Advances in antifungal prophylaxis and empiric therapy in patients with hematologic malignancies

Detection of triazole resistance among Candida species by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS)

MALDI-TOF MS can rapidly identify microorganisms to the species level and may be able to detect antimicrobial resistance. We evaluated the ability of this technology to detect triazole resistance in Candida species.35 C. albicans, 35 C. glabrata, and 37 C. tropicalis strains were exposed to fluconazole, voriconazole, or posaconazole at two different concentrations plus a drug-free control: a midrange concentration (CLSI clinical breakpoint or epidemiologic cut-off value), and a high concentration (fluconazole 64 μg/ml, voriconazole & posaconazole 16 μg/ml). The MALDI-TOF MS spectra at these concentrations were used to create the individual composite correlation index (CCI) matrices for each isolate. When the CCI of the midrange/highest concentration was lower than that of the midrange/null concentration, the strain was classified as resistant. These results were then compared to the classifications for susceptible or resistant obtained by measuring the MICs according to the CLSI M27-A3 antifungal susceptibility testing (AFST) method.The MALDI-TOF MS assay was able to classify triazole susceptibility against all strains. Overall, essential agreement between MALDI-TOF MS and AFST varied between 54% and 97%, and was highest for posaconazole against C. glabrata. The reproducibility of the MALDI-TOF MS assay varied between 54.3 and 82.9% and was best for fluconazole against C. albicans and posaconazole against C. glabrata. Reproducibility was also higher for C. glabrata isolates compared to C. albicans and C. tropicalis.These results demonstrate that MALDI-TOF MS may be used to simultaneously determine the Candida species and classification as susceptible or resistant to triazole antifungals. Further studies are needed to refine the methodology and improve the reproducibility of this assay.

[The Spanish Society of Paediatric Infectious Diseases (SEIP) recommendations on the diagnosis and management of invasive candidiasis]

Candida yeasts are ubiquitous commensals, which can cause opportunistic infection in any location of the body. The source of infection may be both endogenous and exogenous. Invasive candidiasis encompasses different entities ranging from invasive candidiasis to disseminated multiorgan infection. Invasive candidiasis is the third leading cause of nosocomial bloodstream infection and the fourth of all nosocomial infections. It is also the most common invasive fungal infection in non-neutropenic critically ill patients, with a remarkable increase in the last 20 years owing to the increased survival of these patients and to more complex diagnostic, therapeutic and surgical procedures. Its incidence in infants, according to recent reviews, stands at 38.8 cases/100,000 children younger than 1 year. Candida albicans remains the most frequent isolate in invasive infections, although infections caused by other species have risen in the last years, such as C. kruzsei, C. glabrata and C. parapsilosis; the latter causing invasive candidiasis mainly associated with central venous catheter management, especially in neonatal units. The overall mortality of invasive candidiasis is high, with 30-day mortality reaching 20-44% in some series involving paediatric patients. This report provides an update on incidence, epidemiology, clinical presentation, diagnosis, treatment and outcome of invasive infection by Candida spp. in the paediatric patient.

Update on the laboratory diagnosis of invasive fungal infections

Recent advances in the management of patients with haematological malignancies and transplant recipients have paralleled an increase in the incidence of fungal diseases due to pathogenic genera such as Candida and Aspergillus and the emergence of less common genera including Fusarium and Zygomycetes. Despite availability of new antifungal agents these opportunistic infections have high mortality. Rapid and reliable species identification is essential for antifungal treatment, but detection of the increasing diversity of fungal pathogens by conventional phenotypic methods remains difficult and time-consuming, and the results may sometimes be inconclusive, especially for unusual species. New diagnostic techniques (e.g., 1,3-beta-d-glucan detection) could improve this scenario, although further studies are necessary to confirm their usefulness in clinical practice.