Are Sewage Treatment Plants Promoting Antibiotic Resistance?

Abstract

There is widespread speculation that sewage treatment plants (STPs) and aquatic environments in general may be breeding grounds for antibiotic resistant bacteria. We examine the question of whether low concentrations of antibiotics in STPs can provide or contribute to a selective pressure facilitating the acquisition or proliferation of antibiotic resistance among bacteria in the receiving environment. Examination of available literature suggests that relative levels of antibiotic resistance may be increased during sewage treatment processes. However, it is unclear whether this may be partially the result of horizontal gene transfer or entirely due to clonal propagation. While there is circumstantial evidence that the presence of antibiotics or other related genetic promoters in STP wastewaters may contribute to selective pressures for these processes, a definite role is yet to be demonstrated. Future researchers would benefit from the application of non-culture-based techniques because culture limits the possible observations to a small subset of STP microbial diversity.

Sustainability of Water Reclamation: Long-Term Recharge with Reclaimed Wastewater Does Not Enhance Antibiotic Resistance in Sediment Bacteria

“…Garcia-Armisen et al [44] sampled rivers characterized by different levels of recent sewage pollution and found no relation between the level of sewage pollution and the proportion of AR in heterotrophic bacteria for any of the tested antimicrobials. Others warn that correlations between antibiotic concentrations and AR do not provide confirmation of a cause-effect relationship [5], pointing out that a correlation would be expected on the basis that both the antibiotics and bacterial isolates were derived from a common source, excreted by humans and discharged into the environment via sewage outfalls. Moreover, recent work has reported preferential elimination of non-resistant subsets of bacteria during wastewater treatment [45], suggesting that that the preferential elimination of susceptible organisms rather than their resistant counterparts may have an important contribution to AR increase.…”

“…Unfortunately, most wastewater treatment plants (WWTPs) are not designed for the removal of these micropollutants [3,4] and as a result, residual antibiotics are released into the environment with treated wastewater [5]. Since the late 1990s, many classes of antibiotics have been reported in raw sewage and treated wastewater, including beta-lactams [6], sulfonamides, trimethoprim, and macrolides [7], fluoroquinolones [8], and tetracyclines [9].…”

Impact of Manure Fertilization on the Abundance of Antibiotic-Resistant Bacteria and Frequency of Detection of Antibiotic Resistance Genes in Soil and on Vegetables at Harvest

“…The abundance, types of resistance, and distribution of resistance in populations of commensal and pathogenic bacteria vary enormously, no doubt due to varied factors, in particular exposure of the enteric flora to antibiotics in human medicine or as commonly employed in commercial animal production (9,10). Emissions of antibiotic residues and resistant bacteria from various human activities, including animal production, fish production, wastewater treatment, and antibiotic manufacturing, will increase the burden of antibiotic resistance in exposed environmental matrices (11)(12)(13)(14)(15)(16). The abundance and the mobility of antibiotic resistance genes in agricultural soils may be enhanced by various management practices, for example, the application of animal manures, wastewater, or waste treatment residues that contain antibiotic resistance genes on mobile elements and antibiotic residues (17)(18)(19)(20).…”

Sulfonamides in the environment: a review and a case report

“…All important topics are covered, e.g., general information on common types of sulfonamides polluting the environment (Baran et al 2011;Zhang and Li 2011), sample preparation (Namera et al 2011;Samanidou and Karageorgou 2011), and analytical methods used for sulfonamide detection, namely HPLC (Seifrtova et al 2009;Tolika et al 2010), capillary electrophoresis (Garcia-Campana et al 2009;Pinero et al 2011), and immunoassays (Nesterenko et al 2009). Some reviews deal with resistance (Le-Minh et al 2010;Jury et al 2011), or the degradation of different pollutants, sulfonamides included (Sharma 2010). The same topics Contamination of the environment, mainly soil and surface water, is a worldwide problem.…”