Intraoperative Assessment of Endogenous Microbiota in the Breast

Abstract Objective: Breast surgery is considered a clean surgery; however, the rates of infection range between 3 and 15%. The objective of the present study was to intraoperatively investigate the presence of autochthonous microbiota in the breast. Methods: Pieces of breast tissue collected from 49 patients who underwent elective breast surgery (reconstructive, diagnostic, or oncologic) were cultured. The pieces of breast tissue were approximately 1 cm in diameter and were removed from the retroareolar area, medial quadrant, and lateral quadrant. Each piece of tissue was incubated in brain heart infusion (BHI) broth for 7 days at 37°C, and in cases in which the medium became turbid due to microorganism growth, the samples were placed in Petri dishes for culturing and isolating strains and for identifying species using an automated counter. Results: Microorganism growth was observed in the samples of 10 of the 49 patients (20.4%) and in 11 of the 218 pieces of tissue (5%). The detected species were Staphylococcus lugdunensis, Staphylococcus hominis, Staphylococcus epidermidis, Sphingomonas paucimobilis, and Aeromonas salmonicida. No patient with positive samples had clinical infection postoperatively. Conclusion: The presence of these bacteria in breast tissue in approximately 20% of the patients in this series suggests that breast surgery should be considered a potential source of contamination that may have implications for adverse reactions to breast implants and should be studied in the near future for their oncological implications in breast implant-associated large-cell lymphoma etiology.

摘要：
研究背景与目的：乳腺手术被视作清洁手术，但其术后感染率仍处于3%~15%的区间内。本研究旨在术中探究乳腺组织内固有菌群（autochthonous microbiota）的存在情况。
方法：本研究纳入49例行择期乳腺手术（包括重建术、诊断术及肿瘤切除术）的患者，收集其乳腺组织样本。所取组织块直径约1cm，取材部位涵盖乳晕后区、内侧象限与外侧象限。将每块组织置于脑心浸液（Brain Heart Infusion, BHI）肉汤中，于37℃条件下培养7天；若培养基因微生物生长出现浑浊，则将样本转移至培养皿中进行菌株培养与分离，并通过自动化微生物鉴定仪完成菌种鉴定。
结果：49例患者的样本中，10例（20.4%）检出微生物生长；218份组织块样本中，11份（5%）检出微生物生长。所检出的菌种包括路邓葡萄球菌（Staphylococcus lugdunensis）、人葡萄球菌（Staphylococcus hominis）、表皮葡萄球菌（Staphylococcus epidermidis）、少动鞘氨醇单胞菌（Sphingomonas paucimobilis）及杀鲑气单胞菌（Aeromonas salmonicida）。所有样本阳性患者术后均未出现临床感染。
结论：本研究队列中约20%的患者乳腺组织内存在上述细菌，提示乳腺手术可被视为潜在的污染源，该现象或对乳腺植入物不良反应存在潜在影响；未来需针对其在乳腺植入物相关大细胞淋巴瘤（breast implant-associated large-cell lymphoma）病因学中的肿瘤学意义开展进一步研究。