Microcalorimetric detection of staphylococcal biofilm growth on various prosthetic biomaterials after exposure to daptomycin

Abstract

Primary aim of this in vitro study was to test the efficacy of daptomycin to eradicate staphylococcal biofilms on various orthopedic implant materials. Secondary aim was to quantitatively estimate the formation of staphylococcal biofilm. We tested six clinically important biomaterials: Cobalt chrome, pure titanium, grid-blasted titanium, porous plasma-coated titanium with/without hydroxyapatite, and polyethylene. Biofilms of S. aureus and S. epidermidis were formed on the samples and thereafter exposed to daptomycin. Samples were subsequently sonicated in order to detect dislodged biofilm bacteria and transferred to a microcalorimeter for real-time measurement of growth-related heat flow. Minimal biofilm eradication concentration (MBEC) was determined as the lowest concentration of daptomycin required to eradicate biofilm bacteria on the sample. Median MBEC of S. aureus biofilm on smooth metallic surfaces was lower than the rough metallic surfaces. In experiments with S. epidermidis, no pattern was seen in relation to the surface roughness. Regarding the quantitative estimation of staphylococcal biofilm formation on the sample, we found a significantly higher amount of biofilm growth on the rough surfaces than the smooth samples and polyethylene. In conclusion, the presented study showed that daptomycin could eradicate S. aureus biofilm at lower concentrations on the smooth surfaces compared to the rough surfaces, as well as polyethylene. In experiments with daptomycin against S. epidermidis biofilms, no pattern was seen in relation to the surface roughness. Furthermore, we demonstrated a faster detection of staphylococcal heat flow due to higher biofilm quantity on the rough surfaces compared to smooth samples and polyethylene. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2809-2816, 2018.

Titanium Kirschner Wires Resist Biofilms Better Than Stainless Steel and Hydroxyapatite-coated Wires: An In Vitro Study

“…Oga et al found with scanning electron microscopy that S. epidermidis adhered in greater numbers to hydroxyapatite than to the uncoated metals used in this study, 46 and Ravn et al have used microcalorimetry to reach a similar conclusion with S. aureus . 47 In contrast, two other microbiological studies have found that hydroxyapatite is comparatively resistant to staphylococcal adhesion. 27 , 48 Our finding that hydroxyapatite exhibited a similar but slightly increased propensity for biofilm formation with respect to stainless steel mirrors the similar clinical infection rate seen with hydroxyapatite and stainless steel.…”

“… 45 , 49 The slightly greater viable cell surface density measured on hydroxyapatite in this work is likely to be because, at least in part, of its greater roughness. 47 , 50 …”

Highly variable effect of sonication to dislodge biofilm-embedded Staphylococcus epidermidis directly quantified by epifluorescence microscopy: an in vitro model study

“…Results from the 72-h experiment must be interpreted with care as the number of specimens is low. However, we do not suspect less variation by increasing the number of Alternative methods for quantification might be measurement of optical density from resolved biofilm on the plates after sonication, or measurement of heat production from dislodged biofilm by microcaloritmetry [15,19].…”

“…This is apparent in the ongoing debate concerning sonication [8,29], and sonication findings are not included in the Musculoskeletal Infection Society (MSIS) criteria for periprosthetic infection. First, in vitro studies raise the question whether Staphylococcus epidermidis biofilm might respond to sonication unlike other species [4,5,19]. Second, clinical studies, including refinement with PCR-techniques, show no difference in sensitivity of culture of tissue samples compared to culture of sonication fluid [1,12].…”

Thermogenic Characterization and Antifungal Susceptibility of Candida auris by Microcalorimetry

“…IMC time to detection (TTD, h) was defined as the time between the insertion of the ampoule into the microcalorimeter and the exponentially increasing heat flow production exceeding the threshold of 10 µW [27].The maximum heat flow peak (P max , µW), the time of the maximum heat flow peak (T max , h), and the total heat produced (H tot , J) were defined as the highest value of the heat flow-time curve, the time at which the P max was detected, and the cumulative amount of heat produced during the whole experiment, respectively. IMC data were converted into microbiologically relevant information such as growth rate (µ, J/h) and lag phase (λ, h) by deriving according to growth models, as previously reported [17,22,29,30].…”