Klebsiella is a genus of Enterobacteria belonging to the family of Enterobacteriaceae. This genus is composed of a diverse group of Gram-negative, non-spore forming bacilli that produce distinct, mucoid colonies on solid culture media. The Klebsiella organisms are catalase-positive, urease-positive, and oxidase-negative. The large, encapsulated cells can usually be detected with the aid of a microscope. Klebsiella species are opportunistic pathogens, with the majority of clinical isolates recovered from respiratory and urinary tract infections and nosocomial infections.
Klebsiella species are generally rod-shaped, motile, facultatively anaerobic organisms that range in size from 0.5 to 1.5μm in diameter, and 2 to 8μm in length. They have large amounts of mucoid capsular material which is what gives them their characteristic “wood ear” appearance on Gram stain. They contain a variety of different metabolic pathways, including the ability to utilize carbohydrates, amino acids and fatty acids for energy. They can also utilize glucose for their primary carbon source, but can also ferment lactose, maltose, and xylose. They are also able to fix nitrogen from the atmosphere, allowing them to utilize nitrogen as well.
Klebsiella species are also known for their ability to fix nitrogen from the environment, making them useful for industrial production of fertilizer and other agricultural products. They are able to fix nitrogen through the activity of nitrogenase, a system of enzymes that convert atmospheric nitrogen into a form that can be used by other organisms. Klebsiella species have also been used in bioremediation processes, which involve using bacteria to convert hazardous material into harmless substances, lessening the environmental impact.
Klebsiella species are also capable of producing a number of extracellular proteins and enzymes. Some of these enzymes such as proteases, amylases, and phosphatases have been studied for their possible applications in medicine, as they have been determined to have antibacterial and antifungal properties. Other proteins have also been determined to have potential as antigens and vaccines.
Klebsiella is known for its wide range of genetic variation, which occurs through changes in plasmid and chromosomal DNA. This genetic variation makes it possible for Klebsiella species to survive in a variety of environments and to develop resistance to a variety of antibiotics. In some cases, the ability to resist antibiotics can be transferred from one strain to another, creating a greater risk of infection and disease.
In conclusion, Klebsiella is a diverse group of bacteria found in many different environments, for which many different metabolic activities and genetic variability play important roles. Klebsiella species are also known to be opportunistic pathogens, with the majority of clinical isolates recovered from respiratory and urinary tract infections and nosocomial infections. They have also been employed in industrial and bioremediation processes, in addition to producing a variety of extracellular proteins and enzymes which have potential medical applications. Furthermore, the variations in their DNA allow Klebsiella species to survive in different environments and to develop resistance to antibiotics, often transferring this resistance from one strain to another through plasmid and chromosomal DNA alterations.
