Antimicrobial Susceptibility of Gentamicin-impregnated Polymethylmethacrylate Beads after Resterilization

Abstract

Antimicrobial Susceptibility of Gentamicin-impregnated Polymethylmethacrylate Beads after Resterilization

Mason Porramatikul MD*

Damrong Tapanakulsak MD*

Siri Sirimanapong MD*

*Department of Orthopaedics Surgery, BMA Medical College and Vajira Hospital

Objective: To compare the antimicrobial susceptibility to Staphylococcus aureus of Gentamicin-impregnated polymethylmethacrylate beads (GPMMA beads) before and after resterilization with ethylene oxide gas.

Study design: Experimental study (laboratory research).

Materials: A total of twenty four pieces of GPMMA bead were selected in this study. This study was conducted at Department of Orthopaedics Surgery, BMA Medical College and Vajira Hospital.

Methods: All GPMMA beads were equally divided into two groups: control and experimental groups. The experimental group was sterilized again with ethylene oxide gas before testing. The antimicrobial susceptibility was identified by diffusion method of Kirby-Bauer for both groups. Diameter of zone of inhibition was recorded and compared.

Results: In control group, the diameters of zone of inhibition at 24, 72 and 168 hrs were 27.3 ± 1.5, 29.2 ± 1.2, and 29.5 ± 1.2 mm respectively. In experimental group, the diameters of zone of inhibition at 24, 72 and 168 hrs were 29.5 ± 1.2, 30.3 ± 1.4 and 30.8 ± 1.0 mm respectively. Statistical analysis demonstrated significant differences between two groups.

Conclusion: The antimicrobial susceptibility to Staphylococcus aureus of GPMMA beads after resterilization with ethylene oxide gas was not less than the new GPMMA beads.

Vajira Med J 2007 ; 51 : 103 - 109