[Drug-resistance of staphylococcus aureus and detection of mecA gene in all strains isolated from children in Hangzhou].

OBJECTIVE: To study the resistance of staphylococcus aureus (S. aureus) isolated from children in Hangzhou to antibiotics and analyze the clinical value of mecA-PCR in determining oxacillin-resistant isolates.

METHODS: S. aureus isolates were screened by using latex agglutination test and identified with GPI card of Vitek system. Antibiotics sensitivity tests were performed using disk diffusion methods and tests for sensitivity to oxacillin and vancomycin were performed with a further E-test method. The mecA gene was detected with polymerase-chain reaction (PCR).

RESULTS: Of all 259 S. aureus strains, 185 from clinical specimens in inpatients and 74 from pharyngeal swabs in healthy children, 247 strains (95.8%) were beta-lactamase-positive and resistant to penicillin, while 91.1% of all strains were sensitive to oxacillin. All the strains were sensitive to vacomycin and 91.9% of all the strains were susceptible to cefotaxime and ceftriaxone. Resistance to erythromycin, tetracycline, clindamycin, trimethoprim-sulfamethoxazole, chloramphenicol, ofloxacin and rifampin were 48.3%, 30.9%, 21.6%, 11.2%, 10.0%, 2.3% and 1.5%, respectively. The resistance rate to oxacillin, cefotaxime, and ceftriaxone in clinical strains were significantly higher than that in carried strains (P < 0.05), while erythromycin-resistance rate was significantly higher in carried strains than that in clinical isolates (P < 0.05). The mecA-PCR showed that the control strain ATCC25923 and all oxacillin-sensitive S. aureus were mecA-negative, while all oxacillin-resistant strains were mecA-positive instead. Only one strain was mecA-positive in 7 oxacillin-intermediate S. aureus strains.

CONCLUSION: Oxacillin-resistance in S. aureus isolates was low, and mecA-PCR method is a good choice for rapid examination oxacillin-resistant strains.