Module 1: Introduction to Clinical Microbiology & Module 2 Flashcards
Classification
How to determine taxonomic groups based on similiarities
Nomenclature
How we name microorganisms
Identification
How we put a new isolate into a group
Microorganisms
Unicellular, less than 0.1 mm
Eucaryotic
- Organisms have true nucleus
- Several Chromosomes
- Enclosed in a Nuclear Membrane
Procaryotic
- Primitive Nucleus
- No nuclear membrane
- Single Chromosome
Subspecies
Minor differences from the type strain, usually biochemical or serological characteristics that differ.
Type Strain
Reference specimen of the species
Biotype (Biovar)
Subspecies distinguished by biochemical properties
Serotype (Serovar)
Subspecies distinguished by serological or antigenic properties.
Bacterial Cellular Morphology
Morphological characteristics seen on a stained slide under the microscope
Tetrads
Cells divide on two planes and 4 adhere together.
Sarcinae
Cells divide in 3 planes and at right angles to form cubes of 8 cells together
Palisades
Bacteria slip together and form sheets with bacteria lying on top of each other after dividing
Acute Angles
Bacteria snap back at the point of division
Cocci
Ex. Staphylococcus
Round, oval shaped bacteria.
Rods (Bacilli)
Bacteria length is longer than width.
Ex. Salmonella
Spirilla
Vary in shape from slightly curved rods to tight corkscrews
Ex. Treponema
Chaining
Bacteria adhere to each other along one plane
Involution Forms
Dead or degenerating bacteria
Bacterial Colony
- a single bacterium
- divides and all of the daughter bacteria remain together in a visible cluster
- can be seen with the naked eye on agar plates
Cellular Morphology
Microscopic appearance of bacteria on a gram stained slide, need a microscope to see
Colonial Morphology
Macroscopic appearance of bacteria on agar plates. Includes color, consistency, hemolysis, size, colony edge appearance.
Plate Media
- semi solid media inoculated with bacteria
- incubated 1-2 days and read for spreading growth
Tube Media
- test tube of media is inoculated half way down with bacteria
- incubated 1-2 days and read
Bacterial Capsules
An outer Viscous layer excreted by some bacteria
Capsule
Organized and firmly attached to cell wall
Slime Layer
Unorganized and loosely attached to cell wall
Phagocytosis
Organisms can’t be engulfed by body defence cells
Virulence
Better able to invade and get established in host
Protective Layer
For bacterial cells: allows bacteria to adhere to host surfaces.
Cell Wall
Rigid structure outside of plasma membrane, which gives bacterial cells their shape and protects inner contents.
Peptidoglycan
Strengthening substance of bacterial cell wall
Protoplast
Gram positive cell that has lost its cell wall
Spheroplast
Gram negative cell with some outer cell wall still attached
Hypotonic Solution
- water moves into cell causing rupture or lysis
- lower water concentration/higher salt concentration inside cell than outside
Hypertonic Solution
- water leaves cell causing shrinkage
- higher water concentration in cell than outside
Isotonic Solution
- 0.85% saline (NaCl), same concentration as bacterial cells
- no water movement into or out of bacterial cells
Fixation
Process of adhering clinical specimen to a glass slide
Fimbriae
Non-flagellar, hair-like projections on gram positive and negative cells
Pili
- transfer of genetic material between bacterial cells
- Longer than fimbriae
Diffusion
Passive movement from high to low concentration
Osmosis
Passive movement of water
Facilitated Diffusion
Carrier enzymes aid in passive movement from high to low concentration
Permeases
Carrier enzymes in cell membrane that aid in transfer of material across membrane
Active Transport
Requires energy to transport material from low to high concentration
Spores (Endospores)
-formed when nutrients are low or
depleted as a survival technique
-found only in gram positive rods
