Journal of Vaccines & Vaccination

Characterization of the putative polysaccharide gene cluster in multidrug-resistant E. faecium to develop a targeted therapy (vaccine)

9^th Global Summit and Expo on Vaccines & Vaccination

November 30-December 02, 2015 San Francisco, USA

Liaqat Ali1,2, Türkân Sakinc1 and Hubert E Blum1

1University Medical Center Freiburg, Germany 2Albert-Ludwigs-University of Freiburg,Germany

Scientific Tracks Abstracts: J Vaccines & Vaccin

Abstract:

Enterococcus faecium is an emerging multidrug-resistant nosocomial pathogen increased dramatically worldwide and causing bacteremia, endocarditis, urinary tract and surgical site infections in immunocomprised patients. The capsular polysaccharides that contribute to pathogenesis through evasion of the host innate immune system are also involved in hindering leukocyte killing of enterococci. We identified two putative loci with 22 kbp and 19 kbp which contained 11 genes encoding for glycosyltransferases (GTFs); this was confirmed by using genome comparison of already sequenced strains that has no homology to known capsule genes and the EPA (enterococci polysaccharide antigen) locus. The polysaccharideconjugate vaccines have rapidly emerged as a suitable strategy to combat different pathogenic bacteria, therefore, we investigated a capsular polysaccharide biosynthesis CapD protein in E. faecium contains 336 amino acids and had putative function for N-linked glycosylation. The deletion/knock-out capD mutant was constructed and complemented by homologues recombination method and confirmed by using PCR and sequencing. For further characterization and functional analysis, in-vitro cell culture and in-vivo a mouse infection models were used. Our �?capD mutant shows a strong hydrophobicity and all strains exhibited biofilm production. Subsequently, the opsonic activity was tested in an opsonophagocytic assay which shows increased in mutant compared to complemented and wild-type strains but more than two fold decreased in colonization and adherence was seen on surface of uroepithelial cells. However, a significant higher bacterial colonialization was observed in capD mutant during animal bacteremia infection. Further experiments will be needed to characterize the putative mega capsular polysaccharide gene cluster to clarify its function, exact mechanism and involvement in pathogenesis of enteroccocal nosocomial infections, eventually to develop a vaccine/ or targeted therapy.

Biography :

Liaqat Ali is a PhD student (final year) at University of Freiburg, Germany and undergoing research on human pathogens, (enteroccocal infections, vaccine developement). He has published more then 15 research articles; 5 as a principal author and rest with co-author in reputed peer reviewed journals.

Email: liaqatbiotech@gmail.com