| Objective: To understand the clinical distribution of Staphylococcus aureus,the source of clinical specimens and the drug resistance of antimicrobial agents.It was detected the virulence genes in the methicillin-resistant Staphylococcus aureus(MRSA)and the methicillin-sensitive Staphylococcus aureus(MSSA).Those genes can be used to prevent the occurrence to nosocomial infection,control the spread of pathogenic infections,monitor the hospital infection and provide scientific guidence to clinical rational use of antimicrobial agents.Methods: Totally 303 strains of Staphylococcus aureus isolated from July 2015 to July 2016 were collceted from clinical specimens.We combine the traditional manual methods with mass spectrometry to identify species.The antimicrobial susceptibility test of Staphylococcus aureus were detected by using K-B method,and to analyze the results by using WHONET 5.6 software.The polymerase chain reaction(PCR)was used to detect mec A gene and virulence genes,for example staphylococcal entetoxin A(sea),staphyloccal enteroxin B(seb),panton-valetine leukocidin(pvl),hemolysin A(hla),fibronection-binding protein A(fnb A)in 51 strains of MRSA and 52 strains of MSSA,the detection rate of virulence genes in MRSA and MSSA were analyzed by using SPSS 17.0 software.Results: 303 strains of Staphylococcus aureus were detected by cefoxitin disc diffusion method,the MRSA was 125 strains and the MSSA was 178 strains,accounting for 41.3%and 58.7%,respectively.Staphylococcus aureus were mainly from burn department,otolaryngology and neurosurgey,its constituent ratio was 15.2%,11.6% and 10.6%,respectively.Staphylococcus aureus were mainly from wound secretions and sputum,its constituent ratio was 31.0% and 30.7%,respectively.Drug susceptibility testing revealed the resistance rates of MRSA to penicillin G,cefuroxime,cefoxitin,cefotaxime and cefazolin were 100%.MRSA and MSSA to vancomycin,linezolid and teicoplanin wre sensitive.MRSA has higher resistance rates to amikacin,erythromycin,clindamycin,rifampicin,gentamicin,tetracycline,ciprofloxacin and levofloxacin(> 48.0%),the resistance rate of MSSA to erythromycin was 68.0%.51 strains of MRSA and 52 strains of MSSA were detected by mec A gene,the mec A gene carrying rate of MRSA was100%,and the mec A gene carrying rate of MSSA was 0.The prevalence of virulence genes sea,seb,pvl,hla,fnb A were 74.5%(38/51),68.6%(35/51),94.1%(48/51),80.4%(41/51)and 7.8%(4/51)in MRSA strains,respectively.And The prevalence of virulence genes sea,seb,pvl,hla,fnb A were 61.5%(32/52),59.6%(31/52),88.5%(46/52),96.2%(50/51)and 28.8%(15/52)in MSSA strains,respectively.Conclusions: The resistance rate of MRSA to β-lactam antibiotics was very high.And to to mactolides,aminoglycosides,fluoroquinolones,lincomycin,tetracycline,trimethoprim/sulfamethoazole and other antibiotics have different degrees fo durg resistance.The drug resistance of MRSA to a variety of antimicrobial agents was generally higher than MSSA.All strains were sensitive to vancomycin,teicoplanin and linezolid in MRSA and MSSA.The mec A gene was present onlu in MRSA.The virulence genes sea,seb,hla,fnb A and pvl had different carrying rate in MRSA and MSSA.The virulence genes sea,seb and hla had carrying rate difference,it had not statistically significant(P> 0.05).But the carrying rate of virulence genes fnb A and pvl was statistically significant(P <0.05). |
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