User:S4371879

Jeniffer Denisse Loaiza Naranjo Bench D 31/08/16 ^[1]

Classification

Higher order taxa

Bacteria – Terrabcateria group – Actinobacteria – Actinobacteria – Micrococcales – Micrococcaceae – Rothia

Species

Rothia dentocariosa ATCC 17931

Description and significance

Rothia dentocariosa is a bacteria first described and isolated by George and Brown 1967 from human clinical samples of patients with caries [1]. It is a Gram-positive organisms, with a pleomorphic morphology. It present itself as filamentous with branches in plates or in cocci form in fluid environment [2]. It can be seen in clusters, individually or in chains. R. dentocariosa is commonly found in oral cavity of humans and correlated with periodontal diseases [2, 14]. Due to its prevalence and pathologies to humans, it is important to study this organism and its virulence factors.

Examples of citations ^[1], ^[2]

Genome structure

Select a strain for which genome information (e.g. size, plasmids, distinct genes, etc.) is available.

Cell structure and metabolism

Rothia dentocariosa is related to the Actinomyces species but it can be differentiated by its cell wall, which does not possess DAP. Instead, the peptidoglycan is based in L-Lys–Ala3 bridges [2, 12]. The major sugars are galactose, fructose, glucose and ribose, while the fatty acid component consists of methyl-branched fatty acids, unsaturated menaquinones, Diphosphatidylglycerol (DPG) and Phoshatidylglycerol (PG) [2, 23]. Interestingly, dimannosyl diglyceride has higher prevalence in the filamentous from than the coccal form of R. dentocariosa [12]. In order to form the biofilm in the oral cavity, it coaggregates with Actinomyces species such as Actinomyces naeslundii, which uses Type 2-fimbrial adhesins [22].

It does not produce spores, does not have aerial micellium and has no motility. [1,2]. Chemically, It reduces nitrate to ammonia, is catalase positive, oxidase and urease negative, perform nitrate and nitrite reduction, decomposes casein. Uses mannose, sucrose, fructose, maltose, glycerol, glucose and trelahose to ferment lactic and acetic acid. They cannot grow in ammonium ions environment. It cannot hydrolyse starch [2].

Ecology

It is an aerobic bacteria but it can also grow in microaeophilic environments. Grows better at 35° C. The abundance of carbon, oxygen and nitrogen in the oral cavity makes it a comfortable environment for bacteria in general. Streptococci species are the most abundant followed by Haemophilus, Gemella, Rothia and Actinomyces species. Neisseria species and Rothia dentocariosa are one of the early colonizers of the oral cavity. This species appeared in the first 6 hour after colonization, commonly located in the sublingual sulcus. [16]

A symbiotic interaction between R. dentocariosa and humans can happen in the case of nitrate reduction. R. The host provides the bacteria with nutrients, and the bacteria produce nitrite. This can be further processed to nitric oxid, which acts as an antimicrobial agent. Nitrite production was concentrated in the dorsal surface of the tongue. Veilonella was the major group, followed by Acrtinomyces and in the third place were Rothia spp. Less caries were found in patients with high nitrate-reducing ability [5]. It has also been reported that R. dentocariosa is a human pathogen.