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67 terms

Microbiology

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Selective media
Medium that allows growth of certain types of bacteria while permitting growth of another, bacterial isolation
Differential media
Medium that allows one to distinguish between different microorganisms based on a difference in colony appearance (color, shape, or growth pattern) on a colony
Enriched medium
Highly nutritious material (blood, serum, yeast)
Cocci
Spherical in shape
Diplo
pair
Staphlyococcus
Cluster
Tetrad
packets of 4
Sarcina
Packets of 8
Streptococcus
Chain
Bacilli
Rod shaped
Streptobacillus
Chain
Diplobacillus
Pair
Spiral
rigid or flexible
Vibrios
curved rod
Spirilla
helical and rigid
Spirochetes
helical and flexiable
Selective agars
Phenylethyl alcohol, Crystal violet, 7.5% sodium chloride agar.
Phenylethyl alcohol agar
PEA gram positive used for isolation of most gram positive organisms.
Crystal violet agar
Gram negative, inhibitory effect on most gram positive organisms.
7.5% sodium chloride agar
Nonhalophilic, inhibitory, staphylococcus
differential/selective medium
MacConkeys agar is a good example of this because it contains bile salts and crystal violet which inhibit gram positive organisms and allow gram negatives to grow.
Differential media
contains lactose
Mannitol salt agar
yellow means mannitol positive, pink means/ carbohydrate mannitol. Staphylococci exhibit yellow zone surrounding their growth. Change in coloration
MacConkeys agar
gram negative, Either lactose negative or lactose positive, Salmonella
Coliform bacilli
Becomes red
Eosin-methylene blue agar
Only e.coli turns metallic green
Enterobacter aerogenes
Produce thick mucoid, pink colonies
Enriched media
media that have been supplemented with highly nutritious material, blood serum, yeast.
Gamma
No lysis
Alpha
Incomplete lysis
Beta
Complete lysis
TSI Triple sugar-iron test
designed to differentiate among the different groups of genera of the enterobacteriaceae, which are all gram negative bacilli caple of fermenting glucose with production of acid.
Alkaline slant
Red/yellow, alkaline/acid
Acid slant
Yellow/yellow, Acid/Acid
Alkaline slant
No carbohydrate fermentation, Red/Red or orange, Alkaline/Alkaline or Alkaline/No change
Entterobacteriaceae
groups of bacteria that are found in the intertinal tract of humans and lower mammals are classified as these members.
Pathogens
Salmonella and Shigella
Ocasional pathogens
Proteus and Klebsiella
Normal intestinal flora
Escherichia and Enterobacter
SIM
Sulfur indole motility agar
Indole test
1/2 stab SIM (deep), cherry red, 24-48 hours
Methyl Red test
E. coli and E aerogenes. pH range of 4 positive and is red
Methyl Red test
pH range of 6 means negative and is yellow
Citrate
green to deep prussian blue
Citrate positive culture
Identified by the presence of growth on the surface of the slant and is accompanied by blue color.
Citrate negative culture
Will show no growth and the medium and remain green
H2S
Forming an insoluble black ferrous sulfide precipitate that is seen along the line of the stab inoculation and in indicative of H2S production.
Urease test
urease, alkaline, deep pink
Catalase test
Hydrogen peroxide will bubble if positive, No bubble if negative.
Phenylalanine deaminase test
ammonia, green means positive, No color means negative.
Chemotheraputic agents
Chemical substance that destroy or inhibit the growth of microorganisms in living tissue.
Antiseptics
Chemical substance used on living tissue
Disinfectants
used on nonliving materials
Cresols
Lysol solution 2% to 5%, poisonous and must be used externally. Similar to phenol.
Alcohols
70% to kill stuff
Iodine
Tincture of iodine, iodine suspended in alcohol
Concentration
Influences its effects on microorganisms with higher concentrations producing a more rapid death.
length of exposure
All microbes are not destroyed within the same exposure time. Sensitive forms are destroyed more rapidly that resistant ones.
Environmental conditions
Conditions under which a disinfectant or antiseptic affects the chemical agent, Temperature, pH. type of material on which microorganisms exist.
Normal skin flora
Skin has staphylococci, streptococci, enterococci, diptheroid, bacilli, yeast and fungus.
Genitourinary tract
trichomonas, Uti
Blood agar
Golden color, Strep and staph
Chocolate agar
gonorrhea, pink
Mueller Hinton
Black and diphtheria
MSA
Staph and yellow, pigmented or non pigmented
Sabouraud
yeast
Phenol coefficient
Is determined by dividing the highest dilution of the chemical being tested that destroyed the microorganism in 10 minutes.