Prevotella jejuni

From MicrobeWiki, the student-edited microbiology resource
Revision as of 21:11, 12 March 2014 by Marisa.crommett (talk | contribs) (Current Research on Pathogenicity and Celiac Disease)
Jump to: navigation, search
This student page has not been curated.

Classification

Higher order taxa

Bacteria; Bacteroidetes; Bacteroidetes (phylum); Bacteroidetes (class); Bacteroidales (order); Prevotellaceae (family); Prevotella (genus)

Prevotella

The genus Prevotella was named after the French microbiologist A. R. Prévot, a pioneer in anaerobic microbiology. Formerly classified within the genus Bacteroides, the species of Prevotella represent a group of unique phenotypic and phylogenetic qualities that can be readily distinguished from genus Bacteriodes. For example, unlike Bacteroides, Prevotella are sensitive to bile, moderately saccharolytic and lack the enzyme of the pentose phosphate pathway-hexose monophosphate shunt [4]. Prevotella are characterized as gram-negative, obligately anaerobic, nonsporeforming, nonmotile, rods. Members of this genus are typically isolated from the oral cavity, upper respiratory and urogenital tract [3]. The type species of the genus is Prevotella melaninogenica.

Prevotella jejuni

Prevotella jejuni. je.ju′ni. L. gen. n. jejuni of or from the jejunum, referring to the isolation of the type strain from the jejunum. Jejunum is the mid section of the small intestine. Cells are obligately anaerobic, non-motile, Gram-stain-negative bacilli (0.7×0.8–2 µm in size).The optimum conditions for growth are 37 °C and pH 6–7. Compared with other species in Prevotella, such as the type species Prevotella melaninogenica, Prevotella jejuni uniquely was isolated from the human epithelial cells of the small intestine. The typical Prevotella habitat in the human body is the oral cavity. Other habitats or sources for isolation include feces, female genital tract, respiratory tract and from the rumen and hindgut of non-human mammals [3].

Phylogenetic analysis based on comparative 16S rRNA gene sequence analysis revealed close relationships between CD3 : 27, CD3 : 28T and CD3 : 33, between CD3 : 32 and Prevotella histicola CCUG 55407T, and between CD3 : 34 and Prevotella melaninogenica CCUG 4944BT [3].

Description and significance

Habitat

Prevotella jejuni was isolated from the epithelial cells of the human small intestine of a child with celiac disease. Another microbe typically found there includes, campylobacter jejuni, also named after the jejunum of the small intestine. Campylobacter jejuni is considered a pathogen that invades the human epithelial cells, rather than an inhabitant like Prevotella jejuni. Unlike P. jejuni, C.jejuni relies on motility, through use of its flagella, during the course of infection. C. jejuni is also recognized as a leading cause of gastroenteritis [1].

Current Research on Pathogenicity and Celiac Disease

Generally considered nonpathogenic or opportunistic pathogens, species of Prevotella have been associated with serious infections. Strains of other species have demonstrated virulence factors such as hemolysins, hemagglutinins, fimbrial adhesins, proteases and phospholipases [4]. Until now, no species of genus Prevotella has been characterized from the human small intestine. The new taxa study focuses on the isolation of the bacteria from the small intestine of a child with celiac disease (CD), and discusses its potential pathogenicity related to that disease. The purpose of the study is to further study the microbiota of the small intestine of children with CD, especially those born during first epidemic in Sweden [1]. The jejunal microbiota is considered to play a role in the pathogenesis of CD as CD is associated with bacterial overgrowth of the small intestine, which can worsen malabsorption or cause malabsorption despite adherence to treatment [3]. Rod-shaped bacteria constituted a significant fraction of the proximal small intestine microbiota in children born during the Swedish CD epidemic and may have been an important risk factor for CD contributing to the fourfold increase in disease incidence in children below 2 years of age during that time [3]. From this study, the indicated species of rod-shaped bacteria of the microbiotas were from the genuses: Clostridium, Prevotella, and Actinomyces. Additionally, bacteria of all three of these genera were isolated from children born during the Swedish CD epidemic and new Prevotella species were tentatively identified.

Additional studies suggest that the genus Prevotella may contribute to cystic fibrosis, the most common lethal genetic disorder in Caucasians in the U.S. where airway infection accounts for 90% of morbidity and mortality observed in CF patients [2].

References

1. Buelow, Daelynn R., Jeffrey E. Christensen, Jason M. Neal-Mckinney, and Michael E. Konkel. "Campylobacter Jejuni Survival within Human Epithelial Cells Is Enhanced by the Secreted Protein CiaI." Molecular Microbiology 80.5 (2011): 1296-312.

2. Gangwei O, Hedberg M, Hammarström S, et al. Proximal Small Intestinal Microbiota and Identification of Rod-Shaped Bacteria Associated With Childhood Celiac Disease. American Journal Of Gastroenterology [serial online]. December 2009;104(12):3058-3067. Available from: Academic Search Complete, Ipswich, MA. Accessed March 10, 2014.

3. Hedberg, M. E., A. Israelsson, E. R. B. Moore, L. Svensson-Stadler, S. N. Wai, G. Pietz, O. Sandstrom, O. Hernell, M.-L. Hammarstrom, and S. Hammarstrom. "Prevotella Jejuni Sp. Nov., Isolated from the Small Intestine of a Child with Coeliac Disease." International Journal Of Systematic And Evolutionary Microbiology 63.Pt 11 (2013): 4218-223.

4. Shah, H. N., and D. M. Collins. "NOTES: Prevotella, a New Genus To Include Bacteroides Melaninogenicus and Related Species Formerly Classified in the Genus Bacteroides." International Journal of Systematic Bacteriology 40.2 (1990): 205-08.

5. Tursi A, Brandimarte G, Giorgetti G (2003). "High prevalence of small intestinal bacterial overgrowth in celiac patients with persistence of gastrointestinal symptoms after gluten withdrawal". Am J Gastroenterol 98 (4): 839–43. doi:10.1111/j.1572-0241.2003.07379.x. PMID 12738465.

Edited by Marisa Crommett, student of Rachel Larsen at the University of Southern Maine