Cultural and Biochemical Characteristics of Medically Important Bacteria

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Cultural and Biochemical Characteristics of Medically Important Bacteria

Name of Bacteria

Cultural Characteristics

1. Staphylococcus aureus

Colonies on Mannitol Salt Agar (MSA)
Picture Credit: Ms. Samjhana Kapali

Colonies on Mueller Hinton Agar (MHA)

Colonies on Blood Agar (BA) Media
Picture Credit: Ms. Sanjita Khadka

Coagulase Test
[A] Negative
[B] Positive

A. Positive Control; B Negative Control and C. Test: Positive.
Picture Credit: Ms. Samjhana Kapali
2. Salmonella Typhi

Colonies on Mac-Conkey Agar (MA)

Colonies on Xylose-Lysine Deoxycholate Agar (XLD)
Picture Credit: Mr. Saroj Khadka

Colonies on Blood Agar (BA) Media
Picture Credit: Mr. Saroj Khadka
Biochemical Set of Salmonella Typhi.
From Left to Right:
A: Oxidative Test: Positive;
B: Fermentative Test: Positive;
C: Indole: Negative;
D: Methyl Red: Positive;
E: Voges Proskauer: Negative;
F: Citrate Test: Negative;
G: Triple Sugar Iron: Alkaline/Acid, Hydrogen Sulphide Positive, Gas Production Negative;
H: Urea Hydrolysis: Negative.
3.Vibrio cholerae

Colonies on Thiosulfate-Citrate-Bile salts-Sucrose Agar (TCBS)

4.Pseudomonas aeruginosa

Green colonies on Mueller Hinton Agar (MHA)

Biochemical Set of Pseudomonas aeruginosa
From Left to Right:
1: Indole Test: Negative; Motile
2: Methyl Red: Negative;
3: Voges Proskauer: Negative;
4: Urea Hydrolysis: Negative.
5: Citrate Test: Positive;
6: Triple Sugar Iron: Alkaline/Alkaline, Hydrogen Sulphide Negative, Gas Production Negative
7: Oxidative Test: Positive; However, due to pH of the media, the result here is diverted.
8: Fermentative: Negative;


Picture Credit: Ms. Shrijana Bhandari 5.Escherichia coli

Cysteine Lactose Electrolyte Deficient Medium(CLED)

Biochemical Reaction from Left to Right of Anaerogenic E coli.
[1️] TSI: R/Y (A/A), H2S -ve, Gas -
[2️] Citrate: Negative
[3️] Urease: Negative (actually is varibale +ve)
[4️] SIM: Indole +ve, Motility +ve


Picture Credit: Mr. Saroj Khadka

Characteristic Green Metallic Sheen on Eosine Methylene Blue (EMB) Agar Media


Picture Credit: Mr. Saroj Khadka

6.Salmonella Paratyphi A

Colonies on Xylose-Lysine Deoxycholate Agar (XLD)

Biochemical Set of Salmonella Paratyphi A.
From Left to Right:
A: Oxidative Test: Positive;
B: Fermentative Test: Positive;
C: Indole: Negative;
D: Methyl Red: Positive;
E: Voges Proskauer: Negative;
F: Citrate Test: Negative;
G: Triple Sugar Iron: Alkaline/Acid, Hydrogen Sulphide Negative, Gas Production Positive;
H: Urea Hydrolysis: Negative.
7.Klebsiella pneumomiae

Colonies on Mac-Conkey Media
Picture Credit: Mr. Saroj Khadka

Colonies on CLED

Biochemical Set of Klebsiella pneumoniae
From Left to Right:
A: Indole: Negative;
B: Urea Hydrolysis: Positive;
C: Citrate Test: Positive;
D: Triple Sugar Iron: Acid/Acid, Hydrogen Sulphide Negative, Gas Production Positive.
Picture Credit: Mr. Saroj Khadka 8.Enterobacter cloacae

Biochemical Reaction from Left to Right
[1️] TSI: Y/Y (A/A), H2S -ve, Gas +
[2️] Citrate: Positive
[3️] Urease: Negative (actually is varibale +ve)
[4️] SIM: Indole -ve, Motility +ve


Picture Credit: Mr. Saroj Khadka

9.Acenitobater spp.

Biochemical reaction
From Right to Left
[1] Indole: Negative, Non-motile
[2] TSI: Red/Red (i.e. lac/suc non-fermneter), H2S negative, Gas negative
[3] Urease: Negative
[4] Citrate: Positive


Picture Credit: Mr. Saroj Khadka

10. Proteus mirabilis

Bichemical Reactions (from left to right)
[1] Citrate: Negative (Although most strains of P. mirabilis are citrate +ve, some are citrate -ve.)
[2] TSI: Red/Yellow i.e. lactose/sucrose non-fermneter, H2S production, Gas production
[3] Urease: Positive
[4] Indole: Negative, Motile

Picture Credit: Mr. Saroj Khadka

Comments

Unknown said…
please add culture characteristic of most commonly Gram negative bacteria like enterobacter, citrobacter and acinetobacter
Thursday, September 10, 2020 9:14:00 am
Bikram Malla said…
We are pleased to have your comments. We will try to update your request in upcoming days. Thank you. MBLOSTU
Thursday, September 10, 2020 6:12:00 pm
Unknown said…
Informative bro, keep it up.
Tuesday, November 02, 2021 8:17:00 am
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