In vitro characterization of virulence factors among species of the Candida parapsilosis complex

Abstract INTRODUCTION: Candida parapsilosis complex species differ from each other with regard to their prevalence and virulence. METHODS: The hydrolytic enzyme activity, biofilm production, and adhesion to epithelial cells were analyzed in 87 C. parapsilosis complex strains. RESULTS: Among the studied isolates, 97.7%, 63.2%, and 82.8% exhibited very strong proteinase, esterase, and hemolysin activity, respectively. All the C. parapsilosis complex isolates produced biofilms and presented an average adherence of 96.0 yeasts/100 epithelial cells. CONCLUSIONS: Our results show that Candida parapsilosis complex isolates showed different levels of enzyme activity, biofilm production, and adhesion to epithelial cells.

Accuracy in clinical examinations for the diagnosis of vulvovaginitis by CANDIDA SPP. and IN VITRO susceptibility to the main antifungals

Vulvovaginal candidiasis (VVC) is a common infection. This work aims to determine the positive predictive value (PPV) of the clinical diagnosis of VVC and to characterize Candida species isolated from the vaginal mucosa. This cross-sectional study was conducted from February 2016 to February 2017 at the Gynecology and Obstetrics Outpatient Clinic of the Hospital das Clínicas, in Goiânia, Goiás State, Brazil. The study included samples of vaginal secretion from 55 women who complained of vaginal discharge and itching as their main symptoms. The PPV of the clinical diagnosis of VVC was estimated in comparison to the laboratory culture method. The phenotypic methods and molecular tests were performed to identify Candida spp. In vitro susceptibility of Candida spp. isolates to fluconazole, itraconazole, clotrimazole, nystatin, and amphotericin B was determined using the broth microdilution assay. Yeast growth using the enzymes protease, phospholipase, and hemolysin was carried out in media containing respectively bovine albumin, egg yolk, and sheep erythrocytes. A PPV of 61.8% (34/55) was determined. Among the 55 vulvovaginal samples collected, we identified 36 isolates in which C. albicans was the most common species. High resistance to fluconazole and low minimal inhibitory concentration (MIC) values for clotrimazole, nystatin and amphotericin B were observed. All isolates were proteinase and hemolysin producers, while seven strains were phospholipase negative. The clinical diagnosis of VVC presented a moderate PPV, which meant that cultures had to be conducted in the laboratory to confirm infection. The high resistance to fluconazole and itraconazole indicated the importance of the in vitro susceptibility test.

Biofilm forming capability and antifungal susceptibility profile of Candida spp. from blood

Although Candida albicans remains the most frequent Candida species; however other species have emerged as important causes of candidiasis. In this work, we evaluated the in vitro susceptibility profile of C. albicans, C. parapsilosis, and C. tropicalis biofilms isolated from patients with candidemia to fluconazole, voriconazole, amphotericin B, and caspofungin. Differences between the biofilm ultrastructure of the three species were also determined. The isolates were phenotypically determined by growth on a ChromagarTM medium and assimilation profile on ID32C. The Scanning Electron Microscopy method (SEM) on biofilm was performed using polyurethane strips. For the in vitro susceptibility profile a microdilution in broth was used. Sessile cells were resistant to fluconazole, voriconazole and caspofungin. The resistance to amphotericin B was less pronounced and more variable between the tested isolates. In the SEM, slight differences in ultrastructural morphology for each species in biofilms were observed. Our results verified biofilm formation. Low susceptibility to the drugs in the three researched species confirmed the higher virulence of them.

Invasive fungal infection in patients with hematologic disorders in a Brazilian tertiary care hospital

ABSTRACT INTRODUCTION: Invasive fungal infections (IFIs) are an important complication in immunocompromised individuals, particularly neutropenic patients with hematological malignancies. In this study, we aimed to verify the epidemiology and diagnosis of IFIs in patients with hematologic problems at a tertiary hospital in Goiânia-GO, Brazil. METHODS: Data from 117 patients, involving 19 cases of IFIs, were collected. The collected data included diagnosis methods, demographics, clinical characteristics, and in vitro susceptibility to different antifungal agents. Among the 19 cases, 12 were classified as proven IFI and 7 as probable invasive aspergillosis with detection of galactomannan in blood and presence of lung infiltrates in radiographic images. Logistic regression analysis showed that the proven and probable IFIs were associated with increased risk of death. Statistical analysis demonstrated that age, sex, and underlying disease were not independently associated with risk of death in IFI patients. RESULTS: Most bloodstream isolates of Candida spp. exhibited low minimum inhibitory concentrations (MICs) to all antifungal agents tested. Voriconazole and amphotericin had the lowest MICs for Aspergillus spp. and Fusarium spp., but Fusarium spp. showed the least susceptibility to all antifungals tested. Amphotericin B, fluconazole, and itraconazole were found to be inactive in vitro against Acremonium kiliense; but this fungus was sensitive to voriconazole. CONCLUSIONS: Considering the high number of IFI cases, with crude mortality rate of 6%, we could conclude that IFIs remain a common infection in patients with hematological malignancies and underdiagnosed ante mortem. Thus, IFIs should be monitored closely.

Clinical and microbiological features of cryptococcal meningitis

Introduction In this study, the clinical features, underlying diseases and clinical outcomes of patients with cryptococcosis were investigated. In addition, a molecular analysis of the Cryptococcus neoformans species complex isolated from these patients was performed. Methods A prospective study of 62 cases of patients with cryptococcal infection was conducted at the Hospital de Doenças Tropicais de Goiás Dr. Anuar Auad from 2009-2010. Cryptococcal meningitis cases were diagnosed by direct examination and cerebrospinal fluid (CSF) sample culture. The profiling of these patients was assessed. The CSF samples were submitted to India ink preparation and cultured on Sabouraud dextrose agar, and C. neoformans was identified by the production of urease, a positive phenoloxidase test and assimilation of carbohydrates. C. neoformans and C. gattii isolates were distinguished by growth on L-canavanine-glycine-bromothymol blue medium, and molecular analysis was conducted via PCR fingerprinting reactions using M13 and (GACA)4 primers. Results From the 62 patients with cryptococcosis, 71 isolates of CSF were obtained; 67 (94.4%) isolates were identified as C. neoformans var. grubii/VNI, and 4 (5.6%) were identified as C. gattii/VGII. Of these patients, 53 had an HIV diagnosis. The incidence of cryptococcosis was higher among patients 20-40 years of age, with 74.2% of the cases reported in males. Cryptococcus-related mortality was noted in 48.4% of the patients, and the symptoms were altered sensorium, headache, fever and stiff neck. Conclusions The high morbidity and mortality observed among patients with cryptococcosis demonstrate the importance of obtaining information regarding the epidemiological profile and clinical course of the disease in the State of Goiás, Brazil. .