Mohammadi Azad Zohreh, Moravej Hoda, Fasihi-Ramandi Mahdi, Masjedian Faramarz, Nazari Raziyeh, Mirnejad Reza, Moosazadeh Moghaddam Mehrdad
Department Of Microbiology, School Of Basic Science, Qom Branch, Islamic Azad University, Qom, Iran.
Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
J Med Microbiol. 2017 Jul;66(7):919-926. doi: 10.1099/jmm.0.000524. Epub 2017 Jul 12.
In the last few decades, increasing microbial resistance to common antibiotics has attracted researchers' attention to the development of new classes of antibiotics such as antimicrobial peptides. Accordingly, the aim of the current study was to evaluate antimicrobial effects of the CM11 peptide alone and combined with common antibiotics against drug-resistant isolates of Brucella melitensis.
A total of 50 pathogenic samples of B. melitensis were isolated from patients and their antibiotic susceptibility pattern was evaluated by E-test. Then, the synergistic reaction of the peptide with selected antibiotics was evaluated using a chequerboard procedure.
Based on the susceptibility pattern of isolates, ciprofloxacin, rifampin, streptomycin and co-trimoxazole were used for synergistic study. According to the results, synergic effect was observed for streptomycin and co-trimoxazole in combination with the peptide while ciprofloxacin and rifampin showed partial synergy and additive effect, respectively. Consistent with these results, in the time-killing assay, a decrease in colony counts for streptomycin-peptide and co-trimoxazole-peptide was >2 Log10 while for ciprofloxacin-peptide and rifampin-peptide it was about 1.5 Log10 and <2 Log10, which represents synergy, partial synergy and additive interaction, respectively.
These results showed that by antibiotic-CM11 combination, their effective dose can be reduced particularly for drug-resistant isolates. In conclusion, considering the importance of brucellosis caused by B. melitensis in the Middle East beside reports on antibiotic resistance strains, especially against rifampin, which may literally lead to an increase in resistant strains of Mycobacterium tuberculosis in endemic areas, our findings can be used to develop a suitable alternative treatment for brucellosis, and with less risk.
在过去几十年中，微生物对常用抗生素的耐药性不断增加，这促使研究人员关注新型抗生素的开发，如抗菌肽。因此，本研究的目的是评估CM11肽单独以及与常用抗生素联合使用对耐药性羊种布鲁氏菌分离株的抗菌效果。
从患者中分离出总共50株羊种布鲁氏菌致病样本，并通过E试验评估其抗生素敏感性模式。然后，使用棋盘法评估该肽与选定抗生素的协同反应。
根据分离株的敏感性模式，选择环丙沙星、利福平、链霉素和复方新诺明进行协同研究。结果显示，链霉素和复方新诺明与该肽联合使用时具有协同作用，而环丙沙星和利福平分别表现出部分协同作用和相加作用。与这些结果一致，在时间杀菌试验中，链霉素-肽和复方新诺明-肽组合的菌落计数下降>2个对数单位，而环丙沙星-肽和利福平-肽组合的菌落计数下降约1.5个对数单位和<2个对数单位，分别代表协同作用、部分协同作用和相加作用。
这些结果表明，通过抗生素与CM11肽联合使用，可降低其有效剂量，尤其是对耐药分离株。总之，考虑到中东地区羊种布鲁氏菌引起的布鲁氏菌病的重要性，以及关于抗生素耐药菌株的报道，特别是对利福平的耐药，这可能会导致流行地区结核分枝杆菌耐药菌株的增加，我们的研究结果可用于开发一种合适的、风险较低的布鲁氏菌病替代治疗方法。
