Adapting nature's ' s own solution: The effect of rhamnolipid and lytic bacteriophage cocktail on enteric pathogens that proliferate in mucilage

The mucilage event witnessed in the Sea of Marmara in 2021 has emerged as a prominent environmental concern, capturing public attention due to its detrimental effects on ecological, economic, and aesthetic dimensions. Addressing the multifaceted impacts of mucilage demands a nature-centric scientific approach, given its global ramifications spanning economy, public health, international relations, and tourism. Consequently, this study sought to explore alternative approaches for the removal of pathogenic enteric bacteria associated with mucilage occurrences, diverging from conventional methodologies. Specifically, the primary objective was to assess the efficacy of rhamnolipid and a bacteriophage cocktail in mitigating the proliferation of enteric pathogens within mucilaginous environments. During the study, 91 phage isolations were obtained from 45 water samples taken and 10 phages were selected for the broad host range and because of the efficacy tests, a phage cocktail was created with 5 phages. It was found that the mixture of rhamnolipid, phage cocktail and rhamnolipid-phage cocktail reduced bacterial load by 7-9 log10, 9-12 log10 and 9-11 log10 respectively under laboratory conditions. When the study was carried out in seawater, reductions of 4-5 log10, 3 log10 and 4 log10 were achieved. This study has shown that the combined use of rhamnolipid, phage cocktail and rhamnolipidphage cocktail can be considered as the most effective natural solution proposal for reducing bacterial load, both in laboratory conditions and in sea surface water.