Infectious bacterial biofilms represent a threat to public health, industry and economy. They are also considered as harmful organisms for marine animals, water systems, and food processing industry. In this paper, a method of rapidly growing antibacterial ZnO nanowire coatings on a variety of substrates using a fibre laser was demonstrated. Pure well ordered, hexagonal Wurtzite ZnO nanowires of around 90 nm diameter and 1.7 µm in length were successfully formed on a stainless steel, Cu, ITO coated glass and FTO coated glass substrates using a laser-induced hydrothermal process. The coating has been found to be rapidly switchable between being superhydrophobic and superhydrophilic with UV light irradiation. The findings show that long-term (e.g. 4 months) antibacterial properties against Escherichia coli (E. coli) bacteria under standard laboratory light and dark conditions were achieved. A micro/nanoflower-like structure was also produced by tuning the pH value of the used aqueous solution. The flower-like structure also showed high antibacterial activities.