Risk Factors,Gene Distribution And Homology Of Diabetic Foot Infection For Methicillin-Resistant Staphylococcus Aureus

PART I Analysis of Microbial Characteristics and Risk Factors of Methicillin-Resistant Staphylococcus Aureus Infection in Diabetic FootObjective To investigate the risk factors of MRSA infection in diabetic foot infection(DFI),and to analyze the microbial characteristics of DFI patients.To provides the basis for the prevention of hospital sense,the control of the spread of pathogenic bacteria and the rational use of antibiotics.Methods The clinical data of DFI patients in in a third-class a hospital in Anhui province from October 2016 to October 2018 were analyzed retrospectively and divided into methicillin-resistant Staphylococcus aureus infection group and Staphylococcus aureus infection group.Logistic regression models were used to analyze the risk factors of MRSA infection in patients with DFI.At the same time,the information of DFI patients’ pathogenic bacteria infection was derived from the Dong Hua medical technology system,and the distribution of pathogenic bacteria was determined,matrix-assisted laser desorption ionization time-of-flight mass pectrometry(MALDI-TOF-MS)and VITEK-Compact2 were used for identification and drug sensitivity analysis of patients with Staphylococcus aureus infection.Results Among the 337 isolates from 292 patients with DFI,50.45%(170/337)were gram-positive,34(MRSA),40(MSSA),and 158(46.88%)were gram-negative.9 strains of fungi accounted for 2.67%.The resistance rate of MRSA to common antibiotics(tetracycline,oxacillin,cefoxitin,ceftriaxone,Levofloxacin,Moxifloxacin,erythromycin,gentamicin,Clindamycin,Amoxicillin)was significantly higher than that of MSSA(P < 0.05)The isolates were treated with β-lactamases/β-lactamase inhibitors(OR = 1.094,95% CI: 1.015 ~ 1.595),cephalosporins(OR = 1.100,95% CI: 1.016 ~ 1.614),large ulcer area(OR = 1.168,95% CI: 1.029 ~ 1.324),long course of diabetes(OR = 1.176,95% CI: 1.031 ~ 1.342)and combined osteomyelitis(OR = 1.134,95% CI: 1.019 ~ 1.946)was an independent risk factor for MRSA infection in patients with DFI.Conclusions The infection rate of MRSA in patients with DFI is high,and the drug resistance range is wide.Previous use of β-lactamases/β-lactamases inhibitors,cephalosporins,large ulcer area,long duration of diabetes and osteomyelitis can lead to MRSA infection.Therefore,risk factors should be avoided,antibiotics should be used reasonably according to the results of drug sensitivity,timely intervention should be made to avoid the spread of drug-resistant bacteria in DFI patients and improve the quality of life of patients.Part II Analysis of Drug Resistance Genes and Homology of Methicillin-Resistant Staphylococcus Aureus Infection in Diabetic FootObjective To study the distribution of drug-resistant genes and Panton-Valentine leucocidin(PVL)gene of MRSA infection strains in DFI patients,and to analyze their homology.To identify the main drug resistance mechanism of MRSA infection strains in DFI patients,to provide theoretical reference for the choice of antibiotics and disease prevention and control in hospital.Methods A total of 34 MRSA strains 34 strains of MRSA infection isolated from DFI patients were identified,the resistant genes mec A,mec C,aac(6’)/aph(2”),aph(3’)-III,ant(4’,4’”),erm A,erm B,erm C,tet M,tet K,qac A/B and PVL were amplified by polymerase chain reaction.The homology of MRSA was analyzed by matrix assisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF-MS).Results The rates of mec A,aac(6’)/aph(2’”),aph(3’)-III,ant(4’,4”),erm A,erm B,erm C,tet M,tet K,qac A/B,PVL were 91.18%,23.53%,17.65%,11.76%,82.35%,17.65%,35.29%,35.29%,26.47%,76.47%,26.47% respectively.No mec C gene were detected.MALDI-TOF-MS homology analysis divided 34 strains of MRSA into two clusters.Conclusions The drug-resistant genes and disinfectant-resistant genes of MRSA infection in patients with DFI have high carrying rate and high homology.The Clinical workers should strengthen prevention and management,pay attention to strict environmental disinfection and hand hygiene and pay attention to the rational use of antibiotics and disinfectants to avoid cross-contamination and other hospital infection or outbreak of drug-resistant strains.