Halotolerance of pseudomonads isolated from aquatic environment and fish (Sander lucioperca) in the Volga River delta

Introduction. The material shows halophiles bacteria R. Psendomonas the water’s microbiota and the pikeperch in spring and autumn. The attachment of Pseudomonas isolated from these habitats, certain Delta areas has not been identified. 

Materials and methods. 190 “water” strains and 720 ones isolated from fish were experimentally tested. In meat-peptone broth (MPB) with 3.0, 7.0, and 10.0% NaCl content, daily cultures of analyzed bacteria were sown, incubation of which was carried out at 37 °C, and the results were taken into account after 24 and 48 hours.

Results. There were no significant differences in halophilicity in the analyzed strains, except for the autumn season, especially in 10.0% salt solution. Among the isolated pseudomonads, the maximum halotolerance in both biotopes was observed in P. fluorescens and P. alcaligenes in P. putida.

Halophiles strains of Pseudomonas that infect the water and fish had seasonal cycles. A slight decrease in the halophilicity of pseudomonades persistent in water and fish only at concentrations of 3.0 and 10.0 mg/l from spring to summer (1.1-1.2 times), and their significant rise in autumn (1.5 and 1.4 times) in the salt concentration of 3.0 mg/l. In the tested strains in spring and autumn, increased salt tolerance values were noted, which was determined by the hydrological and hydrochemical features of Delta waters and the “transfer” of bacteria in the body of walleye during its migration from the sea to the river.

Conclusion. Analysis of long-term material showed high halophiles studied strains of pseudomonad, indicating that their sanitary and epidemiologic danger, and the ability to remain viable in salted fish products