Patrick C C, Plaunt M R, Hetherington S V, May S M
Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee.
Infect Immun. 1992 Apr;60(4):1363-7. doi: 10.1128/iai.60.4.1363-1367.1992.
An experimental animal model was used to assess the slime layer of Staphylococcus epidermidis as a pathogenic factor in tunnel tract infections. Mice were inoculated with high-slime-producing or non-slime-producing strains of S. epidermidis, either along the length of a subcutaneous catheter or in the area where a catheter had been placed and immediately removed (controls). Among the catheter-bearing mice, the phenotypically distinct staphylococci produced similar, high frequencies of abscess formation (72% [44 of 61] versus 81% [31 of 38]; P = 0.29). In controls, the non-slime-producing organisms were significantly more pathogenic (87% [40 of 46] versus 57% [25 of 44] abscess formation; P = 0.001). No consistent difference was detected between blood isolates obtained from patients with central venous catheter bacteremia and those from neonates with bacteremia in the absence of a prosthetic medical device. Quantitative culture of removed catheters showed greater adherence by the slime-producing isolates (P = 0.014). In this mouse model, slime production by S. epidermidis did not increase the risk of catheter tunnel tract infection, despite the greater catheter adherence of the slime-producing organisms. These findings suggest that traumatized tissue may be a sufficient condition for the development of S. epidermidis catheter-associated infections.
采用实验动物模型评估表皮葡萄球菌的黏液层作为隧道感染致病因素的作用。将高黏液产生型或非黏液产生型表皮葡萄球菌菌株接种于小鼠，接种方式为沿皮下导管全长接种，或在放置导管后立即移除导管的部位接种（对照组）。在携带导管的小鼠中，表型不同的葡萄球菌形成脓肿的频率相似且较高（72%[61只中的44只]对81%[38只中的31只]；P = 0.29）。在对照组中，非黏液产生型菌株的致病性显著更高（形成脓肿的比例为87%[46只中的40只]对57%[44只中的25只]；P = 0.001）。在没有人工医疗装置的情况下，从中心静脉导管菌血症患者分离的血液菌株与从菌血症新生儿分离的血液菌株之间未检测到一致的差异。对移除导管进行定量培养显示，黏液产生型分离株的黏附性更强（P = 0.014）。在该小鼠模型中，尽管黏液产生型菌株对导管的黏附性更强，但表皮葡萄球菌产生黏液并未增加导管隧道感染的风险。这些发现表明，组织创伤可能是表皮葡萄球菌导管相关感染发生的充分条件。
