Occurrence and ecological determinants of the contamination of floodplain wetlands with Klebsiella pneumoniae and pathogenic or antibiotic-resistant Escherichia coli.

Abstract

The survival and multiplication of human pathogenic and antibiotic-resistant bacteria in ecosystems is of increasing concern but has been little explored. Wetlands can be contaminated by water fluxes from rivers and may present environmental conditions leading to bacterial survival and multiplication. To test this hypothesis, we sampled 16 wetlands located along three rivers of the Jura Massif, France. The bacterial contamination of the wetland and river waters was measured monthly over a one-year cycle together with the water physico-chemical characteristics. We assessed the abundance of three pathogenic species: Escherichia coli,Klebsiella pneumoniaeand Pseudomonas aeruginosa. The concentrations of E. coli producing extended-spectrum β-lactamase (ESBL E. coli) or belonging to the phylogenetic group B2 (E. coli B2–more pathogenic) were also measured. We found that rivers carried total E. coli, ESBL E. coli, and K. pneumoniae to wetlands. ESBL E. coli poorly survived in wetlands, whereas total E. coli and K. pneumoniae possibly met favourable physico-chemical conditions for survival and multiplication in these habitats. K. pneumoniae peaked in summer in warm and shallow wetlands. Total E. coli and E. coli B2 potentially reached wetlands through sources other than rivers (hillslope groundwater or leaching from contaminated fields).

Using GFP-Tagged Escherichia coli to Investigate the Persistence of Fecal Bacteria in Vegetated Wetlands: An Experimental Approach

“…To ensure that the experimental conditions were as close as possible to the natural ones (sediment composition, plants and temperature), we referred to natural wetlands of the Ain River in the Jura Massif (France) that have already been studied for bacterial contamination [14]. Rhizotrons were filled with artificial sediment prepared according to the sediment composition of six natural wetlands of the Ain River and those referred in the literature [52,53].…”

“…This species is a commensal of human and animal guts and is released into the environment through feces [ 11 , 12 ]. Once in the environment, the bacteria disperse and reach different ecosystems such as surface water, including wetlands, in which they potentially survive [ 13 , 14 ].…”

High Prevalence of Human-Associated Escherichia coli in Wetlands Located in Eastern France

“…However, its survival is influenced by many factors, such as the carbon sources, temperature, pH, and availability of water ( van Elsas et al, 2011 ). Here, we collected human-associated and 3GC-R isolates from a wide range of conditions (see Henriot et al, 2019 for details). Continuous discharge from WWTPs could explain the high proportion of human-associated E. coli isolates retrieved in low-anthropized environments.…”

“…We previously determined that the concentration of total E. coli was higher in the rivers than in the wetlands with no significant differences in concentrations between wetlands (Henriot et al, 2019). We then divided 125 E. coli isolates into phylogroups and found a high proportion of isolates belonging to phylogroups A and B2, representing half of the isolates retrieved (48.8%).…”

“…Although E. coli contamination of rivers or lakes has been well-documented (Michael et al, 2013), that of wetlands has been less investigated. Indeed, the studied wetlands have varying degrees of connection with the river, can be supplied in water either by the river or by groundwater, and the physical and chemical parameters can vary from those of the river (Henriot et al, 2019). It has been reported that E. coli can survive and grow in the environment (Jang et al, 2017).…”