Question

I need help creating a flowchart on a unknown 89

Chart of Unknown Test and the Result #89

Name of Test	What does it test?	Positive result appears as:	negative results appears as:	Unknown #89 result:
Gram Stain Reaction	Cell envelope morphology	Violet-blue	Red	Negative (pink)
Cell morphology (shape: coccus, bacillus, or spirillum)	Cell shape			Bacillus (Rod shaped)
Cell Arrangement	Cell size or length			Single Bacillus
Pigment	Cell envelope morphology			Pink
Oxygen Requirement	If cell needs oxygen for respiration	Growth occurs on and near the surface of agar	Growth occurs far from the surface of agar	Facultative Anaerobe
Glucose fermentation (acid and gas)	If the pyruvate form glucose fermentation is converted into acid or gas or both	Solution turns yellow invisible bubbles appear in Durham tube	Solution remains red and no visible bubbles in Durham tube	Positive for acid or gas
Lactose Fermentation (acid and gas)	If the pyruvate form lactose fermentation is converted into acid or gas or both	Solution turns yellow and visible bubbles appear in Durham tube	Solution remains red and no visible bubbles appear in Durham tube	Negative for acid and gas
Tryptophan Digestion (indole)	If unknown can Catabolize Tryptophan	Produces purple-red color on the surface	No color is produced	Negative
Methyl-Red	If unknown produces acidic end products	pH indicator changes from yellow to red	pH indicator remain yellow	Positive
Voges-Proskauer	If unknown produces neutral end products	Pink-burgundy color is produced	Solution remains brown-yellow	Negative
Citrate Utilization	If unknown can catabolize citrate	Agar is blue with heavy growth	If agar is green with little growth	Positive
Levine EMB	If unknown can ferment lactose	Colonies have colors	Colonies remain colorless	No results
Luisetti's Agar (florescence)	If unknown can produce florescein	flouresce yellow-green	no fluoresce	Negative
Mortility	If your unknown has flagella	Growth spreads throughout tube four from inoculation point	Growth sticks to the inoculation point	Positive
Starch Hydrolysis	If unknown can catabolize amylose	No reactions with iodine	Area around bacteria will appear dark-blue or red-brown	Negative
Catalase				No results
Cytochrome Oxidase				No results
Cysteine Desulfhydrase	If unknown expresses cysteine desulfhydrase to catabolize cysteine	The medium turns black	The medium remains unchanged, colorless	Positive
Lysine Decarboxylase	Determines if the isolate can remove the carboxylic acid group off the amino acid lysine	Positive is purple because the media is more basic	Negative is 10 if no reaction, yellow if the isolate made acid	Negative
Gelatin Hydrolysis	If the unknown uses gelatins to digest gelatin	Gelatin turns into a liquid	Gelatin remains a solid	Negative
Urea Digestion	If the unknown uses urease to catabolize urea	Urea broth turns hot pink	Urea broth stays straw-yellow	Positive
Mannitol Fermentation (MSA plate)	If the unknown can ferment mannitol	phenol red will turn yellow	phenol red will remain red	Negative
DNase Production	If unknown can utilize DNA as a source of carbon and energy to produce Dnase.	Area around unknown is no longer green but yellow.	Area around unknown remains green.	Negative

Gram negative facultative anaerobic rods

	Citrobacter freundii	Enterobacter aerogenes	Enterobacter cloacae	Erwinia stewertii	Escherichia coli	Proteus mirabilis	Proteus vulgaris	Serratia marcescens
Starch	-	-	-	+	-	-	-	-
Oxidase	-	-	-	-	-	-	-	-
Gelatinase	-	-	-	+	-	(-)	+	+
Cysteine desulhydrase	(+)	-	-	-	-	+	+	-
Lysine decarboxylase	-	+	-	-	+	-	-	+
Urea	-	-	-	-	-	+	+	(-)
Glucose/acid	+	+	+	+	+	+	+	+
Glucose/gas	+	+	+	+	+	+	+	(+)
Lactose/acid	+	+	+	+	+	-	-	(-)
Indole	-	-	-	+	+	-	+	-
Methyl red	+	-	-	+	+	+	+	-
Voges Proskauer	-	+	+	-	-	-	-	+

citrate + + + + - - - +

Answer 1

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The unknown bacteria is Gram negative bacilli which is arranged singularly.

The unknown bacteria can ferment Glucose and produce acid or gas. The bacteria can be any of them.

The unknown bacteria can not ferment lactose. The bacteria may be citrobacter, enterobacter, erwinia or E. Coli.

It shows positive for methyl red test. It may be citrobacter, erwinia or E. coli.

It shows citrate test positive. It may be citrobacter or erwinia.

It shows no starch hydrolysis. So, the unknown bacteria is Citrobacter freundii.

The correct way to solve such problems is that check for each test. Eliminate the ones which shows test wrong. Then you will remain with a single option which is the correct answer.