1682. An Exciting New Approach: Isolation and characterisation of bacteriophages against MDR Acinetobacter baumannii

Abstract

Abstract Background The modern advances in the fields of Medicine and Surgery depend entirely on our ability to treat and prevent infections. However, the rising incidence of antimicrobial resitance in both community and hospital settings has proved to be increasingly challenging. In 2017, WHO published a list of ‘priority pathogens’; antibiotic-resistant bacteria which posed the greatest threat to human health. Among them, A. baumannii was recognized as a critical priority pathogen due to its significant role in nosocomial infections. There was a growing call for new avenues in antimicrobial therapy. One such endeavour was to revisit an old therapeutic option against MDRO, viz. bacteriophage therapy. Numerous instances of successful phage therapy have already been published, with many more becoming available each day. Methods A total of fifty (50) multidrug resistant isolates of A. baumannii were collected. We attempted to isolate bacteriophages from hospital sewage water, against these collected strains, using standard procedure. Then the host range of the isolated phages were analysed against those 50 collected isolates. The lytic activity was confirmed using spot and plaque assays, following the techniques used by Newase et al, with some modifications. The isolated phages were then purified and stained following methods of Ellis et al, with some modifications, and visualised by a ThermoScientific Talos L120C transmission electron microscope (TEM). Graphical Workflow This depicts the workflow of the study. Created with BioRender.com Results A total of three (3) bacteriophages were isolated from the hospital sewage, and their lytic activity against A. baumannii strains were confirmed by the spot assay which showed clear zones on bacterial lawns. The phages, named vB_AbaS_SRNAIIMS002, vB_AbaS_SRNAIIMS008 and vB_AbaP_SRNAIIMS010, showed central clear zones surrounded by halos, in the plaque assay. Finally, all 3 bacteriophages were visualised by TEM, and two of them had morphology suggestive of siphoviridae family, with long tails, while the third had a short stubby tail, characteristic of the podoviridae family. Conclusion The study concludes that 3 novel bacteriophages were isolated from sewage water, all of which were active against MDR A. baumannii strains. This provides impetus to further research towards phage therapy as a novel therapeutic option against MDROs. Disclosures All Authors: No reported disclosures.