title: The elution of colistimethate sodium from polymethylmethacrylate and calcium phosphate cement beads.
abstract: Gram-negative bacilli resistance to all antibiotics, except for colistimethate sodium (CMS), is an emerging healthcare concern. Incorporating CMS into orthopedic cement to treat bone and soft-tissue infections due to these bacteria is attractive, but the data regarding the elution of CMS from cement are conflicting. The in vitro analysis of the elution of CMS from polymethylmethacrylate (PMMA) and calcium phosphate (CP) cement beads is reported. PMMA and CP beads containing CMS were incubated in phosphate-buffered saline and the eluate sampled at sequential time points. The inhibition of the growth of a strain of Acinetobacter baumannii complex by the eluate was measured by disk diffusion and microbroth dilution assays, and the presence of CMS in the eluate was measured by mass spectroscopy.     Bacterial growth was inhibited by the eluate from both PMMA and CP beads. Mass spectroscopy demonstrated greater elution of CMS from CP beads than PMMA beads. The dose of CMS in PMMA beads was limited by failure of bead integrity.    CMS elutes from both CP and PMMA beads in amounts sufficient to inhibit bacterial growth in vitro. The clinical implications of these findings require further study.
authors: Walter Reed National Military Medical Center, Bethesda, Maryland 20889, USA.
authors: Paige
authors: P
authors: Waterman
authors: Melissa
authors: M
authors: Barber
authors: Amy C
authors: AC
authors: Weintrob
authors: Regina
authors: R
authors: VanBrakle
authors: Robin
authors: R
authors: Howard
authors: Michael P
authors: MP
authors: Kozar
authors: Romney
authors: R
authors: Andersen
authors: Glenn
authors: G
authors: Wortmann
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001843:Bone Cements / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry; D003091:Colistin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D016503:Drug Delivery Systems; D019904:Polymethyl Methacrylate / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D001843:Bone Cements; D002130:Calcium Phosphates; D019904:Polymethyl Methacrylate; C020243:calcium phosphate; C004691:colistinmethanesulfonic acid; D003091:Colistin