The bacterial lifecycle in cotton and polyester textiles

Colonization of textiles and subsequent metabolic degradation of sweat and sebum components by axillary skin bacteria cause the characteristic sweat malodor and discoloring of dirty clothes. Once inside the textile, the bacteria can form biofilms that are hard to remove by conventional washing. When the biofilm persists after washing, the textiles retain the sweat odor. In addition to posing a huge industrial problem, textile biofilms constitute an interesting case study of bacterial behavior in periodically wetted and dried substrates with varying surface hydrophobicity. Here we aim to study the bacterial behavior in each of the four stages of the bacterial lifecycle in textiles: adhesion, growth, drying and washing. To accomplish this, we designed a novel in vitro model to mimic physiological sweating while wearing cotton and polyester textiles. The hydrophobic polyester adhered bacteria more strongly and absorbed more sebum, the bacteria’s primary nutrient source. Bacteria were therefore initially more active in polyester textiles than in cotton. However, polyester did not bind water as well as cotton. The increased water content of cotton allowed the bacteria to retain a higher activity after the textile had dried. However, neither of the textiles retained enough water upon drying to prevent the bacteria from irreversibly adhering to the textile fibers by capillary action. This demonstrates that bacterial colonization depends on the hydrophobic and hygroscopic properties of the colonized material while highlighting the possibility of controlling bacterial behavior by either changing the surface properties or the surrounding environment.