• January 31, 2022

Antibiotic resistance is one of the biggest threats to global health, emerging as one of the major causes of death in the coming decades (WHO). Antibiotic resistance is maintained by the antibiotic resistance genes (ARGs). These genes can spread in the bacterial population, which makes the antibiotic ineffective. The ARGs are considered as pollutants because they are found not only in the clinical environment, but far beyond. On the contrary to the other pollutants, genes of a-resistance can “reproduce” and spread in the populations of bacteria far away from the places, where they originated from.

Within the framework of the EU-UNDP project “Improving environmental monitoring in the Black Sea” (EMBLAS-Plus), the distribution of ARGs was investigated in the Black Sea water samples at a region-wide scale, including shelf and offshore areas. Sampling stations were investigated on a transect from northwest shelf (near Danube Delta) to eastern shelf (coast of Georgia). Researchers studied ARGs targeting a wide spectrum of antibiotics (beta-lactams, macrolides, glycopeptides, colistin) including both first-line and last-resort antibiotics.

All studied ARGs were detected in all of the studied samples. The number of ARGs inactivating beta-lactams, vancomycin, were the most numerous. The elevated number of colistin resistance mcr-1 gene is of particular interest, as this gene was reported in Black Sea microbial communities for the first time.

ARGs were significantly higher in number in the shelf areas compared to the open waters, which signals involvement of the anthropogenic impact on the natural resistome of the water ecosystem. The ARGs targeting beta-lactams, vancomycin and last resort antibiotic colistin were of the highest abundance in the northwest shelf, which might be attributed to poorly controlled antibiotic consumption in the riparian countries. The observed correlation between blaCMY, blaSHV and mcr-1 with the Bacteroidetes common to the ruminant microbiome indicates that the potential sources of ARGs in the Black Sea are the riverine and sewage inflow and, to the lesser extent, application of veterinary pharmaceuticals.

The results of the study are presented in the paper “Antibiotic Resistance In Black Sea Microbial Communities” accepted to publication by “Frontiers in Environmental Science” (special issue “Antibiotics and Antibiotic Resistance Genes in Waters: Pollution, Risks, and Control”)

We congratulate the authors Ievgeniia Prekrasna, Mariia Pavlovska, Artem Dzhulai, Evgen Dykyi, Nikiforos Alygizakis and Jaroslav Slobodnik with such an important and highly relevant study! It is a pity, that the study has highlighted one more painful environmental problem of the Black Sea. But identification of such problems are one of the tasks of the scientists, so that decision-makers could take relevant steps towards their solution.