دورية أكاديمية
Chemical Communication of Antibiotic Resistance by Highly Resistant Bacteria.
| العنوان: | Chemical Communication of Antibiotic Resistance by Highly Resistant Bacteria. |
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| المؤلفون: | El-Halfawy, Omar M |
| المصدر: | Electronic Thesis and Dissertation Repository |
| بيانات النشر: | Scholarship@Western |
| سنة النشر: | 2014 |
| المجموعة: | The University of Western Ontario: Scholarship@Western |
| مصطلحات موضوعية: | Antibiotic resistance, Heteroresistance, Communication of antibiotic resistance, Antimicrobial peptides, Bactericidal antibiotics, Polyamines, Putrescine, Population analysis profiling, YceI, Lipocalins, Reactive oxygen species, Bacteriology |
| الوصف: | The overall antibiotic resistance of a bacterial population results from the combination of a wide range of susceptibilities displayed by subsets of bacterial cells. Bacterial heteroresistance to antibiotics has been documented for several opportunistic Gram-negative bacteria, but the mechanism of heteroresistance is unclear. I use Burkholderia cenocepacia as a model opportunistic bacterium to investigate the implications of heterogeneity in the response to the antimicrobial peptide polymyxin B (PmB) and also other bactericidal antibiotics. Here, I report that B. cenocepacia is heteroresistant to PmB. Population analysis profiling identified B. cenocepacia subpopulations arising from a seemingly homogenous culture that are resistant to higher levels of PmB than the rest of the cells in the culture, and protect the more sensitive cells from killing, as well as sensitive bacteria from other species, such as Pseudomonas aeruginosa and Escherichia coli. Communication of resistance depended on upregulation of putrescine synthesis and YceI, a widely conserved low-molecular weight secreted protein. Deletion of genes for the synthesis of putrescine and YceI abrogate protection, while pharmacologic inhibition of putrescine synthesis reduced resistance to PmB. Polyamines and YceI were also required for heteroresistance of B. cenocepacia to various bactericidal antibiotics. I propose that putrescine and YceI resemble "danger" infochemicals whose increased production by a bacterial subpopulation, becoming more resistant to bactericidal antibiotics, communicates higher level of resistance to more sensitive members of the population of the same or different species. Putrescine protects from antibiotics through its ability to compete with PmB for surface binding and protection against antibiotic-induced oxidative stress. YceI proteins are conserved bacterial lipocalins or “bacteriocalins”. Bacteriocalins from different Gram-positive and Gram-negative bacteria are involved in the response to hydrophobic or amphiphilic ... |
| نوع الوثيقة: | text |
| وصف الملف: | application/pdf |
| اللغة: | English |
| العلاقة: | https://ir.lib.uwo.ca/etd/2187Test; https://ir.lib.uwo.ca/context/etd/article/3658/viewcontent/El_Halfawy_Thesis_revised_2.pdfTest |
| الإتاحة: | https://ir.lib.uwo.ca/etd/2187Test https://ir.lib.uwo.ca/context/etd/article/3658/viewcontent/El_Halfawy_Thesis_revised_2.pdfTest |
| رقم الانضمام: | edsbas.352D727F |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |