microbio - intro Flashcards
Requires living host cells for growth thus they are the only obligatory intracellular organism among bacteria
Rickettsia and chlamydia
Replicate only within cells
Inner core of either DNA or RNA but no cytoplasm
Depends on host cells for protein synthesis and energy generation
Fast mutation
Virus
Ribosome subunit of bacteria
70s (50s and 30s)
Ribosome subunits of fungi, Protozoa, helminths, animals and humans
80s (60s + 40s)
Tetracycline inhibits what ribosomal unit?
30s
Buy AT 30, SEll at 50
Erythromycin inhibits what ribosomal subunit of bacteria?
Inhibits 50s
A single circular molecule of loosely organized DNA lacking a nuclear membrane and mitotic apparatus
Nucleiod
Prokaryotes, especially bacteria doesn’t have true nucleus, rather they have..
NUCLEOID
Single, covalently closed circle or a loop of double stranded DNA
Bacterial chromosome
(+) peptidoglycan
(-) sterols
Prokaryotes
(-) peptidoglycan
(+) sterols
Eukaryotes
(+) sterols
Smallest bacteria
Mycoplasma
Mycoplasma genitalium (468 genes)
They have chitin, which is a polymer of N-acetylglucosamine
Fungi
They are determined by its rigid cell walls
Bacterial shape
Determined by orientation and degree of attachment of bacteria at the time of cell division
Bacterial arrangement
Murein or mucopeptide
Structural support and maintains the characteristic shape
Able to withstand media of low osmotic pressure
Peptidoglycan
Backbone of peptidoglycan
Alternating n-acetylglucosamine and N-acetylmuramic acid molecules
Bacteria that has thick peptidoglycan
Gram (+) bacteria
Peptidoglycan synthesis is inhibited by..
Penicillin and cephalosporin
Involved in cross-linking
D-alanine
D-ala-D-ala is targeted by what antibiotic?
Vancomycin
Enterococci is resistant to vancomycin because of different cross-linking sequence in the cell wall of the bacteria
D-ala-lactate
Tears, saliva, and mucus has natural antimicrobial property
This enzyme cleaves the peptidoglycan backbone by breaking GLYCOSYL BOND
Lysozyme
(+) teichoic acid; exotoxin
Gram positive
(-) teichoic acid; endotoxins
Gram negative bacteria
Site of beta-lactamases
Periplasmic space
Acid-fast bacteria
Mycobacteria
Mycobacteria is an acid fast bacteria, resisting decolorization with an acid alcohol after being stained by carbolfuchsin.
What component contributes to this property?
Mycolic acid
True or false: pathologic effects of endotoxins are similar irrespective of organism
True
Responsible for toxic effects of endotoxins. Found in LPS in OM.
Lipid A
Found in the outer layer of gram positive bacteria
Antigenic, induce ab that are SPECIES-SPECIFIC
mediates the adherence of staph to mucosal cells
Teichoic acid
Teichoic acid is a polymer of (2)
Glycosyl phosphate and ribitol phosphate
Invagination of cytoplasmic membrane
Mesosome
Functions as the origin of the transverse septum that divides the cell on half and as the binding site of DNA bacterial ribosomes
Mesosome
Basis of the selective action of several antibiotics
Differences in ribosomal RNAs and proteins
Reserve of high energy stored in the form POLYMERIZED METAPHOSPHATE.
Volutin granules
Gelatinous layer covering the entire bacterium
Composed of polysaccharide
Capsule
Capsule of bacillus anthracis is not composed of polysaccharide, it is composed of..
Glutamic acid
Functions of capsule
Virulence
Identification
Adherence
Antigen in vaccine
One of the ways to visualize capsules, where it swells in the presence of homologous antibodies
Quellung reaction
The energy for flagellar movement provided by ATP
Proton-motive force
Flagellum-like structure that provides undulating motion for spirochetes
Axial filament
Axial filament.
Counterclockwise rotation - ?
Clockwise rotation -?
Counterclockwise rotation - directed motion
Clockwise rotation - tumbling
A polysaccharide coating secreted by many bacteria
Adhere to various structures such as on the surface of teeth by strep.mutans
Glycocalyx or slime layer
Highly resistant structures formed in response to adverse conditions
Spores
Spore-forming bacteria
Clostridium and bacillus
Occurs when nutrients (c and n) are depleted
Sporulation
Spores contains their own DNA
What structure Coats the spores?
Dipicolinic acid (calcium chelator)
Spores can be destroyed by this steam heating
Autoclaving at 121C for 30 min, psi of 15
Bacterium that is an obligate parasite
Treponema PALLIDUM
Obligate intracellular parasite of plants
Viroids
Bacteria produced by this process in which one parent cell divides to form 2 progeny cells
Binary fission
Major determinant of growth of bacteria
Nutrients
4 phases of bacterial growth cycle
1) lag phase
2) log phase
3) stationary phase
4) death phase
In what phase in bacterial growth cycle occurs a vigorous metabolic activity where cells do not divide yet.
Lag phase
In what phase in bacterial growth cycle when there is rapid cell division
Log phase
In what phase in bacterial growth cycle when there is nutrient depletion or toxic products slow down growth until the number of new cells produced balances the cells that die
(Living=death)
Stationary phase
In what phase in bacterial growth cycle when there is a marked decline on the number of viable bacteria.
Death phase
Oxygen generates 2 toxic molecules
Hydrogen peroxide
Superoxide radicals
Obligate anaerobes
Actinomyces
Bacteroides
Clostridium
Facultative anaerobes
Corynebacterium L monocytogenes Mycoplasma B. Anthrax Staphylococcal
Microaerophilic
Campylobacter, helicobacter
Spirochetes (borrelia and treponema)
Streptococcus
Obligate aerobes
Nosy nagging pets must breathe lots of oxygen
Nocardia Neisseria Pseudomonas Mycobacteirum, mycoplasma pneumoniae Bordatell, brucella, bacillus cereus Legionrlla, leptospira
Growth at 4C
Y. Enterocolitica
L. Monocytogenes
Bacteria that grows in amoeba in streams
Legionella
Bacteria that grow well in tap and distilled water
Psedomonas
Virioids has naked RNA or DNA?
RNA
Jumping genes
Transposons
Produce igA protease
N. gonorrheae and meningitidis
H. Influenzae type B
Mobile genetic elements.
Dna pcs that move readily from one site to anothrr eitrhr within or bw dna of bacteria, plasmids and bacteriophahe
Transposons
Hence codes for drug resistance and mutations
Naked proteins with the same aa sequence but have folded differently
Prions
Prion is a normal part of brain. They have alpha helical structure. It become pathologic if
Beta sheet and forms amylod fibrils
Appearance of vacuolated neurons with loss of function and lack of imminr response or inflammation
Spongiform encephalopathies
To prevent prion dse, how to disinfect it properly?
5% hypochlorite soln
1. 0M Na hydroxide
Autoclave 15 psi for 1 hr
Membrane disrupting exotoxins
Pore-forming cytolysin
Pore forming cytolysin
Alpha toxin by staph aureus
A membrane disrupting bacterial exotoxins which contain lecithinase showing a double zone of hemolysis.
Cl. Perfringens alpha toxin
Exotoxins that binds to MHC II receptors
Non specifically activates large number of T cells
Superantigen exotoxins
Superantigen exotoxins examples
Toxic shock syndrome toxin (TSST) by staph aureus
Strep pyogenes exotoxin A (SPE-A)
Component of exotoxin which internalize and inhibits a specific critical intracellular function causing damage to the cell. It is the active toxic portion of toxin
A component
Component of exotoxin that binds to specific cell surface receptors and initiates internalization of the A component. It determines what cell type each toxin damages.
B component
A-B toxin that inhibits protein synthesis (5)
Diptheria toxin Exotoxin A Shigella toxin Shigalike toxin Verotoxin
A-B toxin that inhibits protein synthesis:
Diptheria toxin
EF-2 inhibitor
A-B toxin that inhibits protein synthesis:
Shiga toxin
Of shigella dysenteriae type I
A component cleaves 60s ribosomes
A-B toxin that inhibits protein synthesis:
Verotoxin
Of e.coli serotype O157:H7
Inactivates protein synthesis by removing adenine from the 28s rRNA
Causes bloody diarrhea
A-B toxin that increase cAMP
Labile toxin
Anthrax toxin
Pertussis toxin
Choleragen
Toxin of enterotoxic e.coli
Internalize A component to ADP-ribosylates Gs, which activates an adenylcyclase that produces high level of cAMP
Labile toxin
Components of anthrax toxin
Protective Antigen (PA) that serves as B component Edema factor (EF) that activates adenylcyclase Lethal factor (LF) kills cell
Toxin that inhibits Gi which is the negative regulator of adenylcyclase thru ADP ribosylation thus increasing cAMP
Pertussis toxin
Toxin of vibrio cholerae
Catalyzes ADP-ribosylation of Gs protein ECG activates adenylcyclase that produces high level of cAMP, thus increases water and acid secretion
Choleragen
Neurotoxin of Cl. Tetani which act on cns, inhibiting the inhibitory transmitter GABA
Tetanospasmin
Neurotoxin of Cl. Botulinum that acts on peripheral synapses, blocking the release of neurotransmitters
Botulinum toxin
Bacteria that escapes macrophage and grow inside them
RuMBLeS Rickettsia mycobacteria Brucella listeria shigella
Bacteria that invades the Peyer’s patches thru the phagocytic M cells
Shigella
Linear pcs of DNA
Exogenates
Exchange of two nearly identical pcs of DNA
Homologous recombination
Homologous recombination requires what protein
Rec A protein
Processes of DNA transfer on bacteria
Conjugation, transformation, transduction
Transfer of naked forms of DNA which occurs in same sp of bacteria
Transformation
Bacteria infected by virus
Bacteriophage
Transfer of DNA directly from one living bacterium to another.
Bacterial sex.
Major mechanism for transfer of antibiotic resistance.
Conjugation
Transfer of bacterial genes via phage vectors
Transduction
It a liquid or gel designed to support the growth of microorganisms or cells.
Growth medium or culture medium
Different types of media for growing different types of cell
Differential media Enriched media Nutrient media Transport media Selective media
Growth media used for the growth of only selected microorganisms. An antibiotic (by which the selective microorganisms is resistant) is added to the medium in order to prevent other cells, which do not posses the resistance, from growing.
Selective media
Growth media that distinguishes one microorganism type to another.
This uses biochemical characteristics of the microorganism growing in the presence of specific nutrients or indicators
Differential or indicator media
Examples of differential media
Blood agar Eosin methylene blue EMB MacConkey Mannitol salt agar MSA X-gal plates
Differential media that is used in strep test, contains bovine heart blood that becomes transparent in the presence of hemolytic streptococcus
Blood agar
Differential media for lactose and sucrose fermentation
EMB
Differential media for lactose fermentation
Macconkey
Differential media mannitol fermentation
Mannitol salt agar
Differential media for lac Operon mutants
X-gal plates
Criteria of transport media (5)
1) temporary storage of specimens
2) maintains specimen’s viability without altering their conc
3) contains buffers and salt only
4) lacks C, N and other GF so as to prevent microbial multiplication
5) in isolating anaerobes, must be free from molecular oxygen
Examples of transport media
Thioglycolate
Stuart transport medium
Venkat-ramakrishnan medium
Transport media that uses broth for strict anaerobes
Thioglycolate
Transport media that has a non-nutrient soft agar gel containing a reducing agent to prevent oxidation, charcoal to neutralize
Stuart transport medium
Transport media for vibrio cholera
Venkat-ramakrishnan medium
Growth media commonly used to harvest as many different types of microbes as are present in the specimen.
Contains nutrients required to support the growth of wide variety of organisms.
Nutrient media
Examples of nutrient media
Blood agar
Chocolate agar
Enriched media in which nutritionally rich whole blood supplements is the basic nutrient.
Blood agar
Enriched media that contains heat-treated blood (40-45c) which turns brown
Chocolate agar
Growth media which is the source of AA and N (beef,yeast extracts)
An undefined medium because AA source contains variety of cmpds with the exact composition being unknown
Contains all the elements that most bacteria needed for growth and are non selective
Nutrient agar
Undefined medium (aka basal or complex medium) contains: (3)
- C source
- Water
- Various salts
Defined medium (aka chemically defined medium or synthetic medium) contains:
- All chemical used are known
2. No yeast, animal or plant tissue present
Examples of defined media
Nutrient agar medium
Peptone
Agar
Nutrient agar medium composition
Beef extract- 0.3g (mineral and carbo)
Peptone composition
- 5g protein and N source
0. 5g NaCl as electrolyte
Agar composition
1.5g solidifying agent
100ml distilled water
pH 7
Growth media that contains minimum nutrients possible for colony growth.
Often used to grow wild type microorganism.
Used to select or used against recombinants or exconjugants
Minimal media
Minimal media contains
Carbon source (succinate)
Salts (Mg, N, P)
Water
Type minimal media the contains a single selected agent, usually AA or sugar.
This allows the culturing of specific lines of auxotrophic recombinants
Supplementary minimal media
Selective and differential bacterial media:
Buffered charcoal-yeast extract (BCYE) agar
Legionella
Selective and differential bacterial media:
Chocolate agar
Haemophilus and neisseria for sterile area
Selective and differential bacterial media:
EMB or MacConkey
Enteric bacteria
Selective and differential bacterial media:
Hektoen enteric agar
Salmonella and shigella sp
Selective and differential bacterial media:
Loeffler’s and tellurite medium
Corynebacterium diptheria
Selective and differential bacterial media:
Lowenstein Jensen
Mycobacterium tuberculosis
Selective and differential bacterial media:
Thayer-Martin or New York City agar
Neisseria with area of normal flora
Selective and differential bacterial media:
Regan-Lowe
Bordetella pertussis
Selective and differential bacterial media:
TCBS (alkaline medium)
Vibrio cholerae
Catalase (+)
Coagulase (+) forms golden yellow colonies
Mannitol (+)
Staph aureus
Major protein in the cell wall of staph aureus which binds to Fc portion of IgG
Protein A
Mediates the adherence and phage typing in staph aureus
Teichoic acid
Staph aureus is a normal flora of..
Nose
Typical lesion of staph aureus
Abscess
Toxins of staph aureus and its manifestations
Enterotoxin: vomiting, watery and nonbloody diarrhea
TSST: asso with tampon use, superantigen
Exfoliatin: phage II staph, scalded skin syndrome, superantigen
Alpha toxin: skin necrosis
Diseases caused by staph aureus (6)
Mastitis Blepharitis Cellulitis Osteomyelitis Food poisoning TSS
Coagulase (-)
Staph epidermidis and staph saprophyticus
Staph epidermidis is the normal flora of…
Skin and mucus membrane
Staph epidermidis is ____ sensitive
Novobiocin
Disease caused by staph epidermidis
IV catheter infections
Endocarditis on normal prosthetic heart valves
Treatment for staph epidermidis
Vancomycin
Treatment for staph aureus
Prp
Vancomycin (if methicillin or nafcillin resistant)
Clindamycin
Nafcillin or cloxacillin (if beta lactamases resistant)
Staph that causes UTI in sexually active women
2nd to e.coli
Staph saprophyticus
Treatment for strep saprophiticus
Quinolones
Trimethoprim-sulfamethoxazole
Lancet shape diplococci
Strep pneumoniae
Hemolytic activity of strep pneumoniae
Alpha hemolytic
Strep pneumonia does not live in the presence of…
bile and optochin
Strep pneumoniae is encapsulated thus exhibits what reaction
Quellung reaction
Strep pneumoniae produces this enzyme causing mucosal colonization
IgA protease
Green zone, incomplete hemolysis
Alpha hemolytic
Clear zone, complete hemolysis
Beta hemolytic
Enzymes of beta hemolytic
Streptolysin o and S (hemolysin)
No hemolysis
Gamma hemolytic
Determines group of beta hemolytic strep
C carbo
Most important virulence factor of streps
Provides type specific immunity
M protein
Test in lancefield classification
Precipitin test
Group a strep
Strep pyogenes
Strep pyogene is sensitive to..
Bacitracin
Strep pyogenes causes what disease.
Pharyngitis
Strep pyogenes has what type of capsule
Hyluronic acid capsule
A selective differential agar used to isolate and identify member of enterococcus
Bile esculine agar
Most common bacterial resident of large intestine
Bacteroides
Most common resident of upper respiratory tract
Alpha hemolytic strep and neisseria
Normal flora of conjunctiva
Diptheroids, staph epidermidis and non hemolytic strep
What is the type of sex pili used for bacterial conjugation
Type VII
Cross linking enzyme on the surface of bacteria which is targeted by beta-lactam antibiotics
Transpeptidase
Is cell wall or cell membrane antigenic?
Yes
transport enzyme and oxidative phosphorylation
Plasma membrane
Contains gene for toxins and antibiotic resistance
Plasmid
Inclusion bodies formed when source of N, S, P are depleted and there is excess C
Poly beta hydroxybutyric acid (PHB acid)
Cytokines that cause fever
TNF, IL-1, IL-6
Breaks down the beta 1->4 bonds between NAM and NAG
Lysozyme
Partial cell wall lysozyme digestion
Spheroplast
Complete cell wall lysozyme digestion
Protoplast
Inhibits enolase
Fluoride ion
Enzyme reaction that produces H2O2 + O2
Superoxide dismutase
Enzyme reaction that produces H2O + O2
Catalase
Enzyme reaction that produces ClO + H2O
Myeloperoxidase
Enzyme reaction that produces O2 + H + NADP
NADPH oxidase
Non SI unit for sedimentation rate
Svedberg unit
Svedberg unit is a measure of time, wherein a given particle of a given size and shaape travel to the bottom of the tube under centrifugal force. It is defined exactly how many seconds?
100 fs or 10^-13s
All bacteria have no sterol, instead they have peptidoglycan.
What is the only bacteria which has Sterol?
Mycoplasma.
No cell wall
Thermally dimorphic fungi
Molds at culture medium and room temperature
Yeast at infected tissue