Vulnerability and Resilience of Estuaries to Contamination by Antibiotics and Antibiotic-Resistant Bacteria: a Challenge for the Next Decade - Vulnerability of Coastal Ecosystems and Adaptation - page 82

of the clonal complex “CC17”, sequence of DNA present among the
epidemic hospital strains (Figure 5; [LEA 06]), is maximal among the
strains of Enterococcus faecium isolated in the hospital effluents, and
then decrease along the continuum. This study shows a preferential
disappearance of epidemiologic strains of E. coli and Enterococcus
faecium in favor of other sub-populations of these bacteria species less
resistant to antibiotic and probably better adapted to the aquatic
environment [BER 13, PHA 13, RAT 10].

Figure 2.3(a). Occurence of multiple-resistant strains of E. coli along the medical
center-WWT river continuum: percentage of isolates of E. coli resistant to at least
three antibiotics (dark gray), percentage of isolates of E. coli carrying class1 integron
(light gray) medical center - WWTP river [ORB 11] (see color section)

Figure 2.3(b). Occurence of Enterococcus strains resistant to erythromycin, along
medical center - WWTP - m continuum: (- - -), percentage of Enterococcus strains
resistant to erythromycin (macrolides family), percentage of strains of Enterococcus
resistant to erythromycin carrying corresponding genes ermB ; mefA n ,

ermB+mefA n , unknown genes ( Leclercq et al., 2013) (see color section)