Abstract:

This study aims to investigate a strain of pathogenic bacteria, isolated from the organs of dead pigs on a Jinzhou pig farm. The research encompasses bacterial isolation and identification, drug sensitivity tests, and clinical diagnosis and treatment implications. Gram staining was conducted using LB agar culture, followed by BP special medium culture. Drug sensitivity testing, 16S rDNA sequencing, and mouse pathogenicity testing were also performed. Pathological tissue sections were prepared for microscopic observation. Gram staining microscopy results indicated that the bacterium was Gram-positive cocci. The BP Petri dish revealed black colony growth with a transparent ring around it. Drug sensitivity tests demonstrated high sensitivity to enrofloxacin, ofloxacin, amikacin, and kanamycin. 16S rDNA sequencing revealed a high similarity between the 16S rDNA fragments of this bacterium and Staphylococcus aureus. Microscopic examination of pathological sections revealed significant pathological damage in various tissues and organs. The causative organism on this pig farm was identified as Staphylococcus aureus, which exhibited resistance to certain antibiotics and demonstrated some pathogenicity in the mouse attack test.

Key words: swine, Staphylococcus aureus, separation and identification, drug resistance, drug susceptibility test, 16S rDNA sequencing