Clinical Laboratory Technology
Biochemical Tests
Commonly Used Tests for Aerobic, Gram-positive Cocci
Catalase positive
Taxos A positive
Taxos P or Optochin positive
Camp positive
Bile Esculin positive
6.5% NaCl positive
Bile solubility positive
PYR & LAP positive
Coagulase positive
Catalase negative
Vancomycin positive
Taxos P or Optochin negative
Camp negative
Bile Esculin negative
6.5% NaCl negative
Bile solubility negative
PYR negative & LAP positive
Coagulase negative
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Additional Biochemical Tests
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Commonly Used Tests for Aerobic, Gram-Negative Cocci
Oxidase positive (Gordon & McLeod's Reagent)
Polysaccharide from Sucrose positive
Rapid Sugars
Polysaccharide from sucrose negative
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Standard Biochemical Tests for the
Enterobacteriaceae
Indol
Methyl Red
Triple Sugar Iron agar (TSI)
Decarboxylase Broth (Moeller)
Motility
Phenyl Red Carbohydrate Broth
Malonate Broth
Voges-Proskauer
Simmons Citrate agar
Lysine Iron agar (LIA)
Christensen Urea agar
Phenylalanine
Gas production
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Standard Biochemical Tests for the Nonfermentative Gram-negative Bacilli
OF sugar positive
Nitrate positive (before zinc)
Nitrate positive (after zinc)
Triple Sugar Iron agar (TSI)
Decarboxylase Broth (Moeller) positive
42° C positive
Acetamide positive
Oxidase positive (Kovacs reagent)
OF sugar negative
OF sugar (reaction of fermentative bacilli)
Nitrate negative
Motility
Decarboxylase Broth (Moeller) negative
42° C negative
Acetamide negative
Oxidase negative (Kovacs reagent)
Tests for
Haemophilus
XV positive
Porphyrin (ALU) positive
Satellitism
V only positive
Porphyrin (ALU) negative
Oxidase positive
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Key Tests to rule out
Bacillus anthracis
Positive Motility Test
Lecithinase negative (Right plate)
Penicillin (10 units) sensitive
Key Tests for
Listeria monocytogenes
Positive Camp Test (resembles a shovel, not an arrow)
Positive Motility Test (resembles an umbrella or christmas tree)
Positive Bile Esculin Test
Triple Sugar Iron agar (TSI)
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Key Tests for
Clostridium perfringens
Special Potency Antimicrobial Disks
Lecithinase positive (Left plate)
Reverse Camp Test positive (Arrow points toward Clostridium isolate)
Key Tests for
Bacteroides fragilis group
BBE (Bacteroides Bile Esculin agar) growing
B. fragilis group
Esculin Broth positive
Thioglycolate with Bile positive
Special Potency Antimicrobial Disks
Karen M. Kiser MA MT(ASCP) PBT
Emeritus Professor
Clinical Laboratory Technology/Phlebotomy
St. Louis, MO USA
Updated January 1, 2008
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Biochemical Tests
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