Isolation and characterization of novel lytic bacteriophages against (fluoro)quinolone-resistant Campylobacter strains

Antimicrobial resistance (AMR) has become a global public health concern, particularly in developing countries where antibiotics are often overused and misused. In Bolivia, the indiscriminate use of antibiotics, including (fluoro-)quinolones, has led to the proliferation of multidrug-resistant (MDR) <i>Campylobacter</i> spp., increasing the risk of resistance gene dissemination to other bacteria, and further deepening the AMR problem. To help mitigate the proliferation of MDR bacteria, bacteriophages can be a valuable complementary treatment to antibiotics. In the present study, we isolated and characterized three novel lytic bacteriophages with activity against (fluoro-)quinolone-resistant <i>Campylobacter</i> isolates and <i>C. jejuni</i> strains. The isolated bacteriophages, BMBo_CjP_006, BMBo_CjP_007, and BMBo_CjP_009, belong to the class <i>Caudoviricetes</i> and possess a linear double-stranded DNA genome. Their genome size ranges from 59 to 77 kb, with a GC-content between 42 to 46%. The 90, 144, and 146 predicted coding sequences (CDSs) of the different bacteriophages did not encode any antibiotic resistance, virulence, or lysogenic-associated genes, confirming their genetic safety and lytic nature. The isolated bacteriophages showed a narrow host range and lytic activity against nine (fluoro-)quinolone-resistant <i>Campylobacter</i> spp., including <i>C. jejuni,</i> with lytic activity varying at MOIs from 0.1 to 100, dependent on bacteriophage and host isolate. In addition, the bacteriophages were stable across a pH range of 4 to 10 and a temperature range of -20 °C to 70 °C. These characteristics make them promising for biotechnological applications due to their lytic activity, lack of resistance and virulence genes, and potential utility for product preservation.