Isolation and identification of Pseudoalteromonas piscicida strain Cura‐d associated with diseased damselfish (Pomacentridae) eggs

Abstract

Bacteria were isolated from the diseased eggs of two damselfish (Pomacentridae) species, Amphiprion clarkii and Amblyglyphidodon curacao. Healthy A. clarkii eggs were infected separately with four bacterial isolates from the diseased eggs, as well as with Vibrio parahaemolyticus and Listonella anguillarum. Amphiprion clarkii eggs exposed to Cura‐d, an isolate from diseased A. curacao eggs, showed increased mortality compared to uninfected control eggs. The A. curacao eggs were infected separately with the same two isolates from diseased A. curacao eggs, and similarly, eggs exposed to isolate Cura‐d also showed increased mortality compared to uninfected eggs. However, the increase in mortality associated with exposure to isolate Cura‐d was most significant in A. clarkii eggs. A 16S rDNA comparative sequence analysis identified that isolate Cura‐d was most similar to Pseudoalteromonas piscicida, a known fish pathogen. Both Cura‐d and P. piscicida were found to be polarly flagellated, Gram‐negative rods with an oxidative metabolism which grew on d‐mannose, d‐fructose, sucrose and maltose, but not on l‐threonine. Based on these properties, it is proposed that Cura‐d should be classified as P. piscicida strain Cura‐d. It is concluded that the P. piscicida strain cura‐d was associated with the increased mortality observed in A. clarkii eggs.

A potential bacterial biocontrol agent, strain S2V2 against pathogenic marine Vibrio in aquaculture

“…The pathogenic property of pseudoalteromonads to aquatic organisms is little known. P. piscicida Cura-d is pathogenic to eggs of damselfish (Pomacentridae) species, Amphiprion clarkia (Nelson and Ghiorse 1999). Pujalte et al (2007) reported that P. undina U58 is virulent to European sea bass (Dicentrarchus labrax L.), although the virulence is very low (the LD 50 = 1.3 9 10 7 cfu/fish).…”

Molecular determination of oxytetracycline-resistant bacteria and their resistance genes from mariculture environments of China

“…All of the Pseudoalteromonas isolates were found to be psychrotrophic, could be active all the year once they were released into the surrounding coastal environment via water exchange from the mariculture ponds. These multidrug‐resistant psychrotrophic Pseudoalteromonas bacteria might contribute to direct pathogenesis (Nelson and Ghiorse 1999; Ritchie et al . 2000) or the spread of antibiotic resistance among bacterial pathogens in coastal marine environments and nearby mariculture farms.…”

Colonization of rainbow trout, Oncorhynchus mykiss (Walbaum), eggs by Flavobacterium psychrophilum, the causative agent of rainbow trout fry syndrome

“…The mucous layer of eggs appears to be a good substance for adhesion and colonization by many different bacterial species (Nelson & Ghiorse 1999). Fish pathogens can be transmitted via the eggs horizontally through water, or vertically from the broodstock.…”