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Jessekah Butterworth Bench B Date [1]
Classification
Higher order taxa
Bacteria – Proteobacteria – Betaproteobacteria – Neisseriales – Neisseriaceae – Kingella
Species
Kingella oralis
Strain: strain UB-38 = ATCC 51147 = CCUG 30450 = CIP 103803.[1]
Description and significance
Kingella oralis is a gram-negative, bacilli bacteria that was first observed by Chen et al in 1989, who were investigating the presence of Eikenella corrodens in the human oral cavity.[2] This isolate was further investigated by Dewhirst et al in 1993, who identified several varying characteristics that distinguished the two species from each other including colony morphology on agar and acid production from sugars.
In early identification and research into K. oralis, the bacteria was successfully grown on Trypticase soy agar plates that contain 5% sheep blood, 5mg of hemin per litre and 0.5mg of menadione per litre at 37°C in a humidified anaerobic chamber containing 5% CO2.[3] However the specific growth requirements of K. oralis are still unknown.
K. oralis is found in both supragingival and subgingival plaque, as well as in mucosa and saliva.[4] There is a high association between K. oralis presence and periodontitis.[3][4] Therefore research into K. oralis can potentially aid in periodontitis prevention or treatment.
Genome structure
The representative K. oralis strain ATCC 51147, has a total genome size of 2.41Mb consisting of 2435 genes which encode approximately 2315 proteins and 6 rRNAs. [5] It has a GC% content of 54.3%.
The genome assembly consists of 5 scaffolds that contain no gaps in between and 12 contigs, with a contig N50 of 792,850.[6] K. oralis does not form chromosomes and contains no plasmids either.
Cell structure and metabolism
K. oralis is a gram negative, bacilli(rod)- shaped bacteria that consists of the usual cell was structure of plasma membrane, periplasmic space, thin peptidoglycan layer and an outer membrane containing lipopolysaccharide and proteins. Cells can reach sizes of approximately 0.6 to 0.7µm in diameter by 1 to 3µm in length and will either grow in pairs or chains within the colony.[3]
K. oralis do not have flagella and therefore do not move around very much. However the cells can form spreading colonies allowing the bacteria to have 'twitching motility'.[3]
K. oralis is oxidase positive, but catalase negative.[3] The bacteria has a weak ability to produce acid from glucose but is unable to utilize other sugar compounds, such as lactose, maltose, mannitol, sucrose and xylose, for the same purpose.[3] In addition to this, K. oralis does not reduce nitrate or nitrite, nor produce lysine, ornithine decarboxylase, indole and urease, nor hydrolyze esculin.[3]
Ecology
K. oralis is an aerobe or facultative anaerobe that is predominantly found in supragingival and subgingival dental plaque, but also in mucosa and saliva. [3][4]
To date, there have been no observations or reports of K. oralis in any other environment. However, due to the lack of knowledge of required growth conditions, it is still possible that K. oralis utilizes alternative habitats to the oral microbiome.
The interactions between K. oralis and the human host were unknown in research conducted throughout 1989-1993.[3] And they remain unknown to date, as no further research has been conducted/published.
Pathology
K. oralis was initially isolated and identified from the supragingival and subgingival plaque formation in both adult and juvenile cases of periodontitisis.[4] Therefore was thought that the bacteria is associated with periodontitis, an inflammatory disease of the gums that left untreated can lead to degradation of the oral bone and connective tissue surrounding the teeth.[7] However, the bacteria was also isolated from both plaque formation sites in healthy candidates.[4]
In addition to this, research into the involvement of K. oralis in other oral diseases, found that the bacteria was found most abundant in healthy patients rather than those with oral diseases such as root caries or dental caries.[8][9] Therefore the pathology of K. oralis remains unclear.
Application to biotechnology
Due to the limited knowledge of K. oralis/host interaction and overall function in the oral microbiome, there have been no biotechnology applications of the bacteria to date.
Current research
Research into oral diseases, such as dental caries and root caries, in 2008 found an association between the abundance of K. oralis and the oral health of a person.[8][9] Which is in complete contrast to intial conclusions that K. oralis was associated with periodontitis.
Another study conducted by Ruhl et al in 2014, found using a new coadhesion method that K. oralis was a prominent coadhering partner in biofilm formation in dental plaque.[10] Which was previously unidentified in coaggregation studies. The new discovery of this interaction may assist in the understanding of K. oralis function in biofilms.
Adding on to this discovery, a computational prediction analysis conducted by Coelho et al, stated there are potential interactions between proteases of Porphyromonas gingivalis and K. oralis>.[11] Suggesting a synergistic relationship of bacteria in the oral biofilm that is involved in periodontal disease.
References
1. List of Prokaryotic names with standing in nomenclature
5. NCBI Genome Assembly Annotation: Kingella oralis
6. NCBI Global Genome Statistics: Kingella oralis
- ↑ MICR3004
This page is written by Jessekah Butterworth for the MICR3004 course, Semester 2, 2016
