Comparative analysis of multidrug resistance plasmids and genetic background of CTX-M-producing Escherichia coli recovered from captive wild animals

Multiple interlinked factors are associated with the global resistome, whereas multidrug-resistant (MDR) pathogens have been related to increased mortality rates in humans and animals. CTX-M-type is the most prevalent extended-spectrum -lactamase (ESBL) among Enterobacteriaceae, which raises concern worldwide. Zoological gardens have a high density of animals that live very close to each other and to humans. Therefore, this study aimed to investigate through the whole-genome sequencing (WGS) MDR Escherichia coli lineages obtained from captivity wild animals in a zoo. Genetic background showed a wide resistome for antimicrobials (e.g., blaCTX-M-65, blaCTX-M-8, blaCMY-2, qnrB19), metals (e.g., pcoABCDERS, silABCEP, merACDEPRT), and antibacterial biocides (e.g., sugE, mdfA) among MDR CTX-M-producing E. coli belonging to CC155 and CC156. Mobilome analysis revealed several plasmids, and eight of them were completely characterized, which showed different backbone-encoding genes. Comparative analysis of plasmids blaCTX-M-65/IncHI2-ST3, blaCTX-M-8/IncI1-ST113, and IncQ1 showed a high identity among plasmids obtained from humans and animals worldwide distributed. Besides, several virulence genes, CRISPR, and prophage-related sequences were also detected. The occurrence of MDR E. coli belonging to CCs closely related to humans and food-producing animals and the high similarity among the plasmids from MDR E. coli carrying clinically significant antimicrobial resistance genes may indicate intercontinental dissemination of these lineages and plasmids. Therefore, these findings contribute to the monitoring of antimicrobial resistance and the human-animal-environment interface worldwide.

Draft genome sequence of a multidrug-resistant CTX-M-65-producing Escherichia coli ST156 colonizing a giant anteater (Myrmecophaga tridactyla) in a Zoo

This study aimed to report the draft genome sequence of a multidrug-resistant (MDR) Escherichia coli colonizing a giant anteater (Myrmecophaga tridactyla) in a Brazilian Zoo.
The genome was sequenced using the Illumina MiSeq Platform and de novo genome assembly was performed using SPAdes v. 3.9. The draft genome sequence was annotated using NCBI Prokaryotic Genome Annotation Pipeline. Antibiotic resistance genes, virulence genes, sequence type, serotype and plasmid incompatibility groups were identified using tools from the Center for Genomic Epidemiology.

The genome presented 4970 coding sequences and a GC content of 50.2%. Several antimicrobial resistance genes associated with resistance to ß-lactams (blaTEM-1A and blaCTX-M-65), aminoglycosides [aph(6)-ld, aph(3″)-lb, aph(4)-la, aac(3)-lVa, aadA1 and aadA2], tetracyclines (tetB), sulphonamides (sul2 and sul3), trimethoprim (dfrA8 and dfrA12) and phenicols (floR and cmlA1) were identified. Moreover, mutations in quinolone resistance-determining regions (QRDR) were found. This E. coli isolate also presented virulence genes and belonged to serotype ONT:H25 and ST156 (CC156).

This is the first report of a draft genome sequence of a CTX-M-65-producing E. coli ST156 obtained from a zoo animal, which can be used by genomic surveillance platforms, in order to track transmission dynamics of extended-spectrum ß-lactamase (ESBL)-producing E. coli at the human-animal interface.