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 (.1.5¾10 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. INTRODUCTIONInfections due to bacteria that form biofilms are a clinical problem (Donlan, 2001;Rao et al., 2008 Non-diphtherial corynebacteria have been reported to be infecting pathogens or copathogens in at-risk populations such as immunocompromised patients and patients with indwelling medical devices (Cavendish et al., 1994;Esteban et al., 1999;Wang et al., 2001;Dobler & Braveny, 2003;Schiffl et al., 2004;Lee et al., 2005;Teixido et al., 2007;Dalal & Likhi, 2008).Corynebacterium diphtheriae infections represent a global medical challenge, particularly due to the significant rise in the percentage of adults susceptible to diphtheria (MattosGuaraldi et al., 2001) and the emergence of non-toxigenic strains as the causative agents of endocarditis and other systemic infections . This pathogen is also becoming successful i...

We describe a series of Ralstonia pickettii bloodstream infections (BSI) that occurred in 19 oncohematologic patients admitted to a hospital for patients with cancer, in the city of Rio de Janeiro, from July 1999 to February 2006. Fifty-four R. pickettii isolates were recovered from blood and catheter-tip specimens (1-5 isolates per patient). Two patients eventually died of causes unrelated to R. pickettii BSI. Eight pulsed-field gel electrophoresis genotypes were resolved (A-H), with two detected in more than 1 patient: genotype B, in 2 patients (1.5%), and E, in 12 patients (63.2%). R. pickettii emerged as a new pathogen at our institution, causing at least one outbreak. Cross-transmission of the pathogen, infusion of a putative contaminated intravenous solution, and persistent colonization of medical devices were the likely sources of R. pickettii BSI.