Antibacterial activity testing methods for hydrophobic patterned surfaces

Abstract

One strategy to decrease the incidence of hospital-acquired infections is to avoid the survival of pathogens in the environment by the development of surfaces with antimicrobial activity. To study the antibacterial behaviour of active surfaces, different approaches have been developed of which ISO 22916 is the standard. To assess the performance of different testing methodologies to analyse the antibacterial activity of hydrophobic surface patterned plastics as part of a Horizon 2020 European research project. Four different testing methods were used to study the antibacterial activity of a patterned film, including the ISO 22916 standard, the immersion method, the touch-transfer inoculation method, and the swab inoculation method, this latter developed specifically for this project. The non-realistic test conditions of the ISO 22916 standard showed this method to be non-appropriate in the study of hydrophobic patterned surfaces. The immersion method also showed no differences between patterned films and smooth controls due to the lack of attachment of testing bacteria on both surfaces. The antibacterial activity of films could be demonstrated by the touch-transfer and the swab inoculation methods, that more precisely mimicked the way of high-touch surfaces contamination, and showed to be the best methodologies to test the antibacterial activity of patterned hydrophobic surfaces. A new ISO standard would be desirable as the reference method to study the antibacterial behaviour of patterned surfaces.

Impact of surface topography on the bacterial attachment to micro- and nano-patterned polymer films

“…The antimicrobial behavior of the topographical-based PP films was studied using the touch transfer assay method [40] . Firstly, one-level patterned and unpatterned PP films were tested with Gram-negative E. coli and Gram-positive S. aureus bacteria, as shown in Fig.…”

“…The antimicrobial properties of the patterned PP surfaces were evaluated following the touch transfer assay method [40] , optimized after a consistent comparison with other standard methods. The touch transfer assay assesses the attachment and survival of the remaining viable bacteria directly on the surface of films with the help of a velvet pad previously immersed in the bacterial suspension, thus overcoming the difficulty in spreading the inoculum of bacteria in very hydrophobic surfaces.…”

Investigation of the Mechanical and Liquid Absorption Properties of a Rice Straw-Based Composite for Ayurvedic Treatment Tables

“…Finally, the test samples were removed from the bacterial suspension and were washed three times with 20 mL of distilled water for 10 s and allowed to dry under ambient conditions for 1 h before being sampled. Sampling was done using a swab inoculation method with the sterile swab rubbing on the test samples followed by inoculation in 5% sheep blood agar [57]. The growth of the colonies was noted.…”

Strategii de testare in vitro a suprafețelor neporoase cu proprietăți antibacteriene | [Strategies for in vitro testing of non-porous surfaces with antibacterial properties]

“…Infecțiile nosocomiale reprezintă o problemă foarte importantă de sănătate publică numărul acestora fiind de circa 8,9 milioane de cazuri în țările Uniunii Europene în perioada 2016-2017 (Perez-Gavilan et al, 2021;Suetens et al, 2018).…”

“…În consecință, utilizarea de protocoale adecvate pentru curățarea și dezinfectarea suprafețelor din spitale sunt cruciale pentru a preveni apariția infecțiilor nosocomiale. Folosirea de diverși dezinfectanți pentru suprafețe este cel mai des practicată dar poate fi asociată cu unele dezavantaje legate de faptul că trebuie să fie utilizate în anumite concentrații având grade variate de toxicitate, pot fi aplicate incorect și activitatea lor bactericidă este de scurtă durată, recontaminarea fiind posibilă din nou în câteva minute (Perez-Gavilan et al, 2021).…”