Human milk is the best nutrient for infants. The donor human milk is stored in a milk bank before pasteurization. However, the human milk is not sterile and could be colonized with different types of bacteria. Many studies have shown S. aureus to be the most prevalent potential pathogen detected in human milk. This study characterized 22 methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolates from raw human milk for the presence of virulence genes and agr type. Moreover, the genotypic as identified characterization was realized. The presence of virulence genes sei, seg, sec, seh, and etb was identified in resistant and sensitive strains. We observed the predominance of agr type II. The presence of SCCmec IV (67%, 4/6) and V (33%, 2/6) characterized resistant strains as CA-MRSA. Endemic lineages detected (ST1635/CC5-t002, ST5/CC5-t002, ST72/CC5-t126, ST1/CC1-t127, ST45/CC45-t065, and ST398/t1451) could be related to epidemic clones, such as USA800/ST5, USA700/ST72, USA400/ST1, USA600/ST45, and ST398. This study made it possible to understand the characteristics of virulence and clonality of some strains that circulate in breast milk in our region. The discovery of human milk colonization by MSSA and MRSA strains with molecular characteristics similar to infectious clones spread globally demonstrates the importance of monitoring strains that can spread and cause serious infections.

中文翻译：

---

巴西人乳样品中耐甲氧西林和甲氧西林敏感的金黄色葡萄球菌的分子特征

母乳是婴儿最好的营养品。供体母乳在巴氏消毒前储存在奶库中。然而，人乳不是无菌的，可能被不同类型的细菌定植。许多研究表明，金黄色葡萄球菌是人乳中检测到的最普遍的潜在病原体。该研究对 22 株来自生母乳的耐甲氧西林和甲氧西林敏感的金黄色葡萄球菌进行了鉴定，以确定是否存在毒力基因和 agr 类型。此外，实现了已鉴定的基因型表征。在抗性和敏感菌株中鉴定出毒力基因 sei、seg、sec、seh 和 etb 的存在。我们观察到 agr II 型占优势。SCCmec IV (67%, 4/6) 和 V (33%, 2/6) 的存在将抗性菌株表征为 CA-MRSA。检测到地方性谱系 (ST1635/CC5-t002, ST5/CC5-t002、ST72/CC5-t126、ST1/CC1-t127、ST45/CC45-t065和ST398/t1451）可能与流行性克隆有关，如USA800/ST5、USA700/ST72、USA400/ST1、 USA600/ST45 和 ST398。通过这项研究，可以了解我们地区母乳中传播的一些菌株的毒力和克隆性特征。发现 MSSA 和 MRSA 菌株在人乳中定植，其分子特征类似于在全球传播的传染性克隆，这表明监测可传播并导致严重感染的菌株的重要性。通过这项研究，可以了解我们地区母乳中传播的一些菌株的毒力和克隆性特征。发现 MSSA 和 MRSA 菌株在人乳中定植，其分子特征类似于在全球传播的传染性克隆，这表明监测可传播并导致严重感染的菌株的重要性。通过这项研究，可以了解我们地区母乳中传播的一些菌株的毒力和克隆性特征。发现 MSSA 和 MRSA 菌株在人乳中定植，其分子特征类似于在全球传播的传染性克隆，这表明监测可传播并导致严重感染的菌株的重要性。