# Novel Approaches to Combat Medical Device-Associated BioFilms
## 2 Medical Device-Related Biofilm Infection and the Challenges of Treatment
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Medical Devices** & **Main Microorganisms** & **Infection Rates** & **Reference** \\ \hline Cardiac implantable devices & _S. epidermidis, S. aureus, S. hominis_ & 0.13\%–38.6\% & [42; 43; 44; 45; 46; 47; 48; 49] \\ \hline Hemodialysiszers & _Staphylococci, P. aeruginosa, S. marcscents_ & \(\sim\)18\% & [28; 50; 51; 52] \\ \hline Center venous catheters & _S. aureus, S. epidermidis, P. aeruginosa, candida, B. cereus_ & 3\%–14\% & [17; 53; 54; 55; 56; 57] \\ \hline Urinary catheters & _E. coli, E. cloace, P. mirabilis, Klebsiella, Entercoccus spp., P. aeruginosa, Candida_ & 9.1\%–26.6\% & [33; 58; 59; 60; 61; 62; 63] \\ \hline Ventilator & _P. aeruginosa, A. baumannii, Klebsiella species, S. maltophilis, Enterococcus spp., Candida spp._ & 5\%–40\% & [37; 62; 64; 65; 66; 67; 68; 69] \\ \hline Artificial breasts & _S. aureus_ and _S. epidermidis_ & 0.5\%–5.1\% & [70; 71; 72; 73] \\ \hline Contact lenses & _Staphylococcus spp., P. aeruginosa, C. albicans_ & 2.5\%–6\% & [74; 75; 76; 77] \\ \hline Dental prosthetics & _Streptococcus, Fusobacterium, Campocytophaga, Actinomyces_ & 5.9\%–56\% & [78; 79; 80; 81] \\  & and _Candida_ species & 1\%–15\% & [82; 83; 84; 85; 86; 87] \\ \hline Orthopedic prosthetics & MRSA, MRSE, _S. epidermidis, S. aureus, P. cates, E. faecalis_ & 1\%–15\% & [32; 82; 83; 84; 85; 86; 87] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The main microorganisms involved in the formation of biofilms and infection rates for different medical devices. gene transfer in medical device-related biofilms in recent years and some pathogens used in horizontal gene transfer studies have been directly isolated from biofilms located in implanted medical devices [104]. Many horizontal transfer genes have been identified, such as _p5K41_ and _pT181_, which were identified as the most common staphylococcal horizontal transfer and relaxase genes, as well as aac6-aph2a, ermC, and tetK genes, which were the most common antibiotic resistance genes in _Staphylococcus aureus_ and _Staphylococcus epidermidis_ biofilms [104]. Each of these mechanisms can only partially explain the increase in antimicrobial resistance observed in biofilms. However, in the face of the synergistic effects of these mechanisms, even the most aggressive antibiotic treatment options or combination schemes involving different kinds of antibiotics cannot completely eliminate biofilm infections because of the limited dose of antimicrobial agents and their side effects [105]. In addition, the removal of medical devices can effectively prevent the recurrence of biofilm infections. Although many studies have emphasized the importance of implant removal to avoid the recurrence of infection at the surgical site, not all patients need or can undergo surgical revision surgery for local infections [32]. Implant exchange surgery, that is, the replacement of infected implants with new implants, may not be the best choice for the treatment of biofilm infection due to the high degree of trauma and high infection rate [106], which not only cause great physical and mental damage to patients, but also increase the economic burden on patients and the medical and healthcare system [32; 106]. A study on the treatment of infection with surgical site implants revealed that the average number of surgeries required for infection treatment was 4 (range 1-16), resulting in an average cost of treatment ranging from two hundred and fifty thousand to one million dollars per patient [107].