心脏外科术后深部胸骨切口感染特征及耐药基因检测

Clinical prevalence and characteristics of a deep chest surgical site infection after cardiac surgery

目的监测心脏外科术后深部胸骨切口感染患者感染病原菌特征及耐药基因,为临床抗感染防治提供指导。方法收集2012-2018年医院心外科收治257例心脏外科术后患者。采集患者纵膈脓性分泌物,监测病原学及临床流行特征与分型。 结果257例心脏外科术后患者中,浅表性胸骨切口感染64例,深部胸骨切口感染103例。其中I型37例,II型48例,III型18例。感染患者临床表现为体温>38℃、WBC>10×10^9/L、切口红肿疼痛、切口化脓或裂开、X光检查纵膈增宽的例数分别为71、58、65、77和25例。分离病原菌78株,其中革兰阴性菌45株、革兰阳性菌27株、真菌6株。革兰阴性菌中,铜绿假单胞菌、大肠埃希菌、鲍曼不动杆菌、阴沟肠杆菌、肺炎克雷伯菌、其他革兰阴性菌为15、13、9、5、1和2株;革兰阳性菌中,金黄色葡萄球菌、表皮葡萄球菌、肺炎链球菌、粪肠球菌、其他革兰阳性菌分别为12、8、3、1和3株;真菌中,白假丝酵母菌4株,热带假丝酵母菌2株。15株铜绿假单胞菌对庆大霉素、头孢他啶、头孢吡肟、环丙沙星、哌拉西林他唑巴坦、亚胺培南的耐药率分别为66.67%、46.67%、33.33%、20.00%、6.67%、0.00%。12株金黄色葡萄球菌对庆大霉素、头孢吡肟、左氧氟沙星、莫西沙星、阿米卡星、利福平、万古霉素的耐药率分别为58.33%、41.67%、25.00%、8.33%、16.67%、8.33%、0.00%。2株耐多药铜绿假单胞菌均在mexT处发生错义突变Leu26→Lys,1株mexR处发生错义突变Lys126→Glu。 结论心脏外科术后患者发生深部胸骨切口感染率较高,以铜绿假单胞菌为主。患者术后早期发生感染者即I型和II型居多,常伴有发热、切口化脓或裂开等临床表现。

Objective To determine the clinical prevalence and characteristics of a deep chest surgical site infection after cardiac surgery in order to guide the clinical prevention and treatment of those infections. Methods Subjects were 257patients with a deep chest surgical site infection after cardiac surgery from 2012-2018.Purulent secretions from the mediastinum were collected to determine the etiology,clinical prevalence,and category of chest surgical site infections. Results Of the 257patients who underwent cardiac surgery,64had a superficial chest surgical site infection and 103had a deep sternal site infection.Thirty-seven patients had a type I surgical site infection,48had a type II surgical site infection, and 18had a type III surgical site infection.Clinical manifestations in patients with a superficial chest surgical site infection after cardiac surgery included a higher temperature(>38?C)in 71patients,a higher WBC count(10×10^9/L) in 58,swelling and pain at the surgical wound in 65,pus or separation at the site in 77,and a widened mediastinum according to X-rays in 25.Seventy-eight strains of pathogens were isolated,including 45strains of Gram-negative bacteria, 27strains of Gram-positive bacteria,and 6strains of fungi.Gram-negative bacteria included 15strains of Pseudomonas aeruginosa,13strains of Escherichia coli,9strains of Acinetobacter bauhinia,5strains of Enterobacter cloacae,1strain of Klebsiella pneumoniae,and 1strain of some other Gram-negative bacterium.Gram-positive bacteria included 12strains of Staphylococcus aureus,8strains of S.epidermis,3strains of S.pneumoniae,1strain of E.faecalis,and 3strains of some other Gram-positive bacteria.Fungi included 4strains of Candida albicans and 2strains of C.tropicalis.The 15 strains of P.aeruginosa were resistant to gentamycin at a rate of 66.67%,to ceftazidime at a rate of 46.67%,to cefepime at a rate of 33.33%,to ciprofloxacin at a rate of 20.00%,to piperacillin at a rate of 6.67%,and to imipenem at a rate of 0.00%.The 12strains of S.aureus were resistant to gentamycin at a rate of 58.33%,to cefepime at a rate of 41.67%,to levofloxacin at a rate of 25.00%,to moxifloxacin at a rate of 8.33%,to amikacin at a rate of 16.67%,to rifampicin at a rate of 8.33%,and to vancomycin at a rate of 0.00%.Two multidrug-resistant P.aeruginosastrains had a missense mutation of Leu26→Lys in mexT,and one strain had a missense mutation of Lys126→Glu in mexR. Conclusion The rate of infection was higher in patients with a deep chest surgical site infection after cardiac surgery,and the main pathogen causing those infections was P.aeruginosa.Most patients who developed an infection soon after surgery had a type I or type II surgical site infection.Clinical manifestations included a fever and pus or separation at the surgical site.