Lin Yu-Cheng, Lee Yu-Lin, Chen Yi-Hsin, Tsao Shih-Ming, Wang Wei-Yao
Department of Internal Medicine, Show Chwan Memorial Hospital, Changhua, Taiwan.
School of Medicine, Chung Shan Medical University, Taichung, Taiwan.
Front Med (Lausanne). 2024 Apr 19;11:1378207. doi: 10.3389/fmed.2024.1378207. eCollection 2024.
To outline the epidemiology of puerperal mastitis caused by methicillin-resistant (MRSA) and evaluate the effect of an infection control bundle on its incidence.
A surge in MRSA puerperal mastitis was noted in a community hospital in September 2009. MRSA samples from mastitis cases and the environment underwent typing using multilocus sequence typing (MLST), staphylococcal cassette chromosome (SCC), gene encoding surface protein A (), accessory gene regulator (), and pulsed-field gel electrophoresis (PFGE). The phenotypic characteristics, including superantigen toxin profiles, gene encoding Panton-Valentine leucocidin (), and minimal inhibitory concentration (MIC) against vancomycin, were ascertained. Subsequently, an infection control bundle emphasizing contact precautions was introduced, and mastitis incidence rates pre- and post-intervention were compared.
The majority of cases occurred within 6 weeks post-delivery in first-time mothers. Of the 42 isolates (27 from mastitis and 15 from colonized staff and environmental sources), 25 (92.6%) clinical and 3 (20%) colonized MRSA were identified as ST59-SCCV- t437- group I with a vancomycin MIC of 1 mg/L, -positive, and predominantly with a consistent toxin profile (-s-). PFGE revealed 13 patterns; pulsotype B exhibited clonal relatedness between two clinical and three colonized MRSA samples. Post-intervention, the incidence of both mastitis and MRSA mastitis notably decreased from 13.01 to 1.78 and from 3.70 to 0.99 episodes per 100 deliveries, respectively.
Distinct community-associated MRSA (CA-MRSA) clones were detected among puerperal mastitis patients and colonized staff. The outbreak was effectively controlled following the implementation of a targeted infection control bundle.
概述耐甲氧西林金黄色葡萄球菌（MRSA）引起的产褥期乳腺炎的流行病学特征，并评估感染控制综合措施对其发病率的影响。
2009年9月，一家社区医院发现MRSA引起的产褥期乳腺炎病例激增。对乳腺炎病例及环境中的MRSA样本进行多位点序列分型（MLST）、葡萄球菌盒式染色体（SCC）、表面蛋白A基因（）、辅助基因调节子（）及脉冲场凝胶电泳（PFGE）分型。确定其表型特征，包括超抗原毒素谱、杀白细胞素基因（）及对万古霉素的最低抑菌浓度（MIC）。随后引入强调接触预防措施的感染控制综合措施，并比较干预前后乳腺炎发病率。
大多数病例发生在初产妇产后6周内。在42株分离株（27株来自乳腺炎患者，15株来自定植医护人员及环境）中，25株（92.6%）临床分离株及3株（20%）定植MRSA被鉴定为ST59-SCCV-t437-I型，万古霉素MIC为1mg/L，-阳性，且毒素谱基本一致（-s-）。PFGE显示13种图谱；脉冲型B显示2株临床分离株与3株定植MRSA样本之间存在克隆相关性。干预后，乳腺炎及MRSA乳腺炎发病率分别从每100例分娩13.01例和3.70例显著降至1.78例和0.99例。
在产褥期乳腺炎患者及定植医护人员中检测到不同的社区相关性MRSA（CA-MRSA）克隆株。实施针对性感染控制综合措施后，疫情得到有效控制。
