engleski

Prevalence of antibiotic resistance genes for extended-spectrum β-lactams and carbapenems in wastewater from Croatian wastewater treatment plants

Excessive use of antibiotics in human and veterinary medicine has led to an increased number of multi-drug resistant bacteria carrying multiple genes for antibiotic resistance. Penicillins as one of the most used drugs, early became useless against antibiotic resistant bacteria. For this reason, more antibiotics such as extended-spectrum β-lactams and carbapenems are used. Although they are very effective in bacterial degradations, and carbapenems are considered to be the last line of defense against resistant bacteria, an increase in bacteria overcoming the effects of antibiotics became a worldwide problem. Wastewater treatment plants (WWTPs) are considered one of the main pathways, along with clinical settings, for the dissemination of antibiotic resistance in the environment. The selective pressure of antibiotics and other pollutants during the treatment can create conditions for horizontal gene transfer (HGT), and antibiotic resistant genes (ARGs) can easily be acquired by various bacteria, not only in WWTPs but in downstream environments. Using the quantitative PCR (qPCR) extended-spectrum β- lactamases genes (blaTEM and blaCTX-M-32), and carbapenemases genes (blaKPC-3, blaOXA-48-like, blaNDM, blaVIM, and blaIMP) were quantified from influents and effluents in 7 Croatian WWTPs during the winter and summer season. The most abundant were blaTEM and blaCTX-M-32, as they were found in most influents and were only slightly reduced or enriched in effluents. On the other hand, carbapenemase genes like blaKPC-3, blaOXA-48-like, and blaNDM were sporadically detected, mostly in influents. In addition, blaIMP and blaVIM were mostly enriched during the treatment. The observed results suggest that conventional WWTPs are not adequate for ARGs reduction and prevention of aquatic environment contamination. Improvements in wastewater treatment technologies, and better monitoring, are needed to minimize the impact of environmental pollution, consequently affecting human health.

wastewater treatment plants ; ESBL ; carbapenemases ; antibiotic resistant genes

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