Aspectos clínico-epidemiológicos e microbiológicos de processos infecciosos causados por Corynebacterium spp em pacientes de centro de referência oncológico Rio de Janeiro, Brasil

Abstract

A retrospective study at the InstitutoNacional doCâncer-INCA (National Cancer Institute) in Rio de Janeiro, Brazil examined infections of Corynebacterium sp. in cancer patients. The results were presented in four papers. Article 1 describes microbiological and clinical aspects of corynebacteriosis in cancer patients observed over five years. Article 2 presents cases of bacteremia caused by invasive non-toxigenic corynebacteria observed in 2003-2004 and seven years later in 2012-2013. Article 3 presents atypical clinical cases of cancer patients infected by Corynebacterium diphtheriae, while Article 4 is a study of the major bacterial virulence factors of an isolated strain of C. diphtheriae in infections associated with nephrostomy catheters.In addition to clinical and epidemiological aspects, Article 1 evaluates the antimicrobial resistance profiles and potential virulence factor of microorganisms. Over a period of five years, 932 samples of corynebacteria with antimicrobial resistance profiles were isolated from patients with cancer. The predominant species were Corynebacterium amycolatum (44.7%), Corynebacterium minutissimum (18.3%) and Corynebacterium pseudodiphtheriticum (8.5%).Long-term catheter use and neutropenia were the major conditions for infection by corynebacteria. Solid tumors were the most common underlying illness. The 30-day mortality rate for patients with corynebacteria infections was six times greater in hospitalized patients than for non-hospitalized patients (OR = 5.5, 95% CI = 1.15 to 26.30, p = 0.033).In Article 2, bacteremia caused by corynebacteria were observed in two time frames: 2003 to 2004 (n=38) and 2012 to 2103 (n=24). The multidrug-resistant species C. amycolatum and Corynebacterium jeikeium were responsible for invasive diseases.There were 34 patients with solid tumors and 28 patients with lymphoproliferative diseases, of which 21 had neutropenia and 54 used central venous catheter. Forty-one patients experienced infection related to or associated with intravascular device. Patients with bacteremia responded to treatment with vancomycin after removal of the catheter. The aggressive behavior of the neoplasia, the hospital stay and the use of central venous catheter increased risk of bacteremias by Corynebacterium sp. In Article 3, 17 cases of atypical infections caused by Corynebacterium diphtheriae were diagnosed from 1996 to 2013. The incidence of C. diphtheriae corresponded to 15.8 cases per 100,000 admissions which is 465 times greater than the incidence of diphtheria in the Brazilian population. Toxemic symptoms were observed in nine patients, although clinical signs of classical diphtheria and endocarditis were not observed.The Pulsed-field gel electrophoretic (PFGE) demonstrated a profile of endemic distribution, although there were two cases with identical profiles suggesting health care-related infections.Article 4demonstrates that non-toxigenic C. diphtheriae attaches to biotic and abiotic surfaces with the production of biofilm in polyurethane catheters at the nephrostomy insertion site. The data presented in these papers permit a conclusion the (i) different species of multidrug-resistant corynebacteria are capable of causing infections in cancer patients, including bacteremias; (ii) C. diphtheriae is capable of causing serious infections in immunocompromised individuals, including infections related to the use of disposable devices among at-risk populations such as those with cancer.