Risk Factors Of Nosocomial Mrsa Infection Infection In Burn Patients And Detection Of Drug Resistance And Virulence Genes Of MRSA

Objective To explore the risk factors of nosocomial infection of methicillin-resistant Staphylococcus aureus(MRSA)in burn patients and to detect the drug resistance and the carrying status of virulence genes of MRSA.And to provide evidence for the prevention and treatment of nosocomial MRSA infection in burn patients.Methods A total of 90 burn patients with nosocomial MRSA infection treated in the Burn Department of Gansu provincial Hospital from January 2017 to December 2018 were collected as the case group,and 51 burn patients infected with methicillin-sensitive Staphylococcus aureus(MSSA)in the same period as the control group.The clinical data of the two groups were collected: age,sex,characteristics of injury(burn area,third-degree burn and severity),the data before the first detection of MRSA/MSSA(the number of other pathogenic bacteria,the number and time of using antimicrobials,the number and time of invasive operation,the times of operation and dressing change,shock,anemia time and hypoproteinemia time).Univariate and multivariate logistic regression were used to analyze the risk factors of MRSA infection.The drug resistance of all strains was collected,and the MRSA strains isolated from blood or arteriovenous catheter were collected to detect the carrying status of enterotoxin A(sea),epidermal exfoliation toxin A(eta),? hemolysin(hla),toxic shock syndrome toxin 1(tsst1)and panton-Valentine leukocidin(pvl)gene.Results 1.Among the 141 cases included in this study,the detection rate of MRSA was 63.83%.2.Risk factors: univariate analysis showed that compared with the MSSA group,burns of third degree,the time of using antibiotics before the first detection of bacteria,invasive operation time,anemia time and hypoproteinemia time were significantly correlated with MRSA infection.Multivariate regression analysis showed that burns of third degree,the time of using antibiotics before the first detection of bacteria and hypoproteinemia were independent risk factors of MRSA infection in burn patients.3.Drug resistance: MRSA was only sensitive to vancomycin and linezolid,and the resistance rate to trimethoprim / sulfamethoxazole was 6.7%.The resistance rate to gentamicin and other antibiotics was more than 70%.The resistance rate was significantly higher than that of MSSA.The minimum inhibitory concentration(MIC)of vancomycin to MRSA was significantly higher than that of MSSA.4.The carrying rate of sea and hla genes of MRSA strain was 100%.The carrying rate of Perry pvl gene was low,and it did not carry eta and tsst-1 genes.Conclusion 1.In the clinical diagnosis and treatment of burn patients,attention should be paid to the management of third-degree burn patients,rational use of antibacterial drugs and active correction of hypoproteinemia,so as to shorten the hospital stay and prevent MRSA infection.2.The drug resistance rate of MRSA was generally higher than that of MSSA,and the MIC value of vancomycin to MRSA was significantly higher than that of MSSA.Antibiotics should be selected reasonably according to the patient's condition.3.MRSA strains isolated from the blood or arteriovenous catheter of burn patients in our department mainly carry sea,hla and pvl genes.Therefore,the related symptoms and complications of SEA,HLA and PVL toxins should be paid attention to in clinical treatment.