In 2016 and 2017 the study and analysis of the prevalence of opportunistic pathogenic microorganisms (OPM), resistant to antibacterial drugs in the water reservoirs of Rostov-on-Don were carried out. 1522 strains were isolated and 101 species of microorganisms were identified. In 2016 the percentage of nonfermentative microorganisms (NFM) was 45,9 %, Enterobacteriaceae – 28,6 % and Aeromonadaceae – 24,9 %. In 2017 dominating were the representatives of Aeromonadaceae (39,1 %) and Enterobacteriaceae (37,5 %), the portion of NFM amounted to 23,0 %. The results of OPM antibiotic resistance study demonstrate that in 2017 the proportion of sensitive and monoresistant bacteria considerably decreased, and the number of strains with multiple antibiotic resistances increased. The resistant strains isolated from the external environment should be considered as possible sources of threats to biological security.

In this paper, the results of an investigation of the diversity in microflora species in water bodies of Rostov-on-Don are presented. Susceptibility/resistance of isolated strains to antibacterial drugs (ABD) was studied. A portion of nonfermenting microorganisms (NFMs) constituted of 42.9 %, Enterobacteriaceae family - 28.2 %, Aeromonadaceae family - 23.7 %. In NFM group the sensitivity to all ABD was exhibited by 37.5 % of strains, 43.4 % of strains showed resistance to one antibiotic and 6.3 % were polyresistant (resistance to 3 and more antibiotics). No susceptible strains were detected among Enterobacteriaceae. The resistance to 3 or more ABD for Enterobacteriaceae accounted for 80 %, for Aeromonas - 72 %. In all groups of tested microorganisms, results of the investigation showed a high proportion of strains susceptible to ciprofloxacin, doxycycline, ceftriaxone, levomycetin, gentamicin, imipenem, meropenem, cefoperazone, cefepime. Among Enterobacteriaceae and Aeromonas strains isolates carrying the markers of resistance to ampicillin, nalidixic acid, furagin, co-trimoxazole were found frequently. The performed research of microbial communities in water bodies of Rostov-on-Don made it possible to identify dominant groups of microorganisms in the investigated objects, to reveal pathogenic and opportunistic bacteria, evaluate their antimicrobial resistance with the aim to determine a degree of their potential danger to human health

Toxins - molecular weight compounds produced by microorganisms, animals, plants and possessing antigene properties. Recently due to the perceived threat of terrorist actions identification of a number of bacterial toxins is especially important. A new approach in the identification of toxins associated with the development of mass spectrometry and can be successfully used for analysis of most environmental toxins. The method of MALDI-MS allows the detection of toxins such as Shiga-toxin Escherichia coli, delta-toxin of Staphylococcus aureus, Bacillus cereus particular, botulinum neurotoxin, cholera toxin. Analytical and diagnostic characteristics of the method, the simplicity and speed studies indicate the long term implementation of a method in the practice of laboratory diagnostics in determining toxinproducing of the studied microorganisms.

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