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The below mentioned article provides a short note on Klebsiella.
Introduction to Klebsiella:
Klebsiella are widely distributed in nature, occurring as commensals in intestine and as saprophytes in soil and water. They are non-motile, capsulated rods. They grow on ordinary media. On MacConkey Agar medium, their colonies are large dome shaped, mucoid and pink.
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Mucoid colonies can be identified by string formation, when they are touched and lifted up with platinum wire. They ferment glucose, lactose, sucrose, mannitol with acid and gas production. They are Indole and MR negative, VP and citrate positive Fig. 11.9 (MV(1) C – – + +); they produce urease and are differentiated from Enterobacter which are motile.
Classification of Klebsiella:
Klebsiella have been classified into three species (K. pneumoniae, K. ozaenae and K. rhinoscleromatis) and over 80 serotypes based on biochemical and on the capsular (K) antigenic reactions, respectively
1. K. pneumoniae:
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Klebsiella pneumonia is characterised by massive mucoid inflammatory exudate K. pneumoniae which causes diarrhoea, urinary, pyogenic (abscess, meningitis), nosocomial infections and septicaemia. Some strains of K. pneumoniae produce enterotoxin (similar to heat stable toxin of E. coli) which is determined by plasmid.
K. pneumoniae is the second-most common bacterial flora of intestine of man and animals. It is next to E. coli and is also common in hospitalized patients. The hospital acquired intestinal strains are resistant to a wide spectrum of antibiotics, however, they are sensitive to few drugs (cefoxitin, cefotaxime and ceftazidime).
Through certain respiratory strains K. pneumoniae (Friedlander bacillus) causes severe pneumonia with fatality rate of 80% if untreated. Middle-aged and elderly persons are more susceptible to K. pneumoniae, if they are already suffering from diabetes mellitus, chronic bronchopneumonia or other underlying medical problems.
Capsular serotypes 1-6 are most common in the respiratory tract infection in man, capsular swelling reaction, agglutination, complement fixation, fluorescent antibody, counter Immunoelectrophoresis can be performed for the identification of capsular antigen.
Other Methods of Typing:
Bacteriocins known as Klebocins or pneumonias are produced by many klebsiella strains. In Klebocin typing, a liquid preparation of bacteriocins obtained after induction with mitocin C was used.
The combination of klebocin typing and capsular serotyping can be used for epidemiological study. Besides, phage typing with temperate phages derived from other Klebsiella strains can also be adopted for epidemiological investigation.
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Diagnosis is done by culture and identification by biochemical reactions. Since many strains carry plasmids determining multiple drug resistance, antibiotic sensitivity test should be invariably undertaken.
2. K. ozaenae and K. rhinoscleromatis:
certain subspecies of K. pneumoniae—derived their names from the disease with which they are associated e.g. K. ozaenae was isolated from the nasal mucosa in oezena, a disease characterised by foul smelling nasal discharge with progressive atrophy of mucous membranes; and K. rhinoscleromatis from rhinoscleroma, a chronic granulomatous disease of the nose and pharynx.
