Objective To analyze the sensitivity and results of virulence gene detection of Staphylococcus aureus to frequently-used antibiotics in clinical practice.
Methods Totally 129 isolated strains of Staphylococcus aureus from sterile body fluid samples of pleural effusion, ascites, cerebrospinal fluid and blood were prepared for drug sensitivity test. The minimum inhibitory concentration (MIC) of frequently-used antibiotics such as vancomycin to Staphylococcus aureus was detected by agar dilution method. Polymerase chain reaction (PCR) was used to detect endoresistant genes of mecC and mecA, virulence gene of sasX and panton-valentine leukocidin (PVL) gene in methicillin-resistant Staphylococcus aureus (MRSA).
Results The dilution of oxacillin agar showed that there were 70 strains of MRSA and 59 strains of methicillin-sensitive Staphylococcus aureus (MSSA). The PCR primers of genes of mecA and mecC for 45 strains of isolated MRSA in clinic showed that positive detection rate of mecA was 100.00%, the positive detection rate of sasX was 46.67%(21/45), the negative detection rate of sasX was 53.33%(24/45), and mecC as well as PVL were not detected. MRSA showed a higher drug resistance rate to β amides and certain drug resistance to non β amides such as levofloxacin, amikacin and gentamicin, but more than 75.00% of MRSA were sensitive to trimethoprim and rifampicin. MSSA were sensitive to both β amides and non β amides, and the drug resistance rate was lower than 11.00%; MRSA with negative or positive sasX were resistant to antibiotics such as levofloxacin, fosfomycin and β amides, but the drug resistance rates of sasX negative genes and sasX positive genes to trimethoprim, rifampicin, amikacin and gentamicin were not completely consistent.
Conclusion MRSA is resistant to most antibiotics in clinic, so it is necessary to strengthen the monitoring of MRSA in clinic.
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