Characterization of Candidemia from a Brazilian Surveillance Program
September 01 2016
A major surveillance study in 16 hospitals across five regions of Brazil has recently been conducted, in order to assess the incidence, species distribution, frequency of antifungal resistance and risk factors for bloodstream infections due to Candida species. In other regions the incidence varies highly, but appears to be stable or increasing, despite advances in the medical support of these critically ill patients. The epidemiology has already been studied extensively in the United States and Europe, but there is a lack of data in Latin America and in particular a lack of data on echinocandin resistance.
Between June 2007 and March 2010, clinical data and microbiological features from a total of 2563 nosocomial bloodstream infection episodes were analysed. The identification of blood isolates was performed by routine methods such as API-ID32 or automated systems. Yeast isolates were sent to the Special Laboratory of Mycology at Universidade Federal de São Paulo, for confirmation of species identification and antifungal susceptibility testing. All identifications were confirmed by MALDI-TOF, using the Microflex LT, while antifungal susceptibility testing was performed using the broth microdilution method.
Candida spp. accounted for 137 monomicrobial BSIs and one polymicrobial BSI, making it the 7th most prevalent agent in the study. The majority of patients were male, with a median age of 56 years. 62.4% of candida patients needed intensive care support, and crude mortality during admission was 72%. Predisposing factors include mechanical ventilation (49.6%), haemodialysis (5.8%) and venous catheters (88.3%). The most common underlying conditions were malignancies, while neutropenia was rare.
C. albicans was the most prevalence species (34.3%), while C. parapsilosis, C. tropicalis, and C. glabrata together accounted for another 49.6%. Antifungal susceptibility testing was carried out on 47 out of the 137 Candida isolates. C. albicans, C. tropicalis and C. parapsilosis isolates were susceptible to all 5 antifungal drugs tested, while 36% of C. glabrata isolates (4 out of 11 isolates) were resistant to fluconazole.
The incidence of candidemia is probably underestimated in this study considering that only the first episode of bloodstream infections were evaluated, and that automated blood culture is far more sensitive for the detection of bacteraemia than fungemia.
C. glabrata has been shown to be emerging as a relevant pathogen in Brazil, and fluconazole resistance was shown to be confined mainly to this species. Mortality rates were higher than those observed in the Northern Hemisphere countries, highlighting the need for better clinical management , specifically; early diagnosis, source control and precise antifungal therapy.