Antibiotic resistance genes and class 1 integron: Evidence of fecal pollution as a major driver for their abundance in water and sediments impacted by metal contamination and wastewater in the Andean region of Bolivia

Abstract

26Water and sediment samples affected by mining activities were collected from 27 three lakes in Bolivia, the pristine Andean lake Pata Khota, the Milluni Chico lake 28 directly impacted by acid mine drainage, and the Uru-Uru lake located close to 29 Oruro city and highly polluted by mining activities and human wastewater 30 discharges. Physicochemical parameters, including metal compositions, were 31 analyzed in water and sediment samples. Antibiotic resistance genes (ARGs), 32 were screened for, and verified by quantitative PCR together with the mobile 33 element class 1 integron (intl1) as well as crAssphage, a marker of human fecal 34 pollution. The gene intl1 showed a positive correlation with sul1, sul2, tetA and 35 blaOXA-2. CrAssphage was only detected in Uru-Uru lake and its tributaries and 36 significantly higher abundance of ARGs were found in these sites. Multivariate 37 analysis showed that crAssphage abundance, electrical conductivity and pH were 38 positively correlated with higher levels of intl1 and ARGs. Taken together our 39 results suggest that fecal pollution is the major driver of higher ARGs and intl1 in 40 wastewater and mining contaminated environments. 41 3 48 can be incorporated and replicated in environmental microorganisms, thereby 49 increasing their concentration (3). 50 It has been reported that anthropogenic activities cause pollution of aquatic 51 environments with ARGs and MGEs (4). Wastewater discharges cause co-52 occurrence of MGEs and different ARGs in water and sediments (5). At a 53 continental scale, ARGs in sediments are strongly correlated with MGEs and 54antibiotic residues (6). Recently, it has been observed that microorganisms living in 55 aquatic microbial communities that came from wastewater were able to transfer 56 ARGs via horizontal gene transfer (HGT) after exposure to low levels of antibiotics 57 and biocides (7). Many of the ARGs that can be found in clinical settings have also 58 been found in the environment, suggesting the possibility of movement and 59 dissemination between these two scenarios (8). 60Mining activities cause contamination of downstream water with dissolved 61 metals (9) where heavy metals tend to accumulate in sediments (10). It has been 62 suggested that heavy metals can favor selection of ARGs via co-selection, i.e. the 63 simultaneous acquisition of both, ARG and metal resistance genes, where the 64 presence of metals constitutes the selective pressure (11). Several studies support 65 this relation. Urban soil samples of Belfast in Northern Ireland, exhibited a pattern 66 of co-occurrence between metals (Zn, Cu, Cd, Co, Ni, Hg, Cr and As) and many 67 ARGs. Moreover, the degree of metal toxicity was positively correlated with the 68 abundance of MGEs, and ARGs (12). Metals, as Cu and Zncan in some cases 69 exert stronger selection pressure over soil microbial communities for the selection 70 of resistant bacteria, even more than specific antibiotics (13). In the Dongying river 71 in China, the levels of Cu and Cr were positively c...

Metagenomic Investigation of the Short-Term Temporal and Spatial Dynamics of the Bacterial Microbiome and the Resistome Downstream of a Wastewater Treatment Plant in the Iskar River in Bulgaria

“…The enzyme was also prevalent in water from coastal areas and was associated with a variety of host bacteria [78]. Additionally, it was found in higher absolute abundance in effluent WWTPs water compared to upstream locations or downstream locations [53,54,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79], which aligned well with the current results. In this regard, the comparison of acquired resistance and co-occurrence of ARGs and MGEs identified more hits in the first location, Dragushinovo, that is immediately after the WWTP, thus being consistent with the results of other studies [66][67][68][69][70][71][72][73].…”

“…The full potential of high-throughput sequencing data is often not realized, as many studies focus on a limited subset of analyses, such as the detection and analysis of ARGs. While ARG profiling and detection of anthropogenic factors such as intl1 [52][53][54] and ARGs of clinical relevance such as carbapenem hydrolysing variants of OXA, KPC, and NDM is essential for understanding the spread of AMR, they represent only a fraction of the information that can be derived from sequencing data. Our study extended beyond that by integrating metagenome-assembled genomes (MAGs) into our interpretation of the ARGs, by revealing their antimicrobial resistance genetic potential, thus complementing ARG discovery.…”

Prevalence of Antibiotic Resistance Genes in the Saigon River Impacted by Anthropogenic Activities

“…In a recent study, Agramont et al investigated the contamination of ARGs and class 1 integrons in water and sediment samples that were impacted by human wastewater and mining activities. The authors found that fecal pollution was likely a major driver of ARG and intI1 genes in comparison to the heavy metal pollution [66]; however, it was still unclear if there were any synergistic effects from both fecal pollution and heavy metals on the overall levels and spreads of ARGs and integron genes in the considered aquatic environments.…”

Class 1 integrons in clinical and swine industry isolates of Salmonella Typhimurium from Colombia, dating 1997 to 2017

“…There are reports of contamination with traces of mainly β-lactams and aminoglycosides in environmental and food sources [82, 83]. Human and animal faecal contamination of ground and surface water sources has allowed the spread of pathogenic micro-organisms, antibiotics and other contaminants, increasing the abundance of antibiotic resistance genes associated with class 1 integrons in aquatic environments [83, 84].…”