火器伤致开放性骨缺损细菌感染学研究

Study on bacterial infection of open bone defect caused by firearm injury

目的通过犬火器伤致开放性骨缺损模型研究火器伤的早期致病菌及抗菌谱。方法选取健康比格犬60只,在20 m外用7.62 mm口径步枪对比格犬后腿股骨进行精准射击,建立动物火器伤开放性骨缺损模型。伤后2 h行伤道细菌学取材,清创,并进行伤道和骨缺损测量。将伤道处软组织匀浆后进行细菌培养及药敏实验。结果比格犬均击中股骨干,造模成功率为100.0%(60/60)。伤道入口平均周长为(3.3±1.7)cm,出口平均周长为(7.4±3.4)cm,清创后骨缺损平均长度为(3.3±0.7)cm。造模后,60只犬均存活,存活时间>6周。60例比格犬标本共培养出病原菌9种130株,其中,革兰阳性菌5种78株,革兰阴性菌4种52株。革兰阳性菌中,金黄色葡萄球菌检出率最高,占38.5%(30/78);革兰阴性菌中,铜绿假单胞菌检出率最高,占42.3%(22/52)。革兰阳性菌普遍对利奈唑胺和万古霉素敏感,对青霉素G、头孢唑啉、克林霉素等耐药率较高;革兰阴性菌对包括亚胺培南、美罗培南在内的碳青霉烯类药物敏感性最高。结论比格犬是良好的火器伤骨缺损模型动物。火器伤的早期感染率较高,革兰阳性菌对于传统的β-内酰胺类药物,如青霉素G、一代头孢等存在较高的耐药性,万古霉素、利奈唑胺及碳青霉烯类药物可作为控制火器伤早期感染的一线抗菌药物。

Objective The early pathogenic bacteria and antibacterial spectrum of firearm injury were studied by the model of open bone defect caused by firearm injury in dogs.Methods Sixty healthy Beagles were selected to shoot accurately with a 7.62 mm rifle outside 20 m against the femur of the hind legs of the Beagles to establish an open bone defect model of firearm injury in animals.Bacteriological sampling and debridement of the wound were performed 2 hours after the injury,and the wound and bone defects were measured.After homogenizing the soft tissue of the wound,bacteria culture and drug sensitivity test were carried out.Results Beagles were all hit the femoral shaft,and the success rate of modeling was 100.0%(60/60).The average perimeter of the entrance of the wound was(3.3±1.7)cm,the average perimeter of the exit was(7.4±3.4)cm,and the average length of bone defect after debridement was(3.3±0.7)cm.After modeling,all 60 dogs survived for more than 6 weeks.There were 9 strains of pathogenic bacteria were cultured from 60 Beagle specimens,including 78 strains of 5 gram-positive bacteria and 52 strains of 4 gram-negative bacteria.The highest detection rate of Staphylococcus aureus was 38.5%(30/78)among gram-positive bacteria.The highest detection rate of pseudomonas aeruginosa was 42.3%(22/52)among gram-negative bacteria.Gram-positive bacteria were generally sensitive to linezolid and vancomycin,and had high drug resistance rates to penicillin G,cefazolin,clindamycin,etc.Gram-negative bacteria were most sensitive to carbapenems including imipenem and meropenem.Conclusion Beagle dog is a good animal model of bone defect caused by firearm.The early infection rate of gunshot wound was high,and Gram-positive bacteria had high resistance rate to traditionalβ-lactam drugs such as penicillin G and first generation cephalosporins.Vancomycin,linezolid and carbapenems should be used as the first-line antibiotics to control the early infection of firearm wound.