Abstract

Methicillin-Resistant Staphylococcus aureus (MRSA) biofilms are among the most dangerous infections on medical implants, typically requiring surgical explantation and replacement. This study investigated the thermal susceptibility of MRSA biofilms to thermal shocks from 60 to 80 °C for 1–30 min as well as the effect of various antibiotics (most notably methicillin) on thermal mitigation. Pre- and post-shock exposure to three different classes of antibiotics (ciprofloxacin, tobramycin, and methicillin) at concentrations ranging from 0.25 to 128 μg mL⁻¹ were investigated. MRSA biofilms exhibited thermal susceptibility comparable to other common nosocomial pathogens, such as Pseudomonas aeruginosa, though with greater variability. Exposure to antibiotics of any class significantly decreased the degree of thermal shock required for reliable mitigation, including at subclinical concentration. These combined treatments reduced biofilm population more than the sum of thermal and chemical treatments alone, demonstrating synergism, while also indicating a critical population drop of ∼4.5 log₁₀ beyond which the biofilms typically became non-viable.

摘要

耐甲氧西林金黄色葡萄球菌( MRSA ) 生物膜是医疗植入物上最危险的感染之一，通常需要手术移植和更换。本研究调查了MRSA生物膜对 60 至 80 °C 1-30 分钟热冲击的热敏感性，以及各种抗生素（尤其是甲氧西林）对热缓解的影响。研究了电击前和电击后接触浓度范围为 0.25 至 128 μg mL ^{-1的三种不同类别抗生素（环丙沙星、妥布霉素和甲氧西林）的情况。}MRSA生物膜表现出与其他常见医院病原体（例如铜绿假单胞菌）相当的热敏感性，但变异性更大。接触任何类别的抗生素都会显着降低可靠缓解所需的热冲击程度，包括在亚临床浓度下。这些组合处理减少的生物膜数量比单独的热处理和化学处理的总和还要多，证明了协同作用，同时也表明数量下降了约 4.5 log ₁₀，超过这个值生物膜通常变得不可行。