Abstract:
Baseco Beach is a major port in southwestern Luzon in Manila Bay and is associated with
many anthropogenic activities (Sotto et al., 2015). In 2019, putative Vibrio species were
isolated from Baseco Beach, Manila Bay (Tesoro et al., 2019) and this study through 16S
rRNA sequencing, confirmed one of the five isolates (W4), isolated from seawater, to be
Vibrio parahaemolyticus following Basic Local Alignment Search Tool
(BLAST). Phylogenetic analysis using the 16S rRNA sequence of V. parahaemolyticus
W4, was done using the software MEGAX with existing V. parahaemolyticus, V. fluvialis,
and V. cholerae strains from the National Center for Biotechnology Information (NCBI)
as reference strains. V. parahaemolyticus W4 formed a clade with V. parahaemolyticus
MF372385.1 (Vp9), FM204867.1 (Vp3), and FM204866.1 (Vp4), with V.
parahaemolyticus MF372385.1 being the closest. Based on existing literature, V.
parahaemolyticus Vp9 is an AHPND-positive strain, possessing the pirA virulence gene.
Meanwhile, V. parahaemolyticus Vp3 contains toxR, tlh, and alt genes, and V.
parahaemolyticus Vp4 contains toxR, tlh, and tdh genes. Interestingly, published studies
found that W4, Vp9 and Vp3 were all resistant to ampicillin. Although the three closest V.
parahaemolyticus strains to isolate W4 possessed virulence and antibiotic resistance genes
(ARG), further genomic analysis on W4 is still needed since these genes can be passed
through horizontal gene transfer (HGT). To our knowledge, this is the first study to have
phylogenetically analyzed a putative V. parahaemolyticus isolate from Baseco Beach,
Manila Bay with that of existing data elucidating on the possible public health concern
possessed by this isolate. It is recommended to further assess the growth physiology and
determine the presence of other ARG and virulence genes through molecular biology
techniques such as Polymerase Chain Reaction (PCR).
