Banche Giuliana, Bracco Pierangiola, Allizond Valeria, Bistolfi Alessandro, Boffano Michele, Cimino Andrea, Brach del Prever Elena Maria, Cuffini Anna Maria
Department of Public Health and Pediatrics, University of Torino, Turin, Italy.
Clin Orthop Relat Res. 2015 Mar;473(3):974-86. doi: 10.1007/s11999-014-4024-9.
Microorganism adhesion on polyethylene for total joint arthroplasty is a concern. Many studies have focused on vitamin E-stabilized ultrahigh-molecular-weight polyethylene (UHMWPE), whereas first-generation, highly crosslinked UHMWPE, which is the most commonly used in clinical practice, has been scarcely evaluated.
QUESTIONS/PURPOSES: We aimed (1) to compare the adherence of Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Candida albicans with virgin (untreated) UHMWPE (PE) and crosslinked UHMWPE (XLPE); (2) to correlate the results with the biomaterial surface properties; and (3) to determine whether the decreased adhesion on vitamin E-stabilized UHMWPE (VE-PE) previously recorded for bacteria can also be confirmed for C albicans.
Microbial adhesion of biofilm-producing American Type Culture Collection (ATCC) and clinical strains on XLPE and VE-PE were compared with PE at 3, 7, 24, and 48 hours of incubation and quantified, as colony forming units (CFU)/mL, using a sonication protocol. Sample surfaces were characterized by scanning electron microscopy, roughness and contact angle measurements, attenuated total reflection-Fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopy (XPS) to reveal qualitative differences in surface composition and topography that could influence the microbial adhesion. The results were analyzed by descriptive statistics and tested by unpaired t-tests.
All microorganisms, both ATCC and clinical strains, showed lower adhesion (p < 0.05) on XLPE with adhesion percentages ranging from 18% to 25%, compared with PE with adhesion percentages ranging from 51% to 55%, after 48 hours. Only the ATCC S epidermidis showed a reduced adhesion profile even at 3 hours (adhesion ratio of 14% on XLPE versus 50% on PE) and 24 hours (19% on XLPE versus 55% on PE) of incubation. ATCC and clinical C albicans were less adherent to XLPE than to PE (p < 0.05) showing even at the earlier incubation time points adhesion values always of 10(3) CFU/mL and 10(4) CFU/mL, respectively. Roughness and contact angle were 0.8 ± 0.2 μm and 92° ± 3°, respectively, with no differences among samples. Qualitative differences in the surface chemical composition were revealed by XPS only. A confirmation of the decreased adhesion on VE-PE respect to PE was also registered here for C albicans strains (p < 0.05).
Vitamin E stabilization and crosslinking of UHMWPE are capable of reducing microbial adhesion. Further studies are needed to fully elucidate the mechanisms of modulation of microbial adhesion to medical-grade UHMWPE.
Our results suggest that VE-PE and XLPE may have an added benefit of being more resistant to bacterial adhesion, even fungal strains.
全关节置换术中微生物在聚乙烯材料上的黏附是一个值得关注的问题。许多研究聚焦于维生素E稳定化的超高分子量聚乙烯（UHMWPE），然而，临床实践中最常用的第一代高度交联UHMWPE却很少被评估。
问题/目的：我们旨在（1）比较表皮葡萄球菌、金黄色葡萄球菌、大肠杆菌和白色念珠菌在未处理的原始UHMWPE（PE）和交联UHMWPE（XLPE）上的黏附情况；（2）将结果与生物材料表面特性相关联；（3）确定先前记录的细菌在维生素E稳定化UHMWPE（VE-PE）上黏附减少的情况是否也能在白色念珠菌中得到证实。
将产生物膜的美国典型培养物保藏中心（ATCC）菌株和临床菌株在XLPE和VE-PE上的微生物黏附情况与PE在孵育3、7、24和48小时时进行比较，并使用超声处理方案以菌落形成单位（CFU）/mL进行定量。通过扫描电子显微镜、粗糙度和接触角测量、衰减全反射傅里叶变换红外光谱以及X射线光电子能谱（XPS）对样品表面进行表征，以揭示可能影响微生物黏附的表面成分和形貌的定性差异。结果通过描述性统计进行分析，并通过非配对t检验进行检验。
48小时后，所有微生物，无论是ATCC菌株还是临床菌株，在XLPE上的黏附均较低（p < 0.05），黏附百分比范围为18%至25%，而在PE上的黏附百分比范围为51%至55%。仅ATCC表皮葡萄球菌在孵育3小时（XLPE上的黏附率为14%，PE上为50%）和24小时（XLPE上为19%，PE上为55%）时就显示出黏附减少的情况。ATCC和临床白色念珠菌在XLPE上的黏附性低于PE（p < 0.05），即使在较早的孵育时间点，黏附值分别始终为10³CFU/mL和10⁴CFU/mL。粗糙度和接触角分别为0.8±0.2μm和92°±3°，样品之间无差异。仅通过XPS揭示了表面化学成分的定性差异。在此也证实了白色念珠菌菌株在VE-PE上相对于PE的黏附减少（p < 0.05）。
UHMWPE的维生素E稳定化和交联能够降低微生物黏附。需要进一步研究以充分阐明调节微生物对医用级UHMWPE黏附的机制。
我们的结果表明，VE-PE和XLPE可能具有对细菌甚至真菌菌株黏附更具抗性的额外益处。
