Darouiche R O, Meade R, Mansouri M, Raad I I
Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
J Heart Valve Dis. 1998 Nov;7(6):639-46.
Antimicrobial coating of medical devices has recently emerged as a potentially effective method for preventing device-related infections. The objective of this animal study was to examine in vivo the antimicrobial efficacy of prosthetic heart valve sewing ring fabric coated with: (i) silver; (ii) combined minocycline and rifampin (M/R); or (iii) combined chlorhexidine and chloroxylenol (CH/CX).
A rabbit model of Staphylococcus aureus colonization and infection of subcutaneously implanted fabric of prosthetic heart valve sewing rings was used. Following administration of anesthesia and preoperative antibiotic prophylaxis, 0.5 x 0.5 cm samples of fabric were placed subcutaneously into the back of rabbits. Each rabbit received a total of eight samples: (i) two uncoated; (ii) two silver-coated; (iii) two M/R-coated; and (iv) two CH/CX-coated. After injecting a bacterial inoculum of 2 x 10(5) c.f.u. of S. aureus onto each implanted sample, the wounds were sutured. Rabbits were monitored daily for one week, killed and the test fabrics removed and cultured.
Rates of device colonization, device-related infection and device-related abscess were similar between the uncoated and silver-coated devices. Devices coated with M/R were less likely to be colonized or cause device-related infection when compared with uncoated devices, and less likely to be associated with abscess formation than silver-coated devices. There was a tendency for CH/CX-coated devices to be less colonized than uncoated devices. Only M/R-coated and CH/CX-coated devices produced zones of inhibition in vitro. Implantation of M/R-coated and CH/CX-coated devices in rabbits did not result in detectable systemic concentrations of the antimicrobial coating agents. Colonization of antimicrobial-coated devices was not associated with resistant S. aureus isolates.
These results suggest that silver-coated sewing rings may not prove to be clinically anti-infective. In contrast, antimicrobial-coated sewing rings that produce effective zones of inhibition, particularly those coated with M/R, are likely to be clinically protective.
医疗器械的抗菌涂层最近已成为预防与器械相关感染的一种潜在有效方法。本动物研究的目的是在体内检验涂有以下物质的人工心脏瓣膜缝合环织物的抗菌效果：（i）银；（ii）米诺环素和利福平合剂（M/R）；或（iii）洗必泰和对氯间二甲苯酚合剂（CH/CX）。
采用金黄色葡萄球菌定植和皮下植入人工心脏瓣膜缝合环织物感染的兔模型。给予麻醉和术前抗生素预防后，将0.5×0.5 cm的织物样本皮下植入兔背部。每只兔共接受8个样本：（i）两个未涂层的；（ii）两个涂银的；（iii）两个涂M/R的；（iv）两个涂CH/CX的。在每个植入样本上注射2×10⁵ c.f.u.的金黄色葡萄球菌菌悬液后，缝合伤口。每天对兔进行一周的监测，然后处死，取出测试织物并进行培养。
未涂层和涂银器械的器械定植率、与器械相关的感染率和与器械相关的脓肿发生率相似。与未涂层器械相比，涂有M/R的器械定植或引起与器械相关感染的可能性较小，且与脓肿形成的相关性比涂银器械小。涂有CH/CX的器械有比未涂层器械定植更少的趋势。只有涂有M/R和CH/CX的器械在体外产生抑菌圈。在兔体内植入涂有M/R和CH/CX的器械未导致抗菌涂层剂的可检测全身浓度。抗菌涂层器械的定植与耐甲氧西林金黄色葡萄球菌分离株无关。
这些结果表明，涂银的缝合环可能在临床上没有抗感染作用。相比之下，能产生有效抑菌圈的抗菌涂层缝合环，尤其是涂有M/R的，可能在临床上具有保护作用。
