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Bacterial adhesion on patient-specific implant materials
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Implant-associated infections are a major cause of morbidity and treatment failure after implantation surgery. Initial contamination or later colonization of bacterial pathogens on the biomaterial surface leads to biofilm formation, which is difficult to treat and could result in prolonged antibiotic therapy along with implant removal in some cases. Different surface treatments and the addition of antibacterial coating on these biomaterials are being developed to prevent biofilm production on the implant surface.
This study aimed to assess the bacterial adhesion on patient specific computer aided design and computer aided manufacturing (CAD-CAM) titanium, and polymeric bioresorbable and non-resorbable implant materials. This study investigated the biofilm formation of common pathogens in implant associated infections such as Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Escherichia coli on titanium and its alloys, plastic implant material polyetheretherketone (PEEK), and resorbable polylactic acid (PLA). All material types were tested separately with and without saliva contamination for bacterial adhesion by each bacterial strain.
Results showed no significant difference of tooling and milling techniques on bacterial attachment. Overall, S. aureus was found to be the most adhered strain on most of the materials tested, followed by E. faecalis and E. coli, while the least adhered bacterium was S. mutans. Titanium grade 5 polished and titanium grade 23 showed the maximum level of biofilm formation by most of the pathogens whereas PLA showed less bacterial binding in the majority of the experiments. Salivary pellicle coating significantly increased bacterial biofilm formation by all the strains except for E. coli, which showed no significant difference in saliva and non-saliva-treated materials.
In conclusion, these findings imply that tooling and milling surface treatments had little effect on bacterial attachment, but all materials showed a high degree of bacterial binding. Saliva contamination plays a vital role in favoring pathogens by promoting biofilm formation. Therefore, saliva contamination of implant material should be minimized especially in immunocompromised patients. Remaining trials in this field involve further extensive experimentation in the in vivo models to study the effect of surface treatments on bacterial adhesion and investigate the factors needed to prevent implant associated infections. Original papers Sarfraz, S., Mäntynen, P.-H., Laurila, M., Suojanen, J., Saarnio, J., Rossi, S., Horelli, J., Kaakinen, M., Leikola, J., & Reunanen, J. (2022). Effect of surface tooling techniques of medical titanium implants on bacterial biofilm formation in vitro. Materials, 15(9), 3228. https://doi.org/10.3390/ma15093228 https://doi.org/10.3390/ma15093228 Self-archived version Sarfraz, S., Mäntynen, P.-H., Laurila, M., Rossi, S., Leikola, J., Kaakinen, M., Suojanen, J., & Reunanen, J. (2022). Comparison of titanium and PEEK medical plastic implant materials for their bacterial biofilm formation properties. Polymers, 14(18), 3862. https://doi.org/10.3390/polym14183862 https://doi.org/10.3390/polym14183862 Self-archived version Sarfraz, S., Tamminen, A.-M., Leikola, J., Salmi, S., Kaakinen, M., Sorsa, T., Suojanen, J., & Reunanen, J. (2023). High adherence of oral Streptococcus to polylactic acid might explain implant infections associated with PLA mesh implantation. International Journal of Molecular Sciences, 24(11), 9504. https://doi.org/10.3390/ijms24119504 https://doi.org/10.3390/ijms24119504 Self-archived version Tiivistelmä
Implantti-infektiot ovat merkittävä syy sairastumiseen ja hoidon epäonnistumiseen implantaatioleikkauksen jälkeen. Implantin bakteerikontaminaatio tai myöhempi kolonisaatio implanttimateriaalin pinnalla johtaa biofilmin muodostumiseen, jota on vaikea hoitaa ja joka saattaa joissakin tapauksissa johtaa pitkittyneeseen antibioottihoitoon sekä implantin poistamiseen. Erilaisia pintakäsittelyjä ja antibakteeristen pinnoitteiden lisäämistä näihin biomateriaaleihin kehitetään estämään biofilmin muodostuminen implantin pinnalle.
Tämän tutkimuksen tavoitteena oli arvioida bakteerien tarttumista potilaskohtaisiin CAD-CAM-implanttimateriaaleihin. Tässä työssä tutkittiin yleisten implantti-infektioita aiheuttavien patogeenien, kuten Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis ja Escherichia coli, biofilmin muodostumista titaanilla ja sen seoksilla, muovisella implanttimateriaalilla (polyetheretherketone, PEEK) ja resorboituvalla eli biologisesti hajoavalla polymaitohapolla (polylactic acid, PLA). Kaikki materiaalityypit testattiin sylkikontaminaation kanssa ja ilman, kukin bakteerikanta erikseen.
Tulokset osoittivat, että työstö- ja jyrsintätekniikoilla ei ollut merkittävää eroa bakteerien kiinnittymiseen. S. aureus -bakteeri tarttui eniten suurimpaan osaan testattuja materiaaleja, E. faecalis ja E. coli kiinnittyivät seuraavaksi vahviten, kun taas S. mutans tarttui vähiten. Biofilmin muodostus oli suurinta titaanilaaduissa 5 kiillotettu ja titaani laatu 23, kun taas PLA osoitti vähemmän bakteerisitoutumista suurimmassa osassa kokeita. Sylkipinnoitus lisäsi merkittävästi bakteerien biofilmin muodostumista kaikilla kannoilla paitsi E. coli:lla, joka ei osoittanut merkittävää eroa syljellä ja ei-syljellä käsitellyissä materiaaleissa.
Yhteenvetona voidaan todeta, että materiaalien pintojen työstämisellä ja jyrsinnällä oli vain vähän vaikutusta bakteerien kiinnittymiseen, mutta kaikki materiaalit osoittivat korkeaa bakteerisitoutumista. Sylkikontaminaatio puolestaan lisäsi patogeenien biofilmin muodostusta merkittävästi. Tästä syystä implanttimateriaalin syljen kontaminaatio tulee minimoida erityisesti immuunipuutteisten potilaiden kohdalla. Tulevaisuudessa tutkimusta tulisi jatkaa in vivo -malleissa, joissa tutkitaan pintakäsittelyjen vaikutusta bakteerien tarttumiseen ja implantti-infektioiden ehkäisyyn tarvittavia tekijöitä. Osajulkaisut Sarfraz, S., Mäntynen, P.-H., Laurila, M., Suojanen, J., Saarnio, J., Rossi, S., Horelli, J., Kaakinen, M., Leikola, J., & Reunanen, J. (2022). Effect of surface tooling techniques of medical titanium implants on bacterial biofilm formation in vitro. Materials, 15(9), 3228. https://doi.org/10.3390/ma15093228 https://doi.org/10.3390/ma15093228 Rinnakkaistallennettu versio Sarfraz, S., Mäntynen, P.-H., Laurila, M., Rossi, S., Leikola, J., Kaakinen, M., Suojanen, J., & Reunanen, J. (2022). Comparison of titanium and PEEK medical plastic implant materials for their bacterial biofilm formation properties. Polymers, 14(18), 3862. https://doi.org/10.3390/polym14183862 https://doi.org/10.3390/polym14183862 Rinnakkaistallennettu versio Sarfraz, S., Tamminen, A.-M., Leikola, J., Salmi, S., Kaakinen, M., Sorsa, T., Suojanen, J., & Reunanen, J. (2023). High adherence of oral Streptococcus to polylactic acid might explain implant infections associated with PLA mesh implantation. International Journal of Molecular Sciences, 24(11), 9504. https://doi.org/10.3390/ijms24119504 https://doi.org/10.3390/ijms24119504 Rinnakkaistallennettu versio Academic dissertation to be presented with the assent of the Doctoral Programme Committee of Health and Biosciences of the University of Oulu for public defence in Auditorium F101 of the Faculty of Biochemistry and Molecular Medicine (Aapistie 7), on 5 April 2024, at 12 noonAbstract
Implant-associated infections are a major cause of morbidity and treatment failure after implantation surgery. Initial contamination or later colonization of bacterial pathogens on the biomaterial surface leads to biofilm formation, which is difficult to treat and could result in prolonged antibiotic therapy along with implant removal in some cases. Different surface treatments and the addition of antibacterial coating on these biomaterials are being developed to prevent biofilm production on the implant surface.
This study aimed to assess the bacterial adhesion on patient specific computer aided design and computer aided manufacturing (CAD-CAM) titanium, and polymeric bioresorbable and non-resorbable implant materials. This study investigated the biofilm formation of common pathogens in implant associated infections such as Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Escherichia coli on titanium and its alloys, plastic implant material polyetheretherketone (PEEK), and resorbable polylactic acid (PLA). All material types were tested separately with and without saliva contamination for bacterial adhesion by each bacterial strain.
Results showed no significant difference of tooling and milling techniques on bacterial attachment. Overall, S. aureus was found to be the most adhered strain on most of the materials tested, followed by E. faecalis and E. coli, while the least adhered bacterium was S. mutans. Titanium grade 5 polished and titanium grade 23 showed the maximum level of biofilm formation by most of the pathogens whereas PLA showed less bacterial binding in the majority of the experiments. Salivary pellicle coating significantly increased bacterial biofilm formation by all the strains except for E. coli, which showed no significant difference in saliva and non-saliva-treated materials.
In conclusion, these findings imply that tooling and milling surface treatments had little effect on bacterial attachment, but all materials showed a high degree of bacterial binding. Saliva contamination plays a vital role in favoring pathogens by promoting biofilm formation. Therefore, saliva contamination of implant material should be minimized especially in immunocompromised patients. Remaining trials in this field involve further extensive experimentation in the in vivo models to study the effect of surface treatments on bacterial adhesion and investigate the factors needed to prevent implant associated infections.Tiivistelmä
Implantti-infektiot ovat merkittävä syy sairastumiseen ja hoidon epäonnistumiseen implantaatioleikkauksen jälkeen. Implantin bakteerikontaminaatio tai myöhempi kolonisaatio implanttimateriaalin pinnalla johtaa biofilmin muodostumiseen, jota on vaikea hoitaa ja joka saattaa joissakin tapauksissa johtaa pitkittyneeseen antibioottihoitoon sekä implantin poistamiseen. Erilaisia pintakäsittelyjä ja antibakteeristen pinnoitteiden lisäämistä näihin biomateriaaleihin kehitetään estämään biofilmin muodostuminen implantin pinnalle.
Tämän tutkimuksen tavoitteena oli arvioida bakteerien tarttumista potilaskohtaisiin CAD-CAM-implanttimateriaaleihin. Tässä työssä tutkittiin yleisten implantti-infektioita aiheuttavien patogeenien, kuten Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis ja Escherichia coli, biofilmin muodostumista titaanilla ja sen seoksilla, muovisella implanttimateriaalilla (polyetheretherketone, PEEK) ja resorboituvalla eli biologisesti hajoavalla polymaitohapolla (polylactic acid, PLA). Kaikki materiaalityypit testattiin sylkikontaminaation kanssa ja ilman, kukin bakteerikanta erikseen.
Tulokset osoittivat, että työstö- ja jyrsintätekniikoilla ei ollut merkittävää eroa bakteerien kiinnittymiseen. S. aureus -bakteeri tarttui eniten suurimpaan osaan testattuja materiaaleja, E. faecalis ja E. coli kiinnittyivät seuraavaksi vahviten, kun taas S. mutans tarttui vähiten. Biofilmin muodostus oli suurinta titaanilaaduissa 5 kiillotettu ja titaani laatu 23, kun taas PLA osoitti vähemmän bakteerisitoutumista suurimmassa osassa kokeita. Sylkipinnoitus lisäsi merkittävästi bakteerien biofilmin muodostumista kaikilla kannoilla paitsi E. coli:lla, joka ei osoittanut merkittävää eroa syljellä ja ei-syljellä käsitellyissä materiaaleissa.
Yhteenvetona voidaan todeta, että materiaalien pintojen työstämisellä ja jyrsinnällä oli vain vähän vaikutusta bakteerien kiinnittymiseen, mutta kaikki materiaalit osoittivat korkeaa bakteerisitoutumista. Sylkikontaminaatio puolestaan lisäsi patogeenien biofilmin muodostusta merkittävästi. Tästä syystä implanttimateriaalin syljen kontaminaatio tulee minimoida erityisesti immuunipuutteisten potilaiden kohdalla. Tulevaisuudessa tutkimusta tulisi jatkaa in vivo -malleissa, joissa tutkitaan pintakäsittelyjen vaikutusta bakteerien tarttumiseen ja implantti-infektioiden ehkäisyyn tarvittavia tekijöitä
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