Hey, Good to see you here 😀 …… In this Article, We’re gonna discuss in Detail the Morphology & Culture characteristics of Klebsiella pneumoniae….. If you have any queries, don’t forget to mention in Comments….. Thanks

Morphology of Klebsiella pneumoniae

[wp-svg-icons icon=”point-right” wrap=”i”]Klebsiella pneumoniae is a short, plump, straight rod shape (bacillus) bacterium.



[wp-svg-icons icon=”point-right” wrap=”i”]The size of Klebsiella pneumoniae is about 1–2 µm × 0.5–0.8 µm (micrometer).

[wp-svg-icons icon=”point-right” wrap=”i”]K. pneumoniae is arranged singly, in pairs, or in short chains and sometimes in clusters.

Morphology of klebsiella pneumoniae - laboratory hub - capsuated gram negative rod
Morphology Of Klebsiella pneumoniae

[wp-svg-icons icon=”point-right” wrap=”i”]Klebsiella pneumoniae is a non-motile bacterium.

[wp-svg-icons icon=”point-right” wrap=”i”]K. pneumoniae is a non-flagellated bacterium.

[wp-svg-icons icon=”point-right” wrap=”i”]The Klebsiella pneumoniae is a non–sporing bacterium.

[wp-svg-icons icon=”point-right” wrap=”i”]Capsules are present in Klebsiella pneumoniae which can easily be demonstrated using India ink preparation, appear as a clear halo in a dark background.

[wp-svg-icons icon=”point-right” wrap=”i”]Klebsiella pneumoniae is a Gram -ve (Negative) bacterium.

Culture Requirements of Klebsiella pneumoniae (K. pneumoniae)

[wp-svg-icons icon=”point-right” wrap=”i”]Special requirements – Klebsiella pneumoniae have no complex nutritional requirements and readily grow in an ordinary media like Nutrient Agar medium (NAM). Commonly the NAM & MacConkey Agar medium is used for the cultivation of Klebsiella pneumoniae in Laboratory.




[wp-svg-icons icon=”point-right” wrap=”i”]Optimum temperature – Klebsiella pneumoniae ranges from 15–40°C but the optimum temperature for most of the strains is 37°C and usually cultivated at this temperature in laboratories.

[wp-svg-icons icon=”point-right” wrap=”i”]Optimum pH – K. pneumoniae can survive alkaline pH but not at acidic pH and the maximum growth of the organism is observed at 7.0 i.e. neutral pH. Also, the pH requirement varies as per the strain of Klebsiella pneumoniae.

[wp-svg-icons icon=”point-right” wrap=”i”]Oxygen requirements – Klebsiella pneumoniae (K. pneumoniae) is an aerobic bacterium i.e. grow best in the presence of oxygen and it is also a Facultative anaerobic organism i.e. can grow in the low oxygen environment.

⇒ There are various culture media used for the cultivation of Klebsiella pneumoniae in the laboratory and most commonly the Nutrient Agar medium and MacConkey Agar medium is used, the other media are as follows –

  • Columbia Horse Blood Agar medium
  • Sheep Blood Agar medium
  • Trypticase Soy Agar medium
  • Eosin Methylene Blue Agar (EMB Agar) Medium.
  • The liquid medium (Nutrient Broth medium, TSB medium, etc.).

⇒ The Eosin Methylene Blue Agar (EMB Agar) medium which is the Selective medium for Klebsiella pneumoniae contains Eosin dye and Methylene Blue dye which inhibits the growth of many gram-positive bacteria, inhibits the growth of Shigella and Salmonella species and supports the growth of Klebsiella pneumoniae.




Culture Characteristics of Klebsiella pneumoniae (K. pneumoniae)

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In Liquid culture media like Trypticase soy broth or Nutrient broth, the growth of the bacterium occurs as a turbidity in the broth medium which is further analyzed for the morphology (under the microscope), gram reaction, biochemical tests, and Klebsiella pneumoniae specific tests.

In Blood Agar medium, the Klebsiella pneumoniae colonies are non-hemolytic i.e. shows Gamma Hemolysis (γ-hemolysis).

klebsiella pneumoniae on blood agar medium - laboratory hub - klebsiella on lood agar
Culture Of Klebsiella Pneumoniae On Blood Agar Medium

In MacConkey Agar medium, the colonies of Klebsiella pneumoniae are pink colored due to the lactose fermentation which is of great importance in differentiating K. pneumoniae from other Bacteria present in the specimen, especially from Gram-positive bacteria and Salmonella species which are non–lactose fermentors and gives colorless colonies on MacConkey agar medium.

klebsiella pneumoniae on macconkey agar medium - laboratory hub - klebsiella on macconkey agar medium - k. pneumoniae on macconkey agar medium
Culture Of Klebsiella Pneumoniae On Macconkey Agar

In Eosin Methylene Blue Agar (EMB) medium, the colonies of Klebsiella pneumoniae are Pink to purple in color without green metallic sheen which is of great importance in differentiating K. pneumoniae from other bacteria normally found in Specimen and especially from E. coli which grows with Green metallic sheen.

Klebsiella pneumoniae on EMB medium - laboratory hub - klebsiella pneumoniae on eosin methylene blue medium
Culture Of Klebsiella Pneumoniae On EMB Medium

That’s all about the Morphology and Culture Characteristics of Klebsiella pneumoniae….



Frequently Asked Questions (FAQs)

On nutrient agar, Klebsiella pneumoniae colonies appear large, smooth, and mucoid with a pale yellow coloration. They may also exhibit a stringy consistency.

To identify Klebsiella on a culture plate, a Gram stain can be performed. Klebsiella will appear as Gram-negative rods. Additional tests such as biochemical tests, API systems, or molecular methods can also be employed for accurate identification.

On blood agar, Klebsiella pneumoniae colonies appear round, smooth, and convex with a mucoid consistency. They have a pale white or light gray coloration.

Klebsiella pneumoniae is a facultative anaerobic bacterium that can ferment glucose, lactose, and other sugars. It is also able to produce large amounts of capsule polysaccharides, which contribute to its virulence.

Cultural characteristics of Klebsiella pneumoniae include a preference for nutrient-rich media and the ability to grow at a wide range of temperatures. It also has a tendency to produce a mucoid or stringy consistency in its colonies.

Klebsiella pneumoniae can be grown on a variety of culture media, including nutrient agar, blood agar, MacConkey agar, and eosin methylene blue agar.