Molecular characterization of a 21.4 kilobase antibiotic resistance plasmid from an α-hemolytic Escherichia coli O108:H- human clinical isolate

• Published in: PloS one Vol. 7; no. 4; p. e34718
• Main Authors: Dawes, Fay E, Bulach, Dieter M, Kuzevski, Alexander, Bettelheim, Karl A, Venturini, Carola, Djordjevic, Steven P, Walker, Mark J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 20-04-2012; Public Library of Science (PLoS)
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiotic resistance; Antibiotics; Apoptosis; Bacteria; Biology; Cloning; Conjugation, Genetic - drug effects; Deoxyribonucleic acid; DNA; DNA Transposable Elements - genetics; Drug resistance; Drug Resistance, Microbial - genetics; E coli; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Gene expression; Gene regulation; Gene sequencing; Genes; Gram-negative bacteria; Humans; Immunology; Incompatibility; Infectious diseases; Insertion; Insertion sequences; Integrons - genetics; Medicine; Microbiology; Nucleotide sequence; Pathogens; Plasmids; Plasmids - drug effects; Plasmids - genetics; Proteins; Replication; Replication origins; Streptothricin; Transposase; Transposase gene; Trimethoprim; Queensland Australia; Victoria Australia; New South Wales Australia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0034718

This study characterizes the 21.4 kilobase plasmid pECTm80 isolated from Escherichia coli strain 80, an α hemolytic human clinical diarrhoeal isolate (serotype O108:H-). DNA sequence analysis of pECTm80 revealed it belonged to incompatibility group X1, and contained plasmid partition and toxin-antitoxin systems, an R6K-like triple origin (ori) replication system, genes required for replication regulation, insertion sequences IS1R, ISEc37 and a truncated transposase gene (Tn3-like ΔtnpA) of the Tn3 family, and carried a class 2 integron. The class 2 integron of pECTm80 contains an intact cassette array dfrA1-sat2, encoding resistance to trimethoprim and streptothricin, and an aadA1 gene cassette truncated by the insertion of IS1R. The complex plasmid replication system includes α, β and γ origins of replication. Pairwise BLASTn comparison of pECTm80 with plasmid pE001 reveals a conserved plasmid backbone suggestive of a common ancestral lineage. Plasmid pECTm80 is of potential clinical importance, as it carries multiple genes to ensure its stable maintenance through successive bacterial cell divisions and multiple antibiotic resistance genes.