title: Magnesium alloy AZ91 exhibits antimicrobial properties in vitro but not in vivo.
abstract: Magnesium alloys hold great promise for developing orthopedic implants that are biocompatible, biodegradable, and mechanically similar to bone tissue. This study evaluated the in vitro and in vivo antimicrobial properties of magnesium-9%aluminum-1%zinc (AZ91) and commercially pure titanium (cpTi) against Acinetobacter baumannii (Ab307). The in vitro results showed that as compared to cpTi, incubation with AZ91 significantly reduced both the planktonic (cpTi = 3.45e8, AZ91 = 8.97e7, p < 0.001) colony forming units (CFU) and biofilm-associated (cpTi = 3.89e8, AZ91 = 1.78e7, p = 0.01) CFU of Ab307. However, in vivo results showed no significant differences in the CFU enumerated from the cpTi and AZ91 implants following a 1-week implantation in an established rodent model of Ab307 implant associated infection (cpTi = 5.23e3, AZ91 = 2.46e3, p = 0.29). It is proposed that the in vitro results were associated with an increased pH in the bacterial culture as a result of the AZ91 corrosion process. The robust in vivo buffering capacity likely diminished this corrosion associated pH antimicrobial effect. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 221-227, 2018.
authors.affiliation: Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Emily K
authors.initials: EK
authors.lastname: Brooks
authors.affiliation: Department of Orthopedics, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Richard
authors.initials: R
authors.lastname: Ahn
authors.affiliation: Department of Orthopedics, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Menachem E
authors.initials: ME
authors.lastname: Tobias
authors.affiliation: Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Hansen
authors.affiliation: Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Nicole R
authors.initials: NR
authors.lastname: Luke-Marshall
authors.affiliation: Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Linda
authors.initials: L
authors.lastname: Wild
authors.affiliation: Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Campagnari
authors.affiliation: Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, New York.|Department of Orthopedics, State University of New York at Buffalo, Buffalo, New York.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Ehrensberger
mesh_terms: D040981:Acinetobacter baumannii / Q000254:growth & development*; D000497:Alloys / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D020007:Implants, Experimental / Q000382:microbiology*; D008274:Magnesium / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans
chemical_list: D000497:Alloys; D000890:Anti-Infective Agents; D008274:Magnesium
keywords: antimicrobial; biodegradable; in vivo; infection; magnesium