Project description:Antibiotic resistance associated with the expression of the clinically significant carbapenemases, IMP, KPC, and NDM and OXA-48 in Enterobacteriaceae is emerging as a worldwide calamity to health care. In Australia, IMP-producing Enterobacteriaceae is the most prevalent carbapenemase-producing Enterobacteriaceae (CPE). Genomic characteristics of such carbapenemase-producing Enterobacteriaceae (CPE) are well described, but the corresponding proteome is poorly characterised. We have thus developed a method to analyse dynamic changes in the proteome of CPE under antibiotic pressure. Specifically, we have investigated the effect of meropenem at sub-lethal concentrations to develop a better understanding of how antibiotic pressure leads to resistance. Escherichia coli, producing either NDM, IMP or KPC type carbapenemase were included in this study, and their proteomes were analysed in growth conditions with or without meropenem.
Project description:The exchange of mobile genomic islands (MGIs) between microorganisms is often mediated by phages. As a consequence, not only phage genes are transferred, but also genes that have no particular function in the phage's lysogenic cycle. If they provide benefits to the phage's host, such genes are referred to as ‘morons’. The present study was aimed at characterizing a set of Enterobacter cloacae, Klebsiella pneumoniae and Escherichia coli isolates with exceptional antibiotic resistance phenotypes from patients in a neonatal ward. Unexpectedly, these analyses unveiled the existence of a novel family of closely related MGIs in Enterobacteriaceae. The respective MGI from E. cloacae was named MIR17-GI. Importantly, our observations show that MIR17-GI-like MGIs harbor genes associated with high-level resistance to cephalosporins. Further, we show that MIR17-GI-like islands are associated with integrated P4-like prophages. This implicates phages in the spread of cephalosporin resistance amongst Enterobacteriaceae. The discovery of a novel family of MGIs spreading ‘cephalosporinase morons’ is of high clinical relevance, because high-level cephalosporin resistance has serious implications for the treatment of patients with Enterobacteriaceal infections.
Project description:We used a DNA microarray chip covering 369 resistance types to investigate the relation of antibiotic resistance gene diversity with humansM-bM-^@M-^Y age. Metagenomic DNA from fecal samples of 123 healthy volunteers of four different age groups, i.e. pre-school Children (CH), School Children (SC), High School Students (HSS) and Adults (AD) were used for hybridization. The results showed that 80 different gene types were recovered from the 123 individuals gut microbiota, among which 25 were present in CH, 37 in SC, 58 in HSS and 72 in AD. Further analysis indicated that antibiotic resistance genes in groups of CH, SC and AD can be independently clustered, and those ones in group HSS are more divergent. The detailed analysis of antibiotic resistance genes in human gut is further described in the paper DNA microarray analysis reveals the antibiotic resistance gene diversity in human gut microbiota is age-related submitted to Sentific Reports The antibiotic resistance gene microarray is custom-designed (Roche NimbleGen), based on a single chip containing 3 internal replicated probe sets of 12 probes per resistance gene, covering the whole 315K 12-plex platform spots.
Project description:We used a DNA microarray chip covering 369 resistance types to investigate the relation of antibiotic resistance gene diversity with humans’ age. Metagenomic DNA from fecal samples of 123 healthy volunteers of four different age groups, i.e. pre-school Children (CH), School Children (SC), High School Students (HSS) and Adults (AD) were used for hybridization. The results showed that 80 different gene types were recovered from the 123 individuals gut microbiota, among which 25 were present in CH, 37 in SC, 58 in HSS and 72 in AD. Further analysis indicated that antibiotic resistance genes in groups of CH, SC and AD can be independently clustered, and those ones in group HSS are more divergent. The detailed analysis of antibiotic resistance genes in human gut is further described in the paper DNA microarray analysis reveals the antibiotic resistance gene diversity in human gut microbiota is age-related submitted to Sentific Reports