Pathogenic effects of Vibrio alginolyticus on larvae and postlarvae of the red abalone Haliotis rufescens (original) (raw)
Related papers
Aquaculture Research, 2006
Outbreaks of serious mortality among cultured juvenile cobia Rachycentron canadum L. (weighing 8-10 g) characterized by lethargy, dark skin and ascites in the peritoneal cavity while some fish possessing damaged eyes occurred in July and August of 2001 in Taiwan. Fifteen motile bacterial strains were isolated from head kidney and/or the ascites on tryptic soy agar supplemented with 1% NaCl (TSA1) and/or thiosulphate citrate bile salt (TCBS) sucrose agar plates during the two outbreaks. All the isolates were characterized and identified as Vibrio alginolyticus on the basis of biochemical characteristics, and comparisons with those of the reference strain V. alginolyticus ATCC 17749. The strain C3c01 (a representative of the 15 similar field isolates), was virulent to the cobia with an LD50 value of 3.28 × 10 4 colony forming units/g fish body weight. All the moribund/dead fish exhibited lethargy, dark skin and ascites in the peritoneal cavity as that observed in natural outbreaks. The same bacteria could be reisolated from kidney and the ascites of fish after bacterial challenge using TSA1 and TCBS plates. The results reveal that V. alginolyticus is an infectious agent of vibriosis in the cobia.
Diseases of Aquatic Organisms, 2002
The susceptibility of 7 d old veliger larvae of the scallops Argopecten ventricosus and Nodipecten subnodosus, the penshell Atrina maura, and the Pacific oyster Crassostrea gigas to a pathogenic strain of Vibrio alginolyticus was investigated by challenging the larvae with different bacterial concentrations in a semi-static assay. The results indicate that the larvae of the 2 scallop species are more susceptible to the V. alginolyticus strain than those of the oyster and the penshell. Signs of the disease were similar to bacillary necrosis described in previous work. Interspecies differences in susceptibility to pathogens are discussed.
Applied and environmental microbiology, 2014
Vibrio harveyi is a marine bacterial pathogen responsible for episodic epidemics generally associated with massive mortalities in many marine organisms, including the European abalone Haliotis tuberculata. The aim of this study was to identify the portal of entry and the dynamics of infection of V. harveyi in the European abalone. The results indicate that the duration of contact between V. harveyi and the European abalone influences the mortality rate and precocity. Immediately after contact, the epithelial and mucosal area situated between the gills and the hypobranchial gland was colonized by V. harveyi. Real-time PCR analyses and culture quantification of a green fluorescent protein-tagged strain of V. harveyi in abalone tissues revealed a high density of bacteria adhering to and then penetrating the whole gill-hypobranchial gland tissue after 1 h of contact. V. harveyi was also detected in the hemolymph of a significant number of European abalones after 3 h of contact. In concl...
Vibrio carchariae, a pathogen of the abalone Haliotis tuberculata
Diseases of Aquatic Organisms, 2002
Since 1997, mass mortality of the abalone Haliotis tuberculata L. has occurred in the natural environment along the French coast. The outbreak of disease started on the south coast of Brittany near Concarneau in 1997, then spread to the north of Brittany (in 1998) and the west coast of Normandy (Golfe de St. Malo in 1999). Between 60 and 80% of the abalone died. In 1999, mortality also affected a land-based abalone farm in Normandy during the summer. At this farm, a Vibrio sp. was isolated in abundance from abalone that had just died. The disease was experimentally reproduced by inoculation or by introducing the pathogen into the surrounding water. This vibrio, identified by genotypic and phenotypic characters, is related to V. carchariae. It is similar to the V. carchariae, responsible for mortality in the Japanese abalone Sulculus diversicolor supratexta, but some phenotypic characters differentiate both strains. In 2000, healthy abalone placed in 2 sites on the north and south coasts of Brittany died, and the pathogen V. carchariae could be isolated from dead individuals, demonstrating that the pathogen was probably the cause of the abalone disease that has been occurring since 1997 in Brittany.
Applied and Environmental Microbiology, 2005
Two episodes of mortality of cultured carpet shell clams (Ruditapes decussatus) associated with bacterial infections were recorded during 2001 and 2002 in a commercial hatchery located in Spain. Vibrio alginolyticus was isolated as the primary organism from moribund clam larvae that were obtained during the two separate events. Vibrio splendidus biovar II, in addition to V. alginolyticus, was isolated as a result of a mixed Vibrio infection from moribund clam larvae obtained from the second mortality event. The larval mortality rates for these events were 62 and 73%, respectively. Mortality was also detected in spat. To our knowledge, this is the fist time that these bacterial species have been associated with larval and juvenile carpet shell clam mortality. The bacterial strains were identified by morphological and biochemical techniques and also by PCR and sequencing of a conserved region of the 16S rRNA gene. In both cases bacteria isolated in pure culture were inoculated into spat of carpet shell clams by intravalvar injection and by immersion. The mortality was attributed to the inoculated strains, since the bacteria were obtained in pure culture from the soft tissues of experimentally infected clams. V. alginolyticus TA15 and V. splendidus biovar II strain TA2 caused similar histological lesions that affected mainly the mantle, the velum, and the connective tissue of infected organisms. The general enzymatic activity of both live cells and extracellular products (ECPs), as evaluated by the API ZYM system, revealed that whole bacterial cells showed greater enzymatic activity than ECPs and that the activity of most enzymes ceased after heat treatment (100°C for 10 min). Both strain TA15 and strain TA2 produced hydroxamate siderophores, although the activity was greater in strain TA15. ECPs from both bacterial species at high concentrations, as well as viable bacteria, caused significant reductions in hemocyte survival after 4 h of incubation, whereas no significant differences in viability were observed during incubation with heat-killed bacteria.
Aquaculture studies, 2023
Due to their distinctive look, seahorses are famous in the aquarium trade and traded worldwide for their alleged therapeutic benefits. The present study was conducted to identify the causative agents for larval mortality of Hippocampus kuda and to find a treatment to reduce larval mortality at an ornamental fish hatchery in Sri Lanka. Bacteria causing vibriosis in H. kuda larvae were isolated and identified using morphological and biochemical tests. The disc diffusion method was used with 30 µg of chloramphenicol, streptomycin, tetracycline and ampicillin to evaluate antibiotic susceptibility of isolated bacteria. As pathogenic vibrios were more sensitive to tetracycline, the experimentally infected H. kuda larvae were exposed to 20-50 µg/L tetracycline for 30 days. V. alginolyticus, Vibrio splendidus, V. parahaemolyticus, V. mimicus, Aeromonas hydrophila and Plesiomonas shigelloides were found in H. kuda larvae, while V. alginolyticus and V. splendidus were encountered repeatedly. V. alginolyticus, V. mimicus, V. fluvialis, Aeromonas sp., Micrococcus spp., M. leteus and Bacillus circulans were identified from the larval culture water. V. alginolyticus was sensitive to chloramphenicol and tetracycline, while V. splendidus was sensitive to tetracycline. Tetracycline, 30 mg/L as a bath treatment, effectively treats vibriosis in larval rearing tanks of H. kuda.
Microbial Ecology, 1998
Six-day-old larvae of the catarina scallop, Argopecten ventricosus (=circularis), were infected with different concentrations of Vibrio alginolyticus to determine virulence and to describe vibriosis in this species. The development of vibriosis was compared to the effect of the supernatant of a 24-h V. alginolyticus culture. An experimental larvae culture system (ELCS) yielded a maximum survival of 80% from the 6th to the 19th day (control and low concentrations of V. alginolyticus). No effect was shown with concentrations of V. alginolyticus below 0.5 × 10 5 CFU ml −1 . At concentrations higher than 5.0 × 10 5 CFU ml −1 , swimming depletion, empty stomachs, lipidic granules in the digestive system, velum degradation, and massive mortality were observed. The supernatant of V.
Veterinary Research
Severe economic losses due to diseases in marine larviculture may be linked to vibriosis. To better understand the pathogenesis of vibriosis and evaluate new ways to prevent and combat this important disease, there is a great need for reliable and reproducible experimental infection models. The present study aimed at developing a challenge model for vibriosis in Dover sole larvae and testing its applicability to study the effect of the probiotic treatment. For that purpose, larvae were challenged at 10 days post hatching with Vibrio anguillarum WT, V. anguillarum HI610 or V. harveyi WT. Following administration of V. anguillarum WT via immersion at 1 × 10 7 colony forming units/mL, a larval mortality of 50% was observed at 17 days post-inoculation. In a next step, the probiotic potential of 371 isolates retrieved from Dover sole was assessed by screening for their inhibitory effects against Vibrio spp. and absence of haemolytic activity. One remaining isolate (V. proteolyticus) and V. lentus, known for its protective characteristics in seabass larvae, were further tested in vivo by means of the pinpointed experimental infection model. Neither isolate provided via the water or feed proved to be protective for the Dover sole larvae against challenge with V. anguillarum WT. This developed challenge model constitutes a firm basis to expedite basic and applied research regarding the pathogenesis and treatment of vibriosis as well as for studying the impact of (a)biotic components on larval health.