24 Test Tubes Inoculating.....

Today we inoculated tubes of sucrose, lactose, glucose and nutrient agar with E. coli, Bacillus subtilis, Staph. aureus and our unknown. We also did a quadrant streak on Tributyrin Agar and Starch Agar with E. coli, Bacillus subtilis and our unknown. I still think my known is Staph aureus, but have done little in the last month or so to progress beyond my intial guess.

Mucho Media!

This test indicates that I test negative for dental caries at both 24 and 48 hours. This explains why I never have cavaties. Lucky me, I've inheritted my father's good teeth. My brother on the other hand would probably have a yellow tube at 24 & 48 hours. This means he has marked risk for dental caries. He has my mother's bad teeth or should I saw destructive mouth flora? He has frequent cavaties and problems with his teeth. Count you blessings if you have a green tube!
Here is a face skin culture on a Blood Agar plate. Microbe shows Gamma-Hemolysis (none) created small white circular colonies. Organism is most likely non-aureus Staph, which is considered normal skin flora. Skin from my arm on blood agar. 2 microbes arose. 1 was Beta-hemolytic (complete lysis) and is the large yellow growth. The other was Gamma-hemolytic (no lysis) and is the small round white colonies. The first microbe is most like bacillis normally found in the soil but can sometimes be found as skin flora. The second is most likely non-aureus Staph. Both are considered to be normal skin flora.

Today's Lab Interpritation

Tuesday in lab we inoculate 3 tubes of Thioglycollate broth to determine the oxygen requirements of our unknowns. We inocullate the tubes with E. coli, Clostridium p. and our unknown. We also did a similare exercise with nutrient broth plates using E.C. and C.P. as our controls to compare our unknowns to.

Results:
E. coli: facultative
C.p: strict anaerobic
#30: facultative

Plate Interpritation:
E. coli: facultative
C.p: anaerobe
#30: facultative, with smooth edges and made the medium a slightly darker color.

From the inoculated broth or our working slants we where to make slides for staining and viewing to determine the shape of our unkown as well as the E. coli and Clostridium p.

My slides made from the slant were a little hard to examine. I remade 3 more from the broth but didn't have time to look at them. I did accidently stain all 3 rather than just one. Hopefully I can use these next week.

Microbe Shapes:
E. coli: bacillus
C.p: cocci clusters
#30: Dr. Belcher thought perhaps mine where cocci that formed chains. I couldn't tell becuase my smear was a little thick.

Next week it's gram staining action like you've never seen!

This Weeks Media

Eosin-Methylene Blue is used to select G- lactose fermenters. The selective agent is eosin and methylene blue. The differential agent is methylene blue and lactose. If the organism ferments lactose it is most likely G- and lactose +. Medium is used to grow enteric microbes.
E coli: Microbe tolerates EMB. Microbe ferments lactose. Microbe is most likely G-
S. Aureus: Microbe does not tolerate EMB. Microbe does not ferment lactose. Microbe most likely G+
Ps. aeroginosa:Microbe tolerates EMB. Microbe does not ferment lactose. Microbe most likely G-
Unknown #30: Microbe does not tolerate Eosin & MB. Does not ferment lactose. Most likely G+

Phenyl Ethyl Alcohol is a medium used to select G+ cocci. The selective agent is phenyl ethyl alcohol and there is not a differential agent. Organisms that show good growth on this medium are most likely G+.

E. coli: Microbe does not tolerate Phenyl Ethyl Alcohol. Most likely G-

Ps. aeruginosa: Microbe does not tolerate PEA. Most like G-

S. Aureus: Microbe tolerates PEA. Most likely G+

Unknown #30: Microbe tolerates PEA. Most likely G+

MacConkey Agar is a medium used to select G- lactose fermenters. The selective agent is bile salts and the differential agent is neutral red and lactose. Lactose + microbes appear pink-red. Lactose - microbes appear cream to colorless. This medium is used to grow G- enteric microbes. E. coli: Microbe tolerates bile salts & Crystal Violet dye. Does ferment lactose. Most likely G-

Ps. Aerug: Microbe tolerates bile salts & CV. Does not ferment lactose. Most likely G-

S. Aureus: Microbe does not tolerate Bile salts or CV. Does not ferment lactose. Most likely G+
Unknown #30: Microbe does not tolerate bile salts or CV. Does not ferment lactose. Most likely G+

Mannitol Salt Agar is a medium used to select mannitol fermenting staph microbes. The selective agent is sodium chloride and the differential agent is phenol red. Positive mannitol fermenters turn yellow.
E coli: Microbe does not tolerate Sodium Chloride. Does not ferment Mannitol. Most likely G-

Ps. Aerug: Microbe does not tolerate NaCl. Does not ferment Mannitol. Microbe most likely G-

S. aureus: Microbe tolerates NaCl. Microbe ferments Mannitol. Microbe most likely G+

Unknown #30: Microbe tolerates NaCl. Microbe ferments Mannitol. Microbe most likely G+

Summary:

Unknown #30 had similare growth and fermentation patterns as S. aureus. However, unkown #30 had slightly better growth and fermentation when compared to S. aureus.

Unknown #3o tolerates MSA & PEA and does not tolerate EMB & MAC. It tolerates Phenyl Ethyl Alcohol, NaCl and ferments Mannitol. This microbe is most likely Gram + and tolerates a salty environment.

Inerpreting Growth on Media

1. Purpose/ characteristics of media?
a. selective, differential, both
b. what are the agents
c. types of microbes typically isolated

2. Is there good growth?
Yes: "Microbe tolerates_(selective agent)_" No: "Microbe does not tolerate_(selective agent)_"

3. Is there a change in color?
Yes: "Microbe ferments/uses/poseses_(differential agent)_" No:"Microbe does not ferment/use/poses_(differential agent)_"

4. Microne is most likely "__G-/G+__"

Lab #6

Previously in lab we made a 4 section streak plate on 4 different types of growth medium.
We divided each plate into 4 section like a pie and in each section drew a line from 4 different microbe broths.
Media:
Eosin Methylene Blue Agar
Phenylethyl Alcohol Agar
MacConkey Agar
Mannitol Salt Agar

Microbes:
Unknown #30
E. coli
Staphyloccocus aureus
Psudomonas aeruginosa

E. Coli

Microbe:
Escherichia coli

Common Name:
E. coli

Oxygen requirements:
Facultative (Anaerobic or Aerobic)

Origin:
Intestines of mammals