Microbio Week 1 (Exam 1) Flashcards
T/F: Very few microbes are always pathogenic
True
Most microbes are _____________ pathogenic; but many are potentially pathogenic if they get in the wrong place
never
Name the method of staining used to differentiate bacterial species into two groups
What are the two groups?
Gram staining
Gram + and Gram -
Gram stain differentiates bacteria by their chemical and physical properties of their cell walls by detecting?
Peptidoglycan
Study of living things too small to see (and viruses)
Microbiology
Dr Graham said “things will stay sterile as long as ______ can’t settle on them”
dust
Difference between bacteria (prokaryotes) and eukaryotes
Bacteria lack organelles
What is a “strain”?
Any isolated colony
What does identification and characterization of bacteria typically first involve?
Growth of laboratory “pure cultures”
_________ examination of specimens is faster, and sometimes available
Direct
T/F A strain of bacteria has a different name than the species it comes from
True!
2 cocci
Diplococci
Cluster of cocci
Staphylococci
Chains of cocci
Streptococci
Curved rod
Vibrio
Spheres
Cocci
Rods
Bacili
What is the primary characteristic for classification of bacteria, and is observed at the same time as the shape and arrangement by light microscopy?
Gram stain
What color is gram + bacteria?
Purple
What color is gram - bacteria?
Pink
Presence of both an inner and outer membrane is characteristic of which bacteria?
Gram -
What oral pathology and lesions can be caused by pathogenic bacteria?
Actinomysis
Diptheria
Scarlet fever
Syphilis
Gonorrhea
Father of Microbiology
Anton van Leeuwenhoek
Name the order of increasing complexity of microbes
Virus
Bacteria
Fungi
Parasite
Two categories of parasites
Protozoa and worms
3 types of fungi
Yeast, mold, dimorphic
Uses an emulsion to trap single nucleic acid templates in wells, PCR amplify them, and then light monitor
Pyrosequencing
Bacteria are best defined as what?
a different type of cell
Who discovered the concept of sterility/germ theory?
Louis Pasteur
What has to be done FIRST in order to identify and characterize bacteria?
Grow a pure culture
Steps of Gram stain
- Prepare heat-fixed film of bacteria on slide
- Stain w/ crystal violet (1 min) and rinse w/ water
- Treat w/ iodine (1 min) and rinse w/ water
- Decolorize with acetone/ethanol (few seconds) and rinse w/ water
- Counterstain with basic fuchsin or safranin (1 min) and rinse w/ water
- Blot dry and view under oil immersion
What would happen if we didn’t decolorize with ethanol?
Everything looks purple
What would happen if we didn’t use safranin?
Gram - would be clear
Overview/steps of bacterial ID
Specimen
Direct exam
Culture
Pure culture and ID to species
Species name established
Typing/fingerprinting for taxonomic or epidemiological purposes
3 characteristics used to ID bacteria
Do they grow w/o oxygen?
Are spores formed?
Are they motile?
Growth requires oxygen as final e- acceptor
Aerobic
Growth uses inorganic molecules or CO2
Anaerobic
Energy generating metabolism which involves the Krebs cycle and oxidative phosphorylation by ETCs
Respiration
Conversion of products of glycolysis to other forms w/o additional ATP gains
Fermentation
Which bacteria are able to form metabolically inert forms that are stable for long periods of time in the environment?
Gram +
(ex: Clostridium and Bacillus)
Example of spore-forming bacteria
Terminal (endo) spore of Clostridium tetani
Example of tetanus agent
Clostridium tetani
What method remains the technology of the future?
Sequencing
What is the best way to compare bacteria? (ON EXAM)
16S rRNA gene sequence alignment (we use genus AND species)
What can you use to obtain lots of DNA for sequencing part of the chromosome that codes for the ribosome’s rRNA?
PCR
T/F: RNA sequencing is the final step in identifying bacteria.
False! It’s DNA sequencing
What is the purpose of PCR?
to amplify a specific desired fragment of DNA
When using a phylogenetic tree, you can get ____ clusters that correspond to _____ domains of life
3; 3
The small ribosome subunit ______ rRNA sequence is widely used, with ____% identify threshold used to define a group as a ______ or ______
16S; 97%; type; species
How many types of bacteria are in the human oral cavity?
700
Do entire genome sequences confirm 16S rRNA phylogeny?
YES
What do microbiologists really only use to classify/name bacteria?
Genus and species
T/F The genus and species must be bolded
FALSE; they must be italicized!
What abbreviation is used to represent multiple species within a genus?
“ssp”
Subtyping test based on differences in microbial surfaces aka antigens
Serotyping
Types of bacteria were first recognized by _______, and ________ _________ like cell shape, surface structures, and ability to grow on different media
staining; visible features
__________ (surface antigens) and identification of secreted and other _________ ___________ then allowed further distinctions of bacteria
Serotyping; enzyme activities
We now have nucleic acid (sequence) analyses, particularly _________ comparisons that indentified relationships between __________
rRNA; species
Bacteria divide by asexual ____________ fission
binary
Bacteria are given nutrients as a source of energy and can grow _____________
exponentially
Bacteria grow and assemble substrates into _______________. Name some examples
macromolecules
examples: polymers, proteins, and nucleic acids
How is the energy for biosynthetic pathways obtained?
respiration or fermentation
How are nutrients obtained?
Uptake
T/F: Bacteria can’t tolerate extreme and variable conditions like nutrients, temp, pH, atmosphere.
False! They CAN tolerate
What does glucose become in glycolysis?
2 pyruvate
How is NAD regenerated after glycolysis?
NADH -> NAD via fermentation (pyruvate becomes lactic acid)
Why is respiration favored over fermentation?
With O2, we can generate much more ATP
Pyruvate is completely oxidized to CO2 via?
Krebs cycle
With oxygen, many bacteria can use the Krebs cycle to then generate much more energy through the?
Electron transport chain (ETC)
In the ETC, ATP is generated by what process?
Oxidative phosphorylation
Carbohydrates or other macromolecules are incompletely oxidized, with pyruvate being converted into organic acids or into ethanol and CO2
Fermentation
What is fermentation useful for?
Identifying bacteria biochemically
Name some other electron acceptors that bacteria can use in anaerobic respiration
Nitrate
Sulfate
Carbonate
Other ions
The use of oxygen or other e- acceptors allows _______ _________ ________ and advantages in different environments
more efficient growth
Anaerobic respiration can produce less/more ATP than aerobic respiration
Less
How many moles of ATP are produced from aerobic respiration?
38
What type of phosphorylation does fermentation use?
substrate-level
Most bacteria we discuss are what type?
Facultative anaerobes
Bacteria that can grow in presence or absence of oxygen
Facultative anaerobes
What is the final electron acceptor in fermentation?
An organic molecule
Which bacteria CANNOT tolerate oxygen?
Obligate anaerobes
Which bacteria can only grow in the presence of oxygen?
Aerobes
Why do bacteria need so much metabolism and energy?
To polymerize biological macromolecules from precursors
Some bacteria have very high nutrient requirements, so they can only live where?
Inside cells
(these are call host dependent intracellular bacteria)
Name 2 common human pathogenic bacteria w/ high nutrient requirements
Genus Mycoplasma
Genus Chlamydiae
Lacks peptidoglycan, small size and genome, cause pneumonia, contributes to pelvic inflammatory disease
Mycoplasma
Two cell forms, requires ATP, causes eye infections, genital infections or pneumonia
Chlamydiae
Which bacteria divide in a coordinated fashion and have a polar septum?
Streptococci
Which bacteria divide in a random fashion and have a random septum?
Staphylococci
There are 4 bacteria at noon and they doubled every 30 mins, how many bacteria would there be at 2pm?
64
Name the phases of the bacterial growth curve
Lag phase
Exponential/log phase
Stationary phase
Decline phase
When is growth initiated?
When diluted bacteria is added to a new liquid culture medium
When is growth terminated?
With depletion of nutrients
T/F All cells in a bacterial population are growing
FALSE
Name of non-growing (phenotypically resting) bacteria on complex biofilm populations that can resist the immune system antibiotics; they can also regrow on removal of treatment
Persisters
What’s an alternative to binary fission? When will it occur?
Sporulation
Occurs when nutrients become limited or the environmental conditions become stressful
Term for not metabolically active
Inert
T/F: All bacteria will form spores.
FALSE; only some bacteria produce spores
Asymmetric cell division to produce a tough survival form called a spore
Sporulation
What are the two most common Gram + bacteria that produce spores?
Bacillus (aerobe)
Clostridium (anaerobe)
What are some characteristics of spore forming bacteria?
-asymmetric division
-metabolically inert
-resistant to solar radiation and drying
-contain all components necessary for regeneration and vegetative growth (like a plant seed or fungal cyst)
What is the only way to kill bacterial spores?
Autoclave or bleach
T/F Bacterial spores can die by a 100 degree boil
FALSE
A structured community of micro organisms that is adhered to a surface and enclosed in carbohydrates and proteins
Biofilm
What diseases are caused by dental biofilm?
Dental caries
Periodontitis
Otitis media
Endocarditis
Name the common biofilm bacteria that causes these diseases
1. caries
2. periodontitis
3. otitis media
4. endocarditis
- strep mutans
- anaerobic Gram (-) bacteria
- Moraxella
- viridans streptococci
Which phase of bacterial growth are endospores MOST likely to form?
Stationary
Which Gram (-) bacteria LACKS peptidoglycan? this is an exception
Mycoplasma
Bacterial cells have a rigid cell ______ surrounding the _________ _________
wall; cytoplasmic membrane
What is the only aspect of bacterial cells more complex than in eukaryotic cells?
Envelope (wall/membrane)
Cell walls maintain ________ and __________ and provide strength to bacteria. This is important in resisting changes in osmolarity of the external environment
size; shape
What does the cytoplasmic membrane of bacteria act as?
Selective permeability barrier
The lipid bilayer also contains ________ machinery, __________ apparatus, and environmental sensors
transport; secretion
____________ ___________ machinery is associated w/ inner or cytoplasmic face for oxidative phosphorylation
Electron transport
Flagella are for ___________ while pili are for _____________
motility; attachment
Physical characteristics specific for Gram + bacteria
Wall
Teichoic acids
Thick peptidoglycan layer
Polysaccharide capsule at outermost surface
Physical characteristics specific for Gram - bacteria
Envelope
LPS
Thin peptidoglycan layer
Periplasm
Polysaccharide capsule at outermost surface
T/F: The cell membrane of bacteria is a selectively permeable barrier
True
The ETC is associated with the inner/outer face of the membrane
inner
The lipid bilayer of bacteria contains unique features such as…
1) transport machinery
2) secretion apparatus
3) environmental sensors
Describe the structure of the peptidoglycan cell wall
Repeating disaccharide and cross-linking peptides
What is the major target of antibiotics?
Bacterial cell wall made of peptidoglycan (sugar and protein)
What are M and G in the cell wall peptidoglycan structure?
Carbohydrates
T/F: Techoic acids have a + charge
False!! They’re anionic
These bacteria have Gram + cell walls and stain “acid fast”
Mycobacteria
Why do mycobacteria stain acid fast?
They have additional long-chain fatty acids called “mycolic acids”
What do we compare mycolic acid to? What do we compare peptidoglycan to?
Mycolic acid = wax
Peptidoglycan = glue
What are mycobacteria resistant to?
Decolorization (unlike other Gram + bacteria!!)
LPS acts as a _________ _________ in Gram - bacteria
permeability barrier
Peptidoglycan in Gram - bacteria is shielded by _____, which can contribute to ___________ ____________!
LPS; antibiotic resistance
The LPS layer in Gram (-) bacteria is made of 2 parts. What are they?
1) O antigen: highly variable polysaccharide used for strain typing
2) Lipid A: endotoxin, has inflammatory properties and is called a virulence factor
Endotoxin, has inflammatory properties and is called a virulence factor; part of LPS
Lipid A
Highly variable polysaccharide used for strain typing; part of LPS
O antigen
What is the bioactive component of LPS?
Lipid A
Beyond the bacterial cell wall, there can be an external carbohydrate capsule for both Gram + and Gram - bacteria. What purpose does this serve?
- Adheres to surfaces, forms colonies and biofilms, environmental resistance
- Evades immune system, reduces phagocytosis, shields protein antigens
What is the external carbohydrate capsule made of?
Polysaccharides
(or less often, proteins)
The polysaccharide capsule is now used in?
Vaccines
What does HOK stand for?
H = Flagella
O = O antigen on LPS
K = Capsule
What types of bacteria have flagella?
All motile Gram + and Gram -
Eukaryotic protozoans
What types of bacteria have fimbria/pilli?
Gram - only
What is the function of flagella?
Motility
What is the function of fimbria/pilli?
Attachment
Where are flagella anchored to?
Cell membrane/wall
What is flagella composed of?
Polymerized protein called “flagellin”
What is flagellin recognized by?
Innate immune response
These Gram (-) bacteria have a unique flagella in the periplasmic space
Oral spirochetes
Ex: Treptonema (very important in dentistry!)
T/F Fimbria/pilli are thinner and there are much more per cell than flagella
True
Which is shorter and more rigid:
Flagella or fimbriae/pilli
Fimbriae/pilli
This is a major virulence factor of pathogenic escherichias like E. coli and allows colonization of urinary tract epithelium
Fimbriae/pilli
Fungi are eukaryotes that have a cell wall but lack?
Peptidoglycan
The major component of plant and fungi cell walls are carbohydrates.
Name an example
Chitin
Gram negative bacteria have both an inner and outer membrane. Gram positive bacteria lack the ___________ membrane
outer
Name a gram (-) oral spirochete that has a unique flagella in its periplasmic space
Treptonema
What is the distinction in how the bacterial terms “cell wall” and “envelope” are commonly used?
wall for Gram positives, envelope for Gram negatives
Why are Gram positive bacteria typically more sensitive to widely used antibiotics like beta lactams ?
The peptidoglycan target is on the outside of the bacteria
What is the most significant function of a capsule for a pathogenic bateria?
They can block phagocytosis by immune cells
Which of these features of bacterial walls and envelopes are specific to Gram negative bacteria? Mark all correct answers
Teichoic acids
Capsules
LPS
Flagella
Fimbriae
LPS
Fimbriae
What is the size of the smallest moving object a person can see?
0.1 mm
What was Anthony Leeuwenhoek ‘s nationality?
Dutch
Complete set of microbes in a niche
Microbiome
Entire total gene sequence of a sample or that obtainable from a niche or body site
Metagenome
Bacterial in nature are often growing exponentially.
False
exponential growth is unsustainable, and only seen routinely briefly in lab cultures.
Where does most of the material go when you are composting garabage?
Into the air, as carbon dioxide
Bacterial DNA is present on a linear/circular chromosome with 2 things. What are they?
Circular chromosome with transposons and plasmids
What do bacteria ALWAYS have?
What do bacteria sometimes have?
ALWAYS have transposons
Sometimes have plasmids
Bacteria lack a ___________, but their genetic info is present in a _________ __________ within the cell
nucleus; nuclear region
Bacteria have a ________ ___________ chromosome
single circular
What kind of proteins are associated with the single circular chromosome in bacteria?
Non-specific proteins
(but no histones)
Bacteria have no nuclear membrane, which allows simultaneous _____________ and _____________
transcription; translation
Plasmid DNA replication can be done with?
2 replication forks
__________ can be exchanged between strains
Plasmids
What do plasmids have?
Protein coding regions
What do protein coding regions in plasmids include?
Colonization factors
Virulence determinants
Plasmids contribute to the ____________ of many species
pathogenicity
What can other plasmids carry coding sequences for?
Antibiotic resistance
Conjugation pilli
Entire metabolic pathways
How do plasmids that share a region readily join together?
By cross-over homologous recombination
(called a “Campbell” recombination)
What is central in the origin of recombinant DNA technology?
Plasmids
Repetitive, mobile genetic elements
Transposons
Transposons always encode _______________ enzymes integration into a chromosome target site, with or without additional ________
recombinase; genes
Transposons can move to __________ or back, possibly inactivating an existing ___________
plasmid; gene
Some transposons contain genes for bacterial surface ______, which allows them to move between cells
pilli
Bacteria can encode proteins by maintaining DNA sequences as what 3 things?
Chromsome
Plasmids
Transposons
Who created the “Central Dogma”?
Francis Crick
Describe the “central dogma” of molecular biology
DNA -> (transcription) -> RNA -> (translation) -> Protein
What are the 3 major processes in maintenance and expression of bacterial genetic information?
Replication
Transcription
Translation
DNA synthesis by DNA-dependent DNA polymerases
Replication
mRNA synthesis by RNA polymerases on a DNA template
Transcription
Protein synthesis by ribosomes with tRNA and associated factors
Translation
What are replication, transcription, and translation all important targets for?
Antibiotics
What is central in colonization, virulence, and pathogenicity?
Presence and expression of bacterial genes
(these include cell walls, toxins, flagella, pili, capsule, biofilms, etc)
T/F: DNA replication has 3 forks
False! There are only 2
Why are plasmids important?
1) give the bacteria more capacity
2) allow for communication between bacteria
A resistance plasmid that confers resistance to antibiotics
R plasmid
Plasmids sharing a region readily join together by cross-over homologous recombination
Campbell recombination
Some transposons contain genes coding for bacterial surface pili; this allows them to move between cells. What are these transposons called?
Conjugative transposons
Which enzyme transcribes bacterial DNA into RNA?
RNA polymerase
The function of RNA polymerase is to
Recognize promoters
What does RNA polymerase initiate the synthesis of?
mRNA
A sequence in the DNA that binds RNA polymerase
Promoter
How are bacterial mRNAs are different from eukaryotic mRNAs?
Half of bacterial mRNAs encode for more than 1 protein
(eukaryotic mRNAs can only encode for 1 protein)
Multiple proteins open reading frames are only seen in bacteria
Polycistronic mRNA
Single translatable open reading frame
Monocistronic mRNA
The first ever gene identified was in E. coli and it allowed for ______________ fermentation. It encodes ______ mRNA with ______ protein coding regions, later called a bacterial ________
lactose; 1; 3; operon
An RNA coding region is the heritable unit of controlled gene expression
Gene
What do ribosomes begin translating as they are made?
mRNAs
Ribosomes have 2 components that make up their large and small subunits. What are they?
rRNAs + proteins
Bacterial and eukaryotic ribosomes are different enough to be an important target for what?
Antibiotics
Bacteria have 3 ways of exchanging DNA. Name them
1) transformation
2) transduction
3) conjugation
Cells take up naked DNA from the environment and lyse
(only some bacteria do this)
Transformation
Phages carry host DNA,
(most bacteria do this)
Transduction
Cells mate through specialized appendages; usually between same species
Conjugation
What do DNA recombination and genetic transfer in bacteria allow for the spread of?
Virulence genes and antibiotic resistant genes
DNA goes directly into the environment, often by lysis
Transformation
Bacteria undergoing _____________ have naked DNA susceptible to DNAses
transformation
T/F Transformation requires cell-cell contact
FALSE; cell-cell contact is NOT required in transformation
Virus that attacks bacteria and replicates by invading living cell and using cell’s molecular machinery
Bacteriophage
What are bacteriophages composed of?
DNA and protein
What are the 2 basic types of phages?
- Lytic (aka virulent)
- Lysogenic (aka temperate)
Infection of susceptible bacteria ALWAYS leads to destruction of bacteria and release of new infectious phage
Lytic phage (virulent)
Depending on growth conditions, the phage can either lyse the host or be integrated into the chromosome
Lysogenic phage (temperate)
T/F Phages are NOT perfect machines, and rare mistakes lead to incorporating bacterial DNA into mobile phage particles
True
Name a bacteria that’s encoded by a lysogenic bacteriophage and can cause a membrane-like coating in the throat
Corynebacterium diptheriae
Transfer of F plasmid DNA from F+ donor cell to F- recipient cell
Conjugation
What does an F+ plasmid mean?
You already have the plasmid
F plasmid excised from Hfr chromosome carrying new regions and now the donor is called
F’
Conjugative F plasmids can also integrate like a phase and move host chromosome to an integrated F plasmid called
Hfr+
What is plasmid mediated conjugation known to cause?
Resistance to spread quickly through Gram - species
What is it called when ribosomes begin translating mRNAs as they are made in prokaryotes?
Polysomes
What is the biggest cause of community developed drug resistance?
More antibiotics being used in agriculture and farming
U.S. average antibiotic prescriptions per person per year
0.88 antibiotic prescription/person/year
Selective inhibitor of microbial cells
Antimicrobial
What does a higher prescription dose that is given out longer and more frequently lead to?
More antibiotic resistance
(this is what we see in hospitals)
Which antibiotic is used most often in cattle farming?
Tetracycline
What was the first antibiotic?
Penicillin
One of the first antimicrobial agents discovered in 1935
Sulfonamides
This antimicrobial agent inhibits folic acid synthesis by inhibiting PABA, which inhibits synthesis of purines and pyrimidines
Sulfonamide
What do sulfonamides inhibit?
Folic acid synthesis
T/F You want to treat a bacterial infection with a drug that is specific as possible
True!! We want antibiotics that are narrow spectrum
**they used to think you wanted activity against a wide variety (broad spectrum), but now we know that is incorrect
What is the difference between bactericidal and bacteriostatic
Bactericidal = kills bacteria
Bacteriostatic = inhibits growth of bacteria
The ideal antibacterial agent should have…
1) target is a bacterial factor absent in human cells
2) minimal toxicity and bio-available
3) narrow spectrum
Which is better, broad spectrum or narrow spectrum?
Narrow! This will only kill the unwanted bacteria
Another name for antibiotics
Secondary metabolite
What is a reason that injected penicillin, then oral, remains the #1 antibiotic in dentistry?
It has narrow spectrum (targets Gram + strep only)
What are antibiotics really?
- Antimicrobials produced by live organisms
- Secondary metabolites
What are the 3 major targets of antibiotics?
Bacterial wall synthesis
Protein synthesis
Nucleic acid synthesis
(some also target the membrane or enzymatic functions - ex: Neosporin)
What do antimicrobials rely on?
Selective cellular inhibition
What are the major classes of antibiotics?
Beta-lactams
Macrolides
Tetracyclines
Aminoglycosides
Linocosamides
Quinolones
Class of antibiotics that inhibit cell wall synthesis
B-lactams
3 examples of B-lactams
Penicillins (1st gen)
Cephalosporins (2nd gen)
Carbapenems (3rd gen)
Classes of antibiotics that inhibit ribosome/protein synthesis
Macrolides
Tetracyclines
Aminoglycosides
Lincosamides
Class of antibiotics that inhibit DNA synthesis
Quinolones
3 most common antibiotics in dentistry
- Beta lactams
- Erythromycin or azithromycin
- Clindamycin
(Clindamycin moves up to spot #1 if the pt is elderly, at risk, or has a bone infection!!)
What % of people are allergic to Beta lactams?
3-10%
2 examples of Macrolides
Erythromycin
Azithromycin
Example of Lincosamides
Clindamycin
Example of Quinolones
“-floxacins”
What do bacteria have that is similar to plant cells?
Turgor (can easily lead to lysis)
What do Beta-lactams specifically target in order to inhibit cell wall synthesis?
Peptidoglycan
(NAG-NAM amino sugar polymer + a D-ala cross linked peptide residue)
What reaction does Beta-lactam target that allows them to inhibit cell wall synthesis?
D-ala transpeptidation
B-lactams bind to these proteins which can make the cell wall weaker if bacteria are growing
Penicillin binding proteins (also called wall transpeptidases)
What do Beta-lactams resemble?
D-ala
What is a Beta-lactam technically considered?
Competitive inhibitor
The Beta-lactam Penicillin is a ____ member ring. If you switch the sulfur for a carbon, you get _________, which is also a ____ member ring.
5; Carbapenem; 5
The Beta-lactam Cephalosporin is a ____ member ring
6
Which antibiotic is a “glycopeptide” inhibitor of cell wall synthesis?
Vancomycin
(has similar but different MOA than Beta-lactams)
What does Vancomycin bind to? (this is different than Beta-lactams!!)
D-ala
What is Vancomycin used to treat?
C diff
What is the mechanism of the Macrolide antibiotic Erythromycin?
Binds 23S rRNA of the 50S subunit
Inhibits chain translocation like Clindamycin and Azithromycin
Which drug is #2 in dental usage after Beta-lactams (used when there is an allergy)?
Erythromycin (a Macrolide antibiotic)
What do nucleic acid synthesis inhibitors bind to in non-growing bacteria?
RNA polymerase
(this prevents transcription and gene expression)
4 examples of nucleic acid synthesis inhibitors
Rifampicin
Rifampin
Metronidazole
Sulfonamides
What do DNA synthesis inhibitors (Quinolones) target?
DNA gyrase
Which antibiotic is used for aggressive periodontitis?
Metronidazole
What bacteria does Metronidazole target?
Anaerobic bacteria
What kind of antibiotic is Metronidazole?
Nucleic acid synthesis inhibitor
T/F Development of resistance, which involves altered uptake of a drug, is rare when taking Metronidazole
True!
What can absolutely NOT be mixed with Metronidazole?
Alcohol
15 antibiotics we need to know
Vancomycin
Amoxicillin
Penicillin V vs G
Augmentin
Trimethoprim
Sulfamethoxazole
Cirpofloxacin
Nalidixic Acid
Metronidazole
Rifampicin
Streptomycin
Tetracycline
Azithromycin
Erythromycin
Clindamycin
What are the 4 major classes of antibiotic resistance mechanisms?
- Enzymatic modification/degradation of the antibiotic
- Altering the target of the antibiotic
- Change flux of antibiotic
- Intrinsic resistance
What are the 2 common enzymes targeted in antibiotic resistance?
- B-lactamase (most common)
- Aminoglycoside phosphotransferase
What are the 2 most common mechanisms for altering the target of the antibiotic in antibiotic resistance?
- Spontaneous mutation (most common)
- Acquire new genes/enzymes
What are 2 ways bacteria can change the flux of the antibiotic in antibiotic resistance?
- Pump antibiotic out of cell
- Decreased uptake (more specific pores, multiple antibiotic resistance (MAR))
What are 3 ways bacteria have intrinsic resistance in antibiotic resistance?
- Permeability barrier of Gram -
- Lack of peptidoglycan
- Biofilms
Recombination between two DNA helixes that are aligned over shared sequence (>400 bp)
Homologous recombination
Which one of these is NOT a bacterial genetic element?
Ribosome
Circular chromosome
Transposon
Plasmid
Ribosome
What is unique about bacterial genes or transcription units compared to those of eukaryotes?
They can have more than one protein coding region
What additional capabilities do temperate (or “lysogenic”) bacteriophages have compared to lytic phages?
Ability to do specialized transduction
What is the main reason the community acquired resistant bacterial infections are increasing?
Use of antibiotics in farming, and unregulated disposal of excess drugs
What are antibiotics as found in Nature?
bacterial signal molecules and secondary metabolites; produced by fungi and soil bacteria
What is clavulanic acid?
Inhibitor of Beta lactamase
