Review Pt. 1

Microbiology 3200 with Cobine at Auburn University

About this deck

By: Chris Gluckman
Textbook:

Microbiology: A Human Perspective w/ARIS bind in card
Created: 2011-10-17
Size: 60 flashcards
Views: 36

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A spectrophotometer is used to measure cell turbidity by measuring the absorbance or optical density of a culture t/f

TRUE

Bacteria adap to the new environment in this phase

Lag phase

At least 10% broth displacement in the durham tube is considered a negative for gas production in the MPN presumptive test t/f

FALSE

The pore size of the membrane filter used for microbial testing of water is ___

0.45 um

A microscope with an objective lens magnification of 10x will have a total magnification of

100x

Gram-positive lose the purple crystal violet on washing with 3% alcohol

FALSE

The primary stain in the endospore stain is

malachite green

An example of coliform is

E. coli

The mEndo broth MF plates inhibit the growth of gram-positive organisms t/f

TRUE

Fomites are inanimate objects that can harbor microorganisms t/f

TRUE

4 common colony shapes

punctiform, round, filamentous, irregular

5 common colony margins

smooth, curled, wavy, lobate, filamentous

4 common colony surface characteristics

smooth, concentric, wrinkled, contoured

species tested in bacterial motility - tube method

E. coli (motile) and K. pneumoniae (non-motile)

species tested in bacterial motility - plate method (swarming)

P. mirabilis (swarms) and E. coli (doesn't swarm)

example for flagella stain

Proteus vulgaris (shows peritrichous arrangement)

steps of Gram stain

1. crystal violet - primary stain

2. iodine - mordant

3. alcohol - decolorizer

4. safranin - counter stain

S. aureus morphology

gram +

cocci

E. coli morphology

gram -

rods

B. megabacterium morphology

gram + rods

M. catarrhalis morphology

gram -

cocci

Acid-fast stain used to identify....

Mycobacterium

Nocardia

--have mycolic acid

Kinyoun acid-fast stain

doesn't use heat but requires long exposure to carbolfuschin

Ziehl-neelsen acid-fast stain

requires application of heat for the dye to penetrate the cell wall

Acid-fast stain steps

1. carbolfuschin - primary stain

2. 3% acid alcohol - decolorizer

3. methylene blue - counterstain

Mycobacterium smegmatis acid fast?

YES

Staphylococcuss aureus acid-fast?

2 genera with endospore stage

Bacillus and Clostridium spp.

Schaeffer-Fulton quick spore stain steps

1. flame 10 times

2. malachite green - stains spores

3. safranin - stains vegetative cells

usual concentration of agar

1.5%

examples of differential and selective media (Lab 4)

Mannitol Salt Agar (MSA) differentiates Staph sp. based on ability to ferment mannitol pink-->yellow

Eosin Methylene Blue Agar (EMB) differentiates G- rods based on fermentation of lactose: E. coli colonies w/ green metallic sheen, other G- dark

Complex medium, defined medium

who knows

you know

Sterilization

autoclaving ftw

15 psi at 121C for 15-20 min

Most Probable Number test steps

presumptive

confirmed

completed

define Indicator organisms

associated with the intestinal tract

e.g. Salmonella

define Coliform

indicator that meets 4 criteria:

G-neg rod

non-sporeforming

facultative anaerobe

ferments lactose to acid and gas in 48 hrs at 37C

why is E. coli a good indicator for fecal contamination?

lives in intestines

not usually in soil or water

easily ID'd

not as fastidious as others

MPN presumptive test steps

15 tubes: 5 of dbl strength LST or lactose broth, 10 mL

5 of 1x strength, 1 mL

5 of 1x strength, 0.1 mL

define membrane filter method

water filtered through a membrane with pore size 0.45 um

utilizes m Endo broth MF or EMP agar

ideal sample yields 20-80 coliform colonies

There must be a _____ displacement in Durham tube to be considered positive for gas production

10%

define confirmed test

ensures G-neg rods!

inoculate EMB w/ gas positive tube

streak-plate method

How many CFUs make a countable plate?

30-300

bacterial growth phases

lag phase

log phase

stationary phase

death phase

With a spectrophotometer, the higher the absorbance...

the greater the concentration of bacterial cells

completed test

inoculate TSA plate and LST/lactose broth tube from growth on EMB plate.

Streak for isolation

how to calculate #CFU/mL or /g of food

#CFU counted on plate x reciprocal of dilution

Psychrophiles

-5 to 20C

Mesophiles

20 to 50C

Thermophiles

50 to 80C

Hyperthermophiles

>80C

Psychotrophs

capable of growth at temp higher or lower than their optimum

eg Pseudomonas fluorescens

Neutrophile, Acidophile, Alkaliphiles

duhhh

Hypertonic, Hypotonic, Isotonic

defined in terms of the solution

Halophiles

require high concentrations of salt to grow

eg Halobacterim salinarium (25% salt)

Halotolerant

capable of growth in moderate concentrations of salt

eg. S. aureus 10% salt

ex of obligate aerobe Lab 7

Pseudomonas

ex of obligate anaerobe Lab 7

Clostridium sporogenes

ex of facultative anaerobe Lab 7

E. coli

ex of microaerophile Lab 7

Helicobacter

ex of aerotolerant organism Lab 7

Streptococcus

About this deck

By: Chris Gluckman
Textbook:

Microbiology: A Human Perspective

Microbiology: A Human Perspective w/ARIS bind in card
Created: 2011-10-17
Size: 60 flashcards
Views: 36

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis