矿泉水和山泉水中铜绿假单胞菌污染调查及分离菌株毒力基因与耐药性分析

【目的】初步掌握全国矿泉水和山泉水生产过程中铜绿假单胞菌(Pseudomonas aeruginosa)的污染情况。分析矿泉水与山泉水中铜绿假单胞菌的致病性与耐药性。【方法】研究通过对广西、湖北、云南等全国9个省36家水厂进行采样,共采集108个样本,并根据《饮用天然矿泉水检测方法》国家标准(GB/T 8538-2008)检测其铜绿假单胞菌的污染率、污染水平。对分离出的铜绿假单胞菌菌株进行毒力基因与药敏实验。【结果】全国矿泉水水源水、活性碳过滤后水、成品水的污染率分别为16.7%、16.7%、0,污染水平分别为3.7、2.0、0 CFU/250 m L。全国山泉水水源水、活性碳过滤后水、成品水的污染率分别为66.7%、83.3%、5.6%,污染水平分别为5.1、7.3、2.0 CFU/250 m L。对所分离出的36株铜绿假单胞菌进行毒力基因检测和药敏试验显示:exo U、exo S、phz M、tox A、las B检出率分别为25.0%、75.0%、100%、88.8%、100%,但对美国国家临床实验室标准化委员会标准中14种抗生素均无耐药性。【结论】山泉水水源水、活性碳过滤后水、成品水污染率明显高于矿泉水,但污染水平均较低,无大于40.0 CFU/250 m L样品检出。山泉水活性碳过滤后污染率最高,表明大部分企业在活性碳过滤环节存在污染问题。毒力基因exo U、exo S、phz M、tox A、las B在分离到的36株铜绿假单胞菌检出率高,但分离到的菌株对所选取的14种抗生素均无耐药性。     

云南泡梨中乳酸菌的分离鉴定及其应用

【背景】泡梨是云南省常见的一种腌渍水果,在云南加工食用已经有一百多年的历史,因其味道酸甜可口、风味独特而深受人们喜爱,而目前对泡梨中微生物种群的系统分析和发酵原理的研究尚未见报道。【目的】研究乳酸菌在云南泡梨中的分布及应用,阐明乳酸菌种类对泡梨发酵中风味物质的影响。【方法】从云南省4个不同地区采集12份泡梨样品,经菌落菌体形态、生理生化特性和16SrRNA基因序列分析进行菌种分离与鉴定。利用分离的乳酸菌为菌种进行泡梨的制备,采用GC-MS技术对人工接种的复合乳酸菌发酵与自然发酵泡梨进行风味物质的分析与感官评价。【结果】分离鉴定出79株植物乳杆菌(Lactobacillus plantarum)、 3株类植物乳杆菌(Lactobacillus paraplantarum)、1株戊糖乳杆菌(Lactobacillus pentosus)、1株干酪乳杆菌(Lactobacillus casei)、2株副干酪乳杆菌(Lactobacillus paracasei)和1株短乳杆菌(Lactobacillus brevis),植物乳杆菌为泡梨发酵中的优势菌。将分离所得乳酸菌用于泡梨制备的结果表明,...     

Methylation of DNA in developing embryos of the sea urchin Psammechinus miliaris

Embryos of the sea urchin Psammechinus miliaris have been labelled after fertilization with [6(-3)H]uridine and cultured in filtered sea water. 32-cell, blastula, gastrula and pluteus stages were harvested. The DNA from these embryos was purified and hydrolyzed and the nuclear bases were analyzed by means of high performance liquid chromatography. The ratios of 5-methylcytosine and cytosine demonstrate that the concentrations of 5-methylcytosine are essentially the same in the developmental stages examined (gamma = 95%), which contradicts the hypothesis that methylation of DNA plays a role in cell differentiation.     

腌制蔬菜营养成分的测定

分析了腌制蔬菜中的泡菜 ,盐浸渍菜中所含的主要营养成分的种类及其相对含量。结果显示 :泡菜和盐浸渍菜中水分、灰分、粗蛋白、粗脂肪和粗纤维的含量分别为 4 6 1% ,15 95 % ,10 2 8% ,2 19% ,2 3 2 9%和 3 11% ,2 6 49% ,15 19% ,2 42 % ,2 0 0 5 %。其氨基酸总量为 74 5 0 45mg/g ,6 6 4876mg/g ,其中必需氨基酸占 37 46 39%和43 6 76 1%。     

Evaluation of Factors Affecting Survival of Escherichia coli in Sea Water: V. Studies with Heat- and Filter-sterilized Sea Water1

The bactericidal action of sea water was measured as the difference in survival of cells of Escherichia coli in untreated and autoclaved portions of water samples. The beneficial effect of sterilization by heat on the survival of E. coli in sea water varied with season and was most marked during summer months, however, the magnitude of the effect differed greatly from sample to sample. The more obvious and commonly suggested explanations for the bactericidal action of sea water were tested experimentally. The pH and salinity of sea water were changed by autoclaving, but the direction of the former was detrimental rather than beneficial and the significance of the latter was not clarified. The survival of cells of E. coli in filtered portions of some water samples was greater than that in untreated portions and equal to that in autoclaved portions, indicating that predators and competitors removed by filtration had contributed significantly to the rapid death of the bacterium in the untreated water. However, in the majority of samples tested, survival of E. coli in autoclaved water was considerably greater than survival in filtered water.

The possibility that the beneficial effect of autoclaving over and above that of filtration resulted from inactivation or destruction by heat of bacteriophages and thermolabile toxic substances such as antibiotics was considered. Moreover, the suggestion was tested that the increased survival of E. coli in autoclaved sea water was due to the ability of heat to disrupt and degrade microbial cells and thermolabile compounds and, thereby, to cause an increase in concentration of available nutrients in sea water. It was concluded that the bactericidal action of sea water is not explicable in terms of the destruction or inactivation by heat of bacteriophages or antibiotics. Although added organic matter influenced the survival of E. coli, the test organism was not an effective competitor in sea water and the nutrient levels required to offset the bactericidal action were excessive.

Artificial sea water was demonstrated to exert a bactericidal action comparable to that of natural sea water. Low levels of cysteine which favor survival of E. coli in natural sea water had a similar effect in artificial sea water. Nevertheless, it is not at this time possible to conclude that the factors responsible for the bactericidal action of artificial sea water are identical with those responsible in natural sea water.

     

The composition of Australian fur seal (Arctocephalus pusillus doriferus) milk throughout lactation.

The proximate chemical composition of milk was determined throughout lactation in the Australian fur seal (Arctocephalus pusillus doriferus Wood Jones), a temperate species with an 11-mo lactation period typical of most temperate otariids. Average lipid and protein contents were 42% and 10%, respectively, which is similar to that recorded for the polar otariid species but higher than reported in other temperate, long-lactation species. Milk composition, however, varied substantially throughout lactation, with lipid content rising from 30% soon after parturition to 50% at 230 d postpartum before decreasing to 45% toward weaning. The trend in water content was opposite to that of lipid, while protein content increased only slightly during lactation from 10% to 12%. The peak in lipid content occurred at approximately 70% of the way through lactation, similar to that found in the Australian sea lion and several phocid seal species. Significant positive relationships were found between milk lipid content and both the duration of the preceding foraging trip and body mass. A highly significant and close correlation was found between milk water and lipid contents such that gross energy content may be accurately predicted from water content alone. Similar predictive equations have been found for several other otariid and phocid species, but these appear to differ between phylogenetic groups.     

Modelled and measured dynamics of viruses in Arctic winter sea-ice brines

We describe a model based on diffusion theory and the temperature-dependent mechanism of brine concentration in sea ice to argue that, if viruses partition with bacteria into sea-ice brine inclusions, contact rates between the two can be higher in winter sea ice than in seawater, increasing the probability of infection and possible virus production. To examine this hypothesis, we determined viral and bacterial concentrations in select winter sea-ice horizons using epifluorescence microscopy. Viral concentrations ranged from 1.6 to 82 x 10(6) ml(-1) of brine volume of the ice, with highest values in brines from coldest (-24 to -31 degrees C) ice horizons. Calculated virus-bacteria contact rates in underlying -1 degrees C seawater were similar to those in brines of -11 degrees C ice but up to 600 times lower than those in ice brines at or below -24 degrees C. We then incubated native bacterial and viral assemblages from winter sea ice for 8 days in brine at a temperature (-12 degrees C) and salinity ( approximately 160 psu) near expected in situ values, monitoring their concentrations microscopically. While different cores yielded different results, consistent with known spatial heterogeneity in sea ice, these experiments provided unambiguous evidence for viral persistence and production, as well as for bacterial growth, in -12 degrees C brine.     

Embrionary and larval development of Lytechinus variegatus (Echinoidea: Toxopneustidae) in laboratory conditions at Isla de Margarita-Venezuela

The sea urchin Lytechinus variegatus is a promissory species for aquaculture activities in tropical countries. In Venezuela, this species has some economical importance but their embryonic and larval development had not been studied. We collected specimens from seagrass beds in Margarita Island (Venezuela) and kept them in the laboratory, where they spawned naturally. With filtered sea water (temperature 28 degrees C, salinity 37 psu) and moderate aeration, the eggs and sperm were mixed (relation 1:100) and reached a 90% fertilization rate. The fertilization envelope was observed after two minutes, the first cellular division after 45 minutes and the prism larval stage after 13 hours. The echinopluteus larval stage was reached after 17 hours and metamorphosis after 18 days of planktonic life, when the larvae start their benthic phase.     

Giardia and Cryptosporidium spp. in filtered drinking water supplies.

Giardia and Cryptosporidium levels were determined by using a combined immunofluorescence test for filtered drinking water samples collected from 66 surface water treatment plants in 14 states and 1 Canadian province. Giardia cysts were detected in 17% of the 83 filtered water effluents. Cryptosporidium oocysts, were observed in 27% of the drinking water samples. Overall, cysts or oocysts were found in 39% of the treated effluent samples. Despite the frequent detection of parasites in drinking water, microscopic observations of the cysts and oocysts suggested that most of the organisms were nonviable. Compliance with the filtration criteria outlined by the Surface Water Treatment Rule of the U.S. Environmental Protection Agency did not ensure that treated water was free of cysts and oocysts. The average plant effluent turbidity for sites which were parasite positive was 0.19 nephelometric turbidity units. Of sites that were positive for Giardia or Cryptosporidium spp., 78% would have been able to meet the turbidity regulations of the Surface Water Temperature Rule. Evaluation of the data by using a risk assessment model developed for Giardia spp. showed that 24% of the utilities examined would not meet a 1/10,000 annual risk of Giardia infection. For cold water conditions (0.5 degree C), 46% of the plants would not achieve the 1/10,000 risk level.     

Giardia and Cryptosporidium spp. in filtered drinking water supplies.

Giardia and Cryptosporidium levels were determined by using a combined immunofluorescence test for filtered drinking water samples collected from 66 surface water treatment plants in 14 states and 1 Canadian province. Giardia cysts were detected in 17% of the 83 filtered water effluents. Cryptosporidium oocysts, were observed in 27% of the drinking water samples. Overall, cysts or oocysts were found in 39% of the treated effluent samples. Despite the frequent detection of parasites in drinking water, microscopic observations of the cysts and oocysts suggested that most of the organisms were nonviable. Compliance with the filtration criteria outlined by the Surface Water Treatment Rule of the U.S. Environmental Protection Agency did not ensure that treated water was free of cysts and oocysts. The average plant effluent turbidity for sites which were parasite positive was 0.19 nephelometric turbidity units. Of sites that were positive for Giardia or Cryptosporidium spp., 78% would have been able to meet the turbidity regulations of the Surface Water Temperature Rule. Evaluation of the data by using a risk assessment model developed for Giardia spp. showed that 24% of the utilities examined would not meet a 1/10,000 annual risk of Giardia infection. For cold water conditions (0.5 degree C), 46% of the plants would not achieve the 1/10,000 risk level.     

Habitat selection by sea kraits (Laticauda spp.) at coastal sites of Orchid Island, Taiwan

Three species of amphibious sea kraits (Laticauda spp.) spend variable time at sea and require fresh water for water balance. Both the rate of cutaneous evaporative water loss and the extent of terrestriality are known to differ among them. Laticauda semifasciata has the greatest rate of water loss and the least extent of terrestriality, whereas L. colubrina exhibits the reverse and L. laticaudata is intermediate. These sea kraits tend to be more abundant at places where there are sources of fresh water, but other factors also influence their distribution. To further clarify the habitat requirements, we investigated the abundance of each species of sea krait at six different habitats and the availability of each type of habitat on Orchid Island, Taiwan. The six habitats were high coral reef without fresh water (HR) and with fresh water (HRF); low coral reef without fresh water (LR) and with fresh water (LRF); sand or gravel coast, which has no coral reef, without fresh water (NR) and with fresh water (NRF). The extent of safety judged from the relative availability of retreat sites, from high to low, was HR, LR, and NR among these habitats. More than 75% of individuals counted for each species were found in HRF. We found no sea kraits in NRF and NR. The most available habitat was LR, but no L. laticaudata or L. semifasciata were found in this habitat. We found 3.3% and 16.7% of L. colubrina in LR and HR, respectively. For L. colubrina, the second abundant habitat was HR, whereas for L. laticaudata and L. semifasciata, the second abundant habitat was LRF. We conclude that both safety (availability of retreat sites) and fresh water are important to the habitat selection of sea kraits. Compared with other species, L. colubrina is characterized by a greater extent of terrestrial habit and possibly greater variety of access to sources of fresh water.     

Dissolved extracellular polymeric substances (dEPS) dynamics and bacterial growth during sea ice formation in an ice tank study

Extracellular polymeric substances (EPS) are known to help microorganisms to survive under extreme conditions in sea ice. High concentrations of EPS are reported in sea ice from both poles; however, production and dynamics of EPS during sea ice formation have been little studied to date. This investigation followed the production and partitioning of existing and newly formed dissolved organic matter (DOM) including dissolved carbohydrates (dCHO), dissolved uronic acids (dUA) and dissolved EPS (dEPS), along with bacterial abundances during early stages of ice formation. Sea ice was formed from North Sea water with (A) ambient DOM (NSW) and (B) with additional algal-derived DOM (ADOM) in a 6d experiment in replicated mesocosms. In ADOM seawater, total bacterial numbers (TBN) increased throughout the experiment, whereas bacterial growth occurred for 5d only in the NSW seawater. TBN progressively decreased within developing sea ice but with a 2-fold greater decline in NSW compared to ADOM ice. There were significant increases in the concentrations of dCHO in ice. Percentage contribution of dEPS was highest (63%) in the colder, uppermost parts in ADOM ice suggesting the development of a cold-adapted community, producing dEPS possibly for cryo-protection and/or protection from high salinity brines. We conclude that in the early stages of ice formation, allochthonous organic matter was incorporated from parent seawater into sea ice and that once ice formation had established, there were significant changes in the concentrations and composition of dissolved organic carbon pool, resulting mainly from the production of autochthonous DOM by the bacteria.     

Effects of egg factors on cyclic nucleotide metabolism in sea urchin sperm.

Cyclic AMP in Strongylocentrotus purpuratus sperm was elevated approximately 2-fold by theophylline or 1-methyl-3-isobutylxanthine. Factors released from sea urchin eggs (FRE) elevated sperm cyclic AMP by about 7-fold within 1 min, and the combination of FRE with theophylline increased sperm cyclic AMP up to 100-fold within 1 min. Cyclic GMP in sea urchin sperm was slightly elevated by theophylline, but was lowered by FRE. Cyclic GMP in sperm treated with FRE plus theophylline was not higher than in sperm treated with theophylline alone. The ability of FRE-containing sea water to increase sperm cyclic AMP in the presence of theophylline was altered only slightly if at all by boiling, but it was decreased by about 50% by dialysis and destroyed by ashing. Filtration of FRE on Sephadex G-50 columns yielded two peaks of cyclic AMP-elevating activity. One peak (peak I) was eluted at the column void volume, and the other (peak II) was retained by the column. The cyclic GMP-lowering activity was located in fractions approximately corresponding to peak I of cyclic AMP-elevating activity. Dialysis of FRE-containing sea water before its application to the G-50 column virtually eliminated peak II of the cyclic AMP-elevating activity. When the cyclic AMP-elevating activity in peak I was filtered on Bio Gel A-5m columns, it also migrated at or near the column void volume. Fractions corresponding to peak I contained material that inhibited both guanylate and adenylate cyclase activities in broken cell preparations of sperm and guanylate cyclase from rat lung. The inhibitory material was stable to boiling, non-dialyzable, and destroyed by ashing. Under a variety of conditions, FRE-containing sea water or cyclic AMP-elevating peaks I or II did not stimulate sperm adenylate cyclase activity in broken cell preparations.     

The effect of submergence on heart rate and oxygen consumption of swimming seals and sea lions

Respiratory, metabolic, and cardiovascular responses to swimming were examined in two species of pinniped, the harbor seal (Phoca vitulina) and the California sea lion (Zalophus californianus). 1. Harbor seals remained submerged for 82-92% of the time at swimming speeds below 1.2 m.s-1. At higher speeds, including simulated speeds above 1.4 m.s-1, the percentage of time spent submerged decreased, and was inversely related to body weight. In contrast, the percentage of time spent submerged did not change with speed for sea lions swimming from 0.5 m.s-1 to 4.0 m.s-1. 2. During swimming, harbor seals showed a distinct breathhold bradycardia and ventilatory tachycardia that were independent of swimming speed. Average heart rate was 137 beats.min-1 when swimming on the water surface and 50 beats.min-1 when submerged. A bimodal pattern of heart rate also occurred in sea lions, but was not as pronounced as in the seals. 3. The weighted average heart rate (WAHR), calculated from measured heart rate and the percentage time spent on the water surface or submerged, increased linearly with swimming speed for both species. The graded increase in heart rate with exercise load is similar to the response observed for terrestrial mammals. 4. The rate of oxygen consumption increased exponentially with swimming speed in both seals and sea lions. The minimum cost of transport calculated from these rates ranged from 2.3 to 3.6 J.m-1.kg-1, and was 2.5-4.0 times the level predicted for similarly-sized salmonids. Despite different modes of propulsion and physiological responses to swimming, these pinnipeds demonstrate similar transport costs.     

Determination of hexaconazole in surface water samples from river and the sea by liquid chromatography-electrospray tandem mass spectrometry

A simple and selective method was developed for determining the concentration of hexaconazole in river and sea water samples by using liquid chromatography/tandem mass spectrometry with an electrospray ionization interface in the positive ion mode and selective reaction monitoring mode. Trace amounts of hexaconazole were collected in a Sep-Pak Plus tC18 cartridge that was eluted with methanol. The detection limit for hexaconazole was 6 ng/l. The recovery of a standard aqueous solution containing 1 microg/l was 96%. The recovery of hexaconazole in the river and sea water samples was 95% and 90%, respectively. Hexaconazole was not detected in the sea water samples. Trace peaks of hexaconazole were found in the river water samples, the concentration being less than 6 ng/l in all cases. The biological degradation of hexaconazole was tested by using river water. No degradation of hexaconazole was apparent in river water incubated at 20 degrees C for 3 weeks.     

The effect of early exposure to Vibrio pelagius on the aerobic bacterial flora of turbot, Scophthalmus maximus (L.) larvae

Vibrio pelagius was added to filtered sea water in experimental tanks containing newly-hatched larvae of Scophthalmus maximus. The bacterial load of larvae increased from day 1 post-hatch and by day 14 had reached 5 × 10⁴ bacteria per larva. Vibrio pelagius dominated the aerobic bacterial flora of larvae exposed to this bacterial species but was not detected in larvae not exposed to exogenous bacteria. An enzyme-linked immunosorbent assay using rabbit antiserum against V. pelagius allowed a specific quantitative assay for homologous bacterial antigens in individual larvae, with very little cross-reaction against heterologous bacteria. The results of enzyme-linked immunosorbent assays of V. pelagius antigens in larvae from tank water inoculated with this bacterial species correlated with the bacterial levels found in the larvae by culture on agar plates.     

Sea ice bacterial growth rate, growth efficiency and preference for inorganic nitrogen sources in the Baltic Sea

Seasonal Baltic Sea ice is structurally similar to polar sea ice and provides habitats for diverse ice organism assemblages that are integral to the biogeochemistry and ecology of the sea during winter. Temperature and inorganic nitrogen sources have been suggested to control bacterial growth, with increasing dependence on ammonium at low temperatures. To study the bacterial growth and preference for the nitrogen source, we conducted experiments at 0 and 4°C, using ammonium and nitrate as nitrogen sources at two coastal fast-ice stations in the Gulf of Finland and in the Gulf of Bothnia during three successive winters. The two study sites differ markedly in relation to the allochthonous dissolved organic matter supply from the catchment area. High levels of bacterial growth were recorded at both study sites, with community generation times of 15–37 h. The measured bacterial growth efficiencies of 20–58% suggest that the Baltic sea ice brines provide a rich medium for bacterial growth and efficient functioning of bacteria-based food webs. Our experiments with sea ice samples showed a preference for ammonium at both temperatures and high potential growth in both types of nitrogen supplies. No major differences in phosphorus depletion rates were found at the two temperatures, but rates were always highest when ammonium was added to the experiments. These experiments point out that ice maturity, presumably through changes in bacterial community structure, impacts nitrogen processes and that these processes are pronounced prior to melting of the ice.     

Three sample preparation protocols for polymerase chain reaction based detection of Cryptosporidium parvum in environmental samples

Cryptosporidium parvum is a protozoan parasite responsible for an increasing number of outbreaks of gastrointestinal illness worldwide. In this report, we describe development of sample preparation protocols for polymerase chain reaction (PCR)-based detection of C. parvum in fecal material and environmental water samples. Two of these methods were found adequate for isolation of Cryptosporidium DNA from filtered water pellet suspensions. The first involved several filtration steps, immunomagnetic separation and freeze-thaw cycles. The second method involved filtration, addition of EnviroAmp lysis reagent, freeze-thaw cycles and precipitation of the DNA with isopropanol. Using nested PCR, we detected 100 oocysts/ml of filtered water pellet suspension, with either of the above sample preparation procedures. Nested PCR increased sensitivity of the assay by two to three orders of magnitude as compared to the primary PCR. The detection limit for seeded fecal samples was 10-fold higher than for filtered environmental water pellet suspension. Nested PCR results showed 62.4 and 91.1% correlation with immunofluorescence assay (IFA) for fecal samples and filtered environmental water pellet suspensions, respectively. This correlation decreased to 47.2% and 44.4%, respectively, when only IFA positive samples were analyzed. However, in fecal samples contaminated with a high number (> 10(5)/g) of C. parvum oocysts, this correlation was 100%.     

Combined effect of mild heat and acetic acid treatment for inactivating Escherichia coli O157:H7, Listeria monocytogenes and Salmonella typhimurium in an asparagus puree

AIMS: This study was conducted to validate combined heat and acid treatments for inactivating Escherichia coli O157:H7, Listeria monocytogenes and Salmonella typhimurium in an acidified brine containing, or pickled, asparagus model food. METHODS AND RESULTS: A mixture of three strains of E. coli O157:H7, L. monocytogenes and S. typhimurium were inoculated onto pickled asparagus samples. Combinations of various concentrations of acetic acid [0%, 0.25%, 0.5%, 0.75%, 1%, 1.5% and 2% (v/v)] and various temperatures (40 degrees C, 50 degrees C, 60 degrees C and 75 degrees C) were investigated. Following treatment, asparagus samples were stored at room temperature and enumerated at 0, 0.5, 1, 2 and 3 days. Heat and acetic acid treatments were synergistic. The inhibitory effects of these combined treatments on the tested foodborne pathogens were also effective during storage. Loss of green colour in the pickled asparagus significantly increased with increasing concentrations of acetic acid. CONCLUSIONS: Using a combination of mild heat and acetic acid treatments can successfully control E. coli O157:H7, L. monocytogenes and S. typhimurium in pickled asparagus, combinations of heat and acid are synergistic and effective treatments can be selected to reduce adverse effect on colour which occur during product storage. SIGNIFICANCE AND IMPACT OF THE STUDY: Mild heating plus acetic acid treatment are synergistic, so combined treatments can be developed, which would lower the temperature and amount of acetic acid required for minimally processed vegetables while maintaining pathogen control.     

Evaluation of candidate probiotic strains for gilthead sea bream larvae (Sparus aurata) using an in vivo approach

AIMS: The aim of this study was to evaluate the effect of six bacterial strains on gilthead sea bream larvae (Sparus aurata). METHODS AND RESULTS: Six bacterial strains isolated from well-performing live food cultures were identified by sequencing fragments of their 16s rDNA genome to the genus level as Cytophaga sp., Roseobacter sp., Ruergeria sp., Paracoccus sp., Aeromonas sp. and Shewanella sp. Survival rates of gilthead sea bream larvae transferred to seawater added these bacterial strains at concentrations of 6 +/- 0.3 x 10(5) bacteria ml(-1) were similar to those of larvae transferred to sterilized seawater and showed an average of 86% at 9 days after hatching, whereas, survival rates of larvae transferred to filtered seawater were lower (P < 0.05), and showed an average of 39%, 9 days after hatching. CONCLUSION: Several bacterial strains isolated from well-performing live food cultures showed a positive effect for sea bream larvae when compared with filtered seawater. SIGNIFICANCE AND IMPACT OF THE STUDY: The approach used in this study could be applied as an in vivo evaluation method of candidate probiotic strains used in the rearing of marine fish larvae.