Genus: Klebsiella



Genus: Klebsiella

General characteristic:

• Klebsiella are non motile member of Enterobacteriaceae

• It is gram negative rod (slightly shorter and tick than other Enterobacteriaceae

• Have a polysaccharide capsule, and can be recognized by their large, geryish –white, mucoid colonies (especially if it has high sugar content.

• Non spore forming, aerobic and facultative anaerobic bacteria are killed by moist heat at 55◦C in 30 minutes

• Cultures may remain viable for many weeks, when kept at room temperature.

• There is no haemolysis of horse or sheep red blood cells.

• Oxidase negative, V-P positive, Urease positive (slow) and lactose fermented organism

• Attack sugar fermentativly, produce acid with gas.

Normal habitat:

Found n the intestinal tract of man and animal also it may be found in water, vegetable ….etc. as saprophytic, found also in the hospital environment which cause a nosocomial infection (hospital acquired infection)

Medical important species

• K. pneumoniae

• K. pneumoniae subspecies pneumoniae

• K. pneumoniae subspecies aerogens

• K. pneumoniae subspecies ozaenae

• K. pneumoniae subspecies rhinoscleromatis

Antigenic structure:

• About 80 capsular antigens (K) are presently recognized (used as epidemiological tools in serotyping of organism.

• Somatic antigens (O), there are five different somatic antigens occur in various combinations with the capsular antigens it is found identical with or related to E. coli somatic antigens.

Pathogenicity:

• K. pneumoniae: cause chest infection and occasionally cause of severe bronchopneumonia, some times with multiple abscess formation in the lung.

• K. pneumoniae subspecies aerogens: associated with hospital acquired infection such as

* Urinary tract infection

* Clinical sepsis develops in surgical wound infection

• K. pneumoniae subspecies ozaenae and K. pneumoniae subspecies rhinoscleromatis: cause granulomatous disease of nose (Rhinoscleromatis is a chronic upper respiratory disease where it is associated with prolonged exposure to crowd and unhygienic condition.

Diagnosis:

• Specimens (depending on the site of infection) include: sputum, urine, wound swab and nasal swab and infected tissue.

• Cultivation *aerobic and facultative anaerobic

* Temperature (35- 37 ◦C)

* pH (7 – 7,2)

• On blood agar produce grey white usually mucoid colonies no haemolysis has been detected.

• On Mac conkey agar: most strain are lactose fermented, producing mucoid – pink large colonies and yellow colonies on CLED. K. pneumoniae subspecies rhinoscleromatis is non lactose fermented we use the biochemical test to differentiate between different species.

• On KIA slope butt gas H2S

Y Y + --

Biochemical test:

Primary test:

• Catalase + ve

• Oxidase - ve

• Motility - ve

• Production of acid and gas + ve

• O –F test Fermentative

Secondary:

|Species |V – p |indole |citrate |Urease |Mal |lact |

|K. p. pneumoniae |- |- |+ |+ |+ |+ |

|K. p. aerogens |+ |- |+ |+ |+ |+ |

|K. p. ozaenae |- |- |+ |- |- |+ |

|K. p. rhinoscleromatis |- |- |- |- |+ |- |

Antimicrobial sensitivity:

• Klebsiella often produce beta – lactamase enzyme and are resistant to penicillin.

• Cephalosporin and aminoglycosides are used to treat Klebsiella infections.

• Klebsiella infection of the urine often responds to Trimethoprim.

Enterobacter specie:

• Found in the intestinal tact of human and animal, also found in sewage, water, soil, and diary product.

• Opportunistic pathogen associated with UTI, wound infection, and septicemia in person already in poor health.

• Gram negative motile rod

• On blood agar produce colonies that may resemble those produce by Klebsiella, but not so mucoid.

Biochemical Test

• Catalase + ve

• Oxidase - ve

• Motility - ve

• Production of acid and gas + ve

• O –F test Fermentative

• Indole test - ve

• Citrate utilization test + ve

• MR test - ve

• V – p test + ve

• H2S test - ve

• Urease test - ve

• On KIA slope butt gas H2S

Y Y + --

Set of sugar : lac(+), Man (+), Glucose (+), and Sucrose (d)

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