The myth of antibiotic spider silk

TY - JOUR

T1 - The myth of antibiotic spider silk

AU - Fruergaard, Simon

AU - Lund, Marie Braad

AU - Schramm, Andreas

AU - Vosegaard, Thomas

AU - Bilde, Trine

PY - 2021/10

Y1 - 2021/10

N2 - Spider silk is frequently attributed antimicrobial properties. This notion is based on studies reporting antimicrobial activity (AMA) of spider silk; however, close inspection of these studies reveals that the evidence is conflicting, and at best anecdotal. We performed a systematic study of antimicrobial properties of different silk types from seven species across the spider phylogeny. We found no evidence of AMA of silk in direct contact and disc diffusion assays against Gram-negative Escherichia coli and Pseudomonas putida, and the Gram-positive Bacillus subtilis. Furthermore, staining experiments and fluorescence microscopy showed the presence of live bacteria on silk surfaces indicating no antimicrobial effect on direct contact. A critical evaluation of the literature reveals that published tests of AMA are scarce and that all the studies claiming positive results are compromised by methodological shortcomings. Our analysis demonstrates that the common notion that spider silk is antimicrobial is not supported by empirical data.

AB - Spider silk is frequently attributed antimicrobial properties. This notion is based on studies reporting antimicrobial activity (AMA) of spider silk; however, close inspection of these studies reveals that the evidence is conflicting, and at best anecdotal. We performed a systematic study of antimicrobial properties of different silk types from seven species across the spider phylogeny. We found no evidence of AMA of silk in direct contact and disc diffusion assays against Gram-negative Escherichia coli and Pseudomonas putida, and the Gram-positive Bacillus subtilis. Furthermore, staining experiments and fluorescence microscopy showed the presence of live bacteria on silk surfaces indicating no antimicrobial effect on direct contact. A critical evaluation of the literature reveals that published tests of AMA are scarce and that all the studies claiming positive results are compromised by methodological shortcomings. Our analysis demonstrates that the common notion that spider silk is antimicrobial is not supported by empirical data.

KW - ANTIBACTERIAL PROPERTIES

KW - ANTIMICROBIAL ACTIVITY

KW - ARANEAE

KW - WEB

UR - http://www.scopus.com/inward/record.url?scp=85121286723&partnerID=8YFLogxK

U2 - 10.1016/j.isci.2021.103125

DO - 10.1016/j.isci.2021.103125

M3 - Journal article

C2 - 34755083

SN - 2589-0042

VL - 24

JO - iScience

JF - iScience

IS - 10

M1 - 103125

ER -