Remote Dielectric Sensing Before and After Discharge in Patients With ADHF: The ReDS-SAFE HF Trial.

BACKGROUND: Incomplete treatment of congestion often leads to worsening heart failure (HF). The remote dielectric sensing (ReDS) system is an electromagnetic energy-based technology that accurately quantifies changes in lung fluid concentration noninvasively. OBJECTIVES: This study sought to assess whether an ReDS-guided strategy during acutely decompensated HF hospitalization is superior to routine care for improving outcomes at 1 month postdischarge. METHODS: ReDS-SAFE HF (Use of ReDS for a SAFE discharge in patients with acute Heart Failure) was an investigator-initiated, multicenter, single-blind, randomized, proof-of-concept trial in which 100 patients were randomized to a routine care strategy, with discharge criteria based on current clinical practice, or an ReDS-guided decongestion strategy, with discharge criteria requiring an ReDS value of ≤35%. ReDS measurements were performed daily and at a 7-day follow-up visit, with patients and treating physicians in the routine care arm blinded to the results. The primary outcome was a composite of unplanned visits for HF, HF rehospitalization, or death at 1 month after discharge. RESULTS: The mean age was 67 ± 14 years, and 74% were male. On admission, left ventricular ejection fraction was 37% ± 16%, and B-type natriuretic peptide was 940 pg/L (Q1-Q3: 529-1,665 pg/L). The primary endpoint occurred in 10 (20%) patients in the routine care group and 1 (2%) in the ReDS-guided strategy group (log-rank P = 0.005). The ReDS-guided strategy group experienced a lower event rate, with an HR of 0.094 (95% CI: 0.012-0.731; P = 0.003), and a number of patients needed to treat of 6 to avoid an event (95% CI: 3-17), mainly resulting from a decrease in HF readmissions. The median length of stay was 2 days longer in the ReDS-guided group vs the routine care group (8 vs 6; P = 0.203). CONCLUSIONS: A ReDS-guided strategy to treat congestion improved 1-month prognosis postdischarge in this proof-of-concept study, mainly because of a decrease of the number of HF readmissions. (Use of ReDS for a SAFE discharge in patients with acute Heart Failure [ReDS-SAFE HF]; NCT04305717).

Estresores académicos y sintomatología depresiva en mujeres universitarias económicamente vulnerables durante la pandemia por COVID-19 / Academic stressors and depressive symptomatology among economically vulnerable college women during the COVID-19 pandemic

Resumen Antecedentes Las mujeres universitarias socioeconómicamente vulnerables son un grupo de riesgo para desarrollar problemas de salud mental durante la pandemia por COVID-19, encontrándose que la regulación emocional y factores de apoyo docente pueden moderar este efecto. Objetivo Evaluar un modelo de moderación moderada del apoyo docente sobre las estrategias de regulación emocional (ERE) en la relación entre estresores académicos y sintomatología depresiva en universitarias socioeconómicamente vulnerables. Método 371 mujeres entre 18 y 29 años que cursaban estudios superiores completaron una encuesta donde se evaluó la sintomatología depresiva a través del PHQ-9 y las ERE mediante el CERQ. Para evaluar los estresores académicos y percepción del apoyo docente, se diseñaron preguntas específicas. Resultados Se identificaron dos modelos de efectos indirectos que mostraron que un bajo apoyo docente moderó la moderación de niveles bajos y medios de la estrategia de regulación de planificación en la relación entre los estresores académicos "calidad de aprendizaje online" y "preocupación por el rendimiento académico" con la sintomatología depresiva. Conclusiones Se discute sobre el rol de estrategias de regulación emocional que apuntan a aspectos metacognitivos y apoyo docente como factores protectores para este grupo específico frente a los estresores académicos, principalmente ligados al rendimiento académico.

Abstract Background female university students from socioeconomically vulnerable groups is a high-risk group for the development of mental health problems in the covid-19 pandemic. Objective To evaluate the moderating role of teacher support on emotional regulation strategies (ERS) in the relationship between academic stressors (AS) and depressive symptoms in female university students from socioeconomically vulnerable groups. Method 371 women between 18 and 29 years old who were in higher education completed a survey where depressive symptoms were evaluated through the PHQ-9 and the ERD through CERQ. To assess academic stressors and perception of teacher support, specific questions were designed. Results Two indirect effect models were identified that showed that low teacher support moderated the moderation of low and medium levels of ERS planning in the relationship of "quality of online learning" and "concern for academic performance" with depressive symptoms. Conclusions The role of ERS that points to metacognitive aspects and teaching support as protective factors for this specific group against AS, mainly linked to academic performance is discussed at the end.

Draft Genome Sequences of Five Vibrio neptunius Strains Isolated from Hatcheries of Bivalve Mollusks.

Vibrio neptunius is a Gram-negative bacterium that has been shown to cause disease in marine bivalve mollusk larvae. Here, we report the draft genome sequences and annotations of five V. neptunius strains isolated from larvae of European oyster (Ostrea edulis) and Manila clam (Ruditapes philippinarum) at hatcheries in Galicia, northwest Spain.

Draft Genome Sequence of Vibrio ostreicida Strain PP-203, the Type Strain of a Pathogen That Infects Bivalve Larvae.

Vibrio ostreicida is a Gram-negative gammaproteobacterium that has been shown to cause disease in bivalve larvae. Presented here is the draft genome of the type strain Vibrio ostreicida strain PP-203, which was isolated from the inner surface of an Ostrea edulis (European flat oyster) spat container with recorded deaths at a hatchery in Galicia, Spain.

Encapsulation of live marine bacteria for use in aquaculture facilities and process evaluation using response surface methodology.

New strategies are being proposed in marine aquaculture to use marine bacteria as alternative to antibiotics, as nutritional additive or as immune-stimulant. These approaches are particularly promising for larval and juvenile cultures. In many cases, the bacteria are released in the seawater, where they have to be at appropriate concentrations. In addition, only low-cost technologies are sustainable for this industry, without any complex requirements for use or storage. In this work, we explore the possibilities of preservation of a potential marine probiotic bacterium (Phaeobacter PP-154) as a product suitable for use in marine aquaculture by addition to the seawater. A method which guaranteed the preservation of the viable marine bacteria in a saline medium and their rapid release in the seawater was searched for. In a previous step, classical procedures (freeze-drying and freezing) had been explored, but undesirable results of the interaction of the products obtained with natural seawater led to investigate alternatives. We report the results of the immobilization of the marine bacteria in calcium alginate beads. The final product complies the salinity which allows the requirements of the bacteria without interference with alginate in the formation of beads, and a balanced hardness to retain the bacteria and to be easily released in the marine aquaculture environment. The process was evaluated using the central composite rotatable design (CCRD), a standard response surface methodology (RSM).

Safety of sacubitril/valsartan initiated during hospitalization: data from a non-selected cohort.

AIMS: Sacubitril/valsartan is safe when initiated during hospitalization in a clinical trial setting. Its safety in real-life population is not stablished. We compared the initiation of sacubitril/valsartan during hospitalization in a non-selected population, in the PIONEER-HF trial, and in non-selected outpatients. METHODS AND RESULTS: Multicentre registry included 527 patients: 100 were started on sacubitril/valsartan during hospitalization (19.0%) and 427 as outpatients (81.0%). Compared with those in the pivotal trial, inpatients in our cohort were older (71 ± 12 vs. 61 ± 14 years; P < 0.001); had more frequently Functional Class II (41 [41.0%] vs. 100 [22.7%]; P < 0.001), higher levels of N-terminal pro-B type natriuretic peptide (4044 [1630-8680] vs. 2013 [1002-4132] pg/mL; P < 0.001), better glomerular filtration rate (63.5 [51.0-80.0] vs. 58.4 [47.5-71.5] mL/min; P = 0.01), and higher systolic blood pressure (121 [110-136] vs. 118 [110-133] mmHg; P = 0.03); and received angiotensin-converting enzyme inhibitors/angiotensin receptor blockers more frequently (92 [92.0%] vs. 208 [52.7%]; P < 0.001). Compared with non-selected outpatients, inpatients were older (71 ± 12 vs. 68 ± 12 years, P = 0.02), had more frequent Functional Class III-IV (58 [58.0%] vs. 129 [30.3%], P < 0.001), had higher levels of N-terminal pro-B type natriuretic peptide (4044 [1630-8680] vs. 2182 [1134-4172]; P < 0.001), and were receiving angiotensin-converting enzyme inhibitors/angiotensin receptor blockers target dose less frequently (55 [55.0%] vs. 335 [78.5%]; P < 0.001). They also started sacubitril/valsartan with a low dose (50 mg/12 h) more frequently (80 [80.0%] vs. 209 [48.8%], P < 0.001). The initiation of sacubitril/valsartan in outpatients was an independent predictor of high-dose use (OR 3.1; 95% confidence interval 1.7-5.6, P < 0.001). The follow-up time in both cohorts, including all patients enrolled, was similar (7.0 ± 0.1 vs. 7.2 ± 2.6 months, P = 0.72). All-cause admissions during follow-up were more frequent in inpatients (30 [30.0%] vs. 68 outpatients [15.9%], P = 0.001), with no relevant differences in all-cause mortality. There was no significant difference in sacubitril/valsartan withdrawal rate (17 inpatients [17.0%] vs. 49 outpatients [11.5%], P = 0.13). The incidence of adverse effects was also similar: hypotension (16 inpatients [16.0%] vs. 71 outpatients [16.7%], P = 0.88), worsening renal function (7 inpatients [7.0%] vs. 29 outpatients [6.8%], P = 0.94), and hyperkalaemia (1 inpatient [1.0%] vs. 21 outpatients [4.9%], P = 0.09). We did not register any case of angioedema. CONCLUSIONS: It is safe to initiate sacubitril/valsartan during hospitalization in daily clinical practice. Inpatients have a higher risk profile and receive low starting doses more frequently than outpatients.

Use of acetazolamide in the treatment of patients with refractory congestive heart failure.

AIMS: Optimal diuretic treatment of patients with refractory congestive heart failure (CHF) remains to be elucidated. In this work, we aimed to evaluate the serial changes of functional class and surrogates of fluid overload (weight and antigen carbohydrate 125) after addition of oral acetazolamide in patients with refractory CHF. Likewise, serial changes in renal function, serum electrolytes and pH were evaluated. METHOD: This is an observational retrospective study in which 25 ambulatory patients with refractory CHF that received acetazolamide in addition to standard intensive diuretic strategy were evaluated. Longitudinal assessment of New York Heart Association (NYHA) functional class and biomarkers was analyzed using joint modelling of longitudinal and survival data. RESULTS: All patients showed NYHA class III/IV at baseline. After prescription of acetazolamide, a total of 125 outpatient visits were recorded [median visits per patient: 6 (IQR = 3-7)] during a median follow-up of 152 days (IQR = 80-353). A significant decrease in NYHA class, weight, and antigen carbohydrate 125 was observed. On the other hand, estimated glomerular filtration rate increased over time. No significant changes in systolic blood pressure, serum sodium, potassium, amino-terminal pro-brain natriuretic peptide, and pH occurred. CONCLUSION: In a cohort of patients with refractory CHF treated with an intensive diuretic treatment, the addition of acetazolamide was associated with improvement in functional class and surrogates of fluid overload.

Sobreexpresión de C-MET en carcinoma de vesícula y del tracto biliar: prevalencia y correlación clínico-molecular / Overexpression of C-MET in gallbladder and biliary tract carcinoma: prevalence and clinical-molecular correlation

El objetivo fue determinar la sobreexpresión de c-MET en pacientes con cáncer biliar y analizar asociaciones con parámetros clínicos. Este es un estudio descriptivo, longitudinal, retrospectivo y prospectivo. Se determinó la sobreexpresión por inmunohistoquímica en 58 pacientes con resultados: positivo fuerte, positivo débil y negativo. Se construyeron curvas de supervivencia global con el método de KaplanMeier en todos los pacientes y en subgrupos según estadío, género, origen tumoral y grado de diferenciación histológica. La diferencia en supervivencia global entre subgrupos se analizó por el método log-rank. La asociación entre sobreexpresión y grado de diferenciación se estudió por el método chi cuadrado. Las pruebas estadísticas se realizaron a dos colas con un valor de p 0.05. Veintinueve muestras (50%) fueron negativas, 24 (41%) positivas débiles y 5 (9%) positivas fuertes. La mediana de supervivencia fue 18.2, 11.3 y 11.7 meses en pacientes con sobreexpresión negativa, positiva débil y positiva fuerte, respectivamente. Sin embargo, la diferencia en supervivencia global entre pacientes c-MET negativos y positivos (fuerte y débil) no alcanzó significancia estadística (p 0.068). En los subgrupos los resultados fueron similares. La sobreexpresión se asoció al grado de diferenciación (p 0.015), mostrando una relación inversa; y no se correlacionó con tasa de respuesta a la quimioterapia y tiempo a la progresión. La sobreexpresión de c-MET es frecuente en cáncer biliar, se asocia al grado de diferenciación tumoral y podría tener valor pronóstico. Si la vía c-MET es importante, los fármacos inhibidores tendrían impacto en la supervivencia global (AU)

The objective was to determine the overexpression of c-MET in patients with biliary cancer and to analyze associations with clinical parameters. This is a descriptive, longitudinal, retrospective and prospective study. Overexpression was obtained by immunohistochemistry in 58 patients, with the following results: strong positive, weak positive and negative. Overall survival curves were constructed using the Kaplan-Meier method in all patients and in subgroups according to stage, gender, tumor origin and grade of histological differentiation. The difference in overall survival between groups was analyzed by the log-rank test. The association between overexpression and grade of differentiation was studied using the chisquare method. Statistical tests were two-tailed with a p value 0.05. Twenty nine samples (50%) were negative, 24 (41%) weak positive and 5 (9%) strong positive. Median survival was 18.2, 11.3 and 11.7 months in patients with negative, weak positive and strong positive overexpression, respectively. However, the difference in overall survival between negative and positive (strong and weak together) c-MET patients did not reach statistical significance (p 0.068). In the subgroup analyses the results were similar. Overexpression correlated with tumor grade (p 0.015), showing an inverse association; and was not associated neither with chemotherapy response rate nor with time to progression. Overexpression of c-MET is common in biliary cancer, is associated with grade of tumor differentiation and could have prognostic value. If the c-MET pathway is important, the inhibitory drugs would have an impact on overall survival (AU)

Echogenic mobile images in intraprocedural three-dimensional transesophageal echocardiographic monitoring during percutaneous aortic valve implantation: Incidence, characteristics and clinical implications.

INTRODUCTION AND OBJECTIVES: To investigate the incidence and clinical relevance of the presence of mobile echogenic images (MEI) during transesophageal echocardiography (TEE) for monitoring of transcatheter aortic valve implantation (TAVI). METHODS: Consecutive patients referred to our center for transfemoral or transapical TAVI were included. The procedure was monitored by three-dimensional (3D) TEE and images were analyzed by two independent experts. In-hospital follow-up was carried out and correlated with imaging findings. RESULTS: A total of 104 patients were included. MEI were visualized in 11 patients during the procedure (11%) and in over 50% of cases were identified as thrombi, however no differences in periprocedural stroke were found in follow-up. CONCLUSIONS: Visualization of MEI during 3D TEE monitoring of TAVI is relatively common (11%) and in over 50% of cases they are identified as thrombi. The clinical implications of this finding are uncertain, as despite their frequency, the incidence of clinical stroke in this patient population was no higher. 3D TEE is a useful tool for diagnosis of MEI and can alert the operator to their presence.

Persistence of Antibiotic Resistant Vibrio spp. in Shellfish Hatchery Environment.

The characterization of antibiotic-resistant vibrios isolated from shellfish aquaculture is necessary to elucidate the potential transfer of resistance and to establish effective strategies against vibriosis. With this aim, we analyzed a collection of bacterial isolates obtained from 15 failed hatchery larval cultures that, for the most part, had been treated experimentally with chloramphenicol to prevent vibriosis. Isolates were obtained during a 2-year study from experimental cultures of five different clam species. Among a total of 121 Vibrio isolates studied, 28 were found to be chloramphenicol resistant, suggesting that the shellfish hatchery had been using a sublethal concentration of the antibiotic. Interestingly, chloramphenicol-resistant vibrios showed also resistance to tetracycline and amoxicillin (group A; n = 19) or to streptomycin (group B; n = 9). Chloramphenicol-resistant vibrios were subjected to a PCR amplification and DNA sequencing of the chloramphenicol acetyltransferase genes (cat), and the same approach was followed to study the tetracycline resistance markers (tet). 16S ribosomal RNA (rRNA) gene sequencing revealed that chloramphenicol-resistant vibrios pertained mostly to the Splendidus clade. Conjugation assays demonstrated that various R-plasmids which harbored the cat II/tet(D) genes and cat III gene in groups A and B respectively, were transferred to E. coli and bivalve pathogenic vibrios. Most interestingly, transconjugants exhibited the antibiotic resistance patterns of the donors, despite having been selected only on the basis of chloramphenicol resistance. This is the first report carried out in a bivalve hatchery elucidating the persistence of resistant vibrios, the mechanisms of antibiotic resistance, and the transfer of different R-plasmids.

Following the infection process of vibriosis in Manila clam (Ruditapes philippinarum) larvae through GFP-tagged pathogenic Vibrio species.

Vibriosis represents the main bottleneck for the larval production process in shellfish aquaculture. While the signs of this disease in bivalve larvae are well known, the infection process by pathogenic Vibrio spp. during episodes of vibriosis has not been elucidated. To investigate the infection process in bivalves, the pathogens of larvae as V. tubiashii subsp. europaensis, V. neptunius and V. bivalvicida were tagged with green fluorescent protein (GFP). Larvae of Manila clam (Ruditapes philippinarum) were inoculated with the GFP-labeled pathogens in different infection assays and monitored by microscopy. Manila clam larvae infected by distinct GFP-tagged Vibrio spp. in different challenges showed the same progression in the infection process, defining three infection stages. GFP-tagged Vibrio spp. were filtered by the larvae through the vellum and entered in the digestive system through the esophagus and stomach and colonized the digestive gland and particularly the intestine, where they proliferated during the first 2h of contact (Stage I), suggesting a chemotactic response. Then, GFP-tagged Vibrio spp. expanded rapidly to the surrounding organs in the body cavity from the dorsal to ventral region (Stage II; 6-8h), colonizing the larvae completely at the peak of infection (Stage III) (14-24h). Results demonstrated for the first time that the vibriosis is asymptomatic in Manila clam larvae during the early infection stages. Thus, the early colonization and the rapid proliferation of Vibrio pathogens within the body cavity supported the sudden and fatal effect of the vibriosis, since the larvae exhibited the first signs of disease when the infection process is advanced. As a first step in the elucidation of the potential mechanisms of bacterial pathogenesis in bivalve larvae the enzymatic activities of the extracellular products released from the wild type V. neptunius, V. tubiashii subsp. europaensis and V. bivalvicida were determined and their cytotoxicity was demonstrated in fish and homeothermic cell lines for the first time. That activity was lost after heat treatment.

Vibrio bivalvicida sp. nov., a novel larval pathogen for bivalve molluscs reared in a hatchery.

Three isolates were obtained from cultures of carpet shell clam (Ruditapes decussatus) reared in a bivalve hatchery (Galicia, NW Spain) from different sources: healthy broodstock, moribund larvae and the seawater corresponding to the larval tank. All isolates were studied by a polyphasic approach, including a phylogenetic analysis based on concatenated sequences of the five housekeeping genes ftsZ, gyrB, pyrH, recA and rpoA. The analysis supported their inclusion in the Orientalis clade of the genus Vibrio, and they formed a tight group separated from the closest relatives: Vibrio tubiashii subsp. europaensis, Vibrio tubiashii subsp. tubiashii and Vibrio orientalis. The percentages of genomic resemblance, including average nucleotide identity, DNA-DNA hybridization and in silico genome-to-genome comparison, between the type strain and the closest relatives were below values for species delineation and confirmed the taxonomic position of the new species, which could be differentiated from the related taxa on the basis of several phenotypic and chemotaxonomic features, including FAME and MALDI-TOF-MS. The pathogenicity of the new species was demonstrated in larvae of R. decussatus, Ruditapes philippinarum, Ostrea edulis and Donax trunculus. The results demonstrated that the strains analyzed represented a novel species in the Orientalis clade of the genus Vibrio, for which the name Vibrio bivalvicida sp. nov. is proposed, with 605(T) (= CECT 8855(T)=CAIM 1904(T)) designated as the type strain.

Characterization of pathogenic vibrios isolated from bivalve hatcheries in Galicia, NW Atlantic coast of Spain. Description of Vibrio tubiashii subsp. europaeus [corrected] subsp. nov.

The taxonomic position of the bivalve pathogen PP-638 was studied together with five similar isolates. The strains were isolated from flat oyster (Ostrea edulis) and Manila clam (Venerupis philippinarum) cultures during outbreaks of disease in two shellfish hatcheries (Galicia, NW Spain). The pathogenicity, previously established for PP-638, was demonstrated with all isolates and for several bivalve species, including the original hosts. On the basis of phenotypic characterization and 16S rRNA gene sequences, a tight group was defined within the genus Vibrio. Multilocus sequence analysis (MLSA) based on concatenated sequences of the 16S rRNA gene and the five housekeeping genes recA, rpoA, pyrH, gyrB and ftsZ revealed that these strains form a cluster within the Orientalis clade, close to the species Vibrio tubiashii. The results of MLSA, the DDH rate and the phenotypic differences with the type strain of V. tubiashii supported the differentiation of the Galician isolates as a new subspecies within V. tubiashii, for which the name V. tubiashii subsp. europaeus [corrected] subsp. nov. is proposed (type strain PP-638(T)=CECT 8136(T)=DSM 7349(T)) The emended description of V. tubiashii is included. The pathogenicity assays widen the host range of V. tubiashii to add two unreported species, Venerupis decussata and Donax trunculus, and the described as relatively resistant species V. philippinarum.

Vibrio ostreicida sp. nov., a new pathogen of bivalve larvae.

The taxonomic position of the bivalve pathogen PP-203T was studied together with those of two similar isolates (PP-200 and PP-204). The bacterial strains were isolated from samples of young oyster spat in a bivalve hatchery in Galicia (NW Spain), which was continually affected by outbreaks of disease and severe mortalities. On the basis of 16S rRNA gene sequencing, the three strains formed a cluster within the genus Vibrio and were most closely related to Vibrio pectenicida DSM 19585T (97.9% similarity). Additional multilocus sequence analysis, including sequences of the housekeeping genes rpoA, recA, pyrH, gyrB and ftsZ, and DNA-DNA hybridization experiments indicated that the strains were distinct from currently known species of the genus Vibrio and confirmed the clustering of the three isolates. Several phenotypic features, such as growth in TCBS medium and nitrate reduction, proved useful for distinguishing the proposed novel species from its closest relatives. The findings support the description of a novel species to include the three isolates, for which the name Vibrio ostreicida sp. nov. (type strain PP-203T=CECT 7398T=DSM 21433T) is proposed.

N-acylhomoserine lactone-degrading bacteria isolated from hatchery bivalve larval cultures.

Quorum sensing (QS) systems, which depend on N-acylhomoserine lactone (AHL) signal molecules, mediate the production of virulence factors in many pathogenic microorganisms. One hundred and forty-six bacterial strains, isolated from a bivalve hatchery, were screened for their capacity to degrade five synthetic AHLs [N-butyryl-DL-homoserine lactone (C4-HSL), N-hexanoyl-DL-homoserine lactone (C6-HSL), N-octanoyl-DL-homoserine lactone (C8-HSL), N-decanoyl-DL-homoserine lactone (C10-HSL) and N-dodecanoyl-DL-homoserine lactone (C12-HSL)] using well diffusion agar-plate assays with three biosensors, Chromobacterium violaceum CV026, C. violaceum VIR07 and Agrobacterium tumefaciens NTL4 (pZLR4). The results of these assays led to our choosing four strains (PP2-67, PP2-459, PP2-644 and PP2-663) that were able to degrade all five synthetic AHLs, thus showing a wide spectrum of quorum quenching (QQ) activity. We subsequently confirmed and measured the QQ activity of the four strains by high-performance liquid chromatography plus mass-spectrometry analysis (HPLC-MS). One of the strains which showed the highest AHL-degrading activity, PP2-459, identified as being a member of the genus Thalassomonas was chosen for further study. Finally, using thin-layer chromatography (TLC), we went on to confirm this strain's capacity to degrade the AHLs produced by other non-pathogenic and pathogenic bacteria not taxonomically related.

Review of probiotics for use in bivalve hatcheries.

The aquaculture of bivalve molluscs has attained a considerable level of production but it is not enough to cover the demand of worldwide consumers. In the development of this sector, hatcheries play an important role, as suppliers of competent spat of different bivalves, including species with an aquaculture based on natural extraction present. Besides, these installations may help in the recovery of exhausted natural beds and in the obtaining of populations under genetic selection. Unfortunately, the disease outbreaks caused by bacterial pathogens are frequent, with the loss of complete batches, compromising the regular production and the economic viability of the industry. There are many descriptive studies about these outbreaks, but only a few focused on the control of microbiota. The particularities of bivalve aquaculture in hatchery must be taken into account to design methods of control. A common environment is shared by larvae and bacteria, including both beneficial and potentially pathogenic. The filter-feeding behaviour of larvae increases the strong influence of these populations. The classical treatments are directed toward to the complete elimination of bacteria from culture seawater. That objective is unfeasible, because the cultures are not axenic, and undesirable, since some bacteria enhance larval development. Taking into account these considerations, the most promising alternative is the use of probiotic bacteria. In this review we summarize the scientific literature about this subject, considering the particularities of bivalve larval cultures and the need to adapt the concept of probiotic and the strategies to use in marine bivalve hatcheries.

Inhibitory activity of Phaeobacter strains against aquaculture pathogenic bacteria.

A total of 523 bacterial strains were isolated during a 4-year period from mollusc hatcheries (flat oyster and clams) in Galicia (NW Spain). All of the strains were tested for their antibacterial activity against three larval pathogens (Vibrio anguillarum USC-72, V. neptunius PP-145.98, and Vibrio sp. PP-203). Of the isolates, 52 inhibited at least one of the target strains, and 11 inhibited all of them. The main source of active strains was oyster larvae, followed by water, tank surfaces, spat, and broodstock. Four similar strains, belonging to the genus Phaeobacter, showed the strongest activity. Strain PP-154, selected as representative of this group, displayed a wide spectrum of inhibitory activity against aquaculture pathogens, especially against members of the genus Vibrio, which is responsible for the most larval deaths. The inhibitory ability of such strain on solid medium was confirmed in seawater experiments, and the optimal conditions for antibacterial activity were established. These strains are promising probiotics for aquaculture facilities. Their potential benefit is based on the capacity to control the proliferation of a variety of aquaculture bacterial pathogens in mollusc larval cultures.

Vibrio breoganii sp. nov., a non-motile, alginolytic, marine bacterium within the Vibrio halioticoli clade.

Seven non-motile, facultatively anaerobic, alginolytic marine bacteria were isolated from the cultured clams Ruditapes philippinarum and Ruditapes decussatus. Phylogenetic analysis based on 16S rRNA gene sequences showed that these marine bacteria were closely related to the recently described species Vibrio comitans, Vibrio rarus and Vibrio inusitatus (>or=99.0 % sequence similarity). Phylogenetic analysis based on the housekeeping genes rpoA, recA and atpA grouped the isolates together and allocated them to the Vibrio halioticoli species group. Amplified fragment length polymorphism DNA fingerprinting also grouped them together and enabled them to be differentiated from recognized species of the V. halioticoli clade. DNA-DNA hybridizations showed that the isolates belonged to a novel species; phenotypic features such as the ability to grow at 4 degrees C and in the presence of 6 % NaCl also enabled them to be separated from other species. The DNA G+C content of RD 15.11(T) is 44.4 mol%. The genotypic and phenotypic data showed that the isolates represent a novel species in the V. halioticoli clade. The name Vibrio breoganii sp. nov. is proposed, with RD 15.11(T) (=CECT 7222(T) =LMG 23858(T)) as the type strain.

Inhibitory activity of Phaeobacter strains against aquaculture pathogenic bacteria

A total of 523 bacterial strains were isolated during a 4-year period from mollusc hatcheries (flat oyster and clams) in Galicia (NW Spain). All of the strains were tested for their antibacterial activity against three larval pathogens (Vibrio anguillarum USC-72, V. neptunius PP-145.98, and Vibrio sp. PP-203). Of the isolates, 52 inhibited at least one of the target strains, and 11 inhibited all of them. The main source of active strains was oyster larvae, followed by water, tank surfaces, spat, and broodstock. Four similar strains, belonging to the genus Phaeobacter, showed the strongest activity. Strain PP-154, selected as representative of this group, displayed a wide spectrum of inhibitory activity against aquaculture pathogens, especially against members of the genus Vibrio, which is responsible for the most larval deaths. The inhibitory ability of such strain on solid medium was confirmed in seawater experiments, and the optimal conditions for antibacterial activity were established. These strains are promising probiotics for aquaculture facilities. Their potential benefit is based on the capacity to control the proliferation of a variety of aquaculture bacterial pathogens in mollusc larval cultures (AU)

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