دكتوراه
العلوم والتقنية
UNIVERSITY OF BIRMINGHAM
مجال التميز | التميز الدراسي والبحثي |
البحوث المنشورة |
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البحث (1): | |
عنوان البحث: | The evolution of Bordetella pertussis has selected for mutations of acr that lead to sensitivity to hydrophobic molecules and fatty acids |
رابط إلى البحث: | https://doi.org/10.1080/22221751.2019.1601502 |
تاريخ النشر: | 24/03/2019 |
موجز عن البحث: | Whooping cough, or pertussis, is resurgent in numerous countries worldwide. This has renewed interest in Bordetella pertussis biology and vaccinology. The in vitro growth of B. pertussis has been a source of difficulty, both for the study of the organism and the production of pertussis vaccines. It is inhibited by fatty acids and other hydrophobic molecules. The AcrAB efflux system is present in many different bacteria and in combination with an outer membrane factor exports acriflavine and other small hydrophobic molecules from the cell. Here, we identify that the speciation of B. pertussis has selected for an Acr system that is naturally mutated and displays reduced activity compared to B. bronchiseptica, in which the system appears intact. Replacement of the B. pertussis locus with that of B. bronchiseptica conferred higher levels of resistance to growth inhibition by acriflavine and fatty acids. In addition, we identified that the transcription of the locus is repressed by a LysR-type transcriptional regulator. Palmitate de-represses the expression of the acr locus, dependent on the LysR regulator, strongly suggesting that it is a transcriptional repressor that is regulated by palmitate. It is intriguing that the speciation of B. pertussis has selected for a reduction in activity of the Acr efflux system that typically is regarded as protective to bacteria. |
البحث (2): | |
عنوان البحث: | Antimicrobial Resistance and Comparative Genome Analysis of Klebsiella pneumoniae Strains Isolated in Egypt |
رابط إلى البحث: | https://doi.org/10.3390/microorganisms9091880 |
تاريخ النشر: | 05/09/2021 |
موجز عن البحث: | Klebsiella pneumoniae is an important human pathogen in both developing and industrialised countries that can causes a variety of human infections, such as pneumonia, urinary tract infections and bacteremia. Like many Gram-negative bacteria, it is becoming resistant to many frontline antibiotics, such as carbapenem and cephalosporin antibiotics. In Egypt, K. pneumoniae is increasingly recognised as an emerging pathogen, with high levels of antibiotic resistance. However, few Egyptian K. pneumoniae strains have been sequenced and characterised. Hence, here, we present the genome sequence of a multidrug resistant K. pneumoniae strain, KPE16, which was isolated from a child in Assiut, Egypt. We report that it carries multiple antimicrobial resistance genes, including a blaNDM-1 carbapenemase and extended spectrum β-lactamase genes (i.e., blaSHV-40, blaTEM-1B, blaOXA-9 and blaCTX-M-15). By comparing this strain with other Egyptian isolates, we identified common plasmids, resistance genes and virulence determinants. Our analysis suggests that some of the resistance plasmids that we have identified are circulating in K. pneumoniae strains in Egypt, and are likely a source of antibiotic resistance throughout the world. |