Analysis of drug resistance and biofilm formation of bovine Staphylococcus aureus in Ningxia region

Ma Ruxue; Chang Jiawei; Ma Youqin; Wang Jintao; Ma Yanjie; Wang Guiqin

doi:10.20154/j.cnki.issn1672-9692.2025.10.011

Abstract：The study aims to investigate the antibiotic resistance of Staphylococcus aureus in milk samples of dairy cows with mastitis in Ningxia region,and to provide a reference for the scientific prevention and treatment of Staphylococcus aureus.The biofilm formation ability of 234 strains of Staphylococcus aureus was determined by semi-quantitative crystal violet method,and the formation process of the biofilm was observed by scanning electron microscopy.The resistance of Staphylococcus aureus to 15 kinds of antibiotics was detected by broth dilution method,and the carrying status of genes related to the biofilm of Staphylococcus aureus was detected by polymerase chain reaction(PCR).The results showed that the positive rate of biofilm formation among 234 strains of Staphylococcus aureus was as high as 79.06％(185/234).Under the scanning electron microscope,it can be seen that the bacteria are closely connected into a network structure,forming a biofilm.As time goes by,the biofilm structure becomes increasingly compact.The resistance rate of Staphylococcus aureus to penicillin was the highest(94.87％,222/234),followed by ampicillin(85.90％,201/234).The carrying rates of biofilm-related genes such as icaA in Staphylococcus aureus biofilm-positive bacteria were all higher than those in negative strains.Studies have shown that there is a risk of multi-drug resistance to Staphylococcus aureus in the raw milk of cows with mastitis.The drug resistance of Staphylococcus aureus is related to the formation of biofilms.It is necessary to strengthen the monitoring of drug resistance in cows with mastitis,and pay attention to rational drug use and scientific prevention and treatment.