Wyrsch, ER, Chowdhury, PR, Jarocki, VM, Brandis, KJ & Djordjevic, SP 2020, 'Duplication and diversification of a unique chromosomal virulence island hosting the subtilase cytotoxin in Escherichia coli ST58.', Microbial genomics.View/Download from: Publisher's site
The AB5 cytotoxins are important virulence factors in Escherichia coli. The most notable members of the AB5 toxin families include Shiga toxin families 1 (Stx1) and 2 (Stx2), which are associated with enterohaemorrhagic E. coli infections causing haemolytic uraemic syndrome and haemorrhagic colitis. The subAB toxins are the newest and least well understood members of the AB5 toxin gene family. The subtilase toxin genes are divided into a plasmid-based variant, subAB1, originally described in enterohaemorrhagic E. coli O113:H21, and distinct chromosomal variants, subAB2, that reside in pathogenicity islands encoding additional virulence effectors. Previously we identified a chromosomal subAB2 operon within an E. coli ST58 strain IBS28 (ONT:H25) taken from a wild ibis nest at an inland wetland in New South Wales, Australia. Here we show the subAB2 toxin operon comprised part of a 140 kb tRNA-Phe chromosomal island that co-hosted tia, encoding an outer-membrane protein that confers an adherence and invasion phenotype and additional virulence and accessory genetic content that potentially originated from known virulence island SE-PAI. This island shared a common evolutionary history with a secondary 90 kb tRNA-Phe pathogenicity island that was presumably generated via a duplication event. IBS28 is closely related [200 single-nucleotide polymorphisms (SNPs)] to four North American ST58 strains. The close relationship between North American isolates of ST58 and IBS28 was further supported by the identification of the only copy of a unique variant of IS26 within the O-antigen gene cluster. Strain ISB28 may be a historically important E. coli ST58 genome sequence hosting a progenitor pathogenicity island encoding subAB.
Wyrsch, ER, Chowdhury, PR, Wallis, L, Cummins, ML, Zingali, T, Brandis, KJ & Djordjevic, SP 2020, 'Whole-genome sequence analysis of environmental Escherichia coli from the faeces of straw-necked ibis (Threskiornis spinicollis) nesting on inland wetlands', MICROBIAL GENOMICS, vol. 6, no. 6.View/Download from: Publisher's site
Venturini, C, Zingali, T, Wyrsch, ER, Bowring, B, Iredell, J, Partridge, SR & Djordjevic, SP 2019, 'Diversity of P1 phage-like elements in multidrug resistant Escherichia coli.', Scientific reports, vol. 9, no. 1.View/Download from: Publisher's site
The spread of multidrug resistance via mobile genetic elements is a major clinical and veterinary concern. Pathogenic Escherichia coli harbour antibiotic resistance and virulence genes mainly on plasmids, but also bacteriophages and hybrid phage-like plasmids. In this study, the genomes of three E. coli phage-like plasmids, pJIE250-3 from a human E. coli clinical isolate, pSvP1 from a porcine ETEC O157 isolate, and pTZ20_1P from a porcine commensal E. coli, were sequenced (PacBio RSII), annotated and compared. All three elements are coliphage P1 variants, each with unique adaptations. pJIE250-3 is a P1-derivative that has lost lytic functions and contains no accessory genes. In pTZ20_1P and pSvP1, a core P1-like genome is associated with insertion sequence-mediated acquisition of plasmid modules encoding multidrug resistance and virulence, respectively. The transfer ability of pTZ20_1P, carrying antibiotic resistance markers, was also tested and, although this element was not able to transfer by conjugation, it was able to lysogenize a commensal E. coli strain with consequent transfer of resistance. The incidence of P1-like plasmids (~7%) in our E. coli collections correlated well with that in public databases. This study highlights the need to investigate the contribution of phage-like plasmids to the successful spread of antibiotic resistant pathotypes.
Wyrsch, ER, Hawkey, J, Judd, LM, Haites, R, Holt, KE, Djordjevic, SP & Billman-Jacobe, H 2019, 'Z/I1 Hybrid Virulence Plasmids Carrying Antimicrobial Resistance genes in S. Typhimurium from Australian Food Animal Production.', Microorganisms, vol. 7, no. 9.View/Download from: Publisher's site
Knowledge of mobile genetic elements that capture and disseminate antimicrobial resistance genes between diverse environments, particularly across human-animal boundaries, is key to understanding the role anthropogenic activities have in the evolution of antimicrobial resistance. Plasmids that circulate within the Enterobacteriaceae and the Proteobacteria more broadly are well placed to acquire resistance genes sourced from separate niche environments and provide a platform for smaller mobile elements such as IS26 to assemble these genes into large, complex genomic structures. Here, we characterised two atypical Z/I1 hybrid plasmids, pSTM32-108 and pSTM37-118, hosting antimicrobial resistance and virulence associated genes within endemic pathogen Salmonella enterica serovar Typhimurium 1,4,,12:i:-, sourced from Australian swine production facilities during 2013. We showed that the plasmids found in S. Typhimurium 1,4,,12:i:- are close relatives of two plasmids identified from Escherichia coli of human and bovine origin in Australia circa 1998. The older plasmids, pO26-CRL125 and pO111-CRL115, encoded a putative serine protease autotransporter and were host to a complex resistance region composed of a hybrid Tn21-Tn1721 mercury resistance transposon and composite IS26 transposon Tn6026. This gave a broad antimicrobial resistance profile keyed towards first generation antimicrobials used in Australian agriculture but also included a class 1 integron hosting the trimethoprim resistance gene dfrA5. Genes encoding resistance to ampicillin, trimethoprim, sulphonamides, streptomycin, aminoglycosides, tetracyclines and mercury were a feature of these plasmids. Phylogenetic analyses showed very little genetic drift in the sequences of these plasmids over the past 15 years; however, some alterations within the complex resistance regions present on each plasmid have led to the loss of various resistance genes, presumably as a result of the activity of IS26. These alte...
Wyrsch, ER, Reid, CJ, DeMaere, MZ, Liu, MY, Chapman, TA, Roy Chowdhury, P & Djordjevic, SP 2019, 'Complete Sequences of Multiple-Drug Resistant IncHI2 ST3 Plasmids in Escherichia coli of Porcine Origin in Australia', Frontiers in Sustainable Food Systems, vol. 3.View/Download from: Publisher's site
Melvold, JA, Wyrsch, ER, McKinnon, J, Charles, IG & Djordjevic, SP 2017, 'Identification of a novel qnrA allele, qnrA8, in environmental Shewanella algae', Journal Of Antimicrobial Chemotherapy, vol. 72, no. 10, pp. 2949-2952.View/Download from: Publisher's site
Quinolones are recognized as one of the most widely prescribed classes of antibiotics used to treat infections caused by Gram-negative and Gram-positive bacteria.1 In humans, quinolones are used to treat infections of the urogenital, respiratory and gastroinestinal tracts as well as a range of anatomically diverse infections in swine, poultry, cattle and companion animals and in aquaculture.2 In the environment, fluoroquinolones break down slowly (half-life of ∼100 days) and it is possible to measure trace levels of the drug in exposed environments.3 The environmental impact of quinolones, particularly fluoroquinolones from humans, agriculture and pharmaceutical production facilities, is a cause of concern as residues and metabolic breakdown products released from the body of target species provides a selection pressure that impacts the ecology of non-target bacterial, invertebrate and vertebrate populations, where it can influence natural mutation rates and lateral gene transfer.2
Reid, C, Wyrsch, E, Chowdhury, PR, Zingali, T, Liu, M, Darling, A, Chapman, T & Djordjevic, S 2017, 'Porcine commensal Escherichia coli: A reservoir for class 1 integrons associated with IS26'.View/Download from: Publisher's site
Abstract Porcine faecal waste is a serious environmental pollutant. Carriage of antimicrobial resistance and virulence-associated genes (VAGs) and the zoonotic potential of commensal Escherichia coli from swine is largely unknown. Furthermore, little is known about the role of commensal E. coli as contributors to the mobilisation of antimicrobial resistance genes between food animals and the environment. Here, we report whole genome sequence analysis of 141 E. coli from the faeces of healthy pigs. Most strains belonged to phylogroups A and B1 and carried i) a class 1 integron; ii) VAGs linked with extraintestinal infection in humans; iii) antimicrobial resistance genes bla TEM , aphAl, cmlA, strAB, tet(A) A, dfrA12, dfrA5, sul1, sul2, sul3 ; iv) IS26; and v) heavy metal resistance genes ( merA, cusA, terA ). Carriage of the sulphonamide resistance gene sul3 was notable in this study. The 141 strains belonged to 42 multilocus sequence types, but clonal complex 10 featured prominently. Structurally diverse class 1 integrons that were frequently associated with IS26 carried unique genetic features that were also identified in extraintestinal pathogenic E. coli (ExPEC) from humans. This study provides the first detailed genomic analysis and point of reference for commensal E. coli of porcine origin, facilitating tracking of specific lineages and the mobile resistance genes they carry. Conflict of Interest Statement None to declare.
Reid, CJ, Wyrsch, ER, Roy Chowdhury, P, Zingali, T, Liu, M, Darling, AE, Chapman, TA & Djordjevic, SP 2017, 'Porcine commensal Escherichia coli: a reservoir for class 1 integrons associated with IS26.', Microbial Genomics, vol. 3, no. 12, pp. 1-13.View/Download from: Publisher's site
Porcine faecal waste is a serious environmental pollutant. Carriage of antimicrobial-resistance genes (ARGs) and virulence-associated genes (VAGs), and the zoonotic potential of commensal Escherichia coli from swine are largely unknown. Furthermore, little is known about the role of commensal E. coli as contributors to the mobilization of ARGs between food animals and the environment. Here, we report whole-genome sequence analysis of 103 class 1 integron-positive E. coli from the faeces of healthy pigs from two commercial production facilities in New South Wales, Australia. Most strains belonged to phylogroups A and B1, and carried VAGs linked with extraintestinal infection in humans. The 103 strains belonged to 37 multilocus sequence types and clonal complex 10 featured prominently. Seventeen ARGs were detected and 97 % (100/103) of strains carried three or more ARGs. Heavy-metal-resistance genes merA, cusA and terA were also common. IS26 was observed in 98 % (101/103) of strains and was often physically associated with structurally diverse class 1 integrons that carried unique genetic features, which may be tracked. This study provides, to our knowledge, the first detailed genomic analysis and point of reference for commensal E. coli of porcine origin in Australia, facilitating tracking of specific lineages and the mobile resistance genes they carry.
Wyrsch, E, Roy Chowdhury, P, Chapman, TA, Charles, IG, Hammond, JM & Djordjevic, SP 2016, 'Genomic Microbial Epidemiology Is Needed to Comprehend the Global Problem of Antibiotic Resistance and to Improve Pathogen Diagnosis', Frontiers in Microbiology, vol. 7, no. 843.View/Download from: Publisher's site
Wyrsch, E, Roy Chowdhury, P, Abraham, S, Santos, J, Darling, AE, Charles, IG, Chapman, TA & Djordjevic, SP 2015, 'Comparative genomic analysis of a multiple antimicrobial resistant enterotoxigenic E. coli O157 lineage from Australian pigs.', BMC Genomics, vol. 16, pp. 1-11.View/Download from: Publisher's site
BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) are a major economic threat to pig production globally, with serogroups O8, O9, O45, O101, O138, O139, O141, O149 and O157 implicated as the leading diarrhoeal pathogens affecting pigs below four weeks of age. A multiple antimicrobial resistant ETEC O157 (O157 SvETEC) representative of O157 isolates from a pig farm in New South Wales, Australia that experienced repeated bouts of pre- and post-weaning diarrhoea resulting in multiple fatalities was characterized here. Enterohaemorrhagic E. coli (EHEC) O157:H7 cause both sporadic and widespread outbreaks of foodborne disease, predominantly have a ruminant origin and belong to the ST11 clonal complex. Here, for the first time, we conducted comparative genomic analyses of two epidemiologically-unrelated porcine, disease-causing ETEC O157; E. coli O157 SvETEC and E. coli O157:K88 734/3, and examined their phylogenetic relationship with EHEC O157:H7. RESULTS: O157 SvETEC and O157:K88 734/3 belong to a novel sequence type (ST4245) that comprises part of the ST23 complex and are genetically distinct from EHEC O157. Comparative phylogenetic analysis using PhyloSift shows that E. coli O157 SvETEC and E. coli O157:K88 734/3 group into a single clade and are most similar to the extraintestinal avian pathogenic Escherichia coli (APEC) isolate O78 that clusters within the ST23 complex. Genome content was highly similar between E. coli O157 SvETEC, O157:K88 734/3 and APEC O78, with variability predominantly limited to laterally acquired elements, including prophages, plasmids and antimicrobial resistance gene loci. Putative ETEC virulence factors, including the toxins STb and LT and the K88 (F4) adhesin, were conserved between O157 SvETEC and O157:K88 734/3. The O157 SvETEC isolate also encoded the heat stable enterotoxin STa and a second allele of STb, whilst a prophage within O157:K88 734/3 encoded the serum survival gene bor. Both isolates harbor a large repertoire of antibi...
Roy Chowdhury, P, McKinnon, J, Wyrsch, E, Hammond, JM, Charles, I & Djordjevic, S 2014, 'Genomic interplay in bacterial communities: implications for growth promoting practices in animal husbandry.', Frontiers in Microbiology, vol. 12, no. 5, pp. 394-394.View/Download from: Publisher's site