Complete genome sequence of multidrug-resistant avian pathogenic Escherichia coli strain APEC-O2-MS1170.

Objectives: Avian pathogenic Escherichia coli (APEC) causes colibacillosis, one of the leading causes of mortality and morbidity associated with significant economic losses in the poultry industry. This study aimed to determine antimicrobial resistance and to characterise the genome sequence of a multidrug-resistant (MDR) APEC strain isolated from a broiler chicken.

Methods: Strain APEC-O2-MS1170 was isolated from the broiler yolk sac of a 14-day-old broiler. Antimicrobial susceptibility testing was performed using a Sensititre National Antimicrobial Resistance Monitoring System (NARMS) Gram-negative panel. Whole-genome sequencing was performed using both the long-read sequencing approach with a Nanopore GridION sequencer and short-read sequencing with an Illumina HiSeq X-Ten sequencer to obtain a complete scaffold of the genome and an accurate sequence.

Results: The genome size of strain APEC-O2-MS1170 is 4,993,909 bp with a GC content of 50.7% and 4,651 protein-coding sequences. Public databases were used to identify the virulence-associated gene and antimicrobial resistance gene cargo. Plasmid comparison showed that pAPEC-O2-MS1170-R is a large multidrug resistance IncB/O/K/Z plasmid, while pAPEC-O2-MS1170-ColV shares homology with the APEC ColV virulence plasmid.

Conclusion: The genome sequence of APEC-O2-MS1170 provides valuable information on resistance mechanisms and virulence characteristics of pathogenic E. coli as well as information for tracing the potential spread of this MDR strain.