Philippine Journal of Science
153 (5): 1543-1559, October 2024
ISSN 0031 – 7683
Date Received: 10 Jan 2024
Biodiversity of Aeromonad Myophages: Preliminary Polyphasic Survey of a Collection of A. hydrophila Phages Isolated in the Philippines
Tracey Antaeus D. Gutierrez1,2,4*, Reuel M. Bennett3,4, and Donna May D.C. Papa2,4
1The Graduate School, 2Bacteriophage Ecology, Aquaculture, Therapy, and Systematics (BEATS) Research Group, 3Collections of Microbial Strains, Research Center for the Natural and Applied Sciences, 4Department of Biological Sciences, College of Science, University of Santo Tomas, España, Manila 1015 the Philippines
*Corresponding author: tdgutierrez@ust.edu.ph
Gutierrez TA et al. 2024. Biodiversity of Aeromonad Myophages: Preliminary Polyphasic Survey of a Collection of A. hydrophila Phages Isolated in the Philippines. Philipp J Sci 153(5): 1543–1559.
ABSTRACT
Through a polyphasic approach in classifying bacteriophages, this study determined phenotypic characteristics (stability pH, temperature and saline concentrations, and host range) and genotypic properties using the major capsid gene (g23). Eighteen (18) Aeromonas hydrophila phages (avJB2, avJB3, avJB4, avJB6, avTRAC18, avUSTBG, avSP1, avSP4, avSP5, avSL1, avSL2, av10AA, av10AB, av10BA, av2AA, av2AB, av2AC, and av2BA) previously isolated from different source samples (sewage, lake, pond, and river) were acquired from the Manila, the Philippines, and were initially propagated using the host bacterium, (A. hydrophila BIOTECH 10089). Physiological characterization of phages through stability testing, and host range showed the phages isolated from sewage and polluted river systems exhibited the most stability and polyvalency in infection. Moreover, through these characteristics, the diversity of the phages in the collection was established, resulting in 71% viable phages with varying characteristics. Phylogenetic analysis of g23 sequences, coupled with the phenotypic characteristics of the phages, suggested a highly unique set of phages isolated from four sample types (i.e. sewage, lake, river, and aquaculture pond) that infect A. hydrophila and high similarity in a structural gene sequence, evident in the isolated clustering of these entities when compared with reference phages. The results indicate a widespread distribution of related Aeromonad phages in the country, with phenotypic characteristics that cannot be limited to its environment. Finally, the unique clustering of all 16 Philippine Aeromonad phages –, based on capsid gene (g23) sequences, – suggests a novel group of myophages under the genus Biquartavirus.
Keywords: bioinformatics, marker genes, phage ecology, phage stability