[HALOTOLERANCE OF ENTEROBACTERIA ISOLATED FROM WATER AND FISH IN THE VOLGA RIVER DELTA].

In the article there are presented the results of a study of halotolerance of enterobacteria isolated from water and fish in the Volga River delta, which were dominant in the microbial landscape of these biotopes. Their halotolerance was studied by means of inoculation of daily pure cultures of meat--peptone broth with 3, 7 and 10% of sodium chloride and incubation at 37°C. At that all studied microflora was found to have significant indices of halotolerance with a predominance of aquatic isolates. At that in 3,0 and 7,0 % NaCl concentrations were very similar, but in 10% NaCl broth the halotolerance of water strain was almost 2.0 times higher than the in fish ones. Among isolated Enterobacteriaceae most halophilic bacteria were from the Proteus group, Citrobacteria and Enterobacteria. The halotolerance of isolated enterobacteria in hydroecosystem of the Volga River delta had seasonal specificity and dynamics. There was established the dynamic growth of this sign in the water and fish strains from spring to autumn. Thus, the analysis of the obtained results of the long-term conducted study has shown the wide dissemination of conditionally pathogenic enterobacteria in water and fish, and their high halotolerance and the ability of some of them to remain viable up to salt production. It gives grounds to recommend the necessity of the introduction of them into the normative documentation in the implementation ofthe sanitary-microbiological control of not only raw materials but also ready salted fish production.

[Features of antibiotic resistance of enterobacteria in the Volga River delta].

In the article there are presented the results of a study of antibiotic resistance of Enterobacteriaceae isolated from water of Volga River delta. Found that all the investigated microflora was established to have acquired multiple antibiotic resistance in dependence on the season of the year and the inhabited area. Minimal antibiotic resistance of Enterobacteriaceae was registered to Tobramycin and Chloramphenicol, the maximal resistance--to Benzylpenicillinum and Ampicillin. The data indicate to the significant persistence of antibiotic-resistant Enterobacteriaceae in hydroecosystems of Volga River delta which can be used as markers of sanitary-epidemiological and ecological trouble of the freshwater hydroecosystems.

[Role of Aeromonas in the monitoring of a hydroecosystem in the Volga-Caspian area].

The paper gives data obtained over many years on the quantity of bacteria of the genus Aeromonas in the hydroecosystems of the delta of the Volga and Caspian Sea and in commercial fishes (sturgeon (Acipenseridae), pike perch (Stizostedion), carp (Cyprinus carpio), silurus (Silurus glanis), etc.). It provides a detailed analysis of their seasonal trends and spatial distribution, markers of their pathogenicity, and antibiotic resistance. The findings suggest that Aeromonas is a causative agent of sapronoses and meets the criteria for natural focal infections. They show a wide range of tolerance to the abiotic factors of hydroecosystems, as well as mixotrophy and autrophic nutrition in the environment and they are of great sanitary and hygienic importance.

[Sanitary and microbiological evaluation of the hydrosystem in the Volga river estuary upon anthropogenic pollution].

The paper gives many years' data on the size of the opportunistic and sanitary-significant microflora of pike perches (Stizostedion) and water in the producer's food fish areas of the Volga river estuary, as well as the results of ecological and microbiological studies of the water from the above areas, which include the determination of the total amount of the bacterial plankton on membrane filters, the number of heterotrophic bacteria, which has provided an assessment of the habitat quality of hydrocoles in accordance with the complex ecological classification of the quality of the land's surface water. The paper analyzes the seasonal abundance and spatial distribution of the most common opportunistic microorganisms, as well as the markers of their pathogenicity.

[Sanitary and microbiological assessment of marketable fish of the Volga-Caspian Sea region]. / Sanitarno-mikrobiologicheskaia otsenka promyslovykh ryb Volgo-Kaspiiskogo regiona.

Opportunistic microbes, such as aeromonads, enterobacteria, and pseudomonads, which are responsible for spoiling fish during its storage and processing and capable to initiate pathological processes of fishes are common in the Volga-Caspian Sea region. Investigations demonstrated that it is necessary to develop new procedures for processing fish products, to carry out studies on regulation of microbiological criteria for assessing fish quality. This makes it necessary to make a bacteriological control of fish at all stages of its production.

[Microbiological contamination of fish in the delta of Volga]. / Mikrobiologicheskaia obsemenennost' ryby v del'te Volgi.

Examining 213 bacteriological samples from 57 pike perch has revealed the high contamination of the fish with Enterobacteria in the branchia and intestine, which spread into the viscera and tissues. In the kidney there prevalent Escherichia coli (27.3%). Enterobacteria (20.), and Edvardsiella (16.6). The liver most commonly displayed yeasts and fungi (18.2%). Citrobacteria (14.3). Acinobacteria (14.3%). Many microbial strains had proteolytic and hemolytic activities and a considerable resistance to sodium chloride (7.5%). Acinobacteria, Providencia, and Proteus remain viable in its 10% solution. The findings suggest that the foods from the pike perch should undergo thermal treatment and a thorough bacteriological monitoring from its raw material to finished products to be made.

[Enterobacteria isolated from commercial fishes from the Volga-Caspian basin]. / Enterobakterii, vysevaemye ot promyslovykh ryb Volgo-Kaspiiskogo basseina.

Enteric bacteria, such as Proteus, Citrobacter [correction of Cytobacter], and Providencia, were found to be prevalent particularly in the gills and intestines of marketable fishes of the Volga and Caspian Seas. Half of all the enteric bacteria was detected in the fish kidneys, spleen, and liver. This shows it necessary to standardize different types of fish raw materials.

[Microbial colonization of the caviar of the sturgeon fishes]. / Mikrobnaia obsemenënnost ikry ryb osetrovykh porod.

Samples of black caviar in 47.7% of cases are contaminated by opportunistic bacteria Aeromonas, Proteus, Vibrio, V. parahaemolyticus. Standardization of these micro-organisms content in black caviar is recommended.

[Microbiological evaluation of water pollution in the Volga delta]. / Mikrobiologicheskaia otsenka zagriazneniia vodnykh obektov delty Volgi.

Bacterial contamination of water and fish in the Volga delta region was studied. Water near large enterprises contained more bacteria than at 75 km a distance of downstream. All organs and tissues of sturgeon contained opportunistic bacteria. Bacterial contamination of water is responsible incidences for acute intestinal diseases of the population.