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A genus of gram-negative, nonmotile bacteria. Characteristic large mucoid colonies are due to production of a large amount of capsular material. Species of Klebsiella are commonly found in soil and water, on plants, and in animals and humans. Harmless strains of Klebsiella are beneficial because they fix nitrogen in soil. Pathogenic species include K. pneumoniae, K. rhinoscleromatis, and K. ozaenae, also known as K. pneumoniae subspecies pneumoniae, rhinoscleromatis, and ozaenae.

Klebsiella pneumoniae is the second most frequently isolated colon-related bacterium in clinical laboratories. The carbohydrate-containing capsule of Klebsiella promotes virulence by protecting the encased bacteria from ingestion by leukocytes; nonencapsulated variants of Klebsiella do not cause disease. Capsular types 1 and 2 cause pneumonia; types 8, 9, 10, and 24 are commonly associated with urinary tract infections. See Escherichia, Pneumonia

Klebsiella accounts for a large percentage of hospital-acquired infections, mostly skin infections (in immunocompromised burn patients), bacteremia, and urinary tract infections. It is also the most common contaminant of intravenous fluids such as glucose solutions and other medical devices.

Klebsiella may produce E. coli-like enterotoxins and cause acute gastroenteritis in infants and young children. Enteric illnesses due to Klebsiella are more predominant where populations are more crowded and conditions less sanitary. Other virulence factors of Klebsiella include a relatively high ability to survive and multiply outside the host in a variety of environments, and its relatively simple growth requirements. See Endotoxin

Klebsiella rhinoscleromatis causes rhinoscleroma, a chronic destructive granulomatous disease of the upper respiratory tract that is most common in eastern Europe, central Africa, and tropical South America. Klebsiella ozaenae is one cause of chronic rhinitis (ozena), a destructive atrophy of the nasal mucosa, and is infrequently isolated from urinary tract infections and bacteremia. See Medical bacteriology

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a genus of capsular nonsporiferous bacteria, the typical representative of which is Klebsiella pneumoniae, or Friedländer’s bacillus, a rodlike (0.3–0.5 × 5 microns) organism that occurs singly or in pairs and is nonmotile, gram-negative, and forms a mucous capsule.

Klebsiella pneumoniae grows well on ordinary nutrient media. On solid media it forms round, convex, shiny, mucoid colonies. It ferments glucose, saccharose, and lactose, forming acid and gas; it does not liquefy gelatin; it sours but does not curdle milk; it does not form either hydrogen sulfide or indole; and it reduces nitrates. Klebsiella pneumoniae is a facultative aerobe. Its optimal growth temperature is 37°C. It inhabits the nasal, oral, and intestinal mucosae of healthy persons, but it is conditionally pathogenic and may produce pneumonia in man. Other Klebsiella produce rhinoscleroma and ozena. Klebsiella cause klebsielloses in many farm animals.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A genus of bacteria in the family Enterobacteriaceae; nonmotile, encapsulated rods arranged singly, in pairs, or in chains; some species are human pathogens.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Klebsiella is a species of bacteria that occurs naturally in the environment, but studies have shown that its subspecies, such as Klebsiella pneumoniae, are capable of causing a large number of infections, such as septicaemia (a form of blood poisoning), urinary tract infections and pneumonia.
The researchers found that the Klebsiella had undergone genetic mutations that may have allowed them to survive and continue to function, even without a food source.
coli was 38%, Pseudomonas aeruginosa 30% Klebsiella pneumonia 17%, Acinetobacter baumannii 12%, Citrobacter diversus 2%, Enterobacter agglomerans 1.4%13.
Klebsiella rhinoscleromatis is most frequently the causative agent; however, to our knowledge, 3 case reports of rhinoscleroma secondary to K ozaenae have been reported to date.
Three isolated bacterial species, including Klebsiella pneumoniae sp., Enterobacter aerogenes sp.
Virulence profiles and antibiotic susceptibility patterns of Klebsiella pneumoniae strains isolated from different clinical specimens.
Sundugumuz olgulardaki Klebsiella suslarinin pan-rezistan olmasi, genotipik inceleme yapilamamis olsa da, bu suslarin OXA-48 disinda bir direnc geni icerebilecegini dusundurmektedir.
Results: Positive cultures yielded 585 Klebsiella pneumoniae out of which 220(37.6%) strains were AmpC beta-lactamase-positive on the basis of cefoxitin screening and 126(21.53%) were positive on the basis of inhibitor-based confirmatory method.
Novel carbapenem-hydrolyzing [beta]-lactamase, KPC-1, from a carbapenem-resistant strain of Klebsiella pneumoniae.
Tigecycline is an alternative for MDR Acinetobacter baumannii and Klebsiella pneumoniae carbapenemase-producing bacteria (KPC), but it is not recommended for bacteremia because it does not achieve adequate serum concentration levels and is associated to an increased risk of death (4-5).
coli followed by Klebsiella, while in NSICU Klebsiella pneumoniae was the most common isolate.