Brazilian Journal of medical and biological research

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Potential pathogenic role of aggregative- adhering Corynebacterium diphtheriae of different clonal groups in endocarditis

Hirata Jr., R.; Pereira, G.A.; Filardy, A.A.; Gomes, D.L.R.; Damasco, P.V.; Rosa, A.C.P.; Nagao, P.E.; Pimenta, F.P.; Mattos-Guaraldi, A.L.

Invasive diseases caused by iCorynebacterium diphtheriae /ihave been described increasingly. Several reports indicate the destructive feature of endocarditis attributable to nontoxigenic strains. However, few reports have dealt with the pathogenicity of invasive strains. The present investigation demonstrates a phenotypic trait that may be used to identify potentially invasive strains. The study also draws attention to clinical and microbiological aspects observed in 5 cases of endocarditis due to iC. diphtheriae/i that occurred outside Europe. Four cases occurred in female school-age children (7-14 years) treated at different hospitals in Rio de Janeiro, Brazil. All patients developed other complications including septicemia, renal failure and/or arthritis. Surgical treatment was performed on 2 patients for valve replacement. Lethality was observed in 40% of the cases. Microorganisms isolated from 5 blood samples and identified as iC. diphtheriae/i subsp imitis/i (N = 4) and iC. diphtheriae/i subsp igravis /i(N = 1) displayed an aggregative adherence pattern to HEp-2 cells and identical one-dimensional SDS-PAGE protein profiles. Aggregative-adhering invasive strains of iC. diphtheriae/i showed 5 distinct RAPD profiles. Despite the clonal diversity, all 5 iC. diphtheriae/i invasive isolates seemed to display special bacterial adhesive properties that may favor blood-barrier disruption and systemic dissemination of bacteria. In conclusion, blood isolates from patients with endocarditis exhibited a unique adhering pattern, suggesting a pathogenic role of aggregative-adhering iC. diphtheriae/i of different clones in endocarditis. Accordingly, the aggregative-adherence pattern may be used as an indication of some invasive potential of iC. diphtheriae/i strains.

Keywords: Aggregative adherence; Corynebacterium diphtheriae; Endocarditis; HEp-2 cells; Random amplified polymorphic DNA.

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