Functional transfer of OMV-mediated polymyxin resistance : role of tolR and degS genes in altruistic antibiotic resistance
| dc.contributor.advisor | Fuentes Aravena, Juan | |
| dc.contributor.author | Marchant Gutiérrez, Pedro Fernando | |
| dc.contributor.editor | Facultad de Ciencias de la Vida | |
| dc.date.accessioned | 2022-02-08T20:01:51Z | |
| dc.date.available | 2022-02-08T20:01:51Z | |
| dc.date.issued | 2021 | |
| dc.description | Tesis (Msc. In Biotechnology and Life Sciences) | es |
| dc.description.abstract | Salmonella enterica serovar Typhi is the responsible pathogen of typhoid fever, a severe infective disease with a death toll of around 30% in the pre-antibiotic era. Antibiotic treatment drastically reduced typhoid fever mortality, but the continuous emergence of resistant strains significantly complicates the prognosis. Thus, it becomes essential to study alternative resistance mechanisms to develop new treatments. In previous studies, outer membrane vesicles (OMVs, nanosized lipoprotein compartments) are portraited as complex stress response systems against viral threats and antimicrobial molecules. Additionally, in our lab, it was found that OMVs from S. Typhi mutants with a different genetic context possess different physical properties (e.g., protein and lipid content, size distribution). This result made us wonder whether they could exhibit different defensive properties as well. OMVs are secreted from the outer membrane. In this sense, we hypothesized that OMVs release, exemplified in the case of S. Typhi ΔtolR and ΔdegS mutants, which showed the most noticeable increase in OMV production compared to the parental strain, could act as a transferable resistance mechanism against membrane-acting antibiotics. Hence, we designed a co-cultivation essay with Salmonella Typhimurium 14028S ΔompD::lacZ as a reporter strain, allowing us to determine whether OMVs from these are mutants allow for better survivability not only for the strain producing them but for other bacteria in the same media as well. We also assessed OMV-antibiotic interaction through Zeta potential analysis, supplemented with a bioassay designed in this manuscript to determine relative sequestering of antibiotics by OMVs. Our results suggest OMVs from both the ΔtolR and ΔdegS mutants mediate a significant increase in the resistance of S. Typhi to polymyxin B, and both mutants can functionally transfer this resistance to susceptible bacteria, without the need for genetic exchange. | es |
| dc.identifier.uri | http://repositorio.unab.cl/xmlui/handle/ria/21840 | |
| dc.language.iso | en | es |
| dc.publisher | Universidad Andrés Bello | es |
| dc.subject | Farmacorresistencia Microbiana | es |
| dc.subject | Fiebre Tifoidea | es |
| dc.title | Functional transfer of OMV-mediated polymyxin resistance : role of tolR and degS genes in altruistic antibiotic resistance | es |
| dc.type | Tesis | es |
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