The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increased the incidence of community-onset MRSA infection. Respiratory tract infections caused by MRSA has been noted for their severity; however, repeated relapses that require extended antibiotic therapy are rare. We report a case of relapsing bronchopneumonia caused by CA-MRSA in a 56-year-old man. The patient responded to antibiotics, but repeatedly relapsed after stopping treatment. MRSA was consistently isolated from airway specimens during each relapse. Extended oral antibiotic treatment with trimethoprim/sulfamethoxazole (TMP/SMX) for 6 months achieved infection control. Whole-genome sequencing of the isolated strain revealed that the causative agent was sequence type (ST)1/staphylococcal cassette chromosome mec (SCCmec) type IVa, a clone that is rapidly increasing in Japan. This patient had an unusual course of MRSA bronchopneumonia with repeated relapses. Although the choice of antibiotics for long-term use in MRSA respiratory tract infections has not been well established, TMP/SMX was effective and well tolerated for long-term therapy in this case. The clinical course of infections related to the rapid emerging clone, ST1/SCCmec type IVa warrants further attention.

中文翻译：

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社区相关耐甲氧西林金黄色葡萄球菌引起的复发性支气管肺炎：病例报告

社区相关耐甲氧西林金黄色葡萄球菌 (CA-MRSA) 的出现增加了社区发病的 MRSA 感染的发生率。 MRSA 引起的呼吸道感染以其严重性而闻名。然而，需要延长抗生素治疗的反复复发的情况很少见。我们报告一例由 CA-MRSA 引起的 56 岁男性复发性支气管肺炎病例。患者对抗生素有反应，但停止治疗后病情反复复发。每次复发期间，始终从气道标本中分离出 MRSA。使用甲氧苄啶/磺胺甲恶唑 (TMP/SMX) 延长口服抗生素治疗 6 个月，实现了感染控制。对分离菌株的全基因组测序显示，病原体是序列类型（ST）1/葡萄球菌盒染色体mec（SCCmec）IVa型，这是一种在日本迅速增加的克隆。该患者的 MRSA 支气管肺炎病程不寻常，且反复复发。尽管MRSA呼吸道感染长期使用抗生素的选择尚未确定，但在该病例中，TMP/SMX的长期治疗是有效的且耐受性良好。与快速出现的克隆 ST1/SCCmec IVa 型相关的感染的临床过程值得进一步关注。