Klebsiella oxytoca

Classification

Higher Order Taxa

Domain: Bacteria;

Phylum: Proteobacteria;

Class: Gammaproteobacteria;

Order: Enterobacteriales;

Family: Enterobacteriaceae;

Genus: Klebsiella;

Species: K. oxytoca

NCBI: Taxonomy

Description and Significance

Klebsiella oxytoca is a gram-negative bacterium with a cylindrical rod shape measuring 2 µm by 5µm (1). In the 1950’s the strain M5aI was isolated with a notable characteristic of lacking a polysaccharide capsule. It was first named Aerobacter aerogenes and was later identified as K. pneumoniae, a strong pathogen that causes a form of Pneumoniae. It has recently been classified as K. oxytoca because it differs from K. pneumoniae in that it is indole-positive and able to grow on melezitose, but not 3-hydroxybutyrate.

Genome Structure

The genome for K. oxytoca has been sequenced in several strains. Virginia Bioinformatics Institute sequenced the genome for Klebsiella oxytoca KOX105 and determined the plasma length to be 0.0546Mbp with 0 chromosomes (2). The Genome Sequencing Center at Washington University in St. Louis sample sequenced Klebsiella oxytoca M5aI strain VJSK009 to -5.5X WGS coverage in plasmids and determined total genome length to be 5.28Mbp with 56% total GC content (3). The strain Klebsiella oxytoca KCTC1686 has been sequenced showing genome length of 5.97Mbp. Currently, 10 strains of Klebsiella oxytoca are being sequenced as part of the Human Microbiome Project.

Cell Structure and Metabolism

K. oxytoca have a capsule composed of thick polysaccharide (K antigen) and lipopolysaccharide layer (O antigen) that protects them from phagocytosis and dessication, components of there cellular structure responsible for there pathogenicity (3).

Ecology

K. oxytoca like other Klebsiella spp. can be found in a range of environments, and are commonly referred to as ubiquitous and opportunistic in nature (1). K. oxytoca has been found in mammals and insects, where in humans, these microbes colonize along the mucosa membranes of the colon and nasopharynx, and sometimes skin, however they can be found colonizing on all parts of the body (5). Most infections of K. oxytoca are nosocomial, spreading via the hands of medical staff and outbreaks occuring in patients with immunodeficiency or medicated with antibiotics and have been reported to be found in both prenatal and neonatal infants (6).