Biocontrol of multi-drug resistant pathogenic bacteria in drainage water by locally isolated bacteriophage

In areas with limited water resources, the reuse of treated drainage water for non-potable purposes is increasingly recognised as a valuable and sustainable water resource. Numerous pathogenic bacteria found in drainage water have a detrimental impact on public health. The emergence of antibiotic-resistant bacteria and the current worldwide delay in the production of new antibiotics may make the issue of this microbial water pollution even more challenging. This challenge aided the resumption of phage treatment to address this alarming issue. In this study, strains of Escherichia coli and Pseudomonas aeruginosa and their phages were isolated from drainage and surface water from Bahr El-Baqar and El-Manzala Lake in Damietta governorate, Egypt. Bacterial strains were identified by microscopical and biochemical examinations which were confirmed by 16 S rDNA sequencing. The susceptibility of these bacteria to several antibiotics revealed that most of the isolates had multiple antibiotic resistances (MAR). The calculated MAR index values (> 0.25) categorized study sites as potentially hazardous to health. Lytic bacteriophages against these multidrug-resistant strains of E. coli and P. aeruginosa were isolated and characterized. The isolated phages were found to be pH and heat stable and were all members of the Caudovirales order as recognized by the electron microscope. They infect 88.9% of E. coli strains and 100% of P. aeruginosa strains examined. Under laboratory conditions, the use of a phage cocktail resulted in a considerable reduction in bacterial growth. The removal efficiency (%) for E. coli and P. aeruginosa colonies increased with time and maximized at 24 h revealing a nearly 100% reduction after incubation with the phage mixture. The study candidates new phages for detecting and controlling other bacterial pathogens of public health concern to limit water pollution and maintain adequate hygiene.