Antimicrobial susceptibility testing and drug resistance gene research on coagulase-negative Staphylococcus in hospital-infected patients

XIE Xiao-juan; LAN Tian; GAO Jing

doi:10.13820/j.cnki.gdyx.20225611

Abstract：Objective To analyze the antimicrobial susceptibility of coagulase-negative Staphylococcus isolated from hospital-infected patients from October 1st,2020 to September 30th,2021 and investigate the related resistance genes.Methods A total of 267 strains of coagulase-negative Staphylococcus isolated from clinical specimens in the hospital from October 1st,2020 to September 30th,2021 were selected.Antimicrobial susceptibility testing was performed on the strains using the Kirby-Bauer disk diffusion method and the E-test method.Resistance genes were detected using gene amplification techniques,and the resistance-related genes were analyzed by sequencing.Results Among the 267 strains of coagulase-negative Staphylococcus,the most common species was Staphylococcus epidermidis,with 140 strains,accounting for 52.43％,followed by Staphylococcus hominis,with 39 strains,accounting for 14.61％.Among the coagulase-negative Staphylococcus strains,204 strains(76.40％)were methicillin-resistant coagulase-negative Staphylococcus(MRCNS),and no vancomycin or linezolid-resistant strains were found.Among the coagulase-negative Staphylococcus strains,94.75％carried the mecA resistance gene,74.15％carried the erm A resistance gene,and 69.66％carried the tetM resistance gene.Analysis of the impact of patient age,gender,and resistance genes on a favora-ble clinical outcome revealed that age,mecA resistance gene,and qacA/B/C resistance gene were factors affecting the fa-vorable clinical outcome of coagulase-negative Staphylococcus(CNS)(P＜0.05).Conclusion Patients infected with coagulase-negative Staphylococcus should preferentially be treated with vancomycin or linezolid.Resistance in coagulase-negative Staphylococcus involves multiple resistance mechanisms,and individual strains often express multiple resistance genes,mecA and qacA/B/C resistance genes were independent factors affecting the clinical outcome of patients.