The effect of subminimal inhibitory concentrations of antibiotics on virulence factors expressed by Staphylococcus aureus biofilms
Item TypeJournal Article
MetadataShow full item record
Aims: The effect of subminimal inhibitory concentrations (sub-MICs) of cefalexin, ciprofloxacin and roxithromycin was investigated on some virulence factors [e.g. coagulase, Toxic Shock Syndrome Toxin 1 (TSST-1) and biofilm formation] expressed by Staphylococcus aureus biofilms. Methods and Results: Biofilms were grown with and without the presence of 1 ⁄ 16 MIC of antibiotics on Sorbarod filters. Eluate supernatants were collected, and coagulase and TSST-1 production were evaluated. Coagulase production was reduced in eluates exposed to roxithromycin when compared to control, while TSST-1 production was reduced in biofilms exposed to cefalexin and to a lesser extent, ciprofloxacin. In addition, the ability of Staph. aureus to produce biofilm in microtitre plates in the presence of sub-MIC antibiotics indicated that cefalexin induced biofilm formation at a wide range of sub- MICs. TSST-1 produced from the challenged and control biofilms was purified, and its proliferative activity was studied on single cell suspension of mouse splenocytes using MTS⁄PMS assay. No significant difference in the activity between the treated toxin and the control has been observed. Conclusions: Antibiotics at sub-MIC levels interfere with bacterial biofilm virulence expression depending on the type and concentration of antibiotic used. Significance and Impact of the Study: The establishment of sub-MICs of antibiotics in clinical situations may result in altered virulence states in pathogenic bacteria.
Haddadin R.N.S., et al. 2010. The effect of subminimal inhibitory concentrations of antibiotics on virulence factors expressed by Staphylococcus aureus biofilms. Journal of Applied Microbiology. 108(4): pp.1281-1291. Available from DOI: 10.1111/j.1365-2672.2009.04529.x
RightsPublished version (c)Wiley-Blackwell, available from DOI: 10.1111/j.1365-2672.2009.04529.x. The definitive version is available at www3.interscience.wiley.com
The following license files are associated with this item: