Quantitative Comparison of the Antimicrobial Efficiency of Leaching versus Nonleaching Polymer Materials

Abstract

New antimicrobial materials will be more and more in the focus for hygienic and clinical disease control. Antimicrobial materials have to be distinguished in leaching and nonleaching materials. For many applications of antimicrobial materials on implants the use of nonleaching materials is essential. Therefore, the antimicrobial efficiency of leaching and nonleaching polymers has been investigated quantitatively in vitro in direct comparison on a highly relevant implant of central venous catheters (CVCs) using a well‐established called Certika test. This test is especially designed to test antimicrobial properties of leachable and nonleachable materials. This contribution demonstrates that newly developed nonleaching antimicrobial CVCs are equivalent to conventional leaching CVC systems in their antimicrobial performance against gram‐positive and gram‐negative bacteria, as well as Candida species. The use of new nonleaching antimicrobial polymers as shown here for CVCs represents a different mode of action with the aim to prevent infections also with antibiotic‐resistant strains and reduced side effects.

Unveiling the fate of adhering bacteria to antimicrobial surfaces: expression of resistance-associated genes and macrophage-mediated phagocytosis

“…Results with planktonic cultures continuously exposed to a subinhibitory concentration of Palm also suggested some resistance towards the AMP in solution, evidenced by the 2-fold increase in MIC and MBC. In theory, compounds immobilization, without leaching, should decrease its propensity to induce bacterial resistance as there is no exposure to sub-inhibitory concentrations [19]. In fact, results found in this study suggested that both compounds immobilized on the surfaces (Palm and Vancomycin) exhibited a low propensity to develop bacterial resistance after a long period of exposure, 30 days.…”

“…Another challenge is the potential development of microbial resistance towards the antimicrobials released from the surfaces. Although antimicrobials permanent immobilization has been proposed as an alternative approach to minimize antimicrobial resistance development, because covalent immobilization avoids exposure to sub-inhibitory concentrations [18,19], there is a lack of studies addressing these issues.…”

Antimicrobial Silver Multilayer Coating for Prevention of Bacterial Colonization of Orthopedic Implants

“…Proliferation assay: The SML coated items and blank items were tested against MSSE (RKI 10-00621). The blank items showed a brutto Onset-OD of 10.3 ± 0.8 h, while the SML items showed a brutto Onset-OD of 21.5 ± 11.0 h. This results in an average netto Onset-OD of 11.2 ± 7.3 h, which relates to a >4 Log reduction [55,56] (Figure 3). Proliferation assay: The SML coated items and blank items were tested against MSSE (RKI 10-00621).…”

“…The blank items showed a brutto Onset-OD of 10.3 ± 0.8 hours, while the SML items showed a brutto Onset-OD of 21.5 ± 11.0 hours. This results in an average netto Onset-OD of 11.2 ± 7.3 hours, which relates to a >4 Log reduction [55,56] (Figure 3). Agar immersion test: SML and blank items were challenged with MSSE (RKI 10-00621) and incubated for 24, 72 and 168 hours in agar slurry.…”

“…The in vitro antimicrobial activity of blank and test items was evaluated using a proliferation assay described previously [55,56]. In brief, four replicates of SML coated test items and 4 blank items were incubated in 10% human plasma for 1 hour and subsequently washed in 1 x phosphate buffered saline (PBS) for 10 minutes.…”