Rare Spontaneous Loss of Multiresistance Gene Carrying IncI/ST12 Plasmid in Escherichia coli in Pig Microbiota

• Published in: Antimicrobial agents and chemotherapy Vol. 60; no. 10; pp. 6046 - 6049
• Main Authors: Mourand, Gwenaelle, Touzain, Fabrice, Jouy, Eric, Fleury, Mickael Alain, Denamur, Erick, Kempf, Isabelle
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01-10-2016
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Base Sequence; beta-Lactamases - genetics; beta-Lactamases - metabolism; Chromosome Mapping; Chromosomes, Bacterial - chemistry; Drug Resistance, Multiple, Bacterial; Drug Resistance, Multiple, Bacterial - genetics; Epidemiology and Surveillance; Escherichia coli; Feces - microbiology; Gastrointestinal Microbiome; Gastrointestinal Microbiome - drug effects; Gastrointestinal Microbiome - genetics; Gene Expression; High-Throughput Nucleotide Sequencing; Plasmids; Plasmids - chemistry; Polymerase Chain Reaction; Rifampin - pharmacology; Sequence Deletion; Swine
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/AAC.00864-16

Resistance to extended-spectrum cephalosporins (ESCs) is a matter of considerable concern for public health. Here, we studied the spontaneous loss of an extended-spectrum beta-lactamase (ESBL)-encoding plasmid from a rifampin-resistant Escherichia coli isolate orally inoculated into pigs under controlled conditions. Fecal samples were collected and cultured on rifampin-supplemented medium, and the resistance of the E. coli isolates to ESCs was studied by phenotypic tests, PCR detection of plasmid genes, and complete sequencing. The results showed that only 3 out of 353 rifampin-resistant E. coli isolates were ESC susceptible, and PCR and bioinformatics analysis confirmed the loss of the plasmid. These in vivo experiments indicate that the loss of an ESBL-encoding plasmid seems a rare event in gut microbiota.