Research Center for Anti-Infectious Drugs, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
J Infect Chemother. 2009 Oct;15(5):274-8. doi: 10.1007/s10156-009-0703-y. Epub 2009 Oct 24.
It was reported that some methicillin-resistant Staphylococcus aureus (MRSA) show resistance to vancomycin (VCM) and beta-lactam antibiotics; thus, they are termed beta-lactam antibiotic-induced VCM-resistant MRSA (BIVR). The VCM resistance of MRSA is induced by the administration of beta-lactam antibiotics, but this phenomenon can be difficult to detect in the clinical laboratory. We detected the BIVR strain in a 64-year-old man who had had a ventilator tube inserted directly into the windpipe during long-term VCM therapy. The patient was diagnosed with MRSA pneumonia and septicemia on July 5, 2007, and sulbactam/ampicillin (SBT/ABPC) was administered for 5 days. However, the fever recurred, and administration of VCM was resumed for 7 days from July 19. Fever developed again, and VCM was administered again for 14 days from September 30. BIVR and VCM-low-sensitive MRSA were isolated from blood on October 18 and 22, although the VCM trough concentration was 10.2 microg/ml. On October 27, we changed to a combination of fosfomycin (FOM) and arbekacin (ABK), and thereafter the fever quickly decreased and the clinical symptoms abated. We isolated five MRSA strains from the blood of the patient, three strains of VCM-sensitive MRSA, one strain of BIVR, and one strain of a VCM-low-sensitive MRSA. The DNA band patterns determined by pulsed-field gel electrophoresis were completely identical except for the VCM-low-sensitive MRSA, which was missing one band. Furthermore, the VCM-low-sensitive MRSA became sensitive to beta-lactam antibiotics. Our results indicate the possibility that long-term VCM therapy is one of the factors that allow BIVR or VCM-low-sensitive MRSA to emerge, and this allows VCM therapy for MRSA to fail.
据报道，某些耐甲氧西林金黄色葡萄球菌 (MRSA) 对万古霉素 (VCM) 和β-内酰胺类抗生素表现出耐药性；因此，它们被称为β-内酰胺类抗生素诱导的 VCM 耐药性 MRSA（BIVR）。MRSA 对 VCM 的耐药性是由β-内酰胺类抗生素的给药引起的，但这种现象在临床实验室中可能难以检测到。我们在一名 64 岁男性中检测到 BIVR 菌株，该男性在长期 VCM 治疗期间直接将呼吸机管插入气管。该患者于 2007 年 7 月 5 日被诊断为 MRSA 肺炎和败血症，并给予舒巴坦/氨苄西林（SBT/ABPC）治疗 5 天。然而，发热再次出现，并于 7 月 19 日开始再次给予 VCM 治疗 7 天。发热再次出现，并于 9 月 30 日再次给予 VCM 治疗 14 天。10 月 18 日和 22 日从血液中分离出 BIVR 和 VCM-低敏性 MRSA，尽管 VCM 谷浓度为 10.2 microg/ml。10 月 27 日，我们改为使用磷霉素（FOM）和阿贝卡星（ABK）联合治疗，此后发热迅速下降，临床症状缓解。我们从患者血液中分离出五株 MRSA 菌株，三株 VCM-敏感 MRSA，一株 BIVR 和一株 VCM-低敏性 MRSA。除了 VCM-低敏性 MRSA 缺少一条带外，脉冲场凝胶电泳确定的 DNA 带型完全相同。此外，VCM-低敏性 MRSA 对β-内酰胺类抗生素变得敏感。我们的结果表明，长期 VCM 治疗是导致 BIVR 或 VCM-低敏性 MRSA 出现的因素之一，这使得 VCM 治疗 MRSA 失败。
