Abstract: Objective To explore Staphylococcus aureus genetic diversity and the mechanisms of multi-drug resistance in respiratory tract infections of children. Methods A total of 72 strains of S. aureus were isolated from fresh sputa or throat swab specimens in children with respiratory tract infections. The drug sensitivity was detected by VITEK full automatic microbial identification system，the β-lactam，amino glycosides，tetracycline. Large ring lactone drug resistance gene of the isolates was detected by PCR，and the drug resistance gene frequency of MRSA was calculated. Results Thirty four MRSA positive strains were screened out from 72 strains of S. aureus，34 strains of mecA genes were detected in 72 strains of S. aureus，with a prevalence of 47.2%. The frequency of MSSA resistant to amoxicillin，erythromycin，gentamicin，minocycline was significantly lower than MRSA （P<0.05）. Bacterial sensitivity to non β-lactam and resistance to 1-2 type non β-lactam in MRSA were remarkably lower than MSSA，MRSA multi-drug resistant rate was significantly higher than MSSA （P<0.05）.The tetM，aac（6＇）/ ph（2＇＇），ermA，tetK detection rate in MRSA strains was significantly higher than that of MSSA. The ermC detection rate of MSSA strain was significantly higher than that of MRSA （P<0.05），and there was no significant difference in （3 '） - III gene detection rate between MSSA and MRSA （P＞0.05）. The frequencies of non-resistance gene or1-2 resistance genes in MRSA were lower than those of MSSA. Conclusion The main genotypes associated with resistance of S. aureus are mecA，tetM，aac（6＇）/ ph（2＇＇），ermA，and tetK in respiratory tract infections of children，which may constitute the main mechanism of multiple drug resistance.

Key words: Respiratory infection, Staphylococcus aureus, Drug res