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221 Cards in this Set
- Front
- Back
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What is macroscopic?
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-able to see with the eye
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What is microscopic?
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-not able to see with the eye alone
-anything less than .2 nm in diameter (200um) |
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What are the 3 domains of life?
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-archaea
-bacteria -eukarya |
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What are the characteristics of prokaryotes?
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-no nucleus
-no membrane bound organelles -have ribosomes |
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What are the characteristics of Eukaryotes?
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-has nucleus
-membrane bound organelles |
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What are the characteristics of Archaea?
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-unicellular
-cell wall NOT made of Murein, but phosoplipids joined by ether links (C-O-C) -live in extreme environments -not pathogenic |
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What are the characteristics of bacteria?
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-unicellular
-cell wall made of Murein -cell membrane composed of phosolipids joined by ester links (COO) |
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What is the oldest kingdom in since the dawn of time?
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-bacteria
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What are viruses?
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-not included in any domain
-acellular (no cells) -not living -(infection agents) |
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What is the cell theory?
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-the smallest unit of life is the cell
-needs cell membrane, cytoplasm w/ ribosomes, a nucleus or nucleoid |
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What is the study of phycology?
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-algae
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What is the study of mycology?
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-fungi
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What is the study of protozoology?
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-protozoa
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What is the study of virology?
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-viruses
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What is the study of bacteriology?
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-bacteria
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What is the study of medical microbiology?
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-relationship b/t disease and micro-organisms
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What is the study parasitology?
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-protozoa, helminths, some insects (ones that transfer diseases-mosquitos)
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What is the study of immunology?
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-defense mechanism, antibodies, antigens, allergy/hypersensitivities
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What is the study molecular biology?
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-DNA/RNA sequencing
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What is the study of microbial ecologist?
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-how organisms act in the soil, or other habitats, carbon cycle, nitrogen cycle
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What is the study of microbial physiologist?
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-metabolic pathways, fermentations
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What are decomposers?
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-absorptive hterotrophs (saprophytes live off dead material or saprobes)
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What are antibiotics?
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-chemicals from micro-organisms that will kill or stop the growth of another micro-organism in small concentrations
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What are "chemotherapeutic agents"/magic bullets?
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-affects the pathogen but not the host
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What are examples of chemicals and drugs we get from micro-organisms?
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-acetic acid, alcohol, and insulin
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What foods do we get from micro-organisms?
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-cheese, bread, beer, wine
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How are bacteria good research tools?
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-have 1 chromosome, so easy to work with
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What is spoilage?
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-bacteria/fungi don't know the difference b/t good and bad
-spoil food, shower curtains, walls |
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What are the benefits of micro-organsisms?
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-decomposers
-antibiotics -chemotherapeutic agents/ magic bullets -chemicals and food are derived -research tools |
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What are detrimental aspects of micro-organsisms?
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-spoilage
-cause disease |
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What are light microscopes?
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-microscopes that let you see up to .2 mm (200 um)
-uses visible light |
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How does light travel?
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-in waves
-longer wavelengths have less energy |
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What are usually the 4 objectives in microscopes?
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-100x= oil immersion
-40x=high power -10x= low power 4x=scanning |
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How do you view most bacteria and why?
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-by staining them
-becuase most are clear |
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What is the maximum magnification of our microscopes and why?
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-1000X
-resolving power= .2mm (200um) |
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What is the equation for resolving power?
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RP= wavelength/ 2 x NA
-NA= numerical aperture |
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What does oil do in oil immersion?
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-increases resolving power
-NA get larger -greater resolution |
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Which type of light gives the worst resolution?
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-red light
-highest wavelength |
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What can be seen witha light microscope?
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-algae, protozoa, yeasts, molds (easiest)
-bacteria (harder to see) |
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What is a dark field stop?
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-object in dark field microscope that blocks light from going through the cdenter of microscope
-light goes in an angle -increases contrast of slide |
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What is the appearance of the view in dark-field microscope?
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-black when no specimen
-light bends when there is a specimen -specimen shines |
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Whatwould you use a dark field microscope for?
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-for organisms that are alive but difficult with a bright field microscope
ex.: treponema pallidum -to decrease artifacts(shapes covered in stains) and see shape of specimens better |
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What does an annular stop do?
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-in phase contrast microscope that allows ring of light to go through
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What is the function of the phase-shifting element of a phase contrast microscope?
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-focuses light
-advance light (speed up) to increase brightness -retard light (slow down) to make darker -focuses direct rays, but not incident rays (rays off to the side) |
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What is a phase-contrast microscope used for?
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-live organisms
-unstained organisms -morphology -inclusions |
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What is a flourenscence microscope?
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-has a mercru vapor lamp (intense light source)
-exciter filter -barrier filter -flourescent dye |
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What is the excirer filter used for?
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-filters out >400 um light
-ultraviolet light passes through |
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What is a barrier filter used for?
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-filters out <500 nm light
-blocks out uv light |
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What is flourescent dye used for?
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-absorbs electromagetic energy
-uses quaramine O (type fo dye that flourences yellow) -makes wavelength longer (visible light) |
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What is a flouresence microscope used for?
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-to view mycobacterium
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What do mycobacterium do and how do you view them?
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-causes tuburculosis
-has high lipid content (very waxy) -doesn't stain well -use acid fast stain and oil immersion to view |
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What is treponema pallidum?
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-causes syphilis (STD)
-cork screw shape (spirochete) -stains poorly -shines in dark-field microscope -moves |
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What is immunoflourenscence?
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-a technique to view syphilis and strep throat by flouresence
-when antigen invades body, antibodies are produced -antibodes can be labeled with dye (ex: antisyphilis- Ab + dye) -stain gets on antigen and shines |
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What is a differential interferance contrast microscope? What is the field of view like? What is it used for?
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-uses prisms to view specimens
-increased contrast -color -3-D effect used for live specimens |
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What is a transmission electron microscope? What is the appaearance of the field? what is it used for?
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-be able to see electrons (wavelength .1-.2 nm)
-has condensor magnet -appearance depends on density (more dense= darker) -background is white -1000X more mag. than normal microscope (RP= .0005 um) -can view viruses, inside bacteria, and DNA/proteins |
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What is a scanning electron microscope? What is the appearance of the field? What are its uses
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-RP= .01 um (10 nm)
-10x greater than normal micrscope -see fig 3.25 -to see detailed images on the surface of specimens (eps. bacteria) |
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What is the normal classification of bacteria? why is it important?
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-for names
-descriptions -to group -makes identification easy -can see relationships b/t bacteria -gives us control and helps us solve problems |
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What is the artificial clasification of bacteria?
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-few easily reconizable characteristics
-good for ID, bad for relationships Ex: whittaher puts all prokaryotes in Monera |
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What is the natural classification of bacteria?
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-shows common ancestry
-ex. woese and domains -archaea closly related to us -bacteria is very old |
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What are grancilicutes in Bergey's Manual of Systematic Bacteriology 1st edition?
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-Grancilicutes -thin skin, gram neg (E. coli, klebsiella)
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What are firmicutes in Bergey's Manuel of systematic bacteriology 1st edition?
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thick skin, gram pos
-ex streptococci |
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What are tenercutes in Bergey's Manuel of systematic bacteriology 1st edition?
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soft skin, no cell wall, gram neg.
ex. mycoplasmas |
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What are mendosicutes in Bergey's Manuel of systematic bacteriology 1st edition?
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-faulty skin, no murein
-ex. archea |
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What is the significance of Bergey's manual of systematic Bacteriology?
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-monera was main kingdom
-divided into 4 divisions -divisions were based on cell wall chemistry content wtih gram staining |
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What are cyanobacteria in Bergey's Manuel of systematic bacteriology 2nd edition?
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blue/green, photsynthetic, fouind in water, produce O2
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What are actinobacteria in Bergey's Manuel of systematic bacteriology 2nd edition?
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gram pos w/o G + C ratio (lots of G +C in DNA)
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What are firmicutes in Bergey's Manuel of systematic bacteriology 2nd edition?
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-gram pos, low G+C ratio
ex: streptococci, straphylococci, bacillus, clostridium, and mycoplamas |
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What are examples of proteobacteria?
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E. coli, klebsiella, Neisseria, and Richettsia
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What are examples of Chlamydia?
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-ex. chlamydia trachomatic (common STD)
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What are examples of spirochetes?
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-syphilis (treponema pallidum) and Borrelia (lyme disease)
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What are the 3 basic shapes of bacteria?
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-coccus- spherical
-Bacillus-rod -spiral |
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What are examples of coccus shapped bacteria?
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-staphylococci (boils)
-streptococci (strep throat/ pneumonia) -neisseria (gonorrhea, meningitis) |
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What are examples of bacillis shaped bacteria?
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-bacillus anthracis (anthrax)
-clostidium (tetanus) -E.Coli |
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What are examples of spiral shaped bacteria?
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-vibrio cholerae (one bend)
-spirochetes (triponemu and bocrelia) |
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What is the size of cocci shapped bacteria?
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-1 um
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What is the size of bacillus shaped bacteria?
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.5 um x 2 um
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What is the size of spiral shaped bacteria?
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-.5 um wide
-1-14 um long |
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What is the glycocalyx?
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-outermost layer of microorganisms( esp. bacteria)
-non-living -extracellular (non-essential) -either a slime layer (very thin) or a capsule (very thick) |
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What bacteria have a slime layer as their glycocalyx?
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-staphylococcus
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What bacteria have a capsule as their glycocalyx?
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-klebsiella pnumonia
-streptococcus pneumonia -steptococcus pyozenes -bacillus antracis -haemophilus influenza |
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What is the chemistry of glycocalyx?
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-polysaccharides, proteins, or both
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How is the glycocalyx regulated?
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-by genes
-envrionment can influence expression of genes (such as nutrition) |
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How do glycocalyx capsules appear in colonies?
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-looks like mucus
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How do glycocalyx slime layers appear in colonies?
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-looks shiny, wet
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How do capsules appear under the microscope?
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-only visible through negative stain (stain everything other than the microorganism)
-don't stain well |
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How would you negativly stain klebsiella Pneumonia?
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-smear indian ink on slide and slide is coated black
-organism is purple and capsule is visible as halo around organsism |
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How is the glycocalyx important in identification of bacteria?
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-morphology (rod, cocci, spiral)
-gram stain (pos or neg) -biochem. test (test for enzymes- goes to geus and species) -serovar (serological variety, used today for antibiotic resistance, vaccines (not all), and specific ID |
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What is the function of the glycocalyx?
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-sticky to allow bacteria to form microcolonies (to prevent drying out)
-protects from phagocytosis when colonized -can stick ot other objects -virulent (pathogenic) -non-virulent -animate (host-helps to stick to you -inanimate (catheter-can get picked up and spread) -non-vi |
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What does streptococcus pyogenius do for its glycocalyx?
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-produces hyalunamic acid that is a cement that holds cells together.
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What is gram +?
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When microorganism is stained, turns purple
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What is gram -?
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When microorganism is stained, turns pink
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What is the gram stain for terchoic acid?
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gram +
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What is the gram stain for 0-polysacharides?
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-gram -
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What is the gram stain for lysine
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gram +
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What is the gram stain for daiaminopinelic acid?
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gram -
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What is the gram stain for murein? Thickness?
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50-90% gram + (20-80nm)
10-20% gram - (10nm) |
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What is the gram stain for porins?
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-gram -
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What is the gram stain for second membrane?
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gram -
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What is the gram stain for periplasmic space?
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gram + (thin)
gram - (thick) |
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What is the gram stain for yeast?
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thick cell wall (gram +)
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What is the gram stain for mycoplasma?
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-no cell wall
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Where is the muerin sacchulus?
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-before outer membrane
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What is the outer membrane made of? Function? Significances?
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-made of lipopolysaccarides
-protects cell from some antibiotics, detergents, bile, heavy metals, dyes, and lysozyme -toxic when broken up |
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What is the periplasmic space?
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-space or are b/t cell membrane adn otuer membrane in gram - organisms
-muerin sacchulus is in it |
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What is the plasma membrane?
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-first living part of cell
-protoplast is living part of membrane |
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What is the function of the plasma membrane?
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-regulates what goes in or out of cell
-differentially permemable |
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What is the plasma membrane made of?
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-made of phospholipids (glycerol and 2 fatty acids)
-condensatiion occurs for bonds to form -has hydrophilic head and hydrophobic tail (amphipathic) |
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What are plasma membranes most important for?
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respiration
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What is cholesterol in the plasma membrane?
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-sterol steroid
-found in animals, makes membranes tough -mycoplasma needs cholesterol to toughen the cell b/c of lack of cell wall -fungi have ergoserol instead of cholesterol |
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What is a nucleoid?
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knwon as nucleus in humans- 46 chromosomes
knwon as nucleoid in bacteria- 1 chromosome |
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What are plasmids?
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-extrachromosomal DNA
-small -has resistance genes (way bacteria become resistant to antibodies) -humans have plasmids in mitochondria |
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What are flagella?
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-not visible under microscope (too thin)
-appendages -used for mobility -one piece of filament -spins/rotates cell |
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What are flagella in eukaryotes?
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-on sperm
-has many filaments in each flagella -filaments move back and forth (undulating) |
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What are flagella in prokaryotes?
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-10% of bacteria are mobile
-mycoplasma glides (no flagella) -if bacteria are mobile, then they are virulent |
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What are fimbriae?
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-not for mobility
-shorter and thinner than flagella -both mobile and non mobile have these |
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What do E.coli use fimbriae for?
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-to attach to the epithelial intestinal wall
-considered virulent/pathogenic -used for adherance -Neisseria does same thing to cause gonorrhea |
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What are pili?
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-used for DNA transfer in cell
-conjugation (one bacteria sticking to another) |
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What are endospores?
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-cell dies and releases spore
-spore produces vegetative cell -used to survive adverse conditions (dryness, chemicals) -common in bacillus (anthrax), clostridium (tetanus), spocosarcirae, coxiella burretii |
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What is a culture medium?
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-what bacteria is being grown in or on
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What is animate?
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-alive
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What is inanimate?
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-dead
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What is nonsynthetic complex?
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-at least one ingrediant not chemuically defined
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What is synthetic complex?
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-chemically defined
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What are autotrophs?
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-make their own food
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What vare heterotrophs?
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-can not make their own food
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What are hypotrophs?
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-obligate parasite (needs live host)
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What is a natural media?
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-something from the environment
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What is milk as a media? What is it used for?
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-inanimate, non-synthetic, natural media
-when you make yogurt or cheese to the natural milk media -used to grow heterotophs b/c milk contains organic compounds |
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What is a dead tree branch as a media? What is it used for?
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-inanimate, non-synthetic, natural media
-can grow mushrooms (heterotrophs) |
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What is soil as a media? what is it used for?
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-inanimate, non-synthetic, natural media
-can grow mushrooms (heterotrophs) -can grow algae (autotrophs) |
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What are the advantages of natural media?
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-might be the only media an organism will grow on
-some organisms are unculturable |
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What are the disadvantages of natural media?
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-aren't chemically defined and aren't sterile
-used commerically, bad for lab work |
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What is hot water extract (tea infusion) as a medium?
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-complex, nonsynthetic
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What is BHI medium (blood/heart infusion?
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-boil the brain or heart of cow
-all good nutrients and stuff are extracted and the liquid is filtered off -you make a powder out of the good stuff and sell it |
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What are the advantages of Hot H2O and BHI meidum?
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-sterlizes medium
-major type used clinically -faculative parasites will grow on it -ex. staphylococcu aureus |
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What is synthetic media used for?
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-can be used to gorw autotrophs (sugar plus CO2 added with inorganic N)
heterotrophs (organic N,amino acids, and sugar added) |
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What are the advantages of synthetic media?
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-chemically defined
-sterile |
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What are the disadvantages of syntehtic media?
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-not all organism wik,ll gorw on it, expensive (to isolate A.A.)
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What is isolate for the use of general media?
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-you want to iso,late an organism from the original environment an d grow in on a medium
-for org. in human- add sheep blood -for soil organism- mix in soil from it's environment -for marine org.-use sea salt with simlar composition ex. blood agar, manitol salt agar, Macclonkey's media, EMB |
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What is differentiation in the use of general media?
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-the organism will look differently or act differently on the type of medium
-test for enzymes -use gram staun, morphology, and biochemical (enzyme) tests |
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What is blood agar medium?
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-add sheep blood to BHI medium and make sure the blood stays red
-look for hemolysis -can org. break down blood? |
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What is gamma hemolysis?
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-organism can;t break gown blood
-medium stays red -organism is non-pathogenic |
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What is beta hemolysis?
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blodd is completly broken down
-clear zone around colony -organism is pathogenic |
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What is alpha hemolysis?
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partial break down of blood
-green area present around org. -some pathogenic |
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What is Manitol salt agar?
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-manitol is an alcohol and a sugar
-specifically designed for staphylococcus aureus -bacteria can break down sugar and produces an acid by product -media turns yellow due to the acid while the rest of trghe medium is red (from the phenyl red) |
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What is MacClonkey's Medium?
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-contains lactose
-if bacteria break down, acid forms -Eosin and Methylin blue leak out and a purple nulceated colony appears |
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What is selective media?
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-you select for/favor for the gorwth of aprticular organisms (byadding something to the medium that favors it)
-it also selects against too |
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What is selective in Manitol salt agar? What can grow on this?
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-salt is selective
-7.5% NaCl sol. (most org. live in .5%) -staphylococcus aureus can grow in it -manitol makes it differential, salt makes it selective. |
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What is MacClonkey's agar? What can grow on this?
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-add bile to medium to gorw G- organisms (outer membrane protects them from bile)
-G+ should not grow because they ahve no protection from bile. |
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What is selective in eosin methylin blue agar? What can grow on this?
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-dyes make it selective
-G- are resistant to one dye b/c of the outer membrane -G+ shouldn't grow out |
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What is enriched media?
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-media for organisms that are organisms are Gastidious
(difficult to grow out on another media) |
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What is chocolate agar? What grows on this?
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-a brown agar
-blood is brown heated to the point it changes color -haemophilas influenza bacteria grow on this medium |
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What is a liquefiable solid?
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-BHI agar (agar is an extract from red algae)
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What is the consistency of media?
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-liquid: a "broth"
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What is a BHI broth?
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-there is no solidifying agent (no agar)
-it's what's used in culture tubes -used when you ahve a pure culture -cloudiness |
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What is a liquediable solid?
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-BHI agar (agar is an extract from red algae)
-BHI comes in powdered form |
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How do you liquidfy BHI?
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-add 1.5% agar to it
-boil at 100 deg to liquidfy -put in autoclave to get to 121.5 deg to sterilize -solidify in plate at 40 deg -can reliquidfy if heat to 100 deg -used most in labs -but once solid, can;t reheat w/t messing up media |
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Why can't you add blood agar to a liquidfyable solid?
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-would turn brown (chocolate agar)
-useless for hemolysis test |
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Why is it good to liquidfy silica?
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-can grow stuff directly on it
-good to grow autotrophs b/c silica is an inorganic source |
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What is animate media?
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-alive, must be cellular
-used to grow hypertrophs |
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What is the herpes simplex?
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95% of us have this, but no symptoms
-causes membranes to fuse (multinucleate) |
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What is the cytomegalovirus?
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-type of herpes virus
-causes inclusion bodies (intranuclear) |
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What does the rabies virus do to a cell?
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-intracytoplasmic
-casues cell to have "dark bodies" (Nagri bodies) |
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What are plaquing techniques?
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-virus casues cells to lyse
-ex: polio virus -if virus is near cell membrane (area is clear) |
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What are embryonated eggs used for as a media? What can you grow?
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-can use duck, turkey, or chicken
-need to pass needle through shell -har and not sterile -can cultivate live viruses in while orgaisms as babies -ex: flu, richettsiae, chlamydiae |
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What is an intact animal or plant used for as media? What can you grow?
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-can culture virus in wole organism
ex: hepatitus B-grow in primate surface treponema pallidum- grow in rabbits -mycobacterium laprae- grow in armadillos and chimpanzees |
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Why is moosture required for culture medias?
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-b/t 70-95% water
-bacteria are absorptive -need to conduct diffusion -heterotrophs like us -use hydrolysis |
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Why is food in utilizable form required for culture medias?
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-if growing autotroph -need inorganics
-if growing heterotrophs- need correct organics |
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What pH is required for culture medias?
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-pH=7.0 for best culture
-can priduce acids or basis -use buffers to balance -ex. peptone |
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Why is sterility important for culture medias?
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-need a sterile culture
-don't mix cultures |
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What injurious chemicals are required for culture medias?
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-agar (comes form red algae)
-water (pure) -glassware |
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Why is tonicity important for culture medias?
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when preparing a culture, should be hypotonic
-would make microorganism turgid |
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What is population growth?
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-increase number of individuals
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What is binary fission?
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-to split in half
-each microorganism will produce 2 every 20 min |
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What is the lag phase?
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takes time to start pop. growth
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What is log growth phase?
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-population doubles every 20 min
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What is the stationary phase?
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-carrying capacity of the environment
-can;t increase population -ran out of food |
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What is log death phase?
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-large number of individuals die, but some are still alive
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What is the logarithmic growth scale used for?
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-research
-penicillin doesn;t work during log growth -only lag phase |
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What is cultural emuneration?
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-grow out cells
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What is the advantage of cultural emuneration?
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-count living cells
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What is the disadvanage of cultural emuneration?
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-takes time to get results
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What is the colony count plating method?
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-count every cell
-cells can form colonies |
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What si a colony forming unit?
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-either a single cell or colony
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Which colony plate is apporpriate for counting?
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-25-250 colonies
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What is the membrane filter technique?
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-uses filter paper with holes at .2um
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What is the advantage of using the membrane fitler technique?
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-"sterilizes"
-viruses can still pass through -bacteria get stuck on filter -grows into colony in 24 hours |
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What are the disadvantages of membrane filter technique?
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-can clog up if heavily contaminated
-only good for low loads |
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What is the Most Probable Number?
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-not counting ind. cells
-used for coliforms (E.Coli) -gets standardized w/ serum dilution |
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Whata re coliforms?
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-G(-) rod that can ferment
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What is the advantage of nin-cultural enumeration?
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-quick results
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What is the disadvantage of non-cultural enumeration?
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-count live adn dead and artifacts
-count will be higher |
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What is cytometer count?
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-uses peiroff houger counting chamber
-uses 1cm^2 of square to count -glass is expensive -can calculate volume |
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What is a coulter counter?
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-uses electric beam to count cultures
-very accurate |
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What is the total volume used for in microorgansim count?
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-used for beer (yeast)
-can standardize w/ cytometer count and colony count plating method. |
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What is the turbidometric used for?
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-uses spectrophotomter
-tests how cloudy solution is -cludier solution higher bacterial density -standardize using cytometer count |
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What are variations?
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-change in charactgeristsics
-either in an organism or a parent |
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What is phenotypic variation?
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-temporariy changes in organism
-common -change in gene expresson -not a mutation |
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What is morphological phenotypic variation?
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-cell large when young
-gets smaller as get older |
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What is an example of cultural phenotypic variation?
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-seratia marcescenes (G- rod)
37 deg.- white 25 deg.- red -color change based on temperature |
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What is an example of physiological phenotypic variation?
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E. coli
-has B-galactosidase -makes B-galactoside -ferments lactse -if no more lactose exists, stops making b-galacosidase |
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What is genotypic variation?
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permanent change
-due to mutation -ex. sicle cell amenia -rare (random) |
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Can genotypic variation be directed?
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-NO
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How does a mutation occur?
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-natural mistakes occur
-spontaneous -can be induced -due to x-rays, UV light, chemicals -can be lethal |
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Is E.Coli pathogenic when mutated?
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NO
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What is resistance mutations?
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-occurs when all bactgeria but 1 are killed
-single survival reproduces to give resistance to drug -selects for mutation -penicillum kills senisitve cells, not resistance cells |
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What problerms occur over resistance mutations?
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-resistant staphylococcus aureus methillin
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What is genetic recombination?
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-change in characteristsic
-not mutation -new bacterial DNA -not "sexual" reproduction |
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What is transformation?
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-has donor and recipient
-donor dies -cell breaks apart -recipient picks up pieces of DNA and gains its charactgeristsics -splices in existing DNA |
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What is conjugation?
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-analagus sexual reproduction, not sex
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What does conjugation donor have?
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Genome- circular, contains 1 chromosome
F particle of Fertility factgor-plasmid contains information for its own replication -has DNA that controls pilus -has information for chemical :surface component- reduces neg. charge on surface |
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What does conjugation recipent have?
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-missing plasmid (cannot form pilus)
-more neg. than donor -gets attracted to donor due to opp. charges |
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What is the end result of conjugation?
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-recombinaion (1/100000)
Donor has episome (genetic factor) attached to genome' -takes 90-120 min, stoped before completion -recipient reains neg. charged but w/ new egentic information -as a result, other plasmids exist in bacteria |
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What is Resistance Tranfer Factor?
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R plasmid has RTF and R genes
-RTF= fertility particle-DNA for conjugation -has R genes-allows for resistance (ex. anttibiotics, cell toxins, heavy metals) -major factor why gram neg. bacteria are resistant |
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What does Beta-lactamase do?
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breaks down beta-lactam antibiotics
-penicillin- pinicillinase -cephalosporins-cephalosporinase |
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What gains resistance after conjugation?
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-staphylococci
-Neisseria |
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What is transduction?
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-due to bacteriophage-virus that attacks bacteria
-virus injects DNA -virus makes amistake and puts bacterial DNA instead of viral DNA |
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What is lysogenic conversion?
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-pheotypic change
-simialar to transductions -involves bacteriophage-incorportes viral DNA to bacterial genome -vrial DNA gives characteristsic it normally doesn't have |
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What does coryne bacterium dyptheriae cause?
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-diphtheria
-produces toxins that can kill you -only strains infected with viral DNA can produce toxins |
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What does clostritum botulinum do?
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-priduces botulinum toxin
-only strains infected w/ viral DNA can produce toxins |
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What does streptococcus pyogenes cause?
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-strep throat
-some strains can produce erythrogenic toxin which causes scarlet fever |
