Effectiveness of mechanical cleaning, antibiotics, and induction heating on eradication of Staphylococcus aureus in mature biofilms

Abstract

Aims Here we used a mature seven-day biofilm model of Staphylococcus aureus, exposed to antibiotics up to an additional seven days, to establish the effectiveness of either mechanical cleaning or antibiotics or non-contact induction heating, and which combinations could eradicate S. aureus in mature biofilms. Methods Mature biofilms of S. aureus (ATCC 29213) were grown on titanium alloy (Ti6Al4V) coupons for seven days and were subjected to the following treatments or their combinations: antibiotics, mechanical cleaning, or heat shock by induction heating of 60°C for one minute. Experiments were repeated at least five times. Results In the untreated biofilm, growth up to 1.8×1011 colony-forming units (CFU)/cm2 was observed. Treatment with ciprofloxacin, flucloxacillin, vancomycin, cefuroxime, and amoxicillin all with rifampicin gave 6.0 log, 6.1 log, 1.4 log, 4.8 log, and 3.6 log reduction in CFU/cm2, respectively. Mechanical cleaning alone resulted in 4.9 log reduction and induction heating in 7.3 log reduction. There was an additional effect of ciprofloxacin, flucloxacillin, and induction heating when used in combinations. There was no additional effect for mechanical cleaning. No bacterial growth could be detected after induction heating followed by seven days of ciprofloxacin with rifampicin. Conclusion Mechanical cleaning, antibiotics, and non-contact induction heating reduced the bacterial load of mature S. aureus biofilms with approximately 5 log or more as a single treatment. The effect of mechanical cleaning on mature S. aureus biofilms was limited when used in combination with antibiotics and/or induction heating. Cite this article: Bone Joint Res 2022;11(9):629–638.

Biofilm on total joint replacement materials can be reduced through electromagnetic induction heating using a portable device

“…However, bacterial load measurements are consistent between the discs, and it did not affect the statistical significance of this reduction. Finally, the simplicity of our study design can be considered as a further limitation: a full comprehension of the relative magnitude and clinical feasibility of induction-heating disinfection will require a multidimensional analysis of the isolated and combined effects of induction-heating and other techniques, such as mechanical cleaning and antibiotic therapy; the first results on this regard have been published in recent years [ 11 , 12 ]. Furthermore, this study only assessed the effect of induction heating on 3 bacterial strains, while many other species can be less frequently involved in prosthetic joint infection, and induction-heating effect on them cannot be extrapolated yet.…”

“…Later, the same group published their first results over mature hydrated biofilm of S epidermidis [ 10 ], where a 6.7-log reduction was achieved after induction heating alone up to 60ºC for 3.5 min. Further published results explore the combined effect of induction heating and antibiotics (vancomycin, rifampicin, cefuroxime, ciprofloxacin, amoxicillin, flucloxacillin) and mechanical cleaning [ 11 , 12 ].…”

Efficacy of EDTA-NS irrigation in eradicating Staphylococcus aureus biofilm-associated infection

“…6,7 Many studies demonstrate that biofilm formation plays a pivotal role in the persistence of S. aureus infections. [8][9][10] Biofilm is an aggregated and structured community of bacteria residing in a polymer-based extracellular matrix composed of proteins, DNA, and polysaccharides. 9,11 Besides soft-tissue, S. aureus can also attach to surfaces of medical implants and host tissue; if a mature biofilm develops, it becomes resistant to antibiotic therapy and hinders the infiltration of immune cells, making it difficult to clear the bacteria.…”

Biofilm on total joint replacement materials can be reduced through electromagnetic induction heating using a portable device

“…Later, the same group published their rst results over mature hydrated bio lm of S epidermidis (10), where a 6.7-log reduction was achieved after induction heating alone up to 60ºC for 3.5 minutes. Further published results explore the combined effect of induction heating and antibiotics (vancomycin, rifampicin, cefuroxime, cipro oxacin, amoxicillin, ucloxacillin) and mechanical cleaning (11,12).…”