| Staphylococcus aureus is an important foodborne pathogenic bacterium that is gram-positive and can cause a variety of infections ranging from mild to severe.The cause of this infection is mainly the effect of various virulence factors,including various enterotoxins,a variety of proteases and cytohedins.At the same time,due to the emergence of multiple antibiotic resistances in Staphylococcus aureus,new requirements have been put forward for the drug treatment of Staphylococcus aureus.This study mainly included three aspects: first,the pollution of Staphylococcus aureus from Xinjiang dairy cattle was investigated in the laboratory,and its resistance and virulence genes were detected;second,the mechanism of vancomycin resistance and resistance was preliminarily analyzed,and the sequence analysis of Staphylococcus aureus drug resistance plasmid was carried out.(1)51 strains of Staphylococcus aureus were isolated from 414 samples,the separation rate was 12.32%,the pollution evaluation showed that 18 strains of Staphylococcus aureus were isolated from the fecal sample,accounting for 35.29%;the breast pump swab isolated 13 strains of Staphylococcus aureus,accounting for 25.49%;the milk sample and body surface swab were isolated from 8 strains,accounting for 15.69%;the feed was isolated from 4 strains,accounting for 7.84%.The coding of 10 virulence genes of Staphylococcus aureus from dairy cattle was detected by PCR method,among which there were 2 strains of enterotoxin gene seb,accounting for 3.92%;sec had 27 strains,accounting for 52.94%,fibronectin-binding protein fnb B had 4 strains,accounting for 7.84%,hemolysin gene hla had 49 strains,accounting for96.08%,hlb had 43 strains,accounting for 84.31%,adhesin clfa had 51 strains,accounting for100%,and leukocytin pglum 1 strain accounting for 1.96%.There is 1 strain of antitoxic shock syndrome toxin tst,accounting for 1.96%,and the enterotoxin sea and fibronectin-binding protein fnb A were not detected.The resistance rate of 51 dairy-derived Staphylococcus aureus to 11 antibacterial drugs was,in order: 51 strains resistant to ampicillin,accounting for 100%,44 strains resistant to azithromycin,accounting for 86.27%,sulfonamide isoxazole resistant to 43 strains,accounting for 84.31%,ciprofloxacin resistant to15 strains,accounting for 29.41%,amoxicillin resistant to 8 strains,accounting for 15.69%,cefaxitin and chloramphenicol resistant strains were 6 and 3 strains,accounting for 11.76%and 5.88%,respectively.There were 2 strains of kanamycin resistance,accounting for 3.92%.Among them,multi-drug resistance is also more serious,there are 5 strains of five-fold resistance,accounting for 9.80%,there are 18 strains of quadruple resistance,accounting for35.29%,and there are 23 strains of triple resistance,accounting for 45.00%.(2)Vancomycin resistance testing was carried out on 190 strains of Staphylococcus aureus preserved in the laboratory,and 43 strains of resistant bacteria were found,accounting for 22.63%,and 1 strain was moderately resistant,accounting for 0.53%.Three types of plasmids were extracted from Staphylococcus aureus,the first group was 5 Staphylococcus aureus plasmids containing only1 penicillin resistance gene bla Z,namely p A202,p A269,p X9,p D94,p D115;the second type was 2 Staphylococcus aureus plasmids containing 3 resistance genes(tetracycline tet K,penicillin bla Z,aminoglycoside aad D1),p A92,p E2,and the third type was the Staphylococcus aureus plasmid p D353 without resistance genes.It is the Theta replication p SK639 family plasmid containing three replication initiating proteins and a rich heavy metal transporter.Staphylococcus aureus from dairy cattle in Xinjiang is more seriously contaminated and carries a large number of virulence genes,with high drug resistance and serious multi-drug resistance,of which vancomycin is also highly resistant and contains more resistant plasmids. |
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