Reactivity of phages pools selected by affinity strategies at each selection round by ELISA. Microtiter plate was coated with anti-phage antibody (1:800) and incubated with 2 × 1010 phages/mL followed by the addition of IgG (100 μg/mL). The detection of the reaction was performed with peroxidase conjugated anti-human antibody and OPD as chromogen. Values of absorbance at 492 nm are means of duplicates. Wild phage was used as negative control.