Background: Trace elements (heavy metals) due to their natural and industrial processes are increasingly found in microbial habitats. Enterococci, as the important human pathogens in both community and hospital infections, have shown exhibit intrinsic resistance to various antibiotics and antimicrobial agents. One of the contamination resources is the presence of the bacteria in bathing waters.

Materials and Methods: During a year, this study was performed on 180 samples which collected in 15 prefectures in western regions of Guilan province (Astara, Talesh and port of Anzali). The samples were analyzed to evaluate the amount of heavy metals and the presence of resistant Enterococci to some heavy metals and then the parameters including dissolved oxygen, pH, phosphate and Nitrate contents were measured. Enumeration of bacteria performed with the MPN method. Confirmation of isolated Enterococcus spp. was carried out using the chemical and differential tests. In addition, amount of heavy metals in water samples determined by the atomic absorption method. The Microdilution broth technique was used to determine the susceptibility of isolated Enterococcus spp to the heavy metals (Fe, Pb, Co, Zn, Cr, and Cd).

Results: Out of 180 samples, the presence of Enterococcus was confirmed in 135 cases (68 cases of E. faecium, 36 E. faecalis). Lead was the most common metal measured compared to the other heavy metals. All of the Enterococci strains showed the high-resistance level against Lead, Zinc and Ferrous.

Conclusion: Heavy metals can enter into the environment through the different sources and cause an irreversible affect on different organisms. Based on the several studies, Enterococci are able to transfer the resistant genes to other opportunistic bacteria. Moreover, the bacteria that carry the genes resistant against metals can also develop resistance against antibiotics. Thus, the treatment of the infectious diseases can be more problematic and costly.