microbiolab

Chromogen

Chromogen

a colored mlecule

basic dyes

carry positive charge, bind to cells that have negative charge

acdic dyes

carry negative charge, repelled by cells that carry negative charge

common dyes used

crystal violet, safranin, methylene blue

differential stain

used to distinguish one bacterial group from another

gram stain

most used stain developed by Dr hanz gram.

Gram positive bacteria=

purple

gram negative bacteria=

pink

four regents of gram stain:

primary stain, mordant, decolorizer, and counter stain.

primary stain?

crystal violet. stains cell

mordant?

holds primary dye onto cell

decolorizer?

removes primary dye from gram negative cell.

counter/secondary stain?

recolors cells that lose stain through de colorization

Acid fast stain

used to stain organisms that resist conventional staining/ stains mycobacterium

Ziehl-Neelsen acid fats stain

used to detect mycobacterium, Tuberculosis, and leprae

growth=

cloudy (turbidity)

sterile=

clear (autoclaved)

Areobes?

require oxygen to live.

anaerobes?

do not use oxygen to live

Facultative anaerobes

can live with or without oxygen

aretolerant aerobes?

can tolerate oxygen, but grow better without it

microaerophile?

use oxygen but only at reduced levels.

Thioglycolate broth:

contaisn reducing agent and provides aerobic and anaerobic conditions

toxic O2 products can be converted with what?

Catalase or SOD

Sterilization?

complete destruction of all life forms

what are the autoclave settings?

15 PSI, 121C for 15 minutes

antiseptic?

used on living tissue

disinfectant?

used on on non living material

Bacterio static?

inhibits grwoth of bacteria

bacteriocidal?

kills bacteria

Micrococcus is?

catalase positive

streeptococcus is?

castlase negative

staphylococcus is?

catalase positive

what does catalase do?

converts hydrogen peroxide into water and oyxgen

where is S. epidermidis found?

on the skin

where is S. saprophyticus found?

rectum, urethra , GI tract

Where is S. Aureus found?

Nasal passage and on skin

Hemolysin?

Lyses red blood cells

leukocidin?

destroys white blood cells

Hyaluronidase?

enzyme destroying tissue

Staphylokinase?

destroys fibrin clots

What does coagluase test do?

If S. Aureus is present, blood will clot.

selective media?

ingredients in it to inhibit organisms from growing

What does the novobiocin test do?

Looks for zone of inhibition. SS is resistant, SE is sensitive.

Streptococcusm is

Gram positive, grows on blood agar plate

Gamma?

grows with no hemolysin

Alpha?

partially degardes blood cell. Growth turns green

Beta?

Totally desotryed blood cells. growth is clear.

Streptococcus pyogenes?

causes strepthroat, beta hemolytic

Pyogenic?

Pus producing

Bacitracin test?

interferes with the cell wall antigen.

Bacitracin test results?

S. pyogenes is sensitive.  separates Group A streptococcus from Staph aureus

 -separates Group A from Group B streptococcus

Streptococcus agalactiae

B hemolytic. resistant to bacitracin. found in female vaginal tract

CAMP test?

used for identification of group b hemolytic

CamP test results?

Group B strepococcus.

what is Micrococcus?

Gram positive

Oxidase componets?

TMPD

 Pseudomonas?

gram negative, baciilus. Loves to grow in water. Can cause UTI’s skin infections.

O-f media results?

Bromthymol blue. Green when neutral, yellow when acidic, blue when basic.

Oxidateive=

green

fermentative=

Yellow

CAMP Positive?

Coagulate positive?

Staphylococcus aeuers.

Catalase positive bacteria?

Staphococcus and micrococcus

Oxidase positive Bacteria?

micrococcus.

Coagulase positive bacteria?

Staphococcus Aures

Novobiocin sensitive bacteria?

Staphococcus epidermis.