Antibiotic-resistant Escherichia coli in karstic systems: a biological indicator of the origin of fecal contamination?

Abstract

Occurrences of antibiotic‐resistant Escherichia coli in two springs of a karstic system (NW France) providing drinking water were determined to study the role of aquifers in the dissemination of the resistance genes. Water samples were collected during wet and dry periods and after a heavy rainfall event to investigate E. coli density, antibiotic resistance patterns, and occurrences of class 1, 2, and 3 integrons. By observing patterns of the resistant isolates (i.e. number and type of resistances) and their occurrences, we were able to define two resistant subpopulations, introduced in the aquifer via surface water: (1) R1‐2, characterized by one or two resistance(s), essentially to chloramphenicol and/or tetracycline (96.5%), was always found during the heavy rainfall event; (2) R3‐10, characterized by three or more resistances, mostly resistant to tetracycline (94.1%) and beta‐lactams (86%), was found transiently. Class 1 and 2 integrons were detected, mostly in the R3‐10 subpopulation for class 1 integrons. The characteristics of these two subpopulations strongly suggest that the contamination originates from pasture runoff for the R1‐2 subpopulation and from wastewater treatment plant effluents for the R3‐10 subpopulation. These two subpopulations of E. coli could be used as biological indicators to determine the origin of groundwater contamination.

Prevalence of Antibiotic-Resistant Escherichia coli in Drinking Water Sources in Hangzhou City

“…In this study, 49.50% of the E. coli isolated was resistant to at least one of the tested antibiotics (with an ARI of 0.12) and 24.00% exhibited multiple resistances. The levels of antibiotic resistance are comparable to that in other aquatic environments (Chen et al, 2011; Ribeiro et al, 2012; Machado and Bordalo, 2014; Zhang et al, 2014). It indicates the issue of antibiotic resistance is also serious in qualitied source water.…”

“…Notably, 75.51% of multiple resistant E. coli (37/49) in this study was resistant to tetracycline and β-lactams concurrently. E. coli isolates from WWTP effluents or from the aquatic environments contaminated by these effluents, are present consistently resistant to tetracycline and β-lactams, and are associated with at least one other resistance, such as sulfamides, chloramphenicol, quinolones, in any combination (Ribeiro et al, 2012). Thus, a likely hypothesis for the origin of these multiresistant isolates is the WWTP effluents.…”

“…Natural bodies of water, commonly used for irrigation, aquaculture, or recreation activities, are closely associated with human life. Direct or indirect contact with water (for drinking, or recreational use) contaminated by ARB could harm and infecte the human population with antibiotic resistant pathogens, and/or ARGs carried by bacteria may transfer to microorganisms in humans as a consequence of horizontal gene transfer (Chen et al, 2011; Heuer et al, 2011; Ribeiro et al, 2012; Jiang et al, 2013). Such events would undermine our ability to prevent and control disease, and thus expose a great threat to public health.…”

Change in the Structure of Escherichia coli Population and the Pattern of Virulence Genes along a Rural Aquatic Continuum

“…Indeed, the proportion of E. coli harboring class I integron reached 21% in beach water, and ranged between 21 and 11% in estuary water or between 0 and 11% in karst aquifer depending on the hydrological conditions (Flores Ribeiro et al, 2012; Lupo et al, 2012; Moura et al, 2014; Ghaderpour et al, 2015). Indeed, clinical integrons, considered to be xenogenetic contaminants, could be employed as bioindicators of the risk of the spread of antibiotic resistance in the environment (Gillings, 2014; Borruso et al, 2016).…”

Life on the outside: role of biofilms in environmental persistence of Shiga-toxin producing Escherichia coli

“…At this stage, STEC may persist and grow on fresh produce such as lettuce and can be internalized and survive within plant tissue via a mechanism that is not fully understood (Seo and Frank, 1999; Jeter and Matthysse, 2005; Tyler and Triplett, 2008). Furthermore, manure applied to fields often ends up in ground or surface water through runoff; this water is often used to irrigate fields and water crops (Ribeiro et al, 2012). As a consequence, fields and crops that were not treated with manure can become contaminated with STEC.…”