Novel bacteriophage therapy for controlling metallo-beta-lactamase producing Pseudomonas aeruginosa infection in Catfish

Background: The bacteriophage therapy is an effective antimicrobial approach with potentially important applications in medicine and biotechnology which can be seen as an additional string in the bow. Emerging drug resistant bacteria in aquaculture industry due to unrestricted use of antibiotics warrants more sustainable and environmental friendly strategies for controlling fish infections. The isolated bacteria from fish lesions was characterised based on isolation on selective and differential medium like Pseudomonas agar, gram staining, biochemical tests and 16SrRNA sequencing. The metallo-beta-lactamase (MBL) producing bacterial isolate was evaluated using Imipenem - Ethylenediaminetetraacetic acid (EDTA) disk method. The specific bacteriophage was isolated and concentrated using coal bed developed in our lab at CSIR-NEERI. The isolated and enriched bacteriophage was characterised by nucleotide sequencing and electron microscopy. The phage therapy was applied for treating ulcerative lesion in fish. Results: The pathogenic bacterium responsible for causing ulcerative lesions in catfish species (Clarias gariepinus) was identified as Pseudomonas aeruginosa. One out of twenty P. aeruginosa isolate showing multi drug resistance (MDR) was incidentally found to be MBL producing as determined by Imipenem-EDTA disk method. The phage therapy effectively cured the ulcerative lesions of the infected fish in 8–10 days of treatment, with a sevenfold reduction of the lesion with untreated infection control. Conclusion: Bacteriophage therapy can have potential applications soon as an alternative or as a complement to antibiotic treatment in the aquaculture. We present bacteriophage therapy as a treatment method for controlling MDR P. aeruginosa infection in C. gariepinus. To the best of our knowledge this is a first report of application of phage therapy against MBL producing P. aeruginosa isolated from aquatic ecosystem. Keywords: P. aeruginosa, Multi drug resistance, Metallo-β-lactamase, Bacteriophage therapy, Catfis

Increasing the extraction efficiency of algal lipid for biodiesel production: Novel application of algal viruses

Various studies have been conducted recently using microalgal system for the production of algal lipid for biodiesel production. This study aimed at increasing the extraction efficiency of algal lipid from Chlorella sp. by the application of Chlorella viruses. The calorific value of lipid from Chlorella sp. has been reported to be higher than that of fresh water microalgae, making it a potential candidate to be used as biofuel. This is the first report on novel application of microalgal viruses for improving the extraction efficiency of algal lipid for biodiesel production through viral lysis of Chlorella vulgaris. The algal lipid extraction efficiency, increased by 11.68% in the case of Chlorella virus treated C. vulgaris when compared with Chlorella virus untreated C. vulgaris. The application of Chlorella virus and the viral encoded lytic enzymes for increasing the extraction efficiency of algal lipid will be helpful in optimizing algal biofuel industry in the future.Keywords: Micro-algal system, biodiesel, algal lipid, Chlorella viruses, viral lysis.African Journal of Biotechnology, Vol 13(15), 1666-167