Adriana Lopes Motta

Rhodotorula spp. isolated from blood cultures: clinical and microbiological aspects

The emergence of less common fungal pathogens has been increasingly reported in the last decade. We describe 25 cases of Rhodotorula spp. isolated from blood cultures at a large Brazilian tertiary teaching hospital from 1996-2004. We also investigated the in vitro activity of four antifungal drugs, using a standardized method. The median age of patients was 43 years. The majority of patients (88%) had a central venous catheter (CVC) and 10 (40%) were recipients of a bone marrow transplant. The episode was classified as a bloodstream infection (BSI) in 80% of the patients. Amphotericin B deoxycholate was the most common antifungal used and CVC was removed in 89.5% of the patients. Death occurred in four patients (17.4%), all classified as BSI. All strains were identified as R. mucilaginosa by conventional methods. Misidentification of the species was observed in 20% and 5% of the strains with the Vitek Yeast Biochemical Card and API 20C AUX systems, respectively. Amphotericin B demonstrated good in vitro activity (MIC50/90, 0.5 microg/ml) and the MICs for fluconazole were high for all strains (MIC50/90, >64 microg/ml).

Identification of Candida haemulonii Complex Species: Use of ClinProToolsTM to Overcome Limitations of the Bruker BiotyperTM, VITEK MSTM IVD, and VITEK MSTM RUO Databases

Candida haemulonii is now considered a complex of two species and one variety: C. haemulonii sensu stricto, Candida duobushaemulonii and the variety C. haemulonii var. vulnera. Identification (ID) of these species is relevant for epidemiological purposes and for therapeutic management, but the different phenotypic commercial systems are unable to provide correct species ID for these emergent pathogens. Hence, we evaluated the MALDI-TOF MS performance for the ID of C. haemulonii species, analyzing isolates/strains of C. haemulonii complex species, Candida pseudohaemulonii and Candida auris by two commercial platforms, their databases and softwares. To differentiate C. haemulonii sensu sctricto from the variety vulnera, we used the ClinProToolsTM models and a single-peak analysis with the software FlexAnalysisTM. The BiotyperTM database gave 100% correct species ID for C. haemulonii sensu stricto, C. pseudohaemulonii and C. auris, with 69% of correct species ID for C. duobushaemulonii. Vitek MSTM IVD database gave 100% correct species ID for C. haemulonii sensu stricto, misidentifying all C. duobushaemulonii and C. pseudohaemulonii as C. haemulonii, being unable to identify C. auris. The Vitek MSTM RUO database needed to be upgraded with in-house SuperSpectra to discriminate C. haemulonii sensu stricto, C. duobushaemulonii, C. pseudohaemulonii, and C. auris strains/isolates. The generic algorithm model from ClinProToolsTM software showed recognition capability of 100% and cross validation of 98.02% for the discrimination of C. haemulonii sensu stricto from the variety vulnera. Single-peak analysis showed that the peaks 5670, 6878, or 13750 m/z can distinguish C. haemulonii sensu stricto from the variety vulnera.

First report of a clinical isolate of Candida haemulonii in Brazil

The spectrum of Candida species associated with invasive fungal infections is evolving. New microbiology diagnostic tools, the increasing number of immunosuppressed patients with invasive devices and the use of prophylaxis with fluconazole could contribute to this phenomenon (1). In recent years, an increasing number of rare species with reduced susceptibility to antifungal molecules have been described, including C. ciferrii, C. inconspicua, C. guilliermondii, C. humicola, C. lambica, C. lipolytica, C. norvegensis, C. palmioleophila, C. rugosa, C. valida, C. fermentati, and C. lusitaniae (2)-(5). Data from the SENTRY Antimicrobial Surveillance Program-Fungal Objective (5) concerning bloodstream infections from 2008 and 2009 show that 4.5% of 348 episodes from 10 centers in Latin America were caused by species other than C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei. In 1984, Lavarde et al. (6) reported the first clinical isolate of C. haemulonii from a blood culture. Since then, rare cases of human infections with C. haemulonii have been reported worldwide, including central venous catheter (CVC)-related bloodstream infections in patients from Argentina, Korea, and China (7)-(11); in preterm neonates receiving parenteral nutrition in Kuwait (12); and in a 37-year-old French patient with osteomyelitis of the left hallux (13). This pathogen has not been identified in previous reports of candidemia from Brazil (14)-(17). The present paper reports for the first time a case of fungemia caused by C. haemulonii in a tertiary hospital in the city of Sao Paulo. Clinical features and laboratory analyses, including phenotypic and molecular identification and antifungal susceptibility testing (AST), are described.

Invasive Trichosporon infection in solid organ transplant patients: a report of two cases identified using IGS1 ribosomal DNA sequencing and a review of the literature

Trichosporon species are rare etiologic agents of invasive fungal infection in solid organ transplant (SOT) recipients. We report 2 well‐documented cases of Trichosporon inkin invasive infection in SOT patients. We also conducted a detailed literature review of Trichosporon species infections in this susceptible population. We gathered a total of 13 cases of Trichosporon species infections. Any type of organ transplantation can be complicated by Trichosporon infection. Bloodstream infections and disseminated infections were the most common clinical presentations. Liver recipients with bloodstream or disseminated infections had poor prognoses. Although the most common species was formerly called Trichosporon beigelii, this species name should no longer be used because of the changes in the taxonomy of this genus resulting from the advent of molecular approaches, which were also used to identify the strains isolated from our patients. Antifungal susceptibility testing highlights the possibility of multidrug resistance. Indeed, Trichosporon has to be considered in cases of breakthrough infection or treatment failure under echinocandins or amphotericin therapy. Voriconazole seems to be the best treatment option.

Multilocus Sequence Typing of Candida tropicalis Shows the Presence of Different Clonal Clusters and Fluconazole Susceptibility Profiles in Sequential Isolates from Candidemia Patients in São Paulo, Brazil

ABSTRACT 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).

Fusariose em paciente imunocomprometido: sucesso terapêutico 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.

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.

Trichosporon inkin as an Emergent Pathogen in Patients With Severe Pemphigus

IMPORTANCE To our knowledge, these are the first reports of bloodstream infections by Trichosporon inkin in patients with pemphigus. OBSERVATIONS Trichosporon inkin, a novel organism causing bloodstream infection, was detected in 2 patients with pemphigus. An elderly man with pemphigus foliaceus died despite treatment with liposomal amphotericin B, 3 mg/kg/d, and a young girl with pemphigus vulgaris responded to treatment with voriconazole, 8 mg/kg/d, for 24 days. One of the T inkin isolates had a minimal inhibitory concentration of 2 mg/L against amphotericin B, suggesting resistance to the drug. CONCLUSIONS AND RELEVANCE Delayed suspicion of invasive infection by T inkin may result in a poor outcome in patients with severe forms of pemphigus. This opportunistic infection is highly refractory to conventional potent antifungal treatment.

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.

Candida blankii : an emergent opportunistic yeast with reduced susceptibility to antifungals

In 1968, Buckley and van Uden described the nonfermenting yeast Candida blankii (C. blankii) found in the organs of a mink. Until recently, this microorganism had only been the subject of biotechnological research. However, in 2015, Zaragoza et al. reported a 14-year-old male patient with cystic fibrosis (CF), who had pulmonary exacerbations with repeated isolation of C. blankii from respiratory samples. This finding raised the hypothesis that this yeast could be a relevant pathogen for CF patients.This paper corroborates this initial observation by describing a bloodstream infection by C. blankii in a CF patient who underwent lung transplantation. A 16-year-old female with CF was referred to our lung transplant center in March 2016. Her recent medical history was notable for severe pulmonary exacerbations, which required prolonged hospitalization and mechanical ventilation. Her most recent preadmission sputum cultures collected by the referring hospital showed positive for Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia, Aspergillus sp., including positive samples for Candida sp. (negative germ tube, isolates not available) collected after itraconazole therapy (200 mg/day) used to treat the pulmonary exacerbations. In June 2016, she underwent bilateral lung transplantation at the Hospital das Clínicas, University of São Paulo, Brazil, under antimicrobial prophylaxis consisting of teicoplanin, meropenem, cotrimoxazole and liposomal amphotericin B (L-AMB, 200 mg/day). However, during the infusion of L-AMB, the patient presented hypotension, leading to the discontinuation of the antifungal treatment. On the first postoperative day (POD), the patient developed sepsis, and so blood cultures were collected (Bactec aerobic and anaerobic/Plus, BD). Peripheral and central venous catheter blood cultures became positive for yeasts after 41 (anaerobic bottle) and 72 (aerobic bottles) hours of incubation, respectively. On the third POD, due to the provisional report of yeasts on blood cultures, micafungin (100 mg/day) was prescribed. Blood cultures collected 72 h after the introduction of micafungin became negative; transthoracic echocardiography and fundoscopic eye exam did not show any significant results. The yeast isolate showing pale pink colonies on chromogenic medium (BBL CHROMagar, BD, Sparks, USA) were not identified by MALDI-TOF mass spectrometry (Vitek MSTM, IVD library, bioMérieux, Marcy-L ́Etoile, France). Because clinical improvement was observed, micafungin was maintained for 14 days. The patient was discharged on the 39th POD. The clinical isolate (HCFMUSP01) was later identified as C. blankii after sequence analysis of the internal transcribed spacer 1 (ITS1, GenBank accession no. MF573785) and D1D2 region from the 26S subunit (D1D2, GenBank accession no. MF940140) of the rRNA. Since little is known about this microorganism as an opportunistic pathogen, we further characterized this species in terms of genetic and proteomic diversity, antifungal susceptibility, biofilm production, and in vivo virulence by analyzing the clinical isolate and the strains (IIC1M.1, BX90C, BX81A) from the yeast collection at the Federal University of Minas Gerais, Brazil.