the contrary situation was observed. The percentage of the 

 strains resistant to kanamycin and other aminoglycosides in the 

 Chukchi Sea were considerably higher (77.7 and 92.6% versus 

 17.9 and 28.9% in the Baltic Sea). 



The similar irregularities were found for other genera, 

 isolated from the Chukchi Sea (Table 4). It should be noted that 

 the modal values of MIC of antibiotics for Pseitdomanades 

 from the Chukchi Sea did not exceed (except for methicillin) 

 1 25 |ig/ml. while in similar repre.sentatives of Baltic microflora, 

 the modal MIC values of all antibiotics of the groups of 

 penicillins, chloramphenicol, polymyxin, and nevigramon were 

 1,000 |ag/ml (Table 5). 



TABLE 5 



Modal values of the MIC of antibiotics for murine bacteria, 

 percent. 



TABLE 6 



Antibioticogram of strains of marine Pseudomonades from the 

 Chukchi Sea. 



Note: Modal values of the MIC (jjg/ml) are in the numerator; the 

 proportion of strains with the given modal values (%) in the 

 denominator. 



A similar situation was revealed in the analysis of the 

 modal MIC values for other heterotrophic microorganisms of 

 the. Chukchi Sea. Among the Pseudomonades of both the 

 Chukchi and Baltic Seas, the percentage of those that are shown 

 to be polyresistant to antibiotics is high (92.5%). 



Combination of resistance determinants are presented by 

 18 R-spectra. In contrast to Baltic strains, no dominating 

 R-speclrum was revealed in Chukchi strains (Table 6). 



To determine if it is appropriate to relate the diversity of 

 R-spectra and polyresistance to the antibiotics of the dominating 

 taxonomic groups of heterotrophic microorganisms as criteria 

 of the pollution level of the region under investigation, a 

 comparison of data was obtained for Pseudomonas bacteria, 

 isolated from the Bering, Chukchi, and Baltic Seas (Fig. 1, 

 Table 4). 



In Fig. I, antibiotics were grouped according to the 

 resistance to them by marine microorganisms. Resistance to 

 the first group, comprising ampicillin, kanamycin, and 

 streptomycin, is determined by plasmid genes. Resistance to 

 the second group, comprising benzylpenicillin, methicillin, 

 and monomycin, is determined by chromosomic genes. Figure 

 1 shows that in the Baltic and Chukchi Seas, among bacteria in 

 the genus Pseiidoimmas. the number of strains resistant to the 

 antibiotics is much higher than that in the Bering Sea. In the 

 Baltic Sea, microorganisms of other taxonomic groups were 



more resistant to antibiotics than those in the Chukchi Sea. In 

 the Bering Sea, they were the most sensitive to antibiotics. Of 

 special interest, in the Chukchi Sea, the Pseudomonades and 

 other microorganisms showed more resistance to those 

 antibiotics, which was determined by chromosomic genes. 



Bacteria of the genus Pseudomonas from the impact 

 region of the Baltic Sea possessed a rather high sensitivity to 

 aminoglycosides, especially to gentamicin and kanamycin. 

 Resistance to penicillins was also found in 77.8-93.3% of the 

 cases. In this case, the number of polyresistant strains, having 

 three and more determinants of polyresistance, accounted for 

 95.6%. However, the Baltic strains also possessed the 

 dominating R-spectrum in 42.2% of the strains. 



This information suggests that among the dominant 

 heterotrophic microtlora in the Chukchi and Bering Seas, the 

 formation of strains resistant to antibiotics exists. However, 

 their abundance as a whole is less than in the impact region of 

 the World Ocean, such as the Baltic Sea. Thus, it is possible to 

 state that the percentage of resistance spectra and the level of 

 polyresistant strains in bacterial cenoses reflect the level of 

 pollution in the region. 



Based on toxicological estimates of "stress indices," heavy 

 metals ranks second among pollutants behind pesticides ( Izrael 

 & Tsyban, 1989). Therefore, the abundance of dominant 

 marine bacteria that are resistant to heavy metals, may also 

 characterize the degree of marine pollution. To examine this 

 hypothesis the resistance of Chukchi Sea microflora to Cd, Co, 

 Cu, Ni, Hg, and Ph ions was investigated. Similar responses of 

 the strains from the Baltic Sea were studied for comparison 

 (Tables 7,8). 



106 



