ABSTRACT: Melbourne Genomics Health Alliance 'Controlling Superbugs' Study - Using genomics to track transmission of multidrug-resistant pathogens in hospitals
Project description:Membrane efflux pumps play a major role in bacterial multidrug resistance. The tripartite multidrug efflux pump system from Escherichia coli, AcrAB-TolC, is a target for inhibition to lessen resistance development and restore antibiotic efficacy, with homologs in other ESKAPE pathogens. Here, we rationalize a mechanism of inhibition against the periplasmic adaptor protein, AcrA, using a combination of hydrogen/deuterium exchange mass spectrometry, cellular efflux assays, and molecular dynamics simulations. We define the structural dynamics of AcrA and find that an inhibitor can inflict long-range stabilisation across all four of its domains, whereas an interacting efflux substrate has minimal effect. Our results support a model where an inhibitor forms a molecular wedge within a cleft between the lipoyl and αβ domains of AcrA, diminishing its conformational transmission of drug-evoked signals from AcrB to TolC. This work provides molecular insights into multidrug adaptor protein function which could be valuable for developing antimicrobial therapeutics.
Project description:The study aimed to characterize plasmids mediating carbepenem resistance in Klebsiella pneumoniae in Pretoria, South Africa. We analysed 56 K. pneumoniae isolates collected from academic hospital around Pretoria. Based on phenotypic and molecular results of these isolates, 6 representative isolates were chosen for further analysis using long reads sequencing platform. We observed multidrug resistant phenotype in all these isolates, including resistance to aminoglycosides, tetracycline, phenicol, fosfomycin, floroquinolones, and beta-lactams antibiotics. The blaOXA-48/181 and blaNDM-1/7 were manily the plasmid-mediated carbapenemases responsible for carbapenem resistance in the K. pneumoniae isolates in these academic hospitals. These carbapenemase genes were mainly associated with plasmid replicon groups IncF, IncL/M, IncA/C, and IncX3. This study showed plasmid-mediated carbapenemase spread of blaOXA and blaNDM genes mediated by conjugative plasmids in Pretoria hospitals.
Project description:The epidemic community-acquired methicillin-resistant S. aureus (CA-MRSA) clone USA300 has recently become a leading cause of hospital-associated bloodstream infections (BSI). Leveraging this recent introduction into hospitals and the limited genetic variation across the USA300 strains, we combined microbial comparative genomics with phenotypic analyses to discover adaptive mutations. USA300 isolates from BSI were found to have independently evolved single nucleotide variants in the transcriptional regulator sarZ. sarZ inactivation lead to altered expression of virulence factors, resulting in increased lethality in a murine model of BSI. Thus, USA300 strains can optimize their fitness in hospitals through evolution of higher virulence.
Project description:Genomics to track transmission of Livestock-Associated Methicillin-resistant Staphylococcus aureus from UK pigs in abattoirs during slaughter
| PRJEB67443 | ENA
Project description:Multidrug-resistant pathogens in the food chain
