Fig. S1. A. Chemical characteristics of municipal waters tap 1 and tap 2. Parameters below the limit of detection are expressed as < than detection limit values. Parameters with at least threefold difference between tap 1 and tap 2 are highlighted in grey. The only parameter detected exclusively in tap 1 but in tap 2 is copper (0.079 mg l−1 = 1.2 μM). B. Overview of all validated parameters above the detection limit.

Fig. S2. DIC images of E. coli strains K12 (C600), O157:H7 (EDL933), and O104:H4 (HUSEC041). Strains were grown over night in LB broth to stationary phase and were then imaged at 1000-fold magnification (A–C). Cell dimensions were compared for K12 and EHEC or EHEC/EAEC strains (including the 2011 outbreak strain 11-02027) (D). The results represent the means and standard deviations of at least 200 measured cells per strain. For the E. coli O104:H4 outbreak strain as well as EDL933 and HUSEC041 strains diameter and length were significantly different from E. coli K12 (P < 0.01 for diameter and length; Student&apos;s t-test).

EMI_2604_sm_fS1.tif1790KSupporting info item
EMI_2604_sm_fS2.tif1972KSupporting info item

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