MIP302
MIP302 - Final Exam Questions and
Answers
thermophiles - bacteria that live in environments with elevated temperatures
(above 131°F)
super/hyper thermophile - bacteria that live in environments with extremely
elevated temperatures (above 300°F)
Differential Media - allows for growth of bacteria, but differentiates bacteria based
on some characteristic appearance on a media type
Selective media - allows for certain types of bacteria to grow (inhibits others)
Aerobic bacteria - require atmospheric oxygen
microaerophilic bacteria - Require atmospheric oxygen but at reduced levels
facultative anaerobes - Grow with or without oxygen (better with oxygen)
obligate anaerobe - grow in absense of atmospheric oxygen
Ambient air - Normal air
candle jar - reduced levels of O2, higher levels of CO2
MIP302
,MIP302
GasPak - reduced environment (devoid of O2)
Redox indicators for Gaspak and Candle jar - Redox indicator methylene blue
(blue when oxidized, white in reduced state)
Catalase Test - To see if bacteria produces enzyme catalase; add 3% H2O2 to a
DRY smear of bacteria; produces bubbles=(+); delayed/no bubbles=(-)
Oxidase Test - To see if bacteria produces cytochrome oxidase (uses cytochrome C
and cytocrhome oxidase in ETC); uses Oxidrop as reagent; blue/maroon=oxidized,
(+); colorless= reduced, (-); 3 MIN
PR Glucose Broth - Testing for glucose fermentation; Differential media (ability to
ferment carb); phenol red indicator (yellow in acidic, red in basic); contains
peptone and beef extract in PR broth; Durham tube put in tube to catch gas;
yellow=(+); red=(-); 18-24 hours
Nitrate Broth - Differential media [ability to reduce nitrate (NO3) to nitrite (NO2)]
using anaerobic resp.; Nitrate A and Nitrate B reagents (react w/ nitrite--> red);
RESULTS: red during first round, (+) nitrate reductase, (-) nitrite reductase;
Colorless during first round, inconclusive, add zinc; Red during second round
(Nitrate A, B, and zinc) (-) for nitrate and nitrite reductase; Colorless during second
round (+) nitrate and nitrite reductase; 48 HOURS
MacConkey Agar - To test for lactose fermentation of Gram (-) rods; differential
media (lactose fermentation); selective media (grows Gram - enteric bacilli,
inhibits Gram - cocci and Gram +); neutral red reagent (red in acidic, yellow in
basic); contains peptone and beef extract; RESULTS: red/dark-pink colonies
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surrounded by zone of bile salt, strong lactose fermenter; colorless colonies, do not
ferment lactose; if no growth, cannot make conclusions about lactose fermentation;
18-24 HOURS
Phenylethyl Alcohol (PEA) Agar - Test for Gram (+) growth; Selective (selective
component 1/4 phenylethyl OH); not as stringent as MacConkey; RESULTS:
growth, most likely Gram (+) but have to do a Gram stain to check; 18-24 HOURS
Blood Agar (BAP) - Used to cultivate medically significant bacteria; all-purpose
media; differential (ability to hemolyze red blood cells); includes TSA and sheep
red blood cells; RESULTS: BETA, complete hemolysis, clear zone surrounding
colonies; ALPHA, incomplete lysis, green-ish brown area surrounding colony;
GAMMA, no lysis; Don't look at colony itself to determine results; 24 HOURS
Pseudosel Agar (Cetrimide Agar) - Used to isolate and identify Pseudomonas
aeruginosa; Selective (P. aeruginosa can grow, all others inhibited bc of cetrimide);
Differential (produce pyocyanin); can see under room lighting; RESULTS:
blue/green colonies, positive result, P. aeruginosa; 18-24 HOURS
Pseudomonas Agar F - Used to differentiate bacteria based on ability to produce
pigment fluorescein (differential); all-purpose medium; contains magnesium and
potassium salts (enhance fluorescein production); should be visualized under UV,
even tho can see green pigment in room lighting; RESULTS: glowing under UV,
produces fluorescein, (+); 18-24 HOURS
enteric bacteria - Gram negative facultative anaerobic rods
coliforms - Gram negetaive rods that ferment lactose and produce gas, facultative
anaerobes, and do not produce spores
MIP302
MIP302 - Final Exam Questions and
Answers
thermophiles - bacteria that live in environments with elevated temperatures
(above 131°F)
super/hyper thermophile - bacteria that live in environments with extremely
elevated temperatures (above 300°F)
Differential Media - allows for growth of bacteria, but differentiates bacteria based
on some characteristic appearance on a media type
Selective media - allows for certain types of bacteria to grow (inhibits others)
Aerobic bacteria - require atmospheric oxygen
microaerophilic bacteria - Require atmospheric oxygen but at reduced levels
facultative anaerobes - Grow with or without oxygen (better with oxygen)
obligate anaerobe - grow in absense of atmospheric oxygen
Ambient air - Normal air
candle jar - reduced levels of O2, higher levels of CO2
MIP302
,MIP302
GasPak - reduced environment (devoid of O2)
Redox indicators for Gaspak and Candle jar - Redox indicator methylene blue
(blue when oxidized, white in reduced state)
Catalase Test - To see if bacteria produces enzyme catalase; add 3% H2O2 to a
DRY smear of bacteria; produces bubbles=(+); delayed/no bubbles=(-)
Oxidase Test - To see if bacteria produces cytochrome oxidase (uses cytochrome C
and cytocrhome oxidase in ETC); uses Oxidrop as reagent; blue/maroon=oxidized,
(+); colorless= reduced, (-); 3 MIN
PR Glucose Broth - Testing for glucose fermentation; Differential media (ability to
ferment carb); phenol red indicator (yellow in acidic, red in basic); contains
peptone and beef extract in PR broth; Durham tube put in tube to catch gas;
yellow=(+); red=(-); 18-24 hours
Nitrate Broth - Differential media [ability to reduce nitrate (NO3) to nitrite (NO2)]
using anaerobic resp.; Nitrate A and Nitrate B reagents (react w/ nitrite--> red);
RESULTS: red during first round, (+) nitrate reductase, (-) nitrite reductase;
Colorless during first round, inconclusive, add zinc; Red during second round
(Nitrate A, B, and zinc) (-) for nitrate and nitrite reductase; Colorless during second
round (+) nitrate and nitrite reductase; 48 HOURS
MacConkey Agar - To test for lactose fermentation of Gram (-) rods; differential
media (lactose fermentation); selective media (grows Gram - enteric bacilli,
inhibits Gram - cocci and Gram +); neutral red reagent (red in acidic, yellow in
basic); contains peptone and beef extract; RESULTS: red/dark-pink colonies
MIP302
, MIP302
surrounded by zone of bile salt, strong lactose fermenter; colorless colonies, do not
ferment lactose; if no growth, cannot make conclusions about lactose fermentation;
18-24 HOURS
Phenylethyl Alcohol (PEA) Agar - Test for Gram (+) growth; Selective (selective
component 1/4 phenylethyl OH); not as stringent as MacConkey; RESULTS:
growth, most likely Gram (+) but have to do a Gram stain to check; 18-24 HOURS
Blood Agar (BAP) - Used to cultivate medically significant bacteria; all-purpose
media; differential (ability to hemolyze red blood cells); includes TSA and sheep
red blood cells; RESULTS: BETA, complete hemolysis, clear zone surrounding
colonies; ALPHA, incomplete lysis, green-ish brown area surrounding colony;
GAMMA, no lysis; Don't look at colony itself to determine results; 24 HOURS
Pseudosel Agar (Cetrimide Agar) - Used to isolate and identify Pseudomonas
aeruginosa; Selective (P. aeruginosa can grow, all others inhibited bc of cetrimide);
Differential (produce pyocyanin); can see under room lighting; RESULTS:
blue/green colonies, positive result, P. aeruginosa; 18-24 HOURS
Pseudomonas Agar F - Used to differentiate bacteria based on ability to produce
pigment fluorescein (differential); all-purpose medium; contains magnesium and
potassium salts (enhance fluorescein production); should be visualized under UV,
even tho can see green pigment in room lighting; RESULTS: glowing under UV,
produces fluorescein, (+); 18-24 HOURS
enteric bacteria - Gram negative facultative anaerobic rods
coliforms - Gram negetaive rods that ferment lactose and produce gas, facultative
anaerobes, and do not produce spores
MIP302
