The well-known and rapidly growing phenomenon of bacterial resistance to antibiotics is caused by uncontrolled, excessive and inappropriate use of antibiotics. One of alternatives to antibiotics is Photodynamic Antibacterial Chemotherapy (PACT). In the present study, the effect of PACT using a photosensitizer Rose Bengal alone and in combination with antibiotics including methicillin and derivatives of sulfanilamide synthesized by us was tested against antibiotic-sensitive and antibiotic-resistant clinical isolates of Gram-positive S. aureus and Gram-negative P. aeruginosa. Antibiotic-sensitive and resistant strains of P. aeruginosa were eradicated by Rose Bengal under illumination and by sulfanilamide but were not inhibited by new sulfanilamide derivatives. No increase in sensitivity of P. aeruginosa cells to sulfanilamide was observed upon a combination of Rose Bengal and sulfanilamide under illumination. All tested S. aureus strains (MSSA and MRSA) were effectively inhibited by PACT. When treated with sub-MIC concentrations of Rose Bengal under illumination, the minimum inhibitory concentrations (MIC) of methicillin decreased significantly for MSSA and MRSA strains. In some cases, antibiotic sensitivity of resistant strains can be restored by combining antibiotics with PACT.
广为人知且迅速增长的细菌对抗生素的抗性现象是由抗生素的无序、过度和不当使用引起的。抗生素的替代方案之一是光动力抗菌化疗(PACT)。在本研究中,使用光敏剂罗斯本加上抗生素(包括由我们合成的甲氧苄青霉素和磺胺类衍生物)的PACT对革兰氏阳性金黄色葡萄球菌和革兰氏阴性绿脓杆菌的抗生素敏感和抗生素耐药临床分离株进行了测试。罗斯本在照射下和磺胺类药物的作用下消灭了绿脓杆菌的抗生素敏感和耐药株,但新的磺胺类衍生物却无法抑制它们。在照射下,罗斯本与磺胺类药物的联合对绿脓杆菌细胞对磺胺类药物的敏感性没有增加。所有经过测试的金黄色葡萄球菌株(MSSA和MRSA)均被PACT有效抑制。在照射下用亚最小抑菌浓度的罗斯本处理时,对MSSA和MRSA株的甲氧苄青霉素的最小抑菌浓度(MIC)显著降低。在某些情况下,通过将抗生素与PACT结合可以恢复耐药株的抗生素敏感性。