Isolation of Shigella specific phages: the accurate diagnostic tool and future target for therapy of Shigella infection
Introduction: Shigellosis, severe diarrheal disease caused by Shigella associated with high morbidity and mortality in both developed and developing countries especially in Bangladesh. Global burden estimates >160 million cases yearly, with most affected being children <5 years. Recently, Shigella sonnei, predominant serotype in developed countries, becoming predominant in developing countries replacing S. flexneri. Aim of study was to isolate and characterize Shigella specific phages as accurate typing and diagnostic tool for better understanding of the actual disease burden due to Shigella infection.
Methods: During February 2006-January 2007; July 2014-December 2015, 180 water samples were collected from 16 different sites (rivers, lakes, canals and ponds) in Dhaka, Bangladesh to isolate Shigella specific phages using standard microbiological methods. Among 142 isolated phages, 85 phages were characterized phenotypically using 57 serotypes of Shigella (n=200) including the atypical and new variants, 69 different serotypes of E. coli (n=132), Salmonella (n=12), Vibrio cholerae O1 (n=1), O139 (n=1) and Yersinia (n=1) used for testing susceptibility to phages. PCR and RFLP were done for extensive characterization.
Results: Four phages specifically lysed strains of S. dysenteriae 3, 6; S. boydii 1 and S. sonnei. One phage, lysed all available serotypes of S. flexneri, S. dysenteriae 1 and S. sonnei, positive for T4 phage capsid gene. Nine and five phages have been found which lysed serotypes of S. flexneri only and combination of S. flexneri and S. sonnei respectively. Mixture of 9 phages lysed all serotypes of Shigella and two phages lysed predominant serotypes of Shigella. The phages didn't lyse other enteric bacteria tested. Most of the phages were different from each other determined by RFLP.
Conclusion: One drop of cocktail phage preparation may be used to diagnose any Shigella whereas commercially available 16 different polyvalent antisera needed to confirm those. Isolated phages may also have therapeutic potential.
Methods: During February 2006-January 2007; July 2014-December 2015, 180 water samples were collected from 16 different sites (rivers, lakes, canals and ponds) in Dhaka, Bangladesh to isolate Shigella specific phages using standard microbiological methods. Among 142 isolated phages, 85 phages were characterized phenotypically using 57 serotypes of Shigella (n=200) including the atypical and new variants, 69 different serotypes of E. coli (n=132), Salmonella (n=12), Vibrio cholerae O1 (n=1), O139 (n=1) and Yersinia (n=1) used for testing susceptibility to phages. PCR and RFLP were done for extensive characterization.
Results: Four phages specifically lysed strains of S. dysenteriae 3, 6; S. boydii 1 and S. sonnei. One phage, lysed all available serotypes of S. flexneri, S. dysenteriae 1 and S. sonnei, positive for T4 phage capsid gene. Nine and five phages have been found which lysed serotypes of S. flexneri only and combination of S. flexneri and S. sonnei respectively. Mixture of 9 phages lysed all serotypes of Shigella and two phages lysed predominant serotypes of Shigella. The phages didn't lyse other enteric bacteria tested. Most of the phages were different from each other determined by RFLP.
Conclusion: One drop of cocktail phage preparation may be used to diagnose any Shigella whereas commercially available 16 different polyvalent antisera needed to confirm those. Isolated phages may also have therapeutic potential.
Reference:
Poster Day 4-T12-Pos-31
Session:
Posters Covering the use of viruses to control infection and Processes governing the applied use of viruses
Presenters:
Mahmuda Akter
Session:
Day 4 Posters Covering: The use of viruses to control infection and Processes governing the applied use of viruses
Presentation type:
Poster presentation
Room:
Poster Halls
Date:
Thursday, 21 July 2016
Time:
12:05 - 15:30