Nonlinear forecasting of intertidal shoreface evolution.

Natural systems dominated by sediment transport are notoriously difficult to forecast. This is particularly true along the ocean coastline, a region that draws considerable human attention as economic investment and infrastructure are threatened by both persistent, long-term and acute, event driven processes (i.e., sea level rise and storm damage, respectively). Forecasting the coastline's evolution over intermediate time (daily) and space (tens of meters) scales is hindered by the complexity of sediment transport and hydrodynamics, and limited access to the detailed local forcing that drives fast scale processes. Modern remote sensing systems provide an efficient, economical means to collect data within these regions. A solar-powered digital camera installation is used to capture the coast's evolution, and machine learning algorithms are implemented to extract the shoreline and estimate the daily mean intertidal coastal profile. Methods in nonlinear time series forecasting and genetic programming applied to these data corroborate that coastal morphology at these scales is predominately driven by nonlinear internal dynamics, which partially mask external forcing signatures. Results indicate that these forecasting techniques achieve nontrivial predictive skill for spatiotemporal forecast of the upper coastline profile (as much as 43% of variance in data explained for one day predictions). This analysis provides evidence that societally relevant coastline forecasts can be achieved without knowing the forcing environment or the underlying dynamical equations that govern coastline evolution.

Prevalence of urease in Vibrio parahaemolyticus from the Mississippi Sound.

UNLABELLED: Vibrio parahaemolyticus is a pathogenic marine bacterium that causes food-borne gastroenteritis and, less commonly, wound infections. As is the case for many pathogens, all V. parahaemolyticus strains possess at least one erythrocyte-lysing haemolysin. In addition, many V. parahaemolyticus also possess the enzyme urease. We tested 206 environmental V. parahaemolyticus isolates from Mississippi coastal waters for urease and haemolytic activity using urea agar with added salt and Wagatsuma agar, respectively. The relative abundance of haemolysin-producing V. parahaemolyticus was consistently high throughout the sampling period. In contrast, the number of urease-positive organisms increased from 36% in 2006 to 80% in 2007 and 97% in 2009. We then tested the ability of four strains representing each of the three sample years along with seven other bacterial strains for their ability to grow in seawater urea and raise the pH of this seawater broth. Finally, one of the 4 strains was tested for its ability to form an alkaline microhabitat immediately above its biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study illustrate that V. parahaemolyticus has the ability to create alkaline microhabitats that could enhance virulence, including virulence from haemolysins. This finding could have both clinical and ecological impact as to how V. parahaemolyticus can modify its habitat.

Relationships between environmental factors and pathogenic Vibrios in the Northern Gulf of Mexico.

Although autochthonous vibrio densities are known to be influenced by water temperature and salinity, little is understood about other environmental factors associated with their abundance and distribution. Densities of culturable Vibrio vulnificus containing vvh (V. vulnificus hemolysin gene) and V. parahaemolyticus containing tlh (thermolabile hemolysin gene, ubiquitous in V. parahaemolyticus), tdh (thermostable direct hemolysin gene, V. parahaemolyticus pathogenicity factor), and trh (tdh-related hemolysin gene, V. parahaemolyticus pathogenicity factor) were measured in coastal waters of Mississippi and Alabama. Over a 19-month sampling period, vibrio densities in water, oysters, and sediment varied significantly with sea surface temperature (SST). On average, tdh-to-tlh ratios were significantly higher than trh-to-tlh ratios in water and oysters but not in sediment. Although tlh densities were lower than vvh densities in water and in oysters, the opposite was true in sediment. Regression analysis indicated that SST had a significant association with vvh and tlh densities in water and oysters, while salinity was significantly related to vibrio densities in the water column. Chlorophyll a levels in the water were correlated significantly with vvh in sediment and oysters and with pathogenic V. parahaemolyticus (tdh and trh) in the water column. Furthermore, turbidity was a significant predictor of V. parahaemolyticus density in all sample types (water, oyster, and sediment), and its role in predicting the risk of V. parahaemolyticus illness may be more important than previously realized. This study identified (i) culturable vibrios in winter sediment samples, (ii) niche-based differences in the abundance of vibrios, and (iii) predictive signatures resulting from correlations between environmental parameters and vibrio densities.

Distribution of type III secretion systems in Vibrio parahaemolyticus from the northern Gulf of Mexico.

AIMS: Two well-characterized Vibrio parahaemolyticus pathogenicity factors - thermostable direct haemolysin (TDH) and TDH-related haemolysin - are produced by strains containing the tdh and trh genes, respectively. Most strains of V. parahaemolyticus contain two nonredundant type III secretion systems (T3SS), T3SS1 and T3SS2, both of which contribute to pathogenicity. Furthermore, a recent study has revealed two distinct lineages of the V. parahaemolyticus T3SS2: T3SS2α and T3SS2ß. The aim of this study was to determine the incidence of these pathogenicity factors in environmental isolates of V. parahaemolyticus. METHODS AND RESULTS: We collected 130 V. parahaemolyticus isolates (TCBS agar) containing tdh and/or trh (determined by colony hybridization) from sediment, oyster and water in the northern Gulf of Mexico and screened them and 12 clinical isolates (PCR and agarose gel electrophoresis) for pathogenicity factors tdh, trh, T3SS1, T3SS2α and T3SS2ß. The majority of potential pathogens were detected in the sediment, including all tdh(-) /trh(+) isolates. T3SS2α components were detected in all tdh(+) /trh(-) isolates and zero of 109 trh(+) isolates. One T3SS2α gene, vopB2, was found in all tdh(+) /trh(-) clinical strains but not in any of the 130 environmental strains. Fluorescence in situ hybridization adapted for individual gene recognition (RING-FISH) was used to confirm the presence/absence of vopB2. T3SS2ß was found in all tdh(-) /trh(+) isolates and in no tdh(+) /trh(-) isolates. CONCLUSIONS: The combination of haemolysins found in each isolate consistently corresponded to the presence and type of T3SS detected. The vopB2 gene may represent a novel marker for identifying increased virulence among strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to confirm the presence of T3SS2ß genes in V. parahaemolyticus strains isolated from the Gulf of Mexico and one of the few that examines the distribution and co-existence of tdh, trh, T3SS1, T3SS2α and T3SS2ß in a large collection of environmental strains.

Escherichia coli detection using mTEC agar and fluorescent antibody direct viable counting on coastal recreational water samples.

AIMS: Escherichia coli is the faecal indicator species recommended by the US Environmental Protection Agency (USEPA) for monitoring fresh recreational water. Viable but nonculturable (VBNC) E. coli are living cells that are dormant and not culturable using standard microbiological cultivation methods. This study reports a comparison between the mTEC culture method recommended by USEPA for E. coli enumeration and a fluorescent antibody-direct viable count (FA-DVC) method to visualize living E. coli cells with a microscope. METHODS AND RESULTS: Escherichia coli, faecal coliforms and Enterococcus were detected using standard methods recommended by the USEPA. VBNC E. coli was visualized with FA-DVC. Results were analysed with standard statistical methods (Pearson correlation; paired-sample t-test). Significantly higher numbers of E. coli were detected using the FA-DVC method than using the mTEC method. Escherichia coli results were also compared with faecal coliform (mFC broth) and Enterococcus (mEI agar) counts in the same samples. CONCLUSIONS: The results of this comparative study demonstrate that E. coli can be present in higher numbers than what are detected with standard culture methods. SIGNIFICANCE AND IMPACT OF THE STUDY: This study re-emphasizes the need for a rapid, accurate and precise method for detecting health risks to humans who use recreational waters.

Genetic relatedness among tdh+ and trh+ Vibrio parahaemolyticus cultured from Gulf of Mexico oysters (Crassostrea virginica) and surrounding water and sediment.

Pathogenic Vibrio parahaemolyticus (Vp) (tdh(+)/trh(+)) represent a small percentage of environmental Vp populations, and very little is known about this subpopulation. Repetitive extragenic palindromic PCR and multilocus sequence analysis revealed heterogeneity among 41 Vp containing thermostable direct hemolysin (tdh) and tdh-related hemolysin (trh) that were isolated from Mississippi coastal environments from October 2006 to April 2007. There was no source-specific sequestering in oysters, water, or sediment.

Variability of total and pathogenic Vibrio parahaemolyticus densities in northern Gulf of Mexico water and oysters.

Vibrio parahaemolyticus is indigenous to coastal environments and a frequent cause of seafood-borne gastroenteritis in the United States, primarily due to raw-oyster consumption. Previous seasonal-cycle studies of V. parahaemolyticus have identified water temperature as the strongest environmental predictor. Salinity has also been identified, although it is evident that its effect on annual variation is not as pronounced. The effects of other environmental factors, both with respect to the seasonal cycle and intraseasonal variation, are uncertain. This study investigated intraseasonal variations of densities of total and pathogenic V. parahaemolyticus organisms in oysters and overlying waters during the summer of 2004 at two sites in the northern Gulf of Mexico. Regression analyses indicated significant associations (P < 0.001) between total V. parahaemolyticus densities and salinity, as well as turbidity in water and in oysters at the Mississippi site but not at the Alabama site. Pathogenic V. parahaemolyticus organisms in Mississippi oyster and water samples were detected in 56% (9 out of 16) and 78% (43 out of 55) of samples, respectively. In contrast, 44% (7 out of 16) of oyster samples and 30% (14 out of 47) of water samples from Alabama were positive. At both sites, there was greater sample-to-sample variability in pathogenic V. parahaemolyticus densities than in total V. parahaemolyticus densities. These data suggest that, although total V. parahaemolyticus densities may be very informative, there is greater uncertainty when total V. parahaemolyticus densities are used to predict the risk of infection by pathogenic V. parahaemolyticus than previously recognized.

An evaluation of the use of remotely sensed parameters for prediction of incidence and risk associated with Vibrio parahaemolyticus in Gulf Coast oysters (Crassostrea virginica).

The U.S. Food and Drug Administration recently published a Vibrio parahaemolyticus risk assessment for consumption of raw oysters that predicts V. parahaemolyticus densities at harvest based on water temperature. We retrospectively compared archived remotely sensed measurements (sea surface temperature, chlorophyll, and turbidity) with previously published data from an environmental study of V. parahaemolyticus in Alabama oysters to assess the utility of the former data for predicting V. parahaemolyticus densities in oysters. Remotely sensed sea surface temperature correlated well with previous in situ measurements (R(2) = 0.86) of bottom water temperature, supporting the notion that remotely sensed sea surface temperature data are a sufficiently accurate substitute for direct measurement. Turbidity and chlorophyll levels were not determined in the previous study, but in comparison with the V. parahaemolyticus data, remotely sensed values for these parameters may explain some of the variation in V. parahaemolyticus levels. More accurate determination of these effects and the temporal and spatial variability of these parameters may further improve the accuracy of prediction models. To illustrate the utility of remotely sensed data as a basis for risk management, predictions based on the U.S. Food and Drug Administration V. parahaemolyticus risk assessment model were integrated with remotely sensed sea surface temperature data to display graphically variations in V. parahaemolyticus density in oysters associated with spatial variations in water temperature. We believe images such as these could be posted in near real time, and that the availability of such information in a user-friendly format could be the basis for timely and informed risk management decisions.

Emerging marine diseases--climate links and anthropogenic factors.

Mass mortalities due to disease outbreaks have recently affected major taxa in the oceans. For closely monitored groups like corals and marine mammals, reports of the frequency of epidemics and the number of new diseases have increased recently. A dramatic global increase in the severity of coral bleaching in 1997-98 is coincident with high El Niño temperatures. Such climate-mediated, physiological stresses may compromise host resistance and increase frequency of opportunistic diseases. Where documented, new diseases typically have emerged through host or range shifts of known pathogens. Both climate and human activities may have also accelerated global transport of species, bringing together pathogens and previously unexposed host populations.

Systematic study of the genus Vogesella gen. nov. and its type species, Vogesella indigofera comb. nov.

A blue-pigmented colony that had a metallic copper-colored sheen was isolated in 1973 from a standard spread plate count preparation of oxidation pond sediment. Over the next 11 years, an additional 12 strains of blue-pigmented bacteria were isolated from freshwater samples and compared to several reference strains of bacteria. Morphological and biochemical tests revealed that these 13 isolates were very similar to [Pseudomonas] indigofera ATCC 19706T (T = type strain) and ATCC 14036. A numerical analysis (in which simple matching similarity coefficients were clustered by the unweighted pair group mathematical averaging method) of morphological and biochemical characteristics revealed 90.0% relatedness between the 13 isolates and [P.] indigofera ATCC 19706T and ATCC 14036 and 73.6% relatedness between the 13 isolates and a cluster containing Burkholderia cepacia ATCC 25416T, Janthinobacterium lividum ATCC 12473T, and the Pseudomonas species tested. A phylogenetic analysis, in which both 5S rRNA and 16S rRNA were used, also revealed that the 13 isolates were closely related to each other and to strains ATCC 19706T and ATCC 14036. In addition, both 5S rRNA and 16S rRNA analyses demonstrated that the isolates and strains ATCC 19706T and ATCC 14036 were members of the beta subdivision of the Proteobacteria and were closely related to Chromobacterium violaceum ATCC 12742T but sufficiently distinct to warrant placement in a new genus. Accordingly, we propose that the 13 isolates and strains ATCC 19706T and ATCC 14306 be placed in the genus Vogesella gen. nov., which is named in honor of Otto Voges, who first isolated and described this blue-pigmented eubacterium in 1893. We also propose that [P.] indigofera be renamed Vogesella indigofera comb. nov. and designated the type species of the genus; strain ATCC 19706 is the type strain of this species.

Seasonal incidence of Vibrio vulnificus in the Great Bay estuary of New Hampshire and Maine.

Vibrio vulnificus, a normal bacterial inhabitant of estuaries, is of concern because it can be a potent human pathogen, causing septicemia, wound infections, and gastrointestinal disease in susceptible hosts. From May 1989 through December 1990, oysters and/or water were obtained from six areas in the Great Bay estuary of New Hampshire and Maine. Water was also sampled from three freshwater sites that lead into these areas. V. vulnificus was first detected in the estuary in early July and remained present through September. V. vulnificus was isolated routinely during this period from oysters and water of the Squamscott, Piscataqua, and Oyster Rivers but was only isolated twice from the oysters or water of the Great Bay itself. This study determined that there was a strong correlation (by analysis of variance) between temperature, salinity, and the presence of V. vulnificus in water and oysters. However, other unidentified factors appear to influence its presence in certain areas of the estuary.

Survival after unexpected high serum methotrexate concentrations in a patient with osteogenic sarcoma.

An 18-year-old female patient receiving adjuvant chemotherapy for osteogenic sarcoma developed a pruritic erythematous rash during infusion of the eighth dose of methotrexate (8 g/m2) in the series. In other respects, the infusion proceeded normally but the 24-hour serum concentration of methotrexate was unexpectedly and extremely high, 574 mumols/L. Dosing error was excluded, as was the hypothesis that the high concentrations were due to the presence of methotrexate-specific antibodies. Acute oliguria and renal failure were the primary manifestations of the drug-induced toxicity and the high concentrations can be attributed to decreased renal elimination of the drug over the first 24 hours. Treatment consisted of folinic acid rescue, forced diuresis, sequential charcoal haemoperfusion and haemodialysis, and repeated oral doses of activated charcoal. After examination of the contribution of the extracorporeal procedures and the charcoal to the elimination of the drug, the relative lack of morbidity was attributed primarily to the folinic acid rescue and the intensive supportive care.

Incidence of Vibrio vulnificus in northern New England water and shellfish.

Vibrio vulnificus, an autochthonous inhabitant of the estuarine environment, was detected in water and oysters from the Great Bay Estuary System of New Hampshire and Maine. Previously, it had not been detected north of Boston Harbor on the east coast of the United States. V. vulnificus was detected in water and shellfish samples at five out of ten sites, and only in areas that were not open to recreational shellfishing. Although samples were collected from May into December, V. vulnificus was only detected in shellfish in July and August. Water sampling began in August, and V. vulnificus persisted at one site into October.

Testing for bacterial resistance to arsenic in monitoring well water by the direct viable counting method.

Direct viable counting of metal-resistant bacteria (DVCMR) has been found to be useful in both enumerating and differentiating metal-resistant and metal-sensitive strains of bacteria. The DVCMR bioassay was used to detect effects of low and high concentrations of arsenic and arsenicals on bacterial populations in groundwater. The level of resistance of the bacterial populations to arsenate was determined by the DVCMR bioassay, and the results showed a linear correlation with the total arsenic concentrations in the monitoring well water samples; no correlation was observed by culture methods with the methods employed. Bacteria resistant to 2,000 micrograms of arsenate per ml were isolated from all monitoring well water samples studied. Strains showed similar antibiotic and heavy-metal profiles, suggesting that the arsenic was not a highly selective pressure for arsenic alone. The monitoring well water samples were amended with arsenate and nutrients to determine the biotransformation mechanisms involved. Preliminary results suggest that bacteria indigenous to the monitoring well water samples did not directly transform, i.e., precipitate or volatilize, dissolved arsenic. It was concluded that arsenic contamination of the groundwater can be monitored by the DVCMR bioassay.

Bacterial detoxification of diisopropyl fluorophosphate.

The ability of 18 gram-negative bacterial isolates to detoxify diisopropyl fluorophosphate, a structural analog of the agents soman and sarin, was investigated. Detoxification by both frozen cell sonicates and acetone powders was assayed by two methods, i.e., the hydrolytic release of fluoride, measured by a fluoride-specific ion electrode, and the disappearance of acetylcholinesterase inhibition in vitro. Frozen cell sonicates for all strains exhibited some activity (F- ion release). In general, acetone powder preparations produced higher activity than frozen cell sonicates did, and the highest activities were exhibited by strains with known parathion hydrolase activity. Two ranges in activity were observed, low level, ranging from 0.1 to 7.0 mumol/min per g of protein, and high level, detected only in parathion hydrolase-producing strains, from 47 to greater than 300 mumol/min per g of protein. Results indicate that parathion hydrolase was nonspecific in phosphoesterase activity. Also, it was an effective detoxicant at low concentrations and near-neutral pH.

The fate of enteric pathogenic bacteria in estuarine and marine environments.

Sufficient laboratory and field data are now available to hypothesize that enteric pathogens survive for very long periods of time in sea-water. In fact, these Gram-negative bacteria probably enter into dormancy, during which they remain viable and potentially virulent, yet are non-culturable when traditional bacteriological methods are employed. Increasing use of the world's oceans-for discharge of domestic wastes may result in public health problems in the future from the allochthonous human pathogens accumulating in the marine environment at disposal sites.

Colonization of the gut of the blue crab (Callinectes sapidus) by Vibrio cholerae.

Attachment of Vibrio cholerae to the mucosal surface of the intestine is considered to be an important virulence characteristic. Vibrio cholerae, an autochthonous member of brackish water and estuarine bacterial communities, also attaches to crustacea, a significant factor in multiplication and survival of V. cholerae in nature. The ability of V. cholerae to attach to the gut wall of the blue crab (Callinectes sapidus) was examined, and attachment was observed only in the hindgut and not the midgut of crabs, confirming a requirement for chitin in the attachment of V. cholerae to invertebrate and zooplankton surfaces. The new finding of attachment of V. cholerae to the hindgut of crabs may be correlated with the epidemiology and transmission of cholera in the aquatic environment. The crab model may also prove useful in elucidating the mechanism(s) of ion transport in crustacea.

Coincident plasmids and antimicrobial resistance in marine bacteria isolated from polluted and unpolluted Atlantic Ocean samples.

Sewage effluent and outfall confluence samples were collected at the Barceloneta Regional Treatment Plant in Barceloneta, Puerto Rico; outfall confluence samples at Ocean City, Md., were also collected. Samples from uncontaminated open ocean areas served as clean-water controls. Bacteria were enriched in marine broth 2216 amended with 1 microgram of one of a set of chemicals selected for study per ml: nitrobenzene, dibutyl phthalate, m-cresol, o-cresol, 4-nitroaniline, bis(tributyltin) oxide, and quinone. MICs of the chemicals were determined individually for all isolates. Bacterial isolates were evaluated for resistance to nine different antibiotics and for the presence of plasmid DNA. Treated sewage was found to contain large numbers of bacteria simultaneously possessing antibiotic resistance, chemical resistance, and multiple bands of plasmid DNA. Bacteria resistant to penicillin, erythromycin, nalidixic acid, ampicillin, m-cresol, quinone, and bis(tributyltin) oxide were detected in nearly all samples, but only sewage outfall confluence samples yielded bacterial isolates that were resistant to streptomycin. Bacteria resistant to a combination of antibiotics, including kanamycin, chloramphenicol, gentamicin, and tetracycline, were isolated only from sewage effluent samples. It is concluded that bacterial isolates derived from toxic chemical wastes more frequently contain plasmid DNA and demonstrate antimicrobial resistance than do bacterial isolates from domestic sewage-impacted waters or from uncontaminated open ocean sites.

Vibrio cincinnatiensis sp. nov., a new human pathogen.

A halophilic gram-negative rod was isolated from blood and cerebrospinal fluid collected from a 70-year-old male having no known contact with seafood or salt water. Positive biochemical tests included oxidase, sensitivity to 0/129, O-nitrophenyl-beta-D-galactopyranoside, lysine decarboxylase and fermentation of glucose, salicin, n-inositol, sucrose, L-mannose, L-arabinose, and arbutin. Negative tests included indole, ornithine decarboxylase, arginine dihydrolase fermentation of lactose, and production of gelatinase and urease. The DNA base composition was 45.0 mol% guanine plus cytosine. Numerical taxonomy indicated 70% similarity with known reference Vibrio sp. strains. The 5S rRNA sequence for this strain has been determined: 5'-U G C C U G G C G A C C A U A G C G U U U U G G A C C C A C C U G A U U C C A U G C C G A A C U C A G U A G U G A A A C G A A A C A G C G U C G A U G G U A G U G U G G G G U C U C C C C A U G U G A G A G U A G A A C A U C G C C A G G C A U-3'. Based on the phenetic, molecular genetic, and nucleic acid sequencing data, it is concluded that Vibrio cincinnatiensis represents a new species of the genus Vibrio sensu strictu (as defined by 5S rRNA sequencing results). On a basis of 5S rRNA comparative sequence analysis, the organism appears to share a recent common ancestor with V. gazogenes (98% homology) and close ancestry with V. mimicus, V. fluvialis, and V. metschnikovii.