Adhesion of Aeromonas hydrophila to water distribution system pipes after different contact times

Scanning electron microscopy observation was used to investigate the ability of Aeromonas hydrophila to attach to various water distribution pipe surfaces, such as stainless steel, copper, and polybutylene, after different contact times at ambient and storage temperatures. Surface energy value of each surface was estimated by contact angle measurements using water, alpha-bromonaphthalene, and dimethyl sulfoxide. Our results indicated that Aeromonas cells could easily attach to all surface types after exposures as short as 1 or 4 h at both temperatures (4 and 20 degrees C). Polybutylene, a low-energy surface (41.2 mJ.m-2), followed by stainless steel (65.7 mJ.m-2), was most colonized by Aeromonas cells, whereas few cells were observed on copper, which has a surface energy of 45.8 mJ.m-2. Extracellular materials could also be observed on polybutylene surfaces, especially after 1 and 4 h of exposure at the refrigeration temperature.