*[1],[2]Olorundare, O. O., [3],4Nnadi, N. E., 1Nimzing, L., 1Ayanbimpe, G. M.
1Department of Medical Microbiology, Faculty of Basic Clinical Science, University of Jos, Plateau State, Nigeria
2Department of Pest Management Technology, Federal College of Forestry, Jos Plateau State Nigeria
3Department of Microbiology, Faculty of Natural and Applied Sciences, Plateau State University, Bokkos, Plateau State, Nigeria
4Centre for Phage Biology and Therapeutics, Jos, Plateau State, Nigeria
*Correspondence to: olufunmilolaolorundare@gmail.com; Tel: +2348069697670
Abstract:
Background: Typhoid fever, caused by antibiotic-resistant Salmonella enterica serovar Typhi (Salmonella Typhi), is a significant public health issue, especially in Nigeria, necessitating exploration of alternative treatment strategies such as the use of bacteriophages. Bacteriophages are viruses that specifically infect and replicate within bacteria and play important roles in medicine. The objective of this study is to isolate and characterize two lytic phages against S. Typhi, assess their stability under various environmental conditions and determine their potentials as biocontrol agents and alternatives to antibiotics for treatment of S. Typhi infections.
Methodology: Salmonella Typhi strains previously isolated from stool samples of patients in Jos, Nigeria, were used. Phages were isolated from hospital and poultry wastewater samples using the double-layer agar method. Phage purification and stock preparation were performed using the double-layer agar overlay technique. Stability was assessed by incubating phages at different temperatures, pH levels, and NaCl concentrations. The DNA of the phages were extracted using the DNeasy Blood and Tissue Kit (Qiagen) and the whole genome was then sequenced using the Illumina NextSeq 500 platform. Bioinformatic analysis was conducted using various computational tools.
Results: Two phages, Jerseyvirus Ijeoma and Apdecimavirus Ayanbimpe, were isolated and characterized. The phages were stable at 4oC-37ᵒC which serves as control and maintained a reasonable titre at 45 and 55ᵒ C. Phages were also stable at 0.5% NaCl and pH 8 for at least one hour. Jerseyvirus Ijeoma, with a genome size of 41,747 bp and 56 coding sequences (CDS), showed 81% similarity to Jerseyvirus SS3e. Apdecimavirus Ayanbimpe, with a genome size of 39,601 bp and 48 CDS, exhibited 83% similarity to Apdecimavirus AP10.
Conclusion: Both phages demonstrated good stability under various abiotic factors, maintaining reasonable titres in alkaline and high-salt conditions and at elevated temperatures. Jerseyvirus Ijeoma and Apdecimavirus Ayanbimpe show potential as biocontrol agents and alternatives to antibiotics for treating S. Typhi infections. Their stability and tolerance to diverse conditions make them suitable candidates for phage therapy.
Keywords: Lytic Phages, Phage Stability, Typhoid fever, Antibiotic resistance, Phage Genome, Salmonella Typhi
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