Week 1 Flashcards
DNA sequence analysis of this structure is widely used in bacterial phylogenic analysis
Ribosome
What is the cell wall component unique to bacteria?
Peptidoglycan
Bacteria do NOT have…
No nucleus
No sterol
No membrane bound organelles (mitoch, & lysosomes)
No histones (proteins present in nucleic acid)
No cytoskeleton
Bacteria have a ________ cell wall
Complex
Bacteria reproduce by…
Asexual reproduction / Binary fission
Bacterial ribosomes are…
Smaller 70s
Bacteria have a single circular chromosome, HOWEVER there are some bacteria w/ linear chromosomes. What’s one example?
Borrelia burgdorferi — aka Lyme Disease
*Leptosporidia has more than one chromosome
Gram _______ has very thick peptidoglycan layer.
Gram Positive +
___________ contain mycolic acid and contribute to acid fast _______ staining.
Mycobacteria & Positive staining
Gram _______ has an outer membrane made up of LPS.
Gram Negative -
Gram staining depends on _______________.
Peptidoglycan layer
Primary stain:
Crystal violet
Mordant:
Gram’s Iodine
Decolorizer:
Acid Alcohol
Counter Stain:
Safranin
What are the phases of bacterial growth?
1st- Lag phase
2nd- Log phase
3rd- Stationary phase
Colony counting, Turbidimetry, & Flow cytometry are all way to…
Measure bacterial growth
Lipid A is also known as…
Endotoxin
Many of the clinical signs caused by GRAM NEGATIVE bacteria are due to…
Lipid A / Endotoxin
________ act by binding to receptors on macrophages > macrophages then release cytokines > inflammatory phase
Lipid A / Endotoxin
Gram _______ Lipid A/Endotoxin have an accumulating effect
Negative
Why do we test for Lipid A/Endotoxin?
B/c all pharmaceuticals need to be Endotoxin free — sterilization
What is used for Lipid A/Endotoxin testing?
Limulus Amebocyte Lysate (LAL) aka Horse Shoe Crabs
All bacteria contain peptidoglycan, EXCEPT…
Mycoplasma & Chlamydia
Gram Positive + bacteria contain _______ on their cell walls.
Teichoic Acid
Lipid A/Endotoxin is ________.
Harmful
Locomotion/Motility of bacteria:
Flagella
The number & arrangement of ______ can be used for identification of bacteria.
Flagella
Flagella is located ______.
Outside cell
Spirochetes have _________.
Endoflagella / axial filaments
Endoflagella /Axial Filaments are located in the…
Periplasmic space / inside their bodies
Facilitate adherence to host tissue:
Pili / Fimbriae
Contribute to antigenicity:
Pili / Fimbriae
Pili/Fimbriae are…
Small thread-like structures
Example of bacteria that have Pili/Fimbriae:
- Bordetella Bronchiseptica aka Kennel Cough
- E. coli
Fimbriae antigens in E.coli:
K88= Neonatal piglets K99= Neonatal calves
__________ is a polysaccharide outer coating of the bacteria.
Capsule
Capsules help organisms to evade…
Phagocytosis
Which bacterial species has a non-polysaccharide capsule?
Anthrax
Staining for a capsule is a good diagnostic tool to see if it’s
Anthrax
Bacteria form __________ when there are unfavorable conditions. This is a protective mechanism.
Endospores
What can we do if we have a animal who is having D+ and we suspect Clostridium ?
Take a fecal sample, stain, and look for endoscopes.
Bacterial structures can enhance…
The virulence of bacteria
Presence or absence of these structures facilitates…
Identification of bacteria
Endoflagella/Axial Filaments are present in ________.
Spirochetes
_________ is an outer covering which helps bacteria to evade phagocytosis.
Capsule
__________ helps in bacterial survival.
Spores
Aerobic, Microaerophilic, Capnophilic:
Oxygen required for growth
Obligate anaerobe, Aerotolerant anaerobe:
Oxygen not required OR utilized for growth
Facultative anaerobe:
Oxygen not required BUT can be utilized for growth
Bacterial metabolism can be see for…
Bacterial identification
Bacterial Virulence Factors:
Properties/traits found in isolates that cause disease. BUT are NOT found in isolates of the same species that lack ability to cause disease
Damage caused by bacteria…
- using the hosts nutrients
- direct damage to host cell (toxins)
- hypersensitivity reactions (type 4- delayed : Tuberculosis)
Pathogenicity:
The ability of a pathogen to produce a disease by overcoming the defense mechanisms of the host
Virulence:
The degree of pathogenicity
_______ is released out of the cell, produced in the cell
Exotoxin
_______ is a component of cell wall, liberated when bacteria die & cell wall breaks apart
Endotoxin
What are the 3 types of Exotoxins?
- A-B toxins
- Membrane disrupting toxins
- Superantigens
Tetanus is an example of what kind of toxin?
A-B exotoxin
Most exotoxins are…
A-B toxins
A of A-B toxins are the ______ _______.
Active enzyme
B of A-B toxins are the _______ _______.
Binding component
This exotoxins subunit kills the cell…
A subunit
Example of a superantigen:
Toxic Shock Syndrome from staph
Cause non-specific activation of T-cells…
Superantigens
Result in polyclonal T cell activation & massive cytokine release…
Superantigens
Indiscriminate binding to MHC class II molecule on the antigen presenting cell & T helper cell receptor
Superantigen
________ smaller circular DNA present in bacteria.
Plasmids
________ virus particles which attack.
Bacteriophages
The process by which the bacteria can transfer virulence factors between them:
Conjugation, Transformation, & Transduction
Conjugation:
Where a plasmid/ genetic material can be transferred from one bacteria to another bacteria by direct contact
Transformation:
Alteration of cell from direct uptake & incorporation of exogenous genetic material from surroundings > taken up through cell membrane
Transduction:
DNA is transferred from one bacterium to another by a virus
Biofilm & Quorum Sensing are…
Newer virulence factors
Plasmids & Bacteriophages can be used to mediate…
Transfer of virulence factors
Opportunistic Pathogens:
Organisms that do not cause disease in healthy host, with a healthy immune system
True Pathogens:
Equipped w/ virulence genes for adherence, invasion, evasion from immune system & toxins (anthrax)
Nosocomial Infections:
Hospital acquired infections (methicillin resistant Staphylococcus aureus or Clostridium difficult)
Generally bacteria are ______________ pathogens
Extracellular
Rickettsia & Chlamydia are examples of…
Obligate intracellular pathogen
Mycobacterium is an example of…
Facultative intracellular pathogen (can survive extracellular or intracellular)