Abstract
The aim of the study is to evaluate the effect of acrylic cement CMW1 (DePuy) containing 2,5% of gentamicin and addition of 5 % and 10 % of respective vancomycin, meropeneme and ceftriaxone on growth inhibition of reference strains of MRSA, E. faecalis, S. aureus, P. aeruginosa and E. coli.
From every portion of investigated acrylic cement CMW1 discs were cut with a diameter of 15mm and a thickness of 5mm, average weight 1.365 g (+/− 0,257g). Inoculum was prepared with the reference strains: MR3 S. aureus methicillin-resistant (MRSA), ATCC 29219 E. faecalis, ATCC 25923 S. ureus, ATCC 27853 P. aeruginosa and ATCC 25922 E. coli. A colonies of bacteria taken from a 18-hour culture on solid medium were addend to tubes with sterile physiological saline solution to obtain a density of 0.5 McFarland (5 × 105 CFU / ml). The suspension was distributed evenly over the Mueller-Hinton (MH) medium (Biomerieux, France). Prepared discs of CMW1 cement were put with a sterile forceps on the plate with a dry medium. The plates were incubated aerobically at 24 hr and the temp. 37°C.
After 24 hours the diameter of zone of inhibition of bacterial growth on a plate was measured (in mm) and average size of the inhibition zone was calculated. The CMW1 cement inhibited to a comparable degree growth of reference strains with the exception of E. faecalis. The addition of vancomycin increased by 1/5 inhibitory potential of CMW1 cement on growth of MRSA, S. aureus, P. aeruginosa and E. coli. and significantly for E. faecalis. Changing the concentration of vancomycin, meropeneme and ceftriaxone from 5% to 10% do not increased the inhibitory potential of CMW1 cement on the growth of MRSA, S. aureus, P. aeruginosa, E. coli and E. faecalis. Addition of meropeneme increased inhibitory potential of CMW1 cement against MRSA by 1/3, P. aeruginosa and E. coli by ½, E. faecalis by 3/4 and against S. aureus by 100%. Addition of ceftriaxone to CMW1 cement increased the inhibiting of the growth of MRSA similiarly to 5% and 10% of vancomycin, E. faecalis as meropeneme 5% and 10 %, while the growth of S. aureus and P. aeruginosa, less than meropeneme.
Addition of antibiotics to acrylic cement increased its antibacterial properties. Increase if vancomycine concentrations from 5 to 10% had no stronger antibacterial effect.
