Resistance of Escherichia coli and Enterococcus spp. to selected antimicrobial agents present in municipal wastewater

Abstract

In this study, the susceptibility to erythromycin (E) and to trimethoprim/sulfamethoxazole (SXT) among isolates of Enterococcus spp. and Escherichia coli was tested, respectively. Both fecal indicators were detected and isolated from raw (RW) and treated wastewater (TW) as well as from samples of activated sludge (AS) collected in a local wastewater treatment plant (WWTP). Biodiversity of bacterial community in AS was also monitored using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Additionally, distribution of sul1-3 genes conferring sulfonamide resistance was tested among SXT-resistant E. coli. Simultaneously, basic physicochemical parameters and concentrations of eight antimicrobial compounds (belonging to folate pathway inhibitors and macrolides class) were analyzed in RW and TW samples. Six of the selected antimicrobial agents, namely: erythromycin, clarithromycin, trimethoprim, roxithromycin, sulfamethoxazole, and N-acetyl-sulfamethoxazole were detected in the wastewater samples. Bacterial biodiversity of AS samples were comparable with no relevant differences. Among tested Enterococcus spp., E-resistant isolates constituted 41%. SXT resistance was less prevalent in E. coli with 11% of isolates. The genes conferring resistance to sulfonamides (sul1-3) were detected in SXT-resistant E. coli of wastewater origin with similar frequencies as in other environmental compartments, including clinical ones.

Evaluation of a Parchment Document, the 13th Century Incorporation Charter for the City of Krakow, Poland, for Microbial Hazards

“…The Shannon biodiversity index was calculated. It expresses the diversity of microbial genotypes in an investigated environment, which in this study was the surface of the document (32).…”

Do antibiotics have environmental side-effects? Impact of synthetic antibiotics on biogeochemical processes

“…Many of the studies report an inventory of antibiotic resistance genes (Nesme et al 2014) and many address bacteria in aquatic environments (for review see Kümmerer 2009b) or soils (Gatica and Cytryn 2013). The resistance of bacterial species used as fecal indicators was also often investigated (Luczkiewicz et al 2013;Servais and Passerat 2009). However, despite the proliferation of environmental antibiotic studies in general, relatively few have considered the impact of antibiotics on Becosystem health^ (Gu 2014).…”

The treatment of wastewater containing pharmaceuticals in microcosm constructed wetlands: the occurrence of integrons (int1–2) and associated resistance genes (sul1–3, qacEΔ1)

“…To date, besides sul 1, only two other genes encoding sulfonamide resistance ( sul 2–3) have been identified (Sköld 2001 ) . The sul 2 gene was considered to be mainly located on small non-conjugative plasmids (Radstrom et al 1991), whereas s ul 3 was reported in animals as well as human-liked sources (Luczkiewicz et al 2013; Perreten and Boerlin 2003) and associated with non-classic class 1 integrons (Antunes et al 2005). Most previously described class 2 integrons contain the same array of four gene cassettes, three antibiotic resistance gene cassettes ( dfrA1 , sat , and aadA1 ), conferring resistance to trimethoprim, streptothricin, and spectinomycin/streptomycin, respectively, and the orfX cassette of unknown function (Flores et al 1990).…”

“…Since SMX is excreted mainly in unchanged form, it has been also frequently found in the sewage systems. In the effluents from wastewater treatment plants (WWTPs), SMX was detected in the range from 0.004 to 9.46 μg/L (Trovó et al 2009; Loos et al 2010; Fatta-Kassinos et al 2011; Luczkiewicz et al 2013), while in the receiving waters up to 4 μg/L (Barnes et al 2008). …”