| Abstract | Despite last decades' interventions within local and communitarian programs, the Mediterranean Sea still receives poorly treated urban wastewater (sewage). Wastewater treatment plants (WWTPs) performing primary sewage treatments have poor efficiency in removing microbial pollu-tants, including fecal indicator bacteria, pathogens, and mobile genetic elements conferring resistance to antimicrobials. Using a combination of molecular tools, we investigated four urban WWTPs (i.e., two performing only mechanical treatments and two performing a subsequent conventional secondary treatment by activated sludge) as continuous sources of microbial pollution for marine coastal waters. Sewage that underwent only primary treatments was characterized by a higher content of traditional and alternative fecal indicator bacteria, as well as potentially pathogenic bacteria (especially Acinetobacter, Coxiella, Prevotella, Streptococcus, Pseudomonas, Vibrio, Empedobacter, Paracoccus, and Leptotrichia), than those subjected to secondary treatment. However, seawater samples collected next to the discharging points of all the WWTPs investigated here revealed a marked fecal signature, despite significantly lower values in the presence of secondary treatment of the sewage. WWTPs in this study represented continuous sources of antibiotic resistance genes (ARGs) ermB, qnrS, sul2, tetA, and bla (the latter only for three WWTPs out of four). Still, no clear effects of the two depuration strategies investigated here were detected. Some marine samples were identified as positive to the colistin-resistance gene mcr-1, an ARG that threatens colistin antibiotics' clinical utility in treating infections with multidrug-resistant bacteria. This study provides evidence that the use of sole primary treatments in urban wastewater management results in pronounced inputs of microbial pollution into marine coastal waters. At the same time, the use of conventional treatments does not fully eliminate ARGs in treated wastewater. The complementary use of molecular techniques could successfully improve the evaluation of the depuration efficiency and help develop novel solutions for the treatment of urban wastewater. |
| Text | 461389 2021 10.3390/w13233335 Scopus 2 s2.0 85119995619 16S rDNA fecal bacteria antibiotic resistance marine water sewage potentially pathogenic bacteria Antibiotic resistance genes and potentially pathogenic bacteria in the central adriatic sea Are they connected to urban wastewater inputs Fonti V.; Di Cesare A.; Sangulin J.; Negro P.D.; Celussi M. National Institute of Oceanography and Applied Geophysics OGS, Trieste, 34151, National Institute of Oceanography and Applied Geophysics OGS, 34151, Trieste, Italy, , Italy; Water Research Institute, National Research Council CNR IRSA , Largo Topoli 50, Verbania, 2822, Water Research Institute, National Research Council CNR IRSA , Largo Topoli 50, 2822, Verbania, Italy, , Italy; Institute of Public Health, Zadar, 23000, Institute of Public Health, 23000, Zadar, Croatia, , Croatia Despite last decades interventions within local and communitarian programs, the Mediterranean Sea still receives poorly treated urban wastewater sewage . Wastewater treatment plants WWTPs performing primary sewage treatments have poor efficiency in removing microbial pollu tants, including fecal indicator bacteria, pathogens, and mobile genetic elements conferring resistance to antimicrobials. Using a combination of molecular tools, we investigated four urban WWTPs i.e., two performing only mechanical treatments and two performing a subsequent conventional secondary treatment by activated sludge as continuous sources of microbial pollution for marine coastal waters. Sewage that underwent only primary treatments was characterized by a higher content of traditional and alternative fecal indicator bacteria, as well as potentially pathogenic bacteria especially Acinetobacter, Coxiella, Prevotella, Streptococcus, Pseudomonas, Vibrio, Empedobacter, Paracoccus, and Leptotrichia , than those subjected to secondary treatment. However, seawater samples collected next to the discharging points of all the WWTPs investigated here revealed a marked fecal signature, despite significantly lower values in the presence of secondary treatment of the sewage. WWTPs in this study represented continuous sources of antibiotic resistance genes ARGs ermB, qnrS, sul2, tetA, and bla the latter only for three WWTPs out of four . Still, no clear effects of the two depuration strategies investigated here were detected. Some marine samples were identified as positive to the colistin resistance gene mcr 1, an ARG that threatens colistin antibiotics clinical utility in treating infections with multidrug resistant bacteria. This study provides evidence that the use of sole primary treatments in urban wastewater management results in pronounced inputs of microbial pollution into marine coastal waters. At the same time, the use of conventional treatments does not fully eliminate ARGs in treated wastewater. The complementary use of molecular techniques could successfully improve the evaluation of the depuration efficiency and help develop novel solutions for the treatment of urban wastewater. 13 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85119995619 origin=inward Articolo in rivista Molecular Diversity Preservation International 2073 4441 Water Basel Water Basel Water Basel Water. Basel andrea.dicesare DI CESARE ANDREA |
