# Antibacterial Effect of Topically Administered Transcamic Acid in Large Joint Arthroplasty
###### Abstract  
Tranexamic acid (TXA) is a synthetic derivative of the amino acid lysine and is commonly used as an antifibrinolytic agent in large joint surgery, such as knee arthroplasty, to minimize blood loss and its associated complications. Some studies have suggested that perioperative intravenous TXA application lowers the incidence of postoperative infections after hip and knee arthroplasty. While its effects on bacteria are not its primary purpose, more research is needed further to elucidate the extent of TXA's impact on bacterial inhibition and its clinical relevance. In order to determine possible inhibitory effects, 22 clinically relevant bacterial strains were exposed to different TXA concentrations. Two different assays were performed: a microdilution assay with traditional endpoint measurements and a kinetic growth assay for a time-dependent susceptibility assessment. With the microdilution technique, a growth inhibitory effect became evident at higher TXA concentrations (50 and 100 mg/mL) on eight tested bacterial strains, of which four demonstrated absence of growth at 100 mg/mL, suggesting minimal inhibitory concentration. However, the kinetic growth assay revealed more specific TXA-induced dynamic changes in the bacterial growth of all tested bacterial strains. This study showed that TXA affects the growth dynamics of bacteria by altering their lag phase duration, exponential growth rate, and population density and may contribute to the prevention of implant-associated infections. tranexamic acid; bacterial growth; antimicrobial effect; topical administration; arthroplasty +
Footnote †: journal: Medical  
15 mg/kg, around 5 min before the skin incision. With increased utilization of TXA, due to its beneficial antifibrinolytic properties, the association with a lower incidence of postoperative infection rates has also become apparent [14; 15]. This can partially be explained by the decrease in the number of required blood transfusions and its immunomodulatory properties, together with other direct and indirect TXA effects that might contribute to increased postoperative immunity and wound-healing capacity [16; 17; 18; 19; 20]. In order to avoid any potential systemic side effects when used intravenously, topical application of TXA has increasingly been established in orthopedic clinical practice. It has been shown to be comparatively effective in reducing blood loss and transfusion requirements, with up to 70% lower serum concentrations in comparison with intravenous usage [21]. Other advantages of topical use of TXA include direct and faster effect at the bleeding site, ease of application, and reduction of joint swelling, all of which improve healing and allow for faster rehabilitation after large joint arthroplasty [22; 23; 24]. Additionally, intraarticular infiltration of TXA has proved beneficial in reducing the number of hematomas and other common complications of surgical wounds [22]. Several in vitro studies have demonstrated the cytotoxic effect of TXA on human cells and tissues, with concentrations of 50-100 mg/mL having a significant detrimental effect on most of the studied cells after only a few hours of exposure, while even lower TXA concentrations were sufficient for a similar cytotoxic effect in chronic exposure [23; 24; 25; 26]. Considering the expected local concentrations of 5-100 mg/mL after standard topical application of 1-3 g TXA, a possible cytotoxic effect on bacterial cells is in question. Some recent studies have examined the potential effect of TXA on bacteria and biofilm formation, mostly using _Staphylococcus aureus_ and _Staphylococcus epidermidis_ species, except for one study in which they also analyzed effects on _Cutiibacterium acnes_[27; 28; 29]. In this study, we aimed to investigate the potential antibacterial effect of TXA on the most common pathogenic bacteria associated with PJI and its likely contribution to a reduction of early postoperative infection rates.