway of the cell that controls the passage of materials in and out of the cell.
. Proteins - in the cell membrane act as receptors that “communicate” chemical messages from hormones that influence the function of the cell
. Carbohydrate - chains on the membrane play a part in identification of the cell as specifically belonging to an individual. This is used during tissuetyping prior to organ transplant.
Eukaryotic- Nucleus
A small spherical structure in the central portion of the cell that is surrounded by the nuclear envelope.
. It is the cell’s command center that controls every organelle in the cytoplasm
. It contains the genetic material, DNA (deoxyribonucleic acid)
Eukaryotic- Cell Extension
- Microvilli- are small finger-like projections of the plasma membrane that increase the absorptive capacity of the cell. Ex. Intestinal microvilli
- Cilia - are extremely fine hair-like extensions on the exposed surface of the cell serving as “antennae” for the cell to sense its surroundings. Ex. Cilia in taste buds
Some cilia are capable of moving as a group in one direction to propel mucus ex. Cilia in respiratory tubes - Flagellum- is a single, long projection of the cell used for movement ex. Flagellum of the sperm
Prokaryotes- Structure 6 total
No true nucleus (not enclosed within a membrane)
1. Bacterial Cell Wall
2. Cell Membrane or Cytoplasmic Membrane
3. Capsule & Slime Layer
4. Cytoplasm
5. Flagella
6. Pili
Bacterial Cell Wall
Rigid, gives shape to the cell, forms a physical barrier to the outside of the cell
Cell Membrane or Cytoplasmic Membrane
Lies immediately within the cell wall
. Selectively permeable, involved in cellular respiration
. Secretes bacterial toxins
Capsule & Slime Layer + Function
Sugar coat (polysaccharides) that surrounds the cell wall
. Capsule - strongly attached to the cell wall
. Slime Layer - loosely attached to the cell wall
Functions of both:
1. Protect the bacteria against desiccation & environment toxins
2. Provide ability of bacteria to move on solid surfaces
3. Allow bacteria to anchor on surface of mucous membrane & teeth
Cytoplasm
Gelatinous material contained within the cell membrane
. Contains materials necessary for cell metabolism- water, nutrients, proteins, enzymes - as well as waste products
Flagella
Long, snake-like appendage that allows bacteria to move about its environment
. Typically found in rod-shaped GRAM Negative bacteria
Salmonella organisms with flagella
Pili + Functions
Hair-like structures typically found in GRAM Negative bacteria
Functions:
1. Site of attachment for particular types of bacteria
2. Venue to transfer genetic material to another cell
3. Provide bacteria like ability to attach to other bacteria or surfaces such as lining of intestine
E.Coli organisms with pili
Endospores
. Stable resting stages that barely metabolize and germinate only when conditions improve
. Organisms (bacteria) convert into endospores when environmental conditions are unfriendly to survival
. A means of bacterial survival wherein the genetic material of the cell is enclosed in several protein coats that are resistant to heat, dry conditions and many chemicals
Vegetative Cells
Cells that are actively growing
Binary Fission
A cell dividing into 2 daughter cells as a way of reproduction
Transport Across Cell Membrane
Movement of substances in and out of the cell membrane is accomplished through 2 transport processes:
1. Passive transport- involves the movement of substances from a high concentration to a low concentration. No cellular energy is required
2. Active transport- involves the movement of substances from a low concentration to a high concentration therefore, cellular energy from ATP is required. Active transport occurs only through living membrane
Principles in Passive Transport Processes. 3 total
- Diffusion- requires big pores for the particles to pass through the cell membrane. Solute as well as water both move from high to low concentration to achieve equilibrium.
- Osmosis- is the diffusion of water (only) through selectively permeable membrane that does not allow solutes to pass through
- Filtration- requires the force of hydrostatic pressure gradient that allows water and diffusible solutes to filter out from the solution with higher hydrostatic pressure to the solution with lower hydrostatic pressure
Diffusion
requires big pores for the particles to pass through the cell membrane. Solute as well as water both move from high to low concentration to achieve equilibrium.
Osmosis
is the diffusion of water (only) through selectively permeable membrane that does not allow solutes to pass through
Filtration
requires the force of hydrostatic pressure gradient that allows water and diffusible solutes to filter out from the solution with higher hydrostatic pressure to the solution with lower hydrostatic pressure
Principles in Active Transport Processes:
Ex. Ion pump, phagocytosis, pinocytosis-movement of substances against a concentration gradient
1. Ion pumps are carriers that move ions against concentration gradients. Pumps may be particular to one ion or may be “couples” to pump 2 ions simultaneously (ex. Na+/k+ pump)
2. Large particles are engulfed during phagocytosis, whereas fluid and dissolved substances are brought into the cell in pinocytosis
Exocytosis
Process by which a cell directs the contents of vesicles out of the cell membrane & into the extracellular space
Autotrophic
Self nourishing, acquire food from inorganic matter (carbon dioxide)
Ex. Plants, non-pathogenic bacteria
Heterotrophic
Cannot make its own food
-acquire food from living or dead organic matter
Ex. Humans, animals, pathogenic bacteria
What is Symbiosis & examples of it?
A relationship between 2 organisms that have close contact with each other; the relationship may be beneficial, harmful or neutral.
1. Mutualism
2. Commensalism
3. Parasitism
4. Pathogenic
5. Antibiosis
6. Neutralism (Independence)
- Mutualism
A close relationship beneficial to both organisms
Ex. Oxpecker feeds on ticks on zebras skin; bird gets food & zebra is provided pest control
Escherichia Coli in human intestines obtain nutrients from the food humans eat. Consequently, it produces Vitamin K that is necessary for blood clotting.
- Commensalism
A relationship between 2 organisms in which 1 organism benefits and the other neither benefits nor is harmed.
ex. Remora gosh & shark. The remora fish feeds in the remains of the sharks food; the shark is not harmed
Ex. Natural bacteria in our skin are provided with a home, yet are not harmful to humans
- Parasitism
One organism is harmed by the presence of the other organism
Ex. Relationship between man & helminths (parasitic intestinal worms)
- Pathogenic
One organism is capable of causing disease in the other.
Pathogen- a disease- causing microorganism
Ex. Streptococcus causes tonsillitis
- Antibiosis
One organism produces substances or causes conditions which are lethal for other organisms
Ex. Relationship between human beings & pathogens that can cause death
Ex. Pseudomonas infection can cause death
- Neutralism (Independence)
No organism benefits or is harmed by the relationship
Ex. Relationship between zebras & wildebeests
Normal Flora
Organisms that normally live in and on the bodies of healthy persons without causing harm.
. Potentially pathogenic as they can cause disease if the hosts defenses are lowered or they can enter through surgical wounds to cause disease
Staphylococcus (Flora)
Skin & hair
Escherichia Coli (Flora)
Intestinal tract
Staining methods
Most microorganisms are colorless and difficult to view under the microscope. Stains (dyes) are used to make organisms and their parts more visible:
1. Simple Stain
2. Gram Stain
3. Acid-Fast Stain
4. Endospore Stain
5. Capsule Stain
Simple Stain
. Sufficient to know the shape and basic structures of bacteria
. Dye is applied to a fixed smear, rinsed with water, dried and placed under the microscope for viewing
Gram Stain
. Laboratory technique used to identify bacteria by staining with violet dye/stain and then counter staining with a red dye/stain
What is classified as Gram Positive
If bacteria turns a bluish color
Examples: Staphylococcus, Streptococcus, Clostridium
What is classified as Gram Negative
If bacteria turned a reddish color.
Examples: Salmonella, Hemophilus, Pseudomonas
Acid-Fast Stain
. Acid fast stain binds only to bacteria that have a waxy chemical material in their cell wall (Mycobacterium – organism causing tuberculosis and leprosy).
. Acid Fast Bacteria are visualized as red organisms in a sputum specimen obtained from a patient that is positive for tuberculosis
Mycobacterium
organism causing tuberculosis and leprosy
Endospore Stain
Endospores cannot be stained by ordinary staining procedures because their walls are impermeable to all chemicals
- this procedure uses heat and malachite green stain to see the spores
Capsule Stain
. Stains the background leaving the cells colorless.
. Encapsulated cells appear to have a halo surrounding them.
Culturing Microorganisms
. A sample called inoculum is introduced into a collection of nutrients called a medium
Ex. of inoculum: saliva, blood, urine
. Cultures can be grown in liquid media or solid media
. Microorganisms that grow in solid media are called colonies
Culture
the act of cultivating or growing microorganisms as a step in diagnosing diseases
Microorganisms that grow in solid media are called?
colonies
Taxonomy
the science of classifying and naming organisms
Explain Taxonomic Hierarchy & what mnemonic is used to remember it?
a system of subdivisions of all living organisms
“Did King Philip Come Over For Great Soup”
The mnemonic “Did King Philip Come Over For Great Soup” means what?
From the bottom
- Species – basic grouping unit of living organisms closely related organisms that interbreed
- Genus – made up of species that are related by descent but differ from each other in particular ways
- Family - group of related genera (plural of genus)
- Order - a group of families
- Class – a group of orders
- Phylum/Division - a group of classes
- Kingdom - a group of divisions
- Domain - largest taxonomic group
- composed of bacteria, archaea and eukarya
Classification of Human Taxonomy
Biota[all life on Earth, including precellular life]
. Domain -Eukarya(eukaryotes)
. Kingdom -Animalia
. Phylum -Chordata (with spinal cord)
. Class -Mammalia (all mammals)
. Order -Primates (apes, monkeys)
. Family -Hominidae (great apes)
. Genus -Homo(humans -specific and specialized development of memory/learning/teaching/learning application)
. Species -Homo sapiens[further development and specialization of learning application; active environment transformation, acclimatization and control; infrastructures and advanced technology]
Characteristics of Bacteria
. One-celled, simple organisms
. Reproduce by binary fission or asexual reproduction (simple division that results in 2 cells)
. Identified by the shape of their colonies
. 100 species produce disease in man
Classification of Bacteria According to the Use of Oxygen. 4 total
- Aerobic
- Anaerobic
- Facultative anaerobic
- Microaerophilic
- Aerobic
needs oxygen to survive and reproduce
Example: Streptococcus
- Anaerobic
does not need oxygen to survive and reproduce
Example: Tetanus organism
- Facultative anaerobic
prefers to live without oxygen but can live with oxygen
Example: Staphylococcus
- Microaerophilic
requires oxygen less than that in the atmosphere
Example: Helicobacter pylori
Classification of Bacteria According to Ability to Cause Disease in Man. 2 total
. Pathogenic – produces toxins which cause disease
Examples: Tuberculosis, Gonorrhea, Syphilis
. Nonpathogenic - does not cause disease
Examples: bacteria in large intestines
Types of Bacteria According to Shape. 5 total
- Coccus – spherical or round-shaped
Ex. Staphylococcus aureus – skin infections
Streptococcus pyogenes – throat infection - Bacillus – cylindrical or rod-shaped
Ex. Salmonella typhi – typhoid fever
Escherichia coli – UTI, gastroenteritis - Vibrio – comma-shaped
Ex. Vibrio cholerae – cholera - Spirochete – long, flexible, spiral, motile
Ex. Treponema pallidum – syphilis - Spirilla – long, spiral with rigid cell walls, curved
Ex. Spirillum minus – rat bite fever
Staphylococcus aureus
skin infections
Define Streptococcus pyogenes and what is is an example of?
throat infection
Is an example of Coccus
Define Salmonella typhi and what is is an example of?
typhoid fever
Is an example of Bacillus
Define Escherichia coli and what is is an example of?
UTI, gastroenteritis
Is an example of Bacillus
Define Vibrio cholerae and what is is an example of?
cholera
“Cholera is an acute, diarrheal illness caused by infection of the intestine with the toxigenic bacterium Vibrio cholerae.”
Is an example of Vibrio.
Define Treponema pallidum and what is it an example of?
syphilis
“Treponema pallidum, formerly known as Spirochaeta pallida, is a microaerophilic spirochaete bacterium with subspecies that cause the diseases syphilis, bejel (also known as endemic syphilis), and yaws. It is transmitted only among humans.”
Is an example of Spirochete
Define Spirillum minus and what is is an example of?
rat bite fever.
Is an example of Spirillia
Types of Bacteria According to Arrangement. Total 3
- Diplococci – arranged in pairs
Example: Neisseria Gonorrhea - Streptococci – arranged in chains
Example: Streptococcus pneumoniae, Streptococcus pyogenes - Staphylococci – arranged in grape-like clusters
Example: Staphylococcus aureus
Growth Requirements of Bacteria
. Moisture – drying kills some bacteria
. Food – autotrophic or heterotrophic
. Oxygen or Lack of Oxygen –aerobic, anaerobic, microaerophilic
. Moderate Temperature – high heat kills most bacteria, freezing slows down growth (most pathogens survive within the range of normal temperature in man)
. Neutral pH – acid and alkaline pH is harmful to bacteria; most bacteria grow on neutral pH or slightly alkaline (most pathogens survive within the range of normal pH in man)
. Darkness – most bacteria are killed by direct sunlight
Pathogenicity
– the ability of an organism to gain entry into the host and cause disease
Specialized Bacterial Structures Related to Pathogenicity*
- Endospores
- Capsules
- Flagella
- Endospores
. Round structures of condensed protoplasm (with bacterial DNA) formed within the bacterial cell
. Inactive, dormant forms that can resist drying, boiling, chemical disinfectants, allowing the organism to survive for a long time
. Destroyed ONLY by autoclaving
- Capsules
. Layers that surround many bacterial cells
. May be used for identification of bacteria
. Interferes with phagocytosis; increases virulence or strength of bacteria
- Flagella
. whip-like processes found in some bacilli and spirilla
. Helps in identification of bacteria
. Allows bacteria to move in liquid by their wavelike rhythmic contractions
Toxins Produced by Bacteria
Endotoxin & Exotoxin
Endotoxin
. Less potent
. Contained inside bacterial cell wall
. Released when the bacteria dies and disintegrates
. Salmonella, Shigella
Exotoxin
. Most potent toxins known
. Diffuse out of intact bacterial cells into the surrounding tissue
. Tetanus, diphtheria
Biofilm
. A community of microorganisms such as bacteria or fungi, which are attached to a surface
. Creates a slimy surface when left in water
. Associated with use of medical devices or implants
. Formation involves bacterial attachment, colonization and growth
. The microorganisms are encased in a support matrix, made up of polysaccharides, proteins, DNA and other organic molecules
. CDC estimates that ~70% of bacterial diseases in industrialized countries are caused by biofilms
Fungi
. Unicellular or multicellular simple plant life
. Some are normally found in and on the body
. Extracts nutrition from an external source, no chlorophyll
. Include yeasts (unicellular) and molds (multicellular) that can infect human beings
. Fungal infection (mycosis) may result from prolonged use of antibiotics or from immunosuppression
Fungi -Yeasts
. Unicellular organisms that reproduce by budding
. Some are used commercially in preparing beer, wine and bread
. Common yeast infections (Candida albicans)
Thrush – infects mucous membrane of the mouth
Vulvovaginitis – infection of female genitalia
Thrush (yeast infections)
Infects mucous membrane of the mouth
Vulvovaginitis (yeast infections)
infection of female genitalia
Molds
. Multicellular microorganisms that reproduce by spore-formation
. Some may be seen on food (bread, cheese)
. Common mold mycosis:
Tinea capitis – ringworm of the scalp
Tinea pedis – athlete’s foot
Tinea capitis (mold mycosis)
ringworm of the scalp
Tinea pedis (mold mycosis)
athlete’s foot
Algae
. Unicellular or multicellular simple plant life
. Can produce its own food in the presence of light; has chlorophyll
. Infections are rare and occur in breaks in skin or after surgery
Protozoa
. Unicellular, simple forms of animal life, live in water and soil
. Motile using pseudopods, flagella or cilia
. Reproduce sexually or asexually by fission
. May form CYSTS ( young, inactive form surrounded by capsule)
. Transmitted through contaminated food and/or water
Protozoan Diseases
. Amebic Dysentery – caused by Entamoeba Histolytica
- from intake of contaminated food/water
- manifests as bloody mucoid diarrhea
. Malaria – caused by Plasmodium specie
-Transmitted through the bite of a vector-mosquito, the Anopheles mosquito, from contaminated blood transfusion or use of contaminated hypodermic needles
- characterized by fever, chills
. Giardiasis – Giardia Lamblia from intake of contaminated water
- presents as diarrhea, abdominal discomfort
. Trichomonas – Trichomonas Vaginalis is transmitted sexually, through contaminated douche equipment/examination instruments/towels
- produces profuse, cream-colored, foul-smelling vaginal discharge
Amebic Dysentery
caused by Entamoeba Histolytica
- from intake of contaminated food/water
- manifests as bloody mucoid diarrhea
.
Malaria
caused by Plasmodium specie
-Transmitted through the bite of a vector-mosquito, the Anopheles mosquito, from contaminated blood transfusion or use of contaminated hypodermic needles
- characterized by fever, chills
Giardiasis
Giardia Lamblia from intake of contaminated water
- presents as diarrhea, abdominal discomfort
Trichomonas
Trichomonas Vaginalis is transmitted sexually, through contaminated douche equipment/examination instruments/towels
- produces profuse, cream-colored, foul-smelling vaginal discharge
Helminths (Worms)
. Multicellular animal parasites transmitted through intake of contaminated food/drink or intake of uncooked meat/fish
. Inhabits specific body sites
. May have several stages of life: eggs, larvae, adult stages
Common Helminths that are Parasites in Man
. Roundworms
. Pinworms
. Hookworms
. Trichinellae
. Flatworms (Flukes and Tapeworms)
Rickettsia
. Rickettsia is a group of non-motile, Gram-negative, non-spore forming intracellular bacteria
. Rickettsia species are carried by many ticks, fleas, and lice, and cause diseases in humans such as typhus, Rocky Mountain spotted fever.
Viruses
. Smallest but highly complex organisms that survive and reproduce only inside living cells (intracellular parasites)
. Can infect all organisms – plants, animals, man, bacteria
. Consist of DNA or RNA strands
. Some can be transmitted by direct or indirect contact and even through the placenta
. Can become dormant, show no signs of infection until years later
Virion
Virion – a virus outside of a cell
. Consists of the DNA or RNA strand and a protective protein coat
Lysogenic Cycle (Virus)
As the virus infect the host cell, it mixes with (modifies) the genetic material of the host, remains latent and is transferred to the individual daughter cells as the host cell divides
Lytic Cycle (Virus)
When the genetic material of the virus takes over the host cell and begins producing virions
Bacteriophage
. Viruses that invade and replicate within bacteria
Ex: Staphylophages - specific viruses of the staphylococcal bacteria
Coliphages - specifically infect coliform (bacilli) bacteria
. Do not target human cells
. Used as models for the study of viral infectious mechanisms in laboratories
staphylophages
specific viruses of the staphylococcal bacteria
Coliphages
specifically infect coliform (bacilli) bacteria
Virus and Interferon
Interferon - part of body’s defense against a viral infection
Protein produced by normal body cell that is being attacked by a virus
Blocks the effect of the virus
Types of Viral Diseases
- Dermotrophic – viral infection that affects the skin and mucous membrane
- Pnemotrophic – viral infection that affects the respiratory tract
- Neurotrophic – viral infection affecting the nervous system
- Viscerotrophic – viral infection affecting a specific organ
- Immunotrophic – viral infection that affects the immune system
- Dermotrophic
viral infection that affects the skin and mucous membrane
. Variola – smallpox
. Varicella – chicken pox, shingles (Herpes zoster)
. Rubeola – measles
. Rubella – German measles
. Herpes simplex – cold sores/ fever blisters
- Pnemotrophic
viral infection that affects the respiratory tract
- Common cold – coryza
- Influenza
- Viral pneumonia
- Neurotrophic
viral infection affecting the nervous system
- Poliomyelitis
- Rabies
- Encephalitis
- Viscerotrophic
viral infection affecting a specific organ
. Mumps – salivary gland
. Viral hepatitis – liver
- Immunotrophic
viral infection that affects the immune system
. HIV-AIDS
Virus and Cancer
Viruses – can initiate cancer development by:
1. suppressing the host’simmune system
2. altering hostgenes
Examples:
. Epstein-Barr Virus – Burkitt’s lymphoma
. Hepatitis B Virus – liver cancer (Hepatoma)
. Human papilloma virus – cervical cancer
Healthcare Concerns
. Surgical Technologists are often exposed to deadly viruses in the operating room (Hepatitis B, HIV)
. CDC standard precautions must be observed to prevent transmission of blood-borne pathogens
. Each patient must be considered capable of infecting the health care provider with blood-borne disease
. STs must likewise be aware that they can pass on a viral infection to patients
Candida albicans
Common yeast infection
