Molecular diversity of Photobacterium damselae ssp. piscicida from cultured amberjacks (Seriola spp.) in Japan by pulsed-field gel electrophoresis and plasmid profiles

Abstract

Aims: This study deals with a pulsed-field gel electrophoresis (PFGE) for discriminating between the genetic variants of Photobacterium damselae ssp. piscicida, and characterizing of Japanese field isolates by PFGE together with plasmid profiles and antimicrobial resistances. Methods and Results: A total of 74 field isolates from cultured Japanese amberjacks were used for PFGE. SmaI and NotI enabled to clearly differentiate strains and we obtained 24 of combined PFGE profiles which were distinct from those of classical Japanese and USA reference strains, and classified them into three groups (Ia-Ic). By plasmid size, we could classify these field isolates into three plasmid types, pA-pC. The predominant PFGE-type Ia was closely associated with plasmid-type pA, and Ib showed a moderate association with pB. Ic was closely associated with pC, and multiresistant isolates were not observed in this type. Whole-genomic variations were also observed between isolates having identical detection areas, fish species and detection-date by PFGE. Conclusion: Molecular diversity of P. damselae ssp. piscicida could be detected by PFGE, and some relations among the PFGE-type, plasmid-type and antimicrobial resistances were observed in Japanese field isolates. Significance and Impact of the Study:This study indicated that some genetic transition might have occurred in P. damselae ssp. piscicida around the Japanese seas, and PFGE can be a valuable tool for the epidemiological study of this highly homogeneous subspecies.

Genotypic diversity, and molecular and pathogenic characterization of Photobacterium damselae subsp. piscicida isolated from different fish species in Taiwan

“…In addition, the genetic heterogeneity of this pathogen was previously described when 18 and 11 digesting patterns were obtained using the same restriction enzymes from 74 Japanese field isolates of Phdp (Kijima‐Tanaka et al, 2007). Interestingly, the PFGE results using SmaI as the restriction enzyme in this study and the study by Kijima‐Tanaka et al (2007) are in contrast to those reported by Lucangeli et al (2000), where all 20 Italian field strains showed an identical profile. This suggests that different observations are dependent on the number of isolates, host diversity or the current situation of a specific geographical area.…”

“…To determine the genetic variants of Phdp isolates in different years (2016–2018), the PFGE method was performed, as described previously (Kijima‐Tanaka et al, 2007) with modification. Briefly, Phdp isolates were cultured on TSN agar and harvested, and the cell suspension was adjusted to an OD 600 of 2 in cell suspension buffer (100 mM Tris–HCl, 100 mM EDTA, pH = 8.0).…”

“…This feature has led to difficulties in studying its epidemiology and infectious agent origins (Lucangeli et al, 2000). Different molecular typing methods have been developed to investigate the diversity and relationships between bacteria, and some approaches have been applied for typing the strains of Phdp , including ribotyping (Magariños et al, 1992); random‐amplified polymorphic DNA (RAPD) analysis (Kawanishi et al, 2006; Magariños, Toranzo, Barja, & Romalde, 2000); amplified fragment length polymorphism (AFLP; Kvitt, Ucko, Colorni, Batargias, & Zlotkin, 2002; Thyssen et al, 2000); and pulsed‐field gel electrophoresis (PFGE; Kijima‐Tanaka, Kawanishi, Fukuda, Suzuki, & Yagyu, 2007; Lucangeli et al, 2000). Among these techniques, PFGE is the most precise, reliable and reproducible tool for giving detailed genotyping analysis of the whole genome of bacteria.…”

Various pAQU plasmids possibly contribute to disseminate tetracycline resistance gene tet(M) among marine bacterial community

“…First, a DNA-containing agar plug of each sample was prepared by the previously reported method (Kijima-Tanaka et al, 2007) with the following modifications. Culture fluid containing about 10 8 cells was put into a 15-ml centrifuge tube and centrifuged at 9,000 rpm for 10 min.…”

Patchy distribution of flexible genetic elements in bacterial populations mediates robustness to environmental uncertainty

“…piscicida isolated from amberjacks ( Seriola spp.) in Japan found that all strains had several plasmids (Kijima‐Tanaka et al , 2007). Even though this locally emerging population showed only subtle genomic differences among strains, the distribution of plasmids was heterogeneous.…”