Novel PhoH-encoding vibriophages with lytic activity against environmental Vibriostrains.

Alice N Maina,Miriam Jumba,Kristopher Kiefts,Ramy K Aziz,Hanzada T Nour El-Din,Francis B Mwaura

doi:10.1007/s00203-021-02511-3

Abstract

Cholera is a devastating diarrheal disease that accounts for more than 10% of children's lives worldwide, but its treatment is hampered by a rise in antibiotic resistance. One promising alternative to antibiotic therapy is the use of bacteriophages to treat antibiotic-resistant cholera infections, and control Vibrio cholera in clinical cases and in the environment, respectively. Here, we report four novel, closely related environmental myoviruses, VP4, VP6, VP18, and VP24, which we isolated from two environmental toxigenic Vibrio cholerae strains from river Kuja and Usenge beach in Kenya. High-throughput sequencing followed by bioinformatics analysis indicated that the genomes of the four bacteriophages have closely related sequences, with sizes of 148,180bp, 148,181bp, 148,179bp, and 148,179bp, and a G + C content of 36.4%. The four genomes carry the phoH gene, which is overrepresented in marine cyanophages. The isolated phages displayed a lytic activity against 15 environmental, as well as one clinical, Vibrio cholerae strains. Thus, these novel lytic vibriophages represent potential biocontrol candidates for water decontamination against pathogenic Vibrio cholerae and ought to be considered for future studies of phage therapy.

Highlights

Acute infectious diarrheal diseases remain among the most frequent causes of childhood deaths, accounting for 10–12% of the death toll in children under five years of age, and around 1.4–1.9 million fatalities worldwide (Levy et al 2016)
Cholera is a devastating diarrheal disease that accounts for more than 10% of children’s lives worldwide, but its treatment is hampered by a rise in antibiotic resistance
We report four novel, closely related environmental myoviruses, VP4, VP6, VP18, and VP24, which we isolated from two environmental toxigenic Vibrio cholerae strains from river Kuja and Usenge beach in Kenya

Summary

Introduction

Acute infectious diarrheal diseases remain among the most frequent causes of childhood deaths, accounting for 10–12% of the death toll in children under five years of age, and around 1.4–1.9 million fatalities worldwide (Levy et al 2016). Cholera is a devastating watery diarrheal disease that causes severe dehydration and death if untreated. It is mainly caused by O1 and O139 toxigenic Vibrio cholerae serotypes. The disease is spread through the faecal-oral route and strongly associated with poverty, poor hygiene, clean water shortage, and lack of adequate sanitation facilities (Deen et al 2020). A combination of antibiotics with rehydration therapy relieves the symptoms of cholera and shortens the disease duration. Environmental drug-resistant V. cholerae strains have been recently reported, hampering the treatment option for cholera and urgently calling for adjunct or alternative approaches (Loo et al 2020), such as bacteriophage therapy

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