Synergistic effects of heat and antibiotics on Pseudomonas aeruginosa biofilms

Abstract

Upon formation of a biofilm, bacteria undergo several changes that prevent eradication with antimicrobials alone. Due to this resistance, the standard of care for infected medical implants is explantation of the infected implant and surrounding tissue, followed by eventual reimplantation of a replacement device. Recent studies have demonstrated the efficacy of heat shock for biofilm eradication. To minimize the heat required for in situ biofilm eradication, this study investigated the hypothesis that antibiotics, while ineffective by themselves, may substantially increase heat shock efficacy. The combined effect of heat and antibiotics on Pseudomonas aeruginosa biofilms was quantified via heat shock in combination with ciprofloxacin, tobramycin, or erythromycin at multiple concentrations. Combined treatments had synergistic effects for all antibiotics for heat shock conditions of 60 °C for 5 min to 70 °C for 1 min, indicating an alternative to surgical explantation.

Synergy between induction heating, antibiotics, and N-acetylcysteine eradicates Staphylococcus aureus from biofilm

“…The observed synergistic effect between heat and antibiotics (without NAC) is in accordance with Hajdu et al, who have shown enhancement of antibacterial activity of antimicrobial agents against staphylococcal biofilms by increasing the ambient temperature [15]. Ricker and Nuxoll have also demonstrated this synergistic effect of antibiotics and heat in a Pseudomonas film for erythromycin, tobramycin, and ciprofloxacin [28]. Both Hajdu and Ricker and Nuxoll used heat conduction rather than induction heating [15,28].…”

“…Ricker and Nuxoll have also demonstrated this synergistic effect of antibiotics and heat in a Pseudomonas film for erythromycin, tobramycin, and ciprofloxacin [28]. Both Hajdu and Ricker and Nuxoll used heat conduction rather than induction heating [15,28].…”

Mild magnetic nanoparticle hyperthermia enhances the susceptibility of Staphylococcus aureus biofilm to antibiotics

“…The effect of heat shock on the susceptibility of bacterial biofilms to antibiotics has been studied in experimental systems that induce uniformly increased temperature to culture media [6,13]. For example, the application of heat shock at a DT of 13 C for 30 min or a DT of 23 C for 5 min exhibited synergistic effects in eradicating P. aeruginosa biofilm when combined with antibiotics including ciprofloxacin or tobramycin [28].…”

“…It has been shown that the application of heat shock to the biofilm phase of bacteria by means of uniformly increasing temperature in the culture media could significantly enhance the susceptibility of Staphylococcal as well as Pseudomonas aeruginosa (P. aeruginosa) biofilm to conventional antibiotics [13,14]. Furthermore, the application of AMF on P. aeruginosa biofilm formed on metallic implants rendered the bacteria more susceptible to antibiotics via heat-mediated removal of the biofilm extracellular polymeric substances (EPS) [15].…”

BeQuIK (Biosensor Engineered Quorum Induced Killing): designer bacteria for destroying recalcitrant biofilms

“…Due to the emergence of antibiotic resistance around the globe, many alternative strategies have been developed to eradicate biofilm formation, including physical (heat and ultrasound) (Cai et al, 2017;Ricker and Nuxoll, 2017;Wang et al, 2018), chemical (organic acids) (Ryssel et al, 2009;Ban et al, 2012;Singla et al, 2014) and biological (bacteriophage) (Tkhilaishvili et al, 2018;Gupta et al, 2019) methods. However, there are some limitations to existing treatment methods.…”