Antibiotics and Antibiotic Resistance

The pathogenic and multidrug resistant (MDR) Escherichia coli in poultry products may pose high risk to food safety. The MDR E. coli were selected by antimicrobial susceptibility tests. The Extended-Spectrum β-Lactamases (ESBL) were determined by antibiotics impregnated disks and double disk synergy test. The virulent characteristics, including the biofilm formation, the adhesion, invasion and survivability in Caco-2 and Raw 264.7, the median lethal dose (LD50) in two-day old chickens, were determined via in vitro and in vivo tests. The genes involved in MDR, ESBL and virulence were amplified by PCR. Six MDR E. coli isolates with higher virulence (27, 112, 130, 351, 357 and 381) were selected for next generation sequencing. The multidrug resistance genes (mdtE, F, G, and K) and genes encoding resistance to β-lactams, aminoglycosides, chloramphenicol, fosfomycin, fluoroquinolones and tetracycline were found in one MDR E.coli. The E.coli 381 with higher virulence in cell culture and 1000-fold more virulence in a chicken model than other strains. The Illumina HiSeq2500 transcriptome analysis found that multiple pathways involved in the resistance (e.g mdt for multidrug resistance, mate for efflux family, ompE for outer member, fsr for fosmidomycin resistance and ABC Transporters) and virulence (e.g inv for invasion, BssR and bdm for biofilm formation, NlpD for lipoprotein and ycr for two component systems) were up-regulated in E. coli 381. The results provided critical information about the highly virulent MDR E. coli strain of poultry origin, which can further be used for the development of prevention strategies and treatment procedures.