Phage therapy (PT) shows promising potential in managing biofilm infections, which include refractory orthopedic infections. We report the case of a 13-year-old girl who developed chronic polymicrobial biofilm infection of a pelvic bone allograft after Ewing’s sarcoma resection surgery. Chronic infection by Clostridium hathewayi, Proteus mirabilis and Finegoldia magna was worsened by methicillin-susceptible Staphylococcus aureus exhibiting an inducible Macrolides-Lincosamides-Streptogramin B resistance phenotype (iMLSB). After failure of conventional conservative treatment, combination of in situ anti-S. aureus PT with surgical debridement and intravenous antibiotic therapy led to marked clinical and microbiological improvement, yet failed to prevent a recurrence of infection on the midterm. This eventually led to surgical graft replacement. Multiple factors can explain this midterm failure, among which incomplete coverage of the polymicrobial infection by PT. Indeed, no phage therapy against C. hathewayi, P. mirabilis or F. magna could be administered. Phage-antibiotic interactions were investigated using OmniLog^® technology. Our results suggest that phage-antibiotic interactions should not be considered “unconditionally synergistic”, and should be assessed on a case-by-case basis. Specific pharmacodynamics of phages and antibiotics might explain these differences. More than two years after final graft replacement, the patient remains cured of her sarcoma and no further infections occurred.

中文翻译：

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原位噬菌体治疗金黄色葡萄球菌骨移植多微生物生物膜感染一例：结果和噬菌体-抗生素相互作用

噬菌体疗法 (PT) 在管理生物膜感染（包括难治性骨科感染）方面显示出巨大的潜力。我们报告了一名 13 岁女孩在 Ewing 肉瘤切除手术后发生骨盆同种异体骨移植物慢性多微生物生物膜感染的病例。表现出可诱导的大环内酯类-林可酰胺类-链霉素 B 耐药表型 (iMLSB)的对甲氧西林敏感的金黄色葡萄球菌加重了哈氏梭菌、奇异变形杆菌和Finegoldia magna的慢性感染。常规保守治疗失败后，联合原位抗金黄色葡萄球菌采用手术清创和静脉抗生素治疗的 PT 显着改善了临床和微生物学，但未能防止中期感染复发。这最终导致了手术移植物置换。多种因素可以解释这种中期失败，其中包括 PT 对多种微生物感染的不完全覆盖。事实上，没有针对C. hathewayi、P. mirabilis或F. magna的噬菌体疗法可以施用。使用 OmniLog ^{®研究噬菌体-抗生素相互作用}技术。我们的研究结果表明，不应将噬菌体-抗生素相互作用视为“无条件协同”，而应根据具体情况进行评估。噬菌体和抗生素的特定药效学可能解释了这些差异。在最后一次移植物置换后两年多，患者的肉瘤仍然痊愈，没有发生进一步的感染。