Detection Of Drug Sensitivity And Molecular Epidemiological Investigation Of PVL Gene In 144 Strains Of Staphylococcus Aureus

Objective:To detect the drug susceptibilities of staphylococcus aureus(SA)isolated in Nanchong and investigate the molecular epidemilogical of Panton-Valentin leukocidin(PVL)gene.To clear the epidemic characterisics of methicillin-resistant Staphylococcus aureus(MRSA)carrying PVL gene and provide evidence for clinical treatment.Methods:A toal of 160 clinical isolates of non-repetitive Staphylococcus aureus were collected between Feb 2018 and Sep 2018 from Affiliated Hospital of Chuanbei Medical College in Nanchong.The 16 strains were removed By VITEK-2 automatic bacterial indentification system and VITEK-2 AST-GP67 Test kit,for bacterial indentification and susceptibility testion.The PVL gene in the MRSA strains were detected by using Polymerase chain reaction(PCR).Result:1.The 160 strains of Staphylococcus aureus strains were distributed in the departments of neurosurgery(16.88%),orthopedics(15.63%),pediatric+neonatology+pediatric Surgery(14.38%),burns(12.50%),Intensive Care Unit(8.12%).The strains isolated from hospital were the pus(39.37%),sputum specimens(35.62%),secretion(13.12%)and blood(7.5%).2.Among the 144 strains of Staphylococcus aureus,42 were MRSA,with the detection rate 29.17%,102 were MSS A,with the detection rate 70.83%.The departments with hight detection rate were departments of neurosurgery(28.57%),orthopedics(19.05%).The main sources of the specimens were the sputums pecimens(42.86%),pus(33.33%).3.Among the 160 strains of Staphylococcus aureus,the analysis of minimum inhibitory concentraions(MIC)against of SA show that the drug senstivity rate to quinupristin-dalfopristin,linezolid,vancomyclina and tigecycline were 100%.The high resistance rate to penicillin G,erythromycin,tetracycline,clindamycin,gentamicin were 95.89%,74.31%,37.05%,36.81%and 29.17%.The low resistance rate to ciprofloxacin,levofloxacin,compound sulfamethoxazole,moxifloxacin,rifampicin were 18.75%,18.75%,18.05%,17.36%,11.11%.4.Among the 42 strains of MRS A,a total of 4 strain carried PVL gene,with the positive rate 9.52%.Among the 50 strains of MSSA in the control group,a total of 1 strain carried PVL gene,with the positive rate 2.00%.The analysis of MIC against of MRSA show that the drug senstivity rate to quinupristin-dalfopristin,linezolid,vancomyclin and tigecycline were 100%.The low resistance rate to moxifloxacin and compound sulfamethoxazole were 28.57%and 11.9%.The analysis of MIC against of MRSA carried PVL gene show resistance to clindamycin rythromycin and tetracycline were 100%.The analysis of MIC against of MRSA not carried PVL gene,the high resistance rate to erythromycin,clindamycin,tetracycline were 89.47%?86.84%?55.26%.The low resistance rate to moxifloxacin and compound sulfamethoxazole were 31.58%and 13.16%.5.Among the 42 strains of MRSA,a total of 27 strain carried mecA gene,with the positive rate 64.29%.Among the 50 strains of MSSA in the control group,no mecA gene was detectedConclusion:1.The detection rate of MRSA in our hospital is lower than the whole province and even the whole country,vancomyclin is the first choice for the treatment of infections caused by MRSA,and relatively low resistance rate to compound sulfamethoxazole and moxifloxacin,suggesting that this two antibiotics can be combined as one of options for the treatment of MRSA.Compared with the PVL negative strains of MRSA,The PVL positive strains of MRSA showed better sensitivity to most antimicrobial agents.2.The carrying rate of PVL is 9.52%in MRSA,higher than most hospital(3.5%),therefore,the factor of PVL should be considered in empirical medication.So PVL gene should be detected to make reasonable use of antibiotics.