Rapid identification of methicillin-resistant Staphylococcus could ensure appropriate medical care. A total of 409 Staphylococcus spp. strains were used to develop a reliable MALDI-TOF method for species identification. We tested twelve S. aureus strains to compare three different sample preparation methods and the reproducibility of the methicillin-resistant m/z 2414 ± 2 indicator peak with direct method in triplicate. A total of 65 Staphylococcus spp. strains (including 37 methicillin-resistant strains) from clinical and hospital environment isolates were used to confirm the presence of phenol-soluble modulin (PSM-mec) peptide. All 272 S. aureus strains from 409 samples were correctly identified at species level by MALDI-TOF. The samples prepared by three methods gave spectra with differences in the intensities and presence of certain peaks. The PSM-mec peak was not visible after the extraction method. The peak m/z 2414 ± 2 was only detected in 61% of the methicillin-resistant strains and in none of the methicillin-sensitive strains. The peak reproducibility for the five analyzed S. aureus strains showing the peak at m/z 2414 ± 2 was 87%. The delta-toxin was observed in 49 out of 65 samples regardless of methicillin susceptibility, as well as in all the samples exhibiting the PSM-mec peak. The peak m/z 2414 ± 2 is specific to methicillin-resistant strains carrying the mecA gene, but the absence of peak m/z 2414 ± 2 does not exclude the possibility of resistance to methicillin. Thus, implementing MALDI-TOF analysis in routine laboratory work, especially with clinical samples, would in many cases provide rapid warning about the presence of methicillin-resistant strains.

快速鉴定耐甲氧西林葡萄球菌可以确保适当的医疗保健。共有 409种葡萄球菌属。菌株被用于开发可靠的 MALDI-TOF 方法进行物种鉴定。我们测试了 12 个金黄色葡萄球菌菌株，以比较三种不同的样品制备方法和耐甲氧西林m / z 2414 ± 2 指示剂峰的重现性与直接方法一式三份。共有 65种葡萄球菌属。来自临床和医院环境分离株的菌株（包括 37 株耐甲氧西林菌株）用于确认酚溶性调制蛋白 (PSM-mec) 肽的存在。所有 272金黄色葡萄球菌MALDI-TOF 在物种水平上正确鉴定了来自 409 个样品的菌株。通过三种方法制备的样品给出的光谱在强度和某些峰的存在方面存在差异。提取方法后看不到 PSM-mec 峰。峰m / z 2414 ± 2 仅在 61% 的耐甲氧西林菌株中检测到，而在甲氧西林敏感菌株中均未检测到。五个分析的金黄色葡萄球菌菌株的峰值重现性显示在m / z 2414 ± 2处的峰值为 87%。无论甲氧西林敏感性如何，在 65 个样品中的 49 个中都观察到了 delta-毒素，并且在所有样品中都观察到了 PSM-mec 峰。峰值m / z2414±2是携带mecA基因的耐甲氧西林菌株特异的，但m / z 2414±2峰的缺失不排除甲氧西林耐药的可能。因此，在常规实验室工作中实施 MALDI-TOF 分析，特别是对临床样本，在许多情况下会提供有关耐甲氧西林菌株存在的快速警告。