Abstract: 【Objective】To investigate the cause of yellow and white scours in piglets at a Fujian Province pig farm and provide a basis for precise clinical treatment and prevention, this study isolated and identified Escherichia coli (E.coli) from the intestinal contents of deceased piglets, assessing its virulence, drug resistance, and pathogenicity. 【Method】Intestinal contents were collected from diarrheic deceased piglets. Pathogen isolation and identification were performed using selective culture, Gram staining, biochemical tests, 16S rRNA gene amplification, and serotyping. Virulence and resistance characteristics were further analyzed through virulence gene detection, resistance gene detection, antimicrobial susceptibility testing (AST), and mouse pathogenicity testing.【Result】A pathogenic strain was isolated, which formed red colonies on MacConkey (MAC) agar and pale yellow colonies on Xylose Lysine Deoxycholate (XLD) agar. Gram staining revealed Gram-negative short rods. 16S rRNA gene sequencing showed >99% sequence similarity to E.coli sequences in GenBank, confirming its identification as E.. coli. Serotyping identified it as O2. Virulence gene detection showed the strain carried irp2, iucD, and sta genes. Resistance gene detection revealed it simultaneously harbored 11 resistance genes, including those for quinolones, tetracyclines, β-lactams, macrolides, phenicols, and sulfonamides. Antimicrobial susceptibility testing demonstrated resistance to 15 agents including ofloxacin, streptomycin, ampicillin, tetracycline, erythromycin, lincomycin, and sulfisoxazole, while exhibiting sensitivity to amikacin and spectinomycin. Mouse pathogenicity testing confirmed the isolate was pathogenic, with a median lethal dose (LD50) of 1.60 × 108 CFU.【Conclusion】This study isolated a strain of serotype O2 E.coli from diarrheal piglets on a large-scale pig farm in Fujian Province. This strain carried multiple virulence genes, exhibited severe multidrug resistance, and demonstrated strong pathogenicity. The findings provide valuable insights for the surveillance and control of colibacillosis in the Fujian region.