Virulence factors in Vibrio alginolyticus strains isolated from aquatic environments.

In a microbiological monitoring carried out in various aquatic environment of Sardinia Island (Italy) Vibrio alginolyticus with different virulence phenotypes appeared widely spread. Hemolysis, hemoagglutination and protease production might be together particularly in strains isolated from polluted environments. Adherence capacities to two epithelial cells (Hep-2 and Caco-2) available in laboratory were widely spread in the examined bacterial strains.

A comparison of methods for diarrhoeic shellfish poison detection.

Samples of diarrhoeic shellfish poison (DSP) mussels from several parts of the Italian Adriatic coastline were extracted and tested according to a number of different methods presently available, i.e. Yasumoto's mouse biotest, Kat's biotest, the ELISA test and the HPLC method.

Distribution of F-specific bacteriophages and coliphages in wastewater.

A new method for quantifying F-specific bacteriophages in wastewater is described. Somatic coliphages were also determined. Host-strainSalmonella typhimurium WG 49 was sensitive to only a few bacteriophages and this could have arisen from infection by F-RNA phages.

Sanitary implications associated with the use of eutrophic freshwater.

This review presents the problem of eutrophication of lakes whose waters are used also for potable use. The indirect negative impact of algal blooms as well as the direct consequences of the overgrowth of toxic Cyanophyta are considered. Problems for water treatment plants processing eutrophic raw water are exposed.

Microcystin-like toxins in different freshwater species of Oscillatoria.

In January and September of 1989 and March 1990 blooms of Oscillatoria rubescens, Oscillatoria tenuis and Oscillatoria mougetii were found in Lake Simbirizzi and Lake Flumendosa in Sardinia, and in Lake San Puoto in the Lazio region of Italy. By using different extraction methods and HPLC analysis, two microcystin-like toxins (RR-like and YR-like), similar to some of the toxic compounds produced by the Cyanophycea Microcystis aeruginosa, were detected in these blooms.

Diarrhoeic shellfish toxins in Adriatic Sea mussels evaluated by an ELISA method.

A competitive enzyme immunoassay (ELISA) was used to determine the presence of okadaic acid (OA) and/or dinophysistoxin-1 (DTX-1) in mussels. The accuracy and sensitivity of the ELISA method has been checked. The sensitivity of the method (100 ng/g of hepatopancreas) makes it possible to determine OA concentrations ten times lower than the tolerance limits established by the Health Authorities of many countries.

Identification of enteroviruses isolated from sea-water: indirect immunofluorescence (IIF).

In this research the Enteroviruses presence in sea water was studied. In previous studies presumptive Enteroviruses were revealed in 43% and in 77% of sea water samples analyzed. It was necessary to identify viral particles isolated from marine water because the detection of this kind of virus was performed only on the basis of cytopathic effect appearance on cell cultures.

[Comparative evaluation of Escherichia coli strains as markers for the study of bacteriophages].

The count of coliphages in polluted waters was found to be dependent on many experimental factors. The host-strain used for their enumeration is among the most important. In this paper we report a comparative investigation on the variability of counts of coliphages in sewage as a result of variations in host-strains of Escherichia coli and in methodologies.

Presence of saxitoxin in toxic extracts from Gonyaulax polyedra.

A "red tide" bloom of Gonyaulax polyedra occurred in Italy in Autumn, 1988. Algal concentrated extracts and undiluted water samples from the bloom were tested both with the Microtox system and a mouse bioassay, revealing the presence of paralytic shellfish poison-like neurotoxins. Saxitoxin levels evaluated on the basis of toxicological and instrumental analysis showed discrepancies.

Water hygiene of two swimming pools: microbial indicators.

The microbiological quality of the water of two swimming pools was evaluated to determine which organisms might be the best indicators of pollution. Membrane filtration gave low numbers of the common indicators of faecal pollution but high counts of the indigenous skin bacteria. As illnesses normally contracted in a swimming pool are mostly those of the skin rather than intestinal, it is suggested that the best indicators of the hygienic condition of water in a swimming pool are staphylococci because of their resistance to disinfection, high numbers in the environment, and ease of recovery.