吩噻嗪类染料对耐甲氧西林金黄色葡萄球菌和多药耐药大肠杆菌的光毒性。
Phototoxicity of phenothiazinium dyes against methicillin-resistant Staphylococcus aureus and multi-drug resistant Escherichia coli.
机构信息
Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
出版信息
Photodiagnosis Photodyn Ther. 2012 Mar;9(1):11-5. doi: 10.1016/j.pdpdt.2011.11.004. Epub 2011 Dec 16.
BACKGROUND
Photodynamic inactivation (PDI) has been investigated to cope with the increasing incidence of multidrug-resistant (MDR) pathogens. Here we studied the PDI mediated by methylene blue (MB) and toluidine blue O (TBO) in clinical methicillin-resistant Staphylococcus aureus and MDR Escherichia coli, together with their corresponding American Type Culture Collection (ATCC) strains.
METHODS
Effect of photosensitizer concentration (12.5, 25, 50 μg/ml) and laser irradiation time (10, 20 and 30 min) on lethal photosensitization was investigated.
RESULTS
TBO was more effective. TBO at 50 μg/ml, 46.8 J cm⁻², exhibited 0.7 log killing for MDR E. coli and 1.7 log killing for E. coli (ATCC 25922); 3.1 log killing for MRSA, and 4.2 log killing for S. aureus (ATCC 25923). MB at 50 μg/ml, 163.8 J cm⁻², only exhibited 2.2 log killing in MRSA and 3.1 log killing in S. aureus (ATCC 25923). MB (50 μg/ml, 163.8 J cm⁻²) induced 0.2 log killing for MDR E. coli and 0.3 log killing for E. coli (ATCC 25922). After TBO-PDI, MDR isolates were more susceptible to some antibiotics than control groups.
CONCLUSION
Our studied clinical isolates were more resistant to PDI-mediated killing than their ATCC reference strains. Thus, TBO/MB-mediated PDI in other MDR isolates deserves further investigation.
背景
光动力灭活（PDI）已被研究用于应对日益增加的多药耐药（MDR）病原体。在这里，我们研究了亚甲蓝（MB）和甲苯胺蓝 O（TBO）介导的临床耐甲氧西林金黄色葡萄球菌和多药耐药大肠杆菌，以及它们相应的美国典型培养物保藏中心（ATCC）菌株的 PDI。
方法
研究了光敏剂浓度（12.5、25、50μg/ml）和激光辐照时间（10、20 和 30 分钟）对致死光敏化的影响。
结果
TBO 更有效。TBO 浓度为 50μg/ml、激光能量密度为 46.8 J/cm²，对多药耐药大肠杆菌的杀菌率为 0.7 log，对大肠杆菌（ATCC 25922）的杀菌率为 1.7 log；对耐甲氧西林金黄色葡萄球菌的杀菌率为 3.1 log，对金黄色葡萄球菌（ATCC 25923）的杀菌率为 4.2 log。MB 浓度为 50μg/ml、激光能量密度为 163.8 J/cm²，对耐甲氧西林金黄色葡萄球菌的杀菌率仅为 2.2 log，对金黄色葡萄球菌（ATCC 25923）的杀菌率为 3.1 log。MB（50μg/ml、163.8 J/cm²）诱导多药耐药大肠杆菌的杀菌率为 0.2 log，诱导大肠杆菌（ATCC 25922）的杀菌率为 0.3 log。TBO-PDI 后，与对照组相比，MDR 分离株对一些抗生素的敏感性更高。
结论
我们研究的临床分离株对 PDI 介导的杀伤比其 ATCC 参考菌株更具抗性。因此，TBO/MB 介导的 PDI 在其他 MDR 分离株中值得进一步研究。
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