Format

Send to

Choose Destination

See 1 citation found using an alternative search:

Clin Orthop Relat Res. 2015 Sep;473(9):2874-84. doi: 10.1007/s11999-015-4300-3.

Rifamycin Derivatives Are Effective Against Staphylococcal Biofilms In Vitro and Elutable From PMMA.

Author information

1
Extremity Trauma & Regenerative Medicine Task Area, US Army Institute of Surgical Research, 3698 Chambers Pass, JBSA, Fort Sam Houston, TX, 78234, USA.

Abstract

BACKGROUND:

Local antimicrobial delivery through polymethylmethacrylate beads (PMMA), commonly vancomycin, is used for the treatment of contaminated open fractures but has limited activity against Staphylococcus aureus biofilms, which occur commonly in such fractures. Rifamycins have activity against biofilms and are an effective treatment for osteoarticular infections involving staphylococcal biofilms, but there are limited studies evaluating the activity of rifamycin derivatives, other than rifampin, against biofilms of S. aureus and evaluating incorporation of these drugs into PMMA for treatment of contaminated open fractures.

QUESTIONS/PURPOSES:

(1) Are rifamycin derivatives effective against established biofilms of clinical isolates of S. aureus? (2) Can PMMA be used as a carrier for rifamycin derivatives?

METHODS:

Biofilms were developed and evaluated for susceptibility to a panel of antimicrobials in vitro using the minimum biofilm eradication concentration high-throughput model. Susceptibility was assessed by measuring bacterial recovery at 6 and 24 hours after antimicrobial treatment. Activity of rifamycin derivatives against intracellular bacteria was also evaluated using a gentamicin protection assay. Evaluation of PMMA as a carrier for rifampin and rifamycin derivatives was determined by assessing the curing time subsequent to loading of rifamycins and characterizing the release kinetics of rifamycins at daily intervals for 14 days from PMMA by performing bioassays.

RESULTS:

Rifamycin derivatives between 1 and 8 µg/mL reduced bacteria within biofilms 5- to 9-logs and prevented bacterial recovery up to 24 hours post-treatment, indicating near to complete eradication of biofilms. Rifamycin derivatives at 32 µg/mL had activity against intracellular staphylococci, significantly reducing the number of internalized bacteria with limited effects on osteoblast viability. Rifampin was the only rifamycin observed to have a suitable release profile from PMMA, releasing 49% of the total antibiotic and maintaining a sustained released profile up to 14 days at a mean 28 ± 6 μg/mL.

CONCLUSIONS:

Rifampin can be incorporated into PMMA and eluted at concentrations effective against biofilms and intracellular staphylococci.

CLINICAL RELEVANCE:

Our in vitro findings suggest that local delivery of rifampin may be an effective strategy for the prevention and/or treatment of open fractures where S. aureus biofilms might develop. Clinical studies are needed to characterize what role this approach might have in the prevention and treatment of infections involving biofilms.

PMID:
25896136
PMCID:
PMC4523531
DOI:
10.1007/s11999-015-4300-3
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wolters Kluwer Icon for PubMed Central
Loading ...
Support Center