Rapid identification of moulds and arthroconidial yeasts from positive blood cultures by MALDI-TOF mass spectrometry.

Moulds and arthroconidial yeasts are potential life-threatening agents of fungemia in immunocompromised patients. Fast and accurate identification (ID) of these pathogens hastens initiation of targeted antifungal therapy, thereby improving the patients' prognosis. We describe a new strategy that enabled the identification of moulds and arthroconidial yeasts directly from positive blood cultures by MALDI-TOF mass spectrometry (MS). Positive blood cultures (BCs) with Gram staining showing hyphae and/or arthroconidia were prospectively selected and submitted to an in-house protein extraction protocol. Mass spectra were obtained by Vitek MS™ system, and identifications were carried out with in the research use only (RUO) mode with an extended database (SARAMIS™ [v.4.12] plus in-house database). Fusarium solani, Fusarium verticillioides, Exophiala dermatitidis, Saprochaete clavata, and Trichosporon asahii had correct species ID by MALDI-TOF MS analysis of positive BCs. All cases were related to critically ill patients with high mortality fungemia and direct ID from positive BCs was helpful for rapid administration of targeted antifungal therapy.

Multilocus sequence typing of Candida tropicalis shows the presence of different clonal clusters and fluconazole susceptibility profiles in sequential isolates from candidemia patients in Sao Paulo, Brazil.

The profiles of 61 Candida tropicalis isolates from 43 patients (28 adults and 15 children) diagnosed with candidemia at two teaching hospitals in São Paulo, Brazil, were characterized by multilocus sequence typing (MLST). For the 14 patients who had bloodstream infections, 32 isolates were serially collected from their blood and/or catheters. Thirty-nine diploid sequence types (DSTs) were differentiated. According to the C. tropicalis MLST database (http://pubmlst.org/ctropicalis/), 36 DSTs and 23 genotypes identified from the 61 isolates had not previously been described. This report represents the first study to characterize sequential isolates of C. tropicalis from candidemia cases in South America. Microvariation in a single gene was found in the sequential isolates from 7 patients. The main polymorphisms occurred in the alleles of the XYR1 gene, specifically at nucleotide positions 215, 242, and 344. Macrovariation in six gene fragments was detected in the isolates from 3 patients. eBURST analysis added two new groups to this study (groups 6 and 18). Additionally, susceptibility tests indicate that 3 isolates were resistant to fluconazole. No correlation was found between the DSTs and susceptibility to fluconazole and/or selective antifungal pressure. Two patients were sequentially infected with resistant and susceptible strains. MLST is an important tool for studying the genetic diversity of multiple/sequential isolates of patients with candidemia, allowing the comparison of our data with those from other regions of the world, as well as allowing an analysis of the genetic relationship among several clones in sequential isolates from the same or different candidemia patient sites (blood or catheter).

Evaluation of VITEK 2 for discriminating Trichosporon species: misidentification of Trichosporon non-T. asahii.

The VITEK 2 system was evaluated for the identification of 74 Trichosporon invasive and non-invasive clinical isolates, comparing its results with the IGS1 sequencing. The system correctly identified Trichosporon asahii but not non-T. asahii isolates, which represented nearly 50% of the invasive infections in our nosocomial setting.

Evaluation of the MALDI-TOF VITEK MS™ system for the identification of Candida parapsilosis, C. orthopsilosis and C. metapsilosis from bloodstream infections.

Twenty-nine Candida parapsilosis, seventeen Candida orthopsilosis and two Candida metapsilosis bloodstream isolates were submitted for identification by VITEK-MS™ mass spectrometer. Four isolates, two C. orthopsilosis and two C. metapsilosis, were not identified. Inclusion of Superspectra of both species in this database is required to improve its discrimination power.

Candidemia epidemiology and susceptibility profile in the largest Brazilian teaching hospital complex.

INTRODUCTION: Although the spectrum of fungi causing bloodstream fungal infections continues to expand, Candida spp. remains responsible for the majority of these cases. OBJECTIVE: The purpose of this study was to characterize the candidemia epidemiology, species distribution and antifungal susceptibility patterns at a Brazilian tertiary teaching public hospital with 2,500 beds. METHODS: Records from the microbiology laboratory were used to identify patients with positive blood cultures during 2006. The in vitro activity of amphotericin B, caspofungin, itraconazole, fluconazole, voricanozole, and posaconazole were determined using the Etest method. RESULTS: One hundred and thirty-six cases of candidemia were identified and 100 strains were available for antifungal susceptibility testing. The overall incidence of candidemia was 1.87 cases/1.000 admissions and 0.27 cases/1.000 patient-days. Among the patients, 58.1% were male, and the median age was 40 years old. C. albicans was the most common species (52.2%), followed by C. parapsilosis (22.1%), C. tropicalis (14.8%), and C. glabrata (6.6%). All strains were susceptible to amphotericin B with a MIC90 of 0.5 µg/mL. Overall susceptibility for voriconozole, fluconazole, and caspofungin was > 97% with a MIC90 of 0.064, 4.0 and 1.0 µg/mL, respectively. For itraconazole the susceptibility rate was 81% with a MIC90 of 0.5 µg/mL. Posaconazole also demonstrated good in vitro activity with a MIC90 of 0.25 µg/mL. CONCLUSION: This is the first antifungal susceptibility report in our institution.

Candidemia epidemiology and susceptibility profile in the largest Brazilian teaching hospital complex

INTRODUCTION: Although the spectrum of fungi causing bloodstream fungal infections continues to expand, Candida spp. remains responsible for the majority of these cases. OBJECTIVE: The purpose of this study was to characterize the candidemia epidemiology, species distribution and antifungal susceptibility patterns at a Brazilian tertiary teaching public hospital with 2,500 beds. METHODS: Records from the microbiology laboratory were used to identify patients with positive blood cultures during 2006. The in vitro activity of amphotericin B, caspofungin, itraconazole, fluconazole, voricanozole, and posaconazole were determined using the Etest method. RESULTS: One hundred and thirty-six cases of candidemia were identified and 100 strains were available for antifungal susceptibility testing. The overall incidence of candidemia was 1.87 cases/1.000 admissions and 0.27 cases/1.000 patient-days. Among the patients, 58.1 percent were male, and the median age was 40 years old. C. albicans was the most common species (52.2 percent), followed by C. parapsilosis (22.1 percent), C. tropicalis (14.8 percent), and C. glabrata (6.6 percent). All strains were susceptible to amphotericin B with a MIC90 of 0.5 µg/mL. Overall susceptibility for voriconozole, fluconazole, and caspofungin was > 97 percent with a MIC90 of 0.064, 4.0 and 1.0 µg/mL, respectively. For itraconazole the susceptibility rate was 81 percent with a MIC90 of 0.5 µg/mL. Posaconazole also demonstrated good in vitro activity with a MIC90 of 0.25 µg/mL. CONCLUSION: This is the first antifungal susceptibility report in our institution.

Fusariose em paciente imunocomprometido: sucesso terapêutico com voriconazol / Fusariosis in an immunocompromised patient: therapeutic success with voriconazole

A infecção por Fusarium solani é afecção fúngica potencialmente grave em pacientes imunocomprometidos, sobretudo naqueles portadores de neoplasias hematológicas. A mortalidade é alta,sendo limitadas as opções terapêuticas devido às condições da imunidade do doente e à relativa resistência do fungo aos antifúngicos utilizados de rotina. O voriconazol tem-se mostrado boa alternativa terapêutica em pacientes neutropênicos que apresentam fusariose refratária ou pouco responsiva à anfotericina B. Neste artigo relata-se caso de fusariose em doente imunocomprometido tratado com sucesso com voriconazol.

Fusarium infection is known to be potentially severe in immunocompromised patients, especially those with hematologic malignancies. Mortality rates are high and there are few therapeutic options, due to the severe underlying condition of this group of patients and the relative resistance of Fusarium to conventional antifungal therapy. Voriconazole has been shown to be an effective antifungal agent for neutropenic patients with fusariosis that are refractory or unresponsive to amphotericin B. We report the successful treatment of disseminated Fusarium infection in an immunocompromised host.