In vitro antimicrobial susceptibility testing methods: agar dilution to 3D tissue-engineered models.

In the field of orthopaedic surgery, bacterial invasion of implants and the resulting periprosthetic infections are a common and unresolved problem. Antimicrobial susceptibility testing methods help to define the optimal treatment and identify antimicrobial resistance. This review discusses proven gold-standard techniques and recently developed models for antimicrobial susceptibility testing, while also providing a future outlook. Conventional, gold-standard methods, such as broth microdilution, are still widely applied in clinical settings. Although recently developed methods based on microfluidics and microdroplets have shown advantages over conventional methods in terms of testing speed, safety and the potential to provide a deeper insight into resistance mechanisms, extensive validation is required to translate this research to clinical practice. Recent optical and mechanical methods are complex and expensive and, therefore, not immediately clinically applicable. Novel osteoblast infection and tissue models best resemble infections in vivo. However, the integration of biomaterials into these models remains challenging and they require a long tissue culture, making their rapid clinical implementation unlikely. A method applicable for both clinical and research environments is difficult to realise. With a continuous increase in antimicrobial resistance, there is an urgent need for methods that analyse recurrent infections to identify the optimal treatment approaches. Graphical abstract Timeline of published and partly applied antimicrobial susceptibility testing methods, listed according to their underlying mechanism, complexity and application in research or clinics.

Treatment strategies for chronic osteomyelitis in low- and middle-income countries: systematic review.

OBJECTIVES: To identify a standard treatment regime or highly successful procedure for chronic osteomyelitis in low- and middle-income countries. METHODS: Systematic review following PRISMA guidelines. RESULTS: The initial search resulted in 102 studies of which nine met the inclusion criteria and were analysed qualitatively. The included studies involved 1173 patients from Africa and Asia. All patients were diagnosed with chronic osteomyelitis. Surgical and antibiotic treatment regimens differed substantially. No better judgement than moderate risk of selection bias could be made due to the study designs. CONCLUSIONS: The evidence is not sufficiently robust to identify the most effective treatment, or to even allow a recommendation of the best suitable treatment of chronic osteomyelitis in low-income countries.

Ti surface doping of LiNi0.5Mn1.5O4-δ positive electrodes for lithium ion batteries.

The particle surface of LiNi0.5Mn1.5O4-δ (LNMO), a Li-ion battery cathode material, has been modified by Ti cation doping through a hydrolysis-condensation reaction followed by annealing in oxygen. The effect of different annealing temperatures (500-850 °C) on the Ti distribution and electrochemical performance of the surface modified LNMO was investigated. Ti cations diffuse from the preformed amorphous 'TiO x ' layer into the LNMO surface during annealing at 500 °C. This results in a 2-4 nm thick Ti-rich spinel surface having lower Mn and Ni content compared to the core of the LNMO particles, which was observed with scanning transmission electron microscopy coupled with compositional EDX mapping. An increase in the annealing temperature promotes the formation of a Ti bulk doped LiNi(0.5-w)Mn(1.5+w)-t Ti t O4 phase and Ti-rich LiNi0.5Mn1.5-y Ti y O4 segregates above 750 °C. Fourier-transform infrared spectrometry indicates increasing Ni-Mn ordering with annealing temperature, for both bare and surface modified LNMO. Ti surface modified LNMO annealed at 500 °C shows a superior cyclic stability, coulombic efficiency and rate performance compared to bare LNMO annealed at 500 °C when cycled at 3.4-4.9 V vs. Li/Li+. The improvements are probably due to suppressed Ni and Mn dissolution with Ti surface doping.