engleski

Bacterial resistance to carbapenems in Zagreb wastewater

The increasing prevalence of enterobacteria resistant to carbapenems, antibiotics that are the last resort for treating infections caused by multidrug-resistant Gram-negative bacteria, is a worrisome problem that has reached global proportions. Sewage treatment plants can be reservoirs and sources for the spread of these bacteria in natural watercourses, as well as on land through irrigation, posing a risk to human health. The aim of this study was to isolate and characterize enterobacteria (200 isolates) showing resistance to carbapenems in treated wastewater from the central wastewater treatment plant of the city of Zagreb. Sensitivity of bacterial isolates to 3 carbapenems (ertapenem, imipenem, meropenem) was tested by the microdilution method, and most isolates were resistant to all 3 carbapenems tested. The colorimetric CarbaNP assay confirmed that carbapenem resistance was mediated by carbapenemase production in most of the isolates tested. Most isolates also exhibited a multidrug- resistant phenotype, i.e., resistance to at least 3 classes of antibiotics. PCR analysis confirmed the presence of clinically relevant genes for carbapenemases (blaKPC, blaNDM, blaVIM, blaIMP, or blaOXA-48) in most of the isolates tested. The results of this study suggest that treated municipal wastewater is a reservoir of clinically relevant enterobacteria resistant to carbapenems and that additional disinfection measures are needed to prevent their further spread within and outside the environment.

antibiotic resistance ; carbapenems ; enterobacteria ; wastewater ; sewage treatment plant

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