Decimal reduction times of Pyrodinium bahamense var. compressum and Escherichia coli in chlorine- and ultraviolet-treated seawater.

AIMS: Decimal reduction times (D-values) of the vegetative cells of Pyrodinium bahamense var. compressum and Escherichia coli in ultraviolet- and chlorine-treated seawater were established. METHODS AND RESULTS: The cells of the test organisms were exposed to ultraviolet- and chlorine-treated seawater and maintained at 20-35 ppt salinity and 20 to 35 degrees C. The dinoflagellate cells which cause Paralytic Shellfish Poisoning (PSP) were found to be more resilient than the bacterial cells. Ultraviolet treatment was found to be more effective than chlorine to both test organisms. Irreversible morphological changes in the treated dinoflagellate cells were noted, including protoplast discoloration, cellular membrane leakage and damage to the thecal armour. CONCLUSIONS: The vegetative cells of both test organisms in seawater were more sensitive to ultraviolet treatment than to chlorine exposure. Generally, the dinoflagellate cells were less susceptible than bacterial cells to both disinfection treatments. SIGNIFICANCE AND IMPACT OF THE STUDY: Results of this study may have significant implications in depuration procedures for molluscs and cleaning protocols for ballast waters of ships.

Are Pyrodinium blooms in the Southeast Asian region recurring and spreading? A view at the end of the millennium.

Pyrodinium bahamense (var. compressum) has been the only dinoflagellate species that has caused major public health and economic problems in the Southeast Asian region for more than 2 decades now. It produces saxitoxin, a suite of toxins that cause Paralytic Shellfish Poisoning (PSP). A serious toxicological problem affecting many countries of the world, mild cases of this poisoning can occur within 30 minutes while in extreme cases, death through respiratory paralysis may occur within 2-24 hrs of ingestion of intoxicated shellfish. Blooms of the organism have been reported in Malaysia, Brunei Darussalam, the Philippines and Indonesia. The ASEAN-Canada Red Tide Network has recorded 31 blooms of the organism in 26 areas since 1976 when it first occurred in Sabah, Malaysia. As of 1999, the most hard hit country has been the Philippines which has the greatest number of areas affected (18) and highest number of Paralytic Shellfish Poisoning (PSP) cases (about 1995). Malaysia has reported a total of 609 PSP cases and 44 deaths while Brunei has recorded 14 PSP cases and no fatalities. Indonesia, on the other hand has a record of 427 PSP cases and 17 deaths. Studies on ecological/environmental impacts of these blooms have not been done in the region. Estimates of economic impacts have shown that the loss could be up to USD 300,000 day-1. Most of the data and information useful for understanding Pyrodinium bloom dynamics have come from harmful/toxic algal monitoring and research that have developed to different degrees in the various countries in the region affected by the organism's bloom. Regional collaborative research and monitoring efforts can help harmonize local data sets and ensure their quality and availability for comparative analysis and modeling. Temporal patterns of the blooms at local and regional scales and possible signals and trends in the occurrence/recurrence and spread of Pyrodinium blooms could be investigated. Existing descriptive and simple predictive models of Pyrodinium blooms can be improved and refined to help in the management of the wild harvest and aquaculture of shellfish in a region where the people are dependent on these resources for their daily food sustainance and livelihood.

[Prospective randomized trial of meropenem versus cefotaxime and metronidazole in the treatment of intraabdominal infections]. / Comparación prospectiva, aleatoria y abierta de meropenem frente a cefotaxima y metronidazol en el tratamiento de las infecciones intraabdominales.

BACKGROUND: The empiric antibiotic treatment of intraabdominal infections is in constant evolution. Monotherapy appears to be a desirable goal because of the simplicity of its administration, lack of toxic effects and wide spectrum. PATIENTS AND METHODS: A multicentre, prospective, randomized, open study was carried out to compare two antibiotic regimens in the treatment of intraabdominal infections in patients undergoing surgery. Ninety-eight consecutive patients were randomly allocated into two groups. One group (GM, n = 51) received meropenem (1 g/8 h) and the other (GCM, n = 47) a combination of cefotaxime (2 g/8 h) plus metronidazol (0.5 g/8 h). Clinical and bacteriological responses were assessed at the end of treatment and at 2-4 weeks. RESULTS: The severity of patients as assessed by the APACHE II score was similar in both groups (GM: 7.2 and GCM: 8.1). Three patients in each group could not be evaluated due to premature interruption of treatment or deviation from the protocol. The mean duration of treatment was 7.4 days in GM and 7.9 days in GCM. A satisfactory clinical response was obtained in 95% of patients in both groups. 31 patients (61%) in GM and 26 patients (55%) in GCM were bacteriologically evaluable. Bacteriological erradication was achieved in 94% of patients in GM and in 92% of patients in GCM. CONCLUSION: Meropenem is a good alternative for single antibiotic therapy in intraabdominal infections of moderate severity.