Abstracts

Water Ecosystems

In connection with growing anthropogenic influence on natural ecosystem more and more actual there is a problem of distribution of resistance to antibiotics among microbial populations. Especially sharply this problem is shown for medical used ecosystems, and thus, the big value for humankind. Sample of such ecosystems is the Shira Lake (republic Khakasia).

Heterotrophic bacteria of lake are differed by halotolerance degree. Nonhalophils (resistant to 0-3 % NaCl) are dominant in lake), but also are present marine (resistant to 0 - 5 % NaCl), and moderate (resistant to 0 - 12 %) halotolerance bacteria. Antibiotic resistance dynamics of these groups of bacteria are very complicated. The mathematical model (based of system of the differential equations) was developed for the analysis of various ways of origin of resistance to antibiotics. The complicated model of antibiotic resistance distribution in lake consists of separate systems of the differential equations describing homogenic dynamics of resistance to antibiotics in separate parts of a lake (so-called "chambers") and interactions between these "chambers".

The central part of lake (as the most far from anthropogenic inputs) is most interesting for dynamics antibiotic resistance studies. With the help of mathematical model, the natural data of heterotrophic bactiria resistence to ampicillin and kanamycin at summer 1999 in the center of lake and a resort zone (as the most subject to anthropogenic influence) were analyzed.

With the help of mathematical model, the natural data of heterotrophic bacteria resistance to ampicillin and kanamycin at summer 1999 in the center of lake and a resort zone (as the most subject to anthropogenic influence) were analyzed.

It is shown that in a resort zone, in the middle of a summer, a share of multiple resistance bacteria is sharply increased (up to 100 %), and that, in our opinion, is connected to anthropogenic load. However, influence of anthropogenic factors on the central part of lake much lower in comparison with a resort part. As the mathematical model shows, the account of influence only the anthropogenic factor is obviously insufficient for an explanation of antibiotic resistance dynamics in the central part of Shira Lake. Probably, there should be some natural (nonanthropogenic) factor that appeared at the middle and at the end of the summer. This factor may be algae bloom, and such conception is well coordinated both real dynamics of algae grown and with the account data of model.

The work was supported by grants: Federal Special Purpose Program ''Integration'' № 73; RFBR 01-05-64146.

Note. Abstracts are published in author's edition

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