Chapter 13 - Klebsiella

Abstract

Based on the beneficial microbes of Klebsiella in agroecology, combined with the research progress of Klebsiella bacteria in various fields, this chapter reviews the taxonomy, isolation, simple biochemical methods for identification, and beneficial role of the genus Klebsiella in agroecology. Furthermore, the future research direction was prospected. Klebsiella bacteria tend to be rounder and thicker than other members of the Enterobacteriaceae family. They have no specific growth requirements and grow well on standard laboratory media, but they grow best between 35 and 37°C and at pH 7.2. The taxonomic structure of the genus Klebsiella that is currently widely accepted is given. Uncertain points that still need to be clarified are the distinction between K. planticola and K. ornithinolytica and the phylogenetic distinctness of K. granulomatis and K. pneumoniae. The inclusion of E. aerogenes as K. mobilis is not consensual. Note that the definitions of K. pneumoniae subspecies are based on pathogenesis criteria and not on genomic distinctness. Almost all Klebsiella strains grow in minimal medium with ammonium ions or nitrate as sole nitrogen source and a carbon source without growth factor requirement. Several selective differential media for the isolation and enumeration of Klebsiella spp. were proposed in clinical, industrial, and natural environments. The general methods used for the identification of Klebsiella species are given. Klebsiella showing plant growth-promoting traits have been isolated from the plant rhizosphere. Common bacteria found in the plant rhizosphere are Klebsiella sp. Similarly, strains of Klebsiella can supplement the use of urea-N in plant production either by biological nitrogen fixation (BNF) or growth promotion.