Details

Autor(en) / Beteiligte

• Korzeniewska, Ewa
• Harnisz, Monika

Titel

Relationship between modification of activated sludge wastewater treatment and changes in antibiotic resistance of bacteria

Ist Teil von

• The Science of the total environment, 2018-10, Vol.639, p.304-315

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2018

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Biological treatment processes at wastewater treatment plants (WWTPs), which are the most common methods of sewage treatment, could cause selective elimination and/or changes in the proportions of phenotypes/genotypes within bacterial populations in effluent. Therefore, WWTPs based on activated sludge used in sewage treatment constitute an important reservoir of enteric bacteria which harbour potentially transferable resistance genes. Together with treated wastewater, these microorganisms can penetrate the soil, surface water, rural groundwater supplies and drinking water. Because of this, the aim of this study was to determine the impact of various modification of sewage treatment (the conventional anaerobic/anoxic/oxic (A2/O) process, mechanical-biological (MB) system, sequencing batch reactors (SBR), mechanical-biological system with elevated removal of nutrients (MB-ERN)) on the amount of antibiotic resistant bacteria (ARB) (including E. coli) and antibiotic resistance genes (ARGs) in sewage flowing out of the 13 treatment plants using activated sludge technology. There were no significant differences in ARB and ARGs regardless of time of sampling and type of treated wastewater (p > 0.05). The highest percentage of reduction (up to 99.9%) in the amount of ARB and ARGs was observed in WWTPs with MB and MB-ERN systems. The lowest reduction was detected in WWTPs with SBR. A significant increase (p < 0.05) in the percentage of bacteria resistant to the new generation antibiotics (CTX and DOX) in total counts of microorganisms was observed in effluents (EFF) from WWTPs with A2/O system and with SBR. Among all ARGs analyzed, the highest prevalence of ARGs copies in EFF samples was observed for sul1, tet(A) and qepA, the lowest for blaTEM and blaSHV. Although, the results of presented study demonstrate high efficiency of ARB and ARGs removal during the wastewater treatment processes, especially by WWTPs with MB and MB-ERN systems, EFF is still an important reservoir of ARGs which can be transferred to other microorganisms. [Display omitted] •The number of ARB and ARGs in 13 WWTPs’ influents & effluents were investigated•The percentage of ARB in total bacteria counts increased in effluents compared to WWTP’s influents•The highest counts of ARGs copies in wastewater samples were observed for sul1, tet(A) and qepA•The abundances of ARB and ARGs were related to the applied modification of sewage treatment•The significant increase in ARB and ARGs number was observed in WWTP’s effluents with A2/O and SBR system