Abstract
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.
Original language | English |
---|---|
Pages (from-to) | 1281-1291 |
Number of pages | 11 |
Journal | Journal of Applied Microbiology |
Volume | 108 |
Issue number | 4 |
DOIs | |
Publication status | Published - Apr 2010 |
Keywords
- TSST
- Biofilm
- Coagulase
- Splenocytes
- Subminimal
- Virulence