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Duncan Keogh MICR3004 2017
{{Uncurated}}
Mostafa Al Yassiry
Bench C
12/10/2017
 


==Classification==
==Classification==


===Higher order taxa===
===Higher order taxa===
Bacteria – Bacteroidetes – Bacteroidia – Bacteroidales – Prevotellaceae – ''Prevotella''
===Species===
''P. Oris''


Bacteria – Bacteroidetes – Bacteroidetes – Bacteroidales – Prevotellaceae – Prevotella
==Description and significance==


===Species===
The ''Prevotella'' species are commonly found and cultured from the rumen and hindgut of cattle and sheep. In humans, they make for opportunistic pathogens and are known for causing periodontal and tooth problems <sup>[[#References|[1]]]</sup>. In addition, they have also been found to thrive in the vaginal area, and are sometimes also recovered from the anaerobic infections of the respiratory tract including sinusitis, lung abscess, chronic otitis media, aspiration pneumonia and pulmonary empyema. Studying these bacteria would help scientists and researchers understand better the modes of their spread, their activity and the factors that could hamper their growth, which in turn, could possibly help pave the way for research and development of new drugs and medications to deal with the infections it causes.
==Genome structure==


Prevotella Oris (Previously Bacteroides Oris)
''Prevotella Oris'' has not been completely sequenced <sup>[[#References|[1]]]</sup>. The only two strains from the ''Prevotella'' family that have been completely sequenced are ''Prevotella intermedia 17'' and ''Prevotella ruminicola 23'' <sup>[[#References|[2]]]</sup>.
The genome of Prevotella intermedia 1, had a De novo assembly of 127,972 reads averaging a length of 6,598 bp using the Hierarchical Genome Assembly Process (HGAP). This resulted in two closed circular chromosomes of 606,227-bp and 2,131,046-bp in size with average coverages of 194.0× and 214.6×, respectively and had a GC content of 43.5%.  2,510 coding sequences, as well as 61 RNA sequences were identified <sup>[[#References|[3]]]</sup>.


==Description and significance==
==Cell structure and metabolism==


Prevotella Oris was originally a member of the genus Bacteroides however, it was reclassified in 1990 into the Prevotella genus. Prevotella species make up a large proportion of the bacterial community within the rumen of Bovine, representing up to 60% of the relative abundance of the microbial community when using rRNA analysis . Within humans, Prevotella regularly colonises the oral cavity, and is where the organism was originally isolated. They can also be pathogenic, particularly in invasive anaerobic infections with an origin of infection being linked to respiratory tract entry in many instances . They are also common in subgingival plaque, dental caries and malodour in the oral cavity. Therefore, it can be seen that bacteria of the Prevotella genus are important in both their metagenomic roles within the oral microbiome, metagenomics of the ruminal microbiome of bovine and also, from a biomedical perspective
''Prevotella Oris'' is a gram negative, anaerobic bacterium which has been found to be associated with some major oral and systemic infections. It is a non pigmented bacterium which has been identified through bacterial cultures and lab tests, which are often not usually regarded as a reliable method of detection <sup>[[#References|[1]]]</sup>. This is why, a study conducted in 2007 attempted to develop a PCR assay for the direct detection of the organism <sup>[[#References|[3]]]</sup>. 
of bacterial infections.  
Previous studies have found that ''P. Oris'' is able to produce immunoglobulin A protease, hyaluronidase and b-lactamase which possibly point out to the pathogenic nature of the organism. Studies have found that ''Prevotella'' makes use of steroid hormones as growth factors, which is why, their occurrence is significantly higher in pregnant women, and is also isolated from women suffering from bacterial vaginosis. It has also been found and isolated from dental infections occurring in individuals suffering from Down’s Syndrome, a chromosome disorder.


==Genome structure==  
==Ecology==


Prevotella Oris C735 is available on Biocyc. The genome contains 2690 genes, within a genome of 3,346,228 bp. This includes 185 total pathways, 1094 enzymatic reactions and 50 tRNAs.  
''Prevotella'' bacteria are gram negative, rod shaped and singular cells that are generally found thriving in anaerobic conditions <sup>[[#References|[5]]]</sup>. ''Prevotella Oris'' has been found and isolated from lesions of several oral infections, dentoalveolar abscess <sup>[[#References|[4]]]</sup>, endodontic infections and sometimes even from lesions of systemic infections such as meningitis, empyema and cervical spinal epidural abscess.  
The ''Prevotella'' species, particularly ''Prevotella Oris'', requires hemim for their growth and multiplication. They are also found to use two survival mechanisms to thrive. First, they colonize by binding or attaching themselves to other bacteria, which in turn, creates a larger area of infection than the previously infected area. Secondly, it also possesses natural antibiotic resistant genes, which help it survive and colonize. However, an investigation did reveal how the use of hyaluronic acid as a medium could have bacteriostatic effects on the ''Prevotella'' species, specifically ''Prevotella Oris'' and high molecular weight hyaluronic acid had the maximum impact. An earlier study also attempted to decode the acid tolerance and acid neutralizing activity of this bacteria in oral infections. It was found that ''Prevotella'' in general, thrives more under acidic conditions, and during growth, it tends to increase the pH. Studies on acid neutralization also revealed that the ''Prevotella'' cells produced succinic and isolvaleric acids which clearly suggests the deamination of amino acids, which in turn, clearly explains how ''Prevotella'' survives in both sub gingival and supragingival plaque. Infact, this colonization may also help create an environment in these areas, paving way for ''Porphyromonas gingivalis'', another bacteria, to thrive. ''Prevotella'' has also been found to run down in families, not genetically, but through intrafamilial carriage. While it does display signs of antibiotic resistance, it has been found susceptible to ''clindamycin''.  


==Cell structure and metabolism==  
==Pathology==


Prevotella Oris is a gram-negative, non-motile, rod-shaped, anaerobic bacterium. Prevotella Oris has been found within plaque however, other species of Prevotella are found in higher abundance in comparison. There is evidence to suggest a synergestic relationship between Prevotella species and Fusobacterium nucleatum. This biofilm formation is important in plaque formation within the subgingival crevice. Prevotella Oris C375 lacks a complete TCA cycle on Biocyc but does contain Fermentative pathways for acetate formation via pyruvate, and also nitrate reduction pathways. Prevotella have also been shown to be able to inhibit human immunoglobulin A1. This achieved through a protease that cleaves the immunoglobulin at the hinge site which separates it into the Fab and Fc regions. However, IgG neutralising antibodies can be raised by humans in order to inhibit these proteases. Prevotella Oris is also one of few species of bacteria to produce hyaluronidase, which is able to degrade components of the host extracellular matrix components. Prevotella Oris has also been noted as containing bacterial resistance genes, in particular beta-lactamase. Prevotella Oris also requires Iron for it’s growth, typically of concentration between 0.05–0.5 μM with hemin being a particularly successful due to the production of haemolysin.  
''Prevotella Oris'' has been found to be a cause of some major infections including endodontic infection, periodontal disease <sup>[[#References|[7]]]</sup>, bacteremia, dentoalveolar abscess, and in some cases, is also found to be largely response for the spread of odontogenic infection. In addition, its presence has also been identified in lesions of systemic infections such as cervical spinal epidural abscess <sup>[[#References|[6]]]</sup>, meningitis as well as empyema. The DNA of ''Prevotella Oris'' has also been identified and detected in some pus samples taken from individuals suffering from odontogenic infections.
Apart from thriving in the oral and vaginal areas, ''Prevotella'' has also been recovered from some respiratory tract infections including pneumonia, sinusitis, chronic otitis media, pulmonary empyema and lung abscess <sup>[[#References|[8]]]</sup>. Sometimes, they may also be found in the abscesses and burns near the mouth and in bites, brain abscesses, urinary tract infections and in cases of osteomyelitis.
A study focusing on the gut bacteria of children in different regions also revealed that ''Prevotella'' was found to make up of 53% of the total gut bacteria present in the children in Africa <sup>[[#References|[13]]]</sup>. It is believed that consumption of a diet rich in carbohydrates and fiber may be linked to increased occurrence of these bacteria. In fact, the gut environment was found to change detectably on the consumption of different types of food in this study, but ''Prevotella'' came up more significantly in individuals who consumed a diet rich in carbohydrates.
In addition, Prevotella was also found to intensify and exacerbate colitis in mice as per some new study findings <sup>[[#References|[10]]]</sup>. In another study, it was found that ''Prevotella'' overgrowth caused a reduction in the growth of lactobacillus in mice, which further led to the onset and development of osteomyelitis in the subjects. Conversely, when the growth of ''Prevotella'' was reduced and the growth of lactobacillus was increased, the latter offered protection against osteomyelitis. This study proved to be a clear example of how dietary modifications tend to have a huge impact on the body and gut microflora, which further explains how it could either trigger or suppress certain chronic health conditions, and in this case, osteomyelitis. Another finding also revealed how this bacteria was involved in the progression of carothid atherosclerosis, which further strengthens the studies that have linked poor oral health and the occurrence of dental caries to heart conditions, some of which can be potentially life threatening.  


==Ecology==  
==Application to biotechnology==


Prevotella are found in anaerobic conditions due to their anaerobic classification. Although they are generally a non-pathogenic bacterium, they are regularly isolated from bacterial infection sites and oral disorders, including predominantly endodontic infections and also dentoalveolar abscesses. However, cases of Prevotella isolation from meningitis samples should also be noted. Prevotella are also able to modulate the pH of their surrounding environment, thus allowing them to grow at a range of pH including acidic conditions. This, combined with the ability to grow in nitrogen rich environments along with acid tolerance allows Prevotella to grow in the deep periodontal pockets whilst also allowing the formation and maintenance of plaque, especially in tandem with Fusobacterium nucleatum which is also able to alter environmental pH thus, allowing the maintenance of a solid biofilm in the form of plaque. Prevotella oris is also a regular inhabitant of the vaginal and cervical flora.
''Prevotella Oris'' has not yet been a part of any major groundbreaking studies or researches revolving around the production of compounds and enzymes. Little is known about its genetic sequence-however, new studies are now highlighting different characteristics associated with it.  
However, new and new studies are now being carried out to understand and decode its various applications in different fields <sup>[[#References|[12]]]</sup>. A recent study on the ''Prevotella'' species derived from humans also compared the gene repertoires of its species derived from different other body sites in humans. This reported an open pan genome which clearly demonstrated a vast diversity of gene pool.  


==Pathology==  
==Current research==


As aforementioned, Prevotella Oris is regularly identified in oral infections such as endodontic infections and also dentoalveolar abscesses. Although this is one area which Prevotella can infect, it is important to note it’s ability to disseminate and establish infection in a wide range of locations. The aforementioned hyaluronidase is important in this ability to degrade extracellular matrix allows the entry through various endothelial linings and thus, a greater ease of dissemination. Clinically, Prevotella infections display general symptoms and characteristics of an anaerobic infection. These generally comprise foul-smelling discharge, mucosal location, necrosis and gas within discharges and tissue itself. More specifically, Prevotella oris  is regularly identified within many respiratory infections including sinusitis, respiratory abscesses, pneumonia and pleural empyema. Investigations into the mucosal microbiota of individuals experiencing inflammatory bowel disease has also shown a possible link between Prevotella and disease state. Within patients with Ulcerative Colitis and also Crohn’s Disease, both groups were found to have significantly higher abundance of Prevotella species in comparison to the healthy control group.  
Since there is not a lot known about ''Prevotella Oris'', new and new studies and research findings are highlighting more and more characteristics of this bacterium which could hopefully prove to be helpful in many ways.A recent study published in the Journal of Oral Biosciences attempted to understand and decode the hemolytic activity of ''Prevotella Oris''. The study revealed important facts about how P. Oris displayed an acceleration in hemolytic activity during its growth phase, and then a decrease in the activity was noted during the stationary phase <sup>[[#References|[11]]]</sup>. These findings could possibly help researchers understand its pathogenic potential in different oral and systemic infections.
Another study focused on the development of a PCR assay for the easy detection of ''Prevotella Oris'' in clinical samples. This PCR assay would in turn, help provide a specific and reliable detection method for the bacteria.  
A different research attempted understand the trend of antibiotic resistance in the ''Prevotella'' species, including ''Prevotella Oris''. Different strains of ''Prevotella'' bacteria were taken into consideration and their resistance to different antibiotics including penicillin, metrodinazole, tetracycline, clindamycin and b-lactamase was tested <sup>[[#References|[10]]]</sup>. These findings would prove to be extremely helpful for medical practitioners and would help them understand and determine the right antibiotic to be used for a particular strain, which could in turn, improve patient outcomes.
Another study also focused on understanding antibiotic resistance in different strains of ''Prevotella'' bacteria, and the percentage of susceptibility was also calculated.  
Published in the Dental Research Journal, another finding identified Prevotella species as one of the many bacteria responsible for dental abscesses. This study pointed out that such abscesses respond well to surgical treatments, and antimicrobials can be used to limit the spread of infection. However, it also pointed out that there is a need of good quality clinical trials to be conducted to find out the right treatment. It also highlighted how dental abscesses are poorly discussed in medical history, and if left untreated, they have the potential to progress and transform into major health issues including cavernous sinus thrombosis, septicemia, brain abscess, shock and in some cases may even lead to death.  
Another recent study found a strong link between ''Prevotella'' species thriving in the body, specifically ''Prevotella Corpi'', and an increased risk of the onset of rheumatoid arthritis, an autoimmune disorder that affects millions of people around the globe <sup>[[#References|[9]]]</sup>. It was found that when ''Prevotella'' thrives in the gut, it tends to decrease the occurrence of ''Bacteroides'' which in turn, leads to a loss in the concentration of healthy and beneficial gut microbes. This in turn, supports the systemic immune response associated with joint inflammation, thereby leading to the onset of rheumatoid arthritis. These findings can turn out to be a huge help for individuals affected by the disease, because the current measures taken to deal with it focus solely on reducing the intensity of symptoms and providing relief from pain. If steps are taken to assess and limit the multiplication of the ''Prevotella'' species and a healthy gut environment is maintained, rheumatoid arthritis could be stopped right in its tracks. The antibiotic resistance of ''Prevotella'' has proved to be a major setback, and hopefully, further studies will pave the way for development of new targeted drugs to help treat infections occurring due to these bacteria.  
==References==


==Application to biotechnology==
References examples


Little to no research has been done on Prevotella oris as an organism with applications within biotechnology. However, there is a possibility for applications of Prevotella oris within the agriculture industry. Prevotella Bryantii 25A was investigated as a possible probiotic in managing Subacute Ruminal Acidosis within dairy cattle mainly due to the ability to regulate pH. Although Prevotella Bryantii 25A was unsuccessful, other species of Prevotella, such as Prevotella oris could be viable alternatives.  
1. [Yousefimashouf R, Duerden BI, Eley A, Rawlinson A, Goodwin L. Incidence and distribution of nonpigmented Prevotella species in periodontal pockets before and after periodontal therapy. Microb Ecol Health Dis 1993; 6:35–42]


==Current research==
2. [Riggio MP, Lennon A. Development of a novel PCR assay for detection of Prevotella oris in clinical specimens. FEMS Microbiology Letters 2007; 123-128]


As previously mentioned, research into disorders within agricultural animals such as dairy cattle have investigated the possibility of Prevotella species as viable probiotics. Metabolically, Prevotella oris is largely unclassified and under investigated, so research into this aspect of the bacterium can provide insight into any advantageous effects of commensal colonisation, whilst also suggesting possible mechanisms for the virulent effect that the bacteria can present itself in. The most recent studies published on Prevotella oris all centre around the interactions of the bacteria with the host and also, interactions with other bacterial species within the host. These include classifying the expression levels of the haemolysin and hyaluronidase in different conditions to better understand the organisms influence in infections, and also understanding the role of the bacteria in Irritable Bowel Syndrome disease such as Ulcerative Colitis and Crohn’s Disease which Prevotella Oris has been noted as being in higher levels within hosts whom are affected by these diseases. Furthermore, we can also gain further insights into the role of Prevotella Oris
3. [Brito LCN, Teles FR, Teles RP, Franca EC, Ribeiro-Sobrinho AP, Haffajee AD, Socransky SS. Use of multiple-displacement amplification and checkerboard DNA–DNA hybridization to examine the microbiota of endodontic infections. J Clin Microbiol 2007; 45:3039–49]
within the oral cavity and plaque formation.


==References==
4. [Dymock D, Weightman AJ, Scully C, Wade WG. Molecular analysis of microflora associated with dentoalveolar abscesses. J Clin Microbiol 1996;34:537–42.]


1. [http://www.microbiologyresearch.org/docserver/fulltext/ijsem/40/2/ijs-40-2-205.pdf?expires=1506071487&id=id&accname=guest&checksum=CEC0EA23C5DC86DC77CC77A46B0352EB Shah HN, Collins DM. 1990. Prevotella, a new genus to include Bacteroides melaninogenicus and related species formerly classified in the genus Bacteroides. Int J Syst Bacteriol 40:205-8.]
5. [Civen R, Jousimiessomer H, Marina M, Borenstein L, Shah H, Finegold SM. A retrospective review of cases of anaerobic empyema and update of bacteriology. Clin Infect Dis 1995;20:S224–9]


2. [https://www.ncbi.nlm.nih.gov/pubmed/17235560 Stevenson DM, Weimer PJ. 2007. Dominance of Prevotella and low abundance of classical ruminal bacterial species in the bovine rumen revealed by relative quantification real-time PCR. Applied Microbiology and Biotechnology 75,1:165-74.]
6. [Frat JP, Godet C, Grollier G, Blanc JL, Robert R. Cervical spinal epidural abscess and meningitis due to Prevotella oris and Peptostreptococcus micros after retropharyngeal surgery. Intensive Care Med 2004;30:1695]


3. [https://www.koreamed.org/SearchBasic.php?RID=1007KJM/2003.64.3.254&DT=1 Yoon JY, Choo EJ, Choi SH, Kim MN, Kim NJ, Kim YS, Woo JH, Ryu JS, Chang MS. Clinical characteristics and outcome of invasive Prevotella infection. Korean Journal of Medicine. 2003 Mar 1;64(3):254-9.]
7. [Holdman VL, Moore CEW, Churn JP, Johnson LJ. Bacteroides oris and Bacteroides buccae, new species from human periodontitis and other human infections. Int J Syst Bacteriol 1982;32:125–31]


4. [https://www.ncbi.nlm.nih.gov/pubmed/18524268 Tanaka S, Yoshida M, Murakami Y, Ogiwara T, Shoji M, Kobayashi S, Watanabe S, Machino M, Fujisawa S. 2008. The relationship of Prevotella intermedia, Prevotella nigrescens and Prevotella melaninogenica in the supragingival plaque of children, caries and oral malodor. J Clin Pediatr Dent 32:195-200.]
8. [Holdman VL, Johnson LJ. Description of Bacteroides loesheii sp. nov. and emendation of the descriptions of Bacteroides melaninogenicus (Oliver and Wherry) Roy and Kelly 1939 and Bacteroides denticola Shah and Collins 1981.Int J Syst Bacteriol 1982;32:399–409]


5. [https://biocyc.org/PORI563008-HMP/organism-summary?object=PORI563008-HMP Biocyc Prevotella Oris C375]
9. [Johnson LJ, Holdman VL. Bacteroides intermedius comb. nov. and descriptions of Bacteroides corporis sp. nov. and Bacteroides levii sp. nov. Int J Syst Bacteriol 1983;33:15–25]


6. [https://www.ncbi.nlm.nih.gov/pubmed/21945879 Okuda T, Kokubu E, Kawana T, Saito A, Okuda K, Ishihara K. 2012. Synergy in biofilm formation between Fusobacterium nucleatum and Prevotella species. Anaerobe 18:110-6.]
10. [Martinez JL, Delgado-Iribarren A, Baquero F. Mechanisms of iron acquisition and bacterial virulence. FEMS Microbiol Rev 1990;6:45–56]


7. [https://www.ncbi.nlm.nih.gov/pubmed/2186760 Martinez JL, Delgado-Iribarren A, Baquero F. 1990. Mechanisms of iron acquisition and bacterial virulence. FEMS Microbiol Rev 6:45-56.]
11. [Sato, Toshiya & Kamaguchi, Arihide & Nakazawa, Futoshi. (2012). Purification and characterization of hemolysin from Prevotella oris. Journal of Oral Biosciences. 54. 113–118. 10.1016/j.job.2012.03.002]


8. [https://www.ncbi.nlm.nih.gov/pubmed/20670687 Boyanova L, Kolarov R, Gergova G, Dimitrova L, Mitov I. 2010. Trends in antibiotic resistance in Prevotella species from patients of the University Hospital of Maxillofacial Surgery, Sofia, Bulgaria, in 2003-2009. Anaerobe 16:489-92.]
12. [Tanaka S, Yoshida M, Murakami Y, et al. (2008). "The relationship of Prevotella intermedia, Prevotella nigrescens and Prevotella melaninogenica in the supragingival plaque of children, caries and oral malodor". J Clin Pediatr Dent. 32 (3): 195–200. PMID 18524268. doi:10.17796/jcpd.32.3.vp657177815618l1]


9. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC228842/ Dymock D, Weightman AJ, Scully C, Wade WG. 1996. Molecular analysis of microflora associated with dentoalveolar abscesses. J Clin Microbiol 34:537-42.]
13. [De Filippo, C.; Cavalieri, D.; Di Paola, M.; Ramazzotti, M.; Poullet, J. B.; Massart, S.; Collini, S.; Pieraccini, G.; Lionetti, P. (2010). "Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa". Proceedings of the National Academy of Sciences. 107 (33): 14691–6. PMC 2930426 Freely accessible. PMID 20679230. doi:10.1073/pnas.1005963107]


10. [https://www.ncbi.nlm.nih.gov/pubmed/9573805 Takahashi N, Saito K, Schachtele CF, Yamada T. 1997. Acid tolerance and acid-neutralizing activity of Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum. Oral Microbiol Immunol 12:323-8.]
14. [Nambu, T.; Yamane, K.; Maruyama, H.; Mashimo, C.; Yamanaka, T. (2015). “Complete Genome Sequence of Prevotella intermedia Strain 17-2”. Genome Announcements. 3(4): e00951-15.Published online 2015 Aug 20. doi:  10.1128/genomeA.00951-15]


11. [https://www.ncbi.nlm.nih.gov/pubmed/26261163 Kabeerdoss J, Jayakanthan P, Pugazhendhi S, Ramakrishna BS. 2015. Alterations of mucosal microbiota in the colon of patients with inflammatory bowel disease revealed by real time polymerase chain reaction amplification of 16S ribosomal ribonucleic acid. Indian J Med Res 142:23-32.]


12. [https://www.ncbi.nlm.nih.gov/pubmed/22901468 Chiquette, J., M. J. Allison, and M. Rasmussen. 2012. Use of Prevotella Bryantii 25A and a Commercial Probiotic during Subacute Acidosis Challenge in Midlactation Dairy Cows. Journal of Dairy Science National Institute for Biotechnology.]
<references/>


This page is written by Duncan Keogh for the MICR3004 course, Semester 2, 2017
This page is written by Mostafa Al Yassiry for the MICR3004 course, Semester 2, 2017

Latest revision as of 12:50, 20 October 2017

This student page has not been curated.

Mostafa Al Yassiry Bench C 12/10/2017


Classification

Higher order taxa

Bacteria – Bacteroidetes – Bacteroidia – Bacteroidales – Prevotellaceae – Prevotella

Species

P. Oris

Description and significance

The Prevotella species are commonly found and cultured from the rumen and hindgut of cattle and sheep. In humans, they make for opportunistic pathogens and are known for causing periodontal and tooth problems [1]. In addition, they have also been found to thrive in the vaginal area, and are sometimes also recovered from the anaerobic infections of the respiratory tract including sinusitis, lung abscess, chronic otitis media, aspiration pneumonia and pulmonary empyema. Studying these bacteria would help scientists and researchers understand better the modes of their spread, their activity and the factors that could hamper their growth, which in turn, could possibly help pave the way for research and development of new drugs and medications to deal with the infections it causes.

Genome structure

Prevotella Oris has not been completely sequenced [1]. The only two strains from the Prevotella family that have been completely sequenced are Prevotella intermedia 17 and Prevotella ruminicola 23 [2]. The genome of Prevotella intermedia 1, had a De novo assembly of 127,972 reads averaging a length of 6,598 bp using the Hierarchical Genome Assembly Process (HGAP). This resulted in two closed circular chromosomes of 606,227-bp and 2,131,046-bp in size with average coverages of 194.0× and 214.6×, respectively and had a GC content of 43.5%. 2,510 coding sequences, as well as 61 RNA sequences were identified [3].

Cell structure and metabolism

Prevotella Oris is a gram negative, anaerobic bacterium which has been found to be associated with some major oral and systemic infections. It is a non pigmented bacterium which has been identified through bacterial cultures and lab tests, which are often not usually regarded as a reliable method of detection [1]. This is why, a study conducted in 2007 attempted to develop a PCR assay for the direct detection of the organism [3]. Previous studies have found that P. Oris is able to produce immunoglobulin A protease, hyaluronidase and b-lactamase which possibly point out to the pathogenic nature of the organism. Studies have found that Prevotella makes use of steroid hormones as growth factors, which is why, their occurrence is significantly higher in pregnant women, and is also isolated from women suffering from bacterial vaginosis. It has also been found and isolated from dental infections occurring in individuals suffering from Down’s Syndrome, a chromosome disorder.

Ecology

Prevotella bacteria are gram negative, rod shaped and singular cells that are generally found thriving in anaerobic conditions [5]. Prevotella Oris has been found and isolated from lesions of several oral infections, dentoalveolar abscess [4], endodontic infections and sometimes even from lesions of systemic infections such as meningitis, empyema and cervical spinal epidural abscess. The Prevotella species, particularly Prevotella Oris, requires hemim for their growth and multiplication. They are also found to use two survival mechanisms to thrive. First, they colonize by binding or attaching themselves to other bacteria, which in turn, creates a larger area of infection than the previously infected area. Secondly, it also possesses natural antibiotic resistant genes, which help it survive and colonize. However, an investigation did reveal how the use of hyaluronic acid as a medium could have bacteriostatic effects on the Prevotella species, specifically Prevotella Oris and high molecular weight hyaluronic acid had the maximum impact. An earlier study also attempted to decode the acid tolerance and acid neutralizing activity of this bacteria in oral infections. It was found that Prevotella in general, thrives more under acidic conditions, and during growth, it tends to increase the pH. Studies on acid neutralization also revealed that the Prevotella cells produced succinic and isolvaleric acids which clearly suggests the deamination of amino acids, which in turn, clearly explains how Prevotella survives in both sub gingival and supragingival plaque. Infact, this colonization may also help create an environment in these areas, paving way for Porphyromonas gingivalis, another bacteria, to thrive. Prevotella has also been found to run down in families, not genetically, but through intrafamilial carriage. While it does display signs of antibiotic resistance, it has been found susceptible to clindamycin.

Pathology

Prevotella Oris has been found to be a cause of some major infections including endodontic infection, periodontal disease [7], bacteremia, dentoalveolar abscess, and in some cases, is also found to be largely response for the spread of odontogenic infection. In addition, its presence has also been identified in lesions of systemic infections such as cervical spinal epidural abscess [6], meningitis as well as empyema. The DNA of Prevotella Oris has also been identified and detected in some pus samples taken from individuals suffering from odontogenic infections. Apart from thriving in the oral and vaginal areas, Prevotella has also been recovered from some respiratory tract infections including pneumonia, sinusitis, chronic otitis media, pulmonary empyema and lung abscess [8]. Sometimes, they may also be found in the abscesses and burns near the mouth and in bites, brain abscesses, urinary tract infections and in cases of osteomyelitis. A study focusing on the gut bacteria of children in different regions also revealed that Prevotella was found to make up of 53% of the total gut bacteria present in the children in Africa [13]. It is believed that consumption of a diet rich in carbohydrates and fiber may be linked to increased occurrence of these bacteria. In fact, the gut environment was found to change detectably on the consumption of different types of food in this study, but Prevotella came up more significantly in individuals who consumed a diet rich in carbohydrates. In addition, Prevotella was also found to intensify and exacerbate colitis in mice as per some new study findings [10]. In another study, it was found that Prevotella overgrowth caused a reduction in the growth of lactobacillus in mice, which further led to the onset and development of osteomyelitis in the subjects. Conversely, when the growth of Prevotella was reduced and the growth of lactobacillus was increased, the latter offered protection against osteomyelitis. This study proved to be a clear example of how dietary modifications tend to have a huge impact on the body and gut microflora, which further explains how it could either trigger or suppress certain chronic health conditions, and in this case, osteomyelitis. Another finding also revealed how this bacteria was involved in the progression of carothid atherosclerosis, which further strengthens the studies that have linked poor oral health and the occurrence of dental caries to heart conditions, some of which can be potentially life threatening.

Application to biotechnology

Prevotella Oris has not yet been a part of any major groundbreaking studies or researches revolving around the production of compounds and enzymes. Little is known about its genetic sequence-however, new studies are now highlighting different characteristics associated with it. However, new and new studies are now being carried out to understand and decode its various applications in different fields [12]. A recent study on the Prevotella species derived from humans also compared the gene repertoires of its species derived from different other body sites in humans. This reported an open pan genome which clearly demonstrated a vast diversity of gene pool.

Current research

Since there is not a lot known about Prevotella Oris, new and new studies and research findings are highlighting more and more characteristics of this bacterium which could hopefully prove to be helpful in many ways.A recent study published in the Journal of Oral Biosciences attempted to understand and decode the hemolytic activity of Prevotella Oris. The study revealed important facts about how P. Oris displayed an acceleration in hemolytic activity during its growth phase, and then a decrease in the activity was noted during the stationary phase [11]. These findings could possibly help researchers understand its pathogenic potential in different oral and systemic infections. Another study focused on the development of a PCR assay for the easy detection of Prevotella Oris in clinical samples. This PCR assay would in turn, help provide a specific and reliable detection method for the bacteria. A different research attempted understand the trend of antibiotic resistance in the Prevotella species, including Prevotella Oris. Different strains of Prevotella bacteria were taken into consideration and their resistance to different antibiotics including penicillin, metrodinazole, tetracycline, clindamycin and b-lactamase was tested [10]. These findings would prove to be extremely helpful for medical practitioners and would help them understand and determine the right antibiotic to be used for a particular strain, which could in turn, improve patient outcomes. Another study also focused on understanding antibiotic resistance in different strains of Prevotella bacteria, and the percentage of susceptibility was also calculated. Published in the Dental Research Journal, another finding identified Prevotella species as one of the many bacteria responsible for dental abscesses. This study pointed out that such abscesses respond well to surgical treatments, and antimicrobials can be used to limit the spread of infection. However, it also pointed out that there is a need of good quality clinical trials to be conducted to find out the right treatment. It also highlighted how dental abscesses are poorly discussed in medical history, and if left untreated, they have the potential to progress and transform into major health issues including cavernous sinus thrombosis, septicemia, brain abscess, shock and in some cases may even lead to death. Another recent study found a strong link between Prevotella species thriving in the body, specifically Prevotella Corpi, and an increased risk of the onset of rheumatoid arthritis, an autoimmune disorder that affects millions of people around the globe [9]. It was found that when Prevotella thrives in the gut, it tends to decrease the occurrence of Bacteroides which in turn, leads to a loss in the concentration of healthy and beneficial gut microbes. This in turn, supports the systemic immune response associated with joint inflammation, thereby leading to the onset of rheumatoid arthritis. These findings can turn out to be a huge help for individuals affected by the disease, because the current measures taken to deal with it focus solely on reducing the intensity of symptoms and providing relief from pain. If steps are taken to assess and limit the multiplication of the Prevotella species and a healthy gut environment is maintained, rheumatoid arthritis could be stopped right in its tracks. The antibiotic resistance of Prevotella has proved to be a major setback, and hopefully, further studies will pave the way for development of new targeted drugs to help treat infections occurring due to these bacteria.


References

References examples

1. [Yousefimashouf R, Duerden BI, Eley A, Rawlinson A, Goodwin L. Incidence and distribution of nonpigmented Prevotella species in periodontal pockets before and after periodontal therapy. Microb Ecol Health Dis 1993; 6:35–42]

2. [Riggio MP, Lennon A. Development of a novel PCR assay for detection of Prevotella oris in clinical specimens. FEMS Microbiology Letters 2007; 123-128]

3. [Brito LCN, Teles FR, Teles RP, Franca EC, Ribeiro-Sobrinho AP, Haffajee AD, Socransky SS. Use of multiple-displacement amplification and checkerboard DNA–DNA hybridization to examine the microbiota of endodontic infections. J Clin Microbiol 2007; 45:3039–49]

4. [Dymock D, Weightman AJ, Scully C, Wade WG. Molecular analysis of microflora associated with dentoalveolar abscesses. J Clin Microbiol 1996;34:537–42.]

5. [Civen R, Jousimiessomer H, Marina M, Borenstein L, Shah H, Finegold SM. A retrospective review of cases of anaerobic empyema and update of bacteriology. Clin Infect Dis 1995;20:S224–9]

6. [Frat JP, Godet C, Grollier G, Blanc JL, Robert R. Cervical spinal epidural abscess and meningitis due to Prevotella oris and Peptostreptococcus micros after retropharyngeal surgery. Intensive Care Med 2004;30:1695]

7. [Holdman VL, Moore CEW, Churn JP, Johnson LJ. Bacteroides oris and Bacteroides buccae, new species from human periodontitis and other human infections. Int J Syst Bacteriol 1982;32:125–31]

8. [Holdman VL, Johnson LJ. Description of Bacteroides loesheii sp. nov. and emendation of the descriptions of Bacteroides melaninogenicus (Oliver and Wherry) Roy and Kelly 1939 and Bacteroides denticola Shah and Collins 1981.Int J Syst Bacteriol 1982;32:399–409]

9. [Johnson LJ, Holdman VL. Bacteroides intermedius comb. nov. and descriptions of Bacteroides corporis sp. nov. and Bacteroides levii sp. nov. Int J Syst Bacteriol 1983;33:15–25]

10. [Martinez JL, Delgado-Iribarren A, Baquero F. Mechanisms of iron acquisition and bacterial virulence. FEMS Microbiol Rev 1990;6:45–56]

11. [Sato, Toshiya & Kamaguchi, Arihide & Nakazawa, Futoshi. (2012). Purification and characterization of hemolysin from Prevotella oris. Journal of Oral Biosciences. 54. 113–118. 10.1016/j.job.2012.03.002]

12. [Tanaka S, Yoshida M, Murakami Y, et al. (2008). "The relationship of Prevotella intermedia, Prevotella nigrescens and Prevotella melaninogenica in the supragingival plaque of children, caries and oral malodor". J Clin Pediatr Dent. 32 (3): 195–200. PMID 18524268. doi:10.17796/jcpd.32.3.vp657177815618l1]

13. [De Filippo, C.; Cavalieri, D.; Di Paola, M.; Ramazzotti, M.; Poullet, J. B.; Massart, S.; Collini, S.; Pieraccini, G.; Lionetti, P. (2010). "Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa". Proceedings of the National Academy of Sciences. 107 (33): 14691–6. PMC 2930426 Freely accessible. PMID 20679230. doi:10.1073/pnas.1005963107]

14. [Nambu, T.; Yamane, K.; Maruyama, H.; Mashimo, C.; Yamanaka, T. (2015). “Complete Genome Sequence of Prevotella intermedia Strain 17-2”. Genome Announcements. 3(4): e00951-15.Published online 2015 Aug 20. doi: 10.1128/genomeA.00951-15]


This page is written by Mostafa Al Yassiry for the MICR3004 course, Semester 2, 2017