Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Chiayi.
College of Medicine, Chang Gung University, Taoyuan.
J Infect Dis. 2024 Sep 23;230(3):e568-e578. doi: 10.1093/infdis/jiae096.
Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 is a globally disseminated MRSA lineage. Herein, we investigated whether MRSA ST45 isolates from cellulitis and from osteomyelitis display distinctive phenotypic and genomic characteristics.
A total of 15 MRSA ST45 isolates from cellulitis (CL-MRSA; n = 6) or osteomyelitis (OM-MRSA; n = 9) were collected in a Taiwan hospital. These MRSA ST45 isolates were characterized for their antimicrobial susceptibility, biofilm-forming ability, cellular infectivity in vitro, and pathogenicity in vivo. Four CL-MRSA and 6 OM-MRSA ST45 isolates were selected for whole-genome sequencing (WGS).
Antibiotic resistance tests showed that all OM-MRSA ST45 strains, but not CL-MRSA ST45 strains, were resistant to ciprofloxacin, levofloxacin, gentamicin, and doxycycline. Compared to the CL-MRSA ST45 isolates, the OM-MRSA ST45 isolates had stronger biofilm-forming ability and cellular infectivity and caused more severe disease in mice. WGS analysis revealed that these OM-MRSA ST45 isolates carry multiple common mutations or polymorphisms in genes associated with antibiotic resistance and virulence. Moreover, the transposable elements IS256 and IS257R2 were found only in the OM-MRSA ST45 isolates.
The emergence and spread of the highly pathogenic and multidrug-resistant ST45 MRSAs identified from osteomyelitis may pose a serious threat on public health.
耐甲氧西林金黄色葡萄球菌（MRSA）序列型（ST）45 是一种全球传播的 MRSA 谱系。在此，我们研究了来自蜂窝织炎和骨髓炎的 MRSA ST45 分离株是否表现出独特的表型和基因组特征。
在一家台湾医院共收集了 15 株来自蜂窝织炎（CL-MRSA；n=6）或骨髓炎（OM-MRSA；n=9）的 MRSA ST45 分离株。对这些 MRSA ST45 分离株的抗菌药物敏感性、生物膜形成能力、体外细胞感染性和体内致病性进行了表征。选择了 4 株 CL-MRSA 和 6 株 OM-MRSA ST45 分离株进行全基因组测序（WGS）。
抗生素耐药性测试表明，所有 OM-MRSA ST45 株均对环丙沙星、左氧氟沙星、庆大霉素和强力霉素耐药，而 CL-MRSA ST45 株则无耐药性。与 CL-MRSA ST45 分离株相比，OM-MRSA ST45 分离株具有更强的生物膜形成能力和细胞感染力，并在小鼠中引起更严重的疾病。WGS 分析显示，这些 OM-MRSA ST45 分离株在与抗生素耐药性和毒力相关的基因中携带多种常见突变或多态性。此外，仅在 OM-MRSA ST45 分离株中发现了转座元件 IS256 和 IS257R2。
从骨髓炎中分离出的高致病性和多药耐药性 ST45-MRSA 的出现和传播可能对公共卫生构成严重威胁。
