First report of Streptococcus iniae in red porgy (Pagrus pagrus, L.)

Abstract

This work describes the first isolation of Streptococcus iniae in red porgy, Pagrus pagrus (L.), and the first European isolation of this pathogen in gilthead seabream, Sparus aurata (L.). In both farmed fish species, infection resulted in lethargy, anorexia, abnormal swimming, exophthalmia and sudden death, with mortality rates of over 25% in red porgy and 10% in gilthead seabream. Beta-haemolytic Gram-positive cocci, catalase negative and oxidase negative, were isolated in pure culture from internal organs. Conventional and rapid identification systems, and 16S rRNA gene partial sequencing were used to identify the causative agent of the natural disease. LD50 trials were carried out to show the virulence of this isolated strain in these species, with values of 1.7 × 104 CFU per fish in red porgy and 1.32 × 105 CFU per fish in gilthead seabream. The most prominent lesions were meningoencephalitis and multifocal infiltration of macrophage cells in the kidney and spleen.

Fatal bacterial septicemia in a bottlenose dolphin Tursiops truncatus caused by Streptococcus iniae

“…The API 20 Strep test (Zhou et al 2008, El Aamri et al 2010) result was unable to identify the Streptococcus species ( 122: 195-203, 2017 lar identification based on sequencing of the 16S rRNA gene was performed to confirm the bio chemical identification. A polymerase chain reaction-amplified product of the 16S rRNA gene was sequenced, and the sequence obtained was subjected to BLAST analysis against the National Center for Biotechnology Information (NCBI) database.…”

“…A polymerase chain reaction-amplified product of the 16S rRNA gene was sequenced, and the sequence obtained was subjected to BLAST analysis against the National Center for Biotechnology Information (NCBI) database. The 1011 bp fragment showed 100% similarity with sequence AF335572 (type strain NR 025148; El Aamri et al 2010), identifying the isolated strain as S. iniae. …”

“…Aerobic bacterial cultures were obtained from the lung, hilar lymph nodes, liver, pancreas, and digestive tract. A gram-positive coccus was isolated from the hilar lymph nodes and pancreas on blood agar and trypticase soy agar incubated at 25°C for 24 h. The genus of the bacterium was identified using a conventional rapid identification system (API 20 Strep), and the species was verified using 16S rRNA gene partial sequencing (Zhang et al 2000, El Aamri et al 2010) with BLAST analysis. …”

Streptococcus iniae in Gilthead Seabream (Sparus aurata, L.) and Red Porgy (Pagrus pagrus, L.)

“…3 The strain was cultured on trypticase soy agar at 22 C for 24 hours. Bacterial cultures were grown overnight at 22 C in trypticase soy broth (TSB) supplemented with 0.5% (v/v) yeast extract (TSBY) without agitation.…”

“…The first worldwide isolation of S. iniae in cultured red porgy, as well as the first European isolation in gilthead seabream, was reported recently. 3 The strain causing this outbreak, S. iniae IUSA-1, was used in this study to reproduce the disease and scrutinize injuries by TEM analysis in gilthead seabream and red porgy. The lesions are similar in both fish, despite the difference in the rate mortality.…”