Quantitative PCR Monitoring of Antibiotic Resistance Genes and Bacterial Pathogens in Three European Artificial Groundwater Recharge Systems

Abstract

Aquifer recharge presents advantages for integrated water management in the anthropic cycle, namely, advanced treatment of reclaimed water and additional dilution of pollutants due to mixing with natural groundwater. Nevertheless, this practice represents a health and environmental hazard because of the presence of pathogenic microorganisms and chemical contaminants. To assess the quality of water extracted from recharged aquifers, the groundwater recharge systems in Torreele, Belgium, Sabadell, Spain, and Nardò, Italy, were investigated for fecal-contamination indicators, bacterial pathogens, and antibiotic resistance genes over the period of 1 year. Real-time quantitative PCR assays for Helicobacter pylori, Yersinia enterocolitica, and Mycobacterium avium subsp. paratuberculosis, human pathogens with long-time survival capacity in water, and for the resistance genes ermB, mecA, blaSHV-5, ampC, tetO, and vanA were adapted or developed for water samples differing in pollutant content. The resistance genes and pathogen concentrations were determined at five or six sampling points for each recharge system. In drinking and irrigation water, none of the pathogens were detected. tetO and ermB were found frequently in reclaimed water from Sabadell and Nardò. mecA was detected only once in reclaimed water from Sabadell. The three aquifer recharge systems demonstrated different capacities for removal of fecal contaminators and antibiotic resistance genes. Ultrafiltration and reverse osmosis in the Torreele plant proved to be very efficient barriers for the elimination of both contaminant types, whereas aquifer passage followed by UV treatment and chlorination at Sabadell and the fractured and permeable aquifer at Nardò posed only partial barriers for bacterial contaminants.

Occurrence of Tylosin-Resistant Enterococci in Swine Manure and Tile Drainage Systems under No-Till Management

“…The identification of tylosin resistant genes present in enterococci was confirmed by PCR (Bockelmann et al, 2009;Sutcliffe et al, 1996b). Colonies isolated on mE agar from swine manure, soil, tile water samples in each simulation were grown on BHI Agar slants before extraction for PCR analysis.…”

“…The employment of PCR in detecting resistant genes have been well documented (Baele et al, 2000;Bockelmann et al, 2009;Chen et al, 2007;Dutka-Malen et al, 1995;Kariyama et al, 2000;Ke et al, 1999;Luthje and Schwarz, 2007;Sutcliffe et al, 1996b).…”

“…The most common is real-time PCR or quantitative PCR, in which the amplication process can be monitored when a flourescent dye or a florescently labelled probe is added to the PCR reaction (Bockelmann et al, 2009;Chen et al, 2007). Real-time PCR enables both detection and quantification of one or more specific sequences in a DNA sample.…”

“…The polymerase chain reaction (PCR) is now widely used to enable detection of low levels of target sequences, and it has become a key procedure in the detection and identification of bacteria and genes from a variety of environments including soil, water, and fecal materials (Bockelmann et al, 2009;Lucena et al, 2006;Sapkota et al, 2007). The employment of PCR in detecting resistant genes have been well documented (Baele et al, 2000;Bockelmann et al, 2009;Chen et al, 2007;Dutka-Malen et al, 1995;Kariyama et al, 2000;Ke et al, 1999;Luthje and Schwarz, 2007;Sutcliffe et al, 1996b).…”

Occurrence of antibiotic resistance genes in reclaimed water and river water in the Werribee Basin, Australia

“…Water is a vector for the transfer of ARGs from human and animal waste into the natural environment (JETACAR 1999;Witte 2000;Chee-Sanford et al 2001;Koike et al 2007;Baquero et al 2008) and the aquatic environment has been identified as a reservoir for antibiotic resistance (Biyela et al 2004;Martinez 2008). Only in recent years has there been increased interest in the prevalence of antibiotic-resistant organisms or genes in waterways and waste water (Zhang et al 2009), although very few studies have investigated highly treated effluent (Bockelmann et al 2009). This research was aimed at evaluating the possible input of antibiotic resistance from a relatively new source -reclaimed water -which has the potential to act as another contamination source back into agriculture.…”