Could bacteriophages help with managing cholera in The Democratic Republic of Congo (DRC)?

This is the authors' abstract. We don't add key points for this paper.

Background: Cholera is still a public health issue in developing countries. Rehydration and sanitary improvements are the main prevention strategies, though antibiotics could shorten infection-spans. Given antibiotic resistance and the lack of widespread vaccinations, bacteriophage (phage) therapy could be a solution. In the past ten years, more than 60% of reported cholera cases occur in Africa, with the largest percentage in the DRC, where cholera has been endemic since the seventies. Methods & Materials: Phages (47 environmental, 8 clinical specimens, Haiti, 2016) were isolated via plaque purification and spotted against bacterial strains. Titer was normalized to e8, clearings scored based on appearance, and preliminary efficiency of plating (EOP) of the phages was determined. Bacterial strains (n = 56) from the DRC (Lubumbashi, Kinshasa, Uvira and Bukavu) were isolated during 2014-2017; strain O395 (O1/classical) was used as reference. Species confirmation was assessed through MALDI-TOF (Bruker). Strain diversity was determined with rep-PCR fingerprinting (DiversiLabTM, BioMérieux). Antibiogram was performed via (Kirby-Bauer)-diffusion method. Results: MALDI-TOF confirmed 77% of isolates as Vibrio cholerae. Serotypically they were O1, mostly Inaba and exceptionally Ogawa. Bacterial genotyping revealed high similarity (>97%). Antibiogram (n = 19) showed resistance to Cotrimoxazole (95%), Ciprofloxacine (21%), Chloramphenicol (11%), but not to Ampicilline, Cefotaxime and Tetracycline. Lytic spectrum: φ6 lysed 48.8% strains + O395 with medium intensity (score 3: turbid; 4: mostly clear/halo); φ20S and φ20B lysed 4.7% strains + O395 with medium intensity and 95.3% strains with high intensity (scores 5: clear/resistant colonies; 6: clear); φ26S and φ26B lysed 2.3% and 97.7% strains + O395 with medium and high intensity, respectively; φ26P and φ37B lysed 4.7% and 95.3% strains + O395 with medium and high intensity, respectively. Host-range analysis: 5 types of phages seem to be present. Preliminary EOP shows a decrease in the titer of 1 or 2-fold in the hosts compared to the reference strain. Conclusion: Five phages could potentially be used as treatment and biocontrol tools. However, further phenotypic and genomic (sequencing) characterization of bacteria and phages is ongoing. The isolation sites are representative of the DRC area, resulting in a good V. cholerae strain panel for phage (cocktail) testing.