Gomes Débora L R, Martins Carlos A S, Faria Lúcia M D, Santos Louisy S, Santos Cintia S, Sabbadini Priscila S, Souza Mônica C, Alves Gabriela B, Rosa Ana C P, Nagao Prescilla E, Pereira Gabriela A, Hirata Raphael, Mattos-Guaraldi Ana L
Laboratory of Diphtheria and Corynebacteria of Medical Relevance, Faculty of Medicine, University of the State of Rio de Janeiro, UERJ, Rio de Janeiro, RJ, Brazil.
Hospital Infection Control Committee, National Cancer Institute, INCA, Health Ministry, Rio de Janeiro, RJ, Brazil.
J Med Microbiol. 2009 Nov;58(Pt 11):1419-1427. doi: 10.1099/jmm.0.012161-0. Epub 2009 Jul 23.
Corynebacterium diphtheriae still represents a global medical challenge, particularly due to the significant number of individuals susceptible to diphtheria and the emergence of non-toxigenic strains as the causative agents of invasive infections. In this study, we characterized the clinical and microbiological features of what we believe to be the first case of C. diphtheriae infection of a percutaneous nephrostomy catheter insertion site in an elderly patient with a fatal bladder cancer. Moreover, we demonstrated the potential role of adherence, biofilm formation and fibrin deposition traits in C. diphtheriae from the catheter-related infection. Non-toxigenic C. diphtheriae isolated from the purulent discharge (named strain BR-CAT5003748) was identified by the API Coryne system (code 1 010 324) and a multiplex PCR for detection of dtxR and tox genes. Strain BR-CAT5003748 showed resistance to oxacillin, ceftazidime and ciprofloxacin. In experiments performed in vitro, the catheter isolate was classified as moderately hydrophobic and as moderately adherent to polystyrene surfaces. Glass provided a more effective surface for biofilm formation than polystyrene. Micro-organisms adhered to (>1.5 x 10(6) c.f.u.) and multiplied on surfaces of polyurethane catheters. Microcolony formation (a hallmark of biofilm formation) and amorphous accretions were observed by scanning electron microscopy on both external and luminal catheter surfaces. Micro-organisms yielded simultaneous expression of localized adherence-like and aggregative-like (LAL/AAL) adherence patterns to HEp-2 cells. Interestingly, the coagulase tube test resulted in the formation of a thin layer of fibrin embedded in rabbit plasma by the non-toxigenic BR-CAT5003748 strain. In conclusion, C. diphtheriae should be recognized as a potential cause of catheter-related infections in at-risk populations such as elderly and cancer patients. LAL/AAL strains may be associated with virulence traits that enable C. diphtheriae to effectively produce biofilms on catheter surfaces. Biofilm formation and fibrin deposition could have contributed to the persistence of C. diphtheriae at the infected insertion site and the obstruction of the nephrostomy catheter.
白喉棒状杆菌仍然是一个全球性的医学挑战，特别是因为有大量个体对白喉易感，以及非产毒株作为侵袭性感染的病原体出现。在本研究中，我们描述了我们认为是首例发生在一名患有致命膀胱癌的老年患者经皮肾造瘘导管插入部位的白喉棒状杆菌感染的临床和微生物学特征。此外，我们证明了在与导管相关的感染中，白喉棒状杆菌的黏附、生物膜形成和纤维蛋白沉积特性的潜在作用。从脓性分泌物中分离出的非产毒白喉棒状杆菌（命名为菌株BR-CAT5003748）通过API棒状杆菌系统（代码1 010 324）和用于检测dtxR和tox基因的多重PCR进行鉴定。菌株BR-CAT5003748对苯唑西林、头孢他啶和环丙沙星耐药。在体外进行的实验中，导管分离株被分类为中度疏水且中度黏附于聚苯乙烯表面。玻璃比聚苯乙烯为生物膜形成提供了更有效的表面。微生物黏附于（>1.5×10⁶ c.f.u.）并在聚氨酯导管表面繁殖。通过扫描电子显微镜在导管的外部和管腔表面均观察到微菌落形成（生物膜形成的标志）和无定形沉积物。微生物对HEp-2细胞同时产生局部黏附样和聚集样（LAL/AAL）黏附模式。有趣的是，凝固酶试管试验导致非产毒BR-CAT5003748菌株在兔血浆中形成一层嵌入的薄纤维蛋白层。总之，白喉棒状杆菌应被视为老年和癌症患者等高危人群中与导管相关感染的潜在病因。LAL/AAL菌株可能与使白喉棒状杆菌能够在导管表面有效产生生物膜的毒力特性有关。生物膜形成和纤维蛋白沉积可能导致白喉棒状杆菌在感染的插入部位持续存在并导致肾造瘘导管阻塞。
