医院感染患者凝固酶阴性葡萄球菌的药敏试验以及耐药基因研究

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

目的 分析2020年10月1日至2021年9月30日全院医院感染患者凝固酶阴性葡萄球菌的药敏情况并对相关耐药基因进行研究。方法 选择2020年10月1日至2021年9月30日全院临床分离的凝固酶阴性葡萄球菌株共267株,通过Kirby-Bauer纸片扩散法与E-test法对菌株进行药敏试验,应用基因扩增技术测定耐药基因,并测序分析株种耐药相关基因。结果 凝固酶阴性葡萄球菌共267株,其中占比最大的菌种为表皮葡萄球菌共140株,占比52.43%;其次为人葡萄球菌共39例,占比14.61%。凝固酶阴性葡萄球菌共267株,其中耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)204株,占比76.40%,未发现万古霉素、利奈唑胺耐药株。凝固酶阴性葡萄球菌共267株,其中94.75%的菌株携带mecA耐药基因,74.15%携带ermA耐药基因,69.66%携带tetM耐药基因。分析患者年龄、性别、耐药基因对良好临床结局的影响,发现年龄、mecA基因耐药基因、qacA/B/C耐药基因为凝固酶阴性葡萄球菌良好临床结局的影响因素(P<0.05)。结论 感染凝固酶阴性葡萄球菌的患者可首选万古霉素、利奈唑胺进行抗菌治疗,凝固酶阴性葡萄球菌耐药涉及多种耐药机制,且单个菌株常合并表达多个耐药基因,mecA与qacA/B/C耐药基因为患者临床结局的独立影响因素。

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 ermA resistance gene,and 69.66%carried the tetM resistance gene.Analysis of the impact of patient age,gender,and resistance genes on a favorable clinical outcome revealed that age,mecA resistance gene,and qacA/B/C resistance gene were factors affecting the favorable 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.