Methylene blue@silver nanoprisms conjugates as a strategy against Candida albicans isolated from balanoposthitis using photodynamic inactivation.

Balanoposthitis can affect men in immunocompromised situations, such as HIV infection and diabetes. The main associated microorganism is Candida albicans, which can cause local lesions, such as the development of skin cracks associated with itching. As an alternative to conventional treatment, there is a growing interest in the photodynamic inactivation (PDI). It has been shown that the association of photosensitizers with metallic nanoparticles may improve the effectiveness of PDI via plasmonic effect. We have recently shown that the association of methylene blue (MB), a very known photosensitizer, with silver prismatic nanoplatelets (AgNPrs) improved PDI of a resistant strain of Staphylococcus aureus. To further investigate the experimental conditions involved in PDI improvement, in the present study, we studied the effect of MB concentration associated with AgNPrs exploring spectral analysis, zeta potential measurements, and biological assays, testing the conjugated system against C. albicans isolated from a resistant strain of balanoposthitis. The AgNPrs were synthesized through silver anisotropic seed growth induced by the anionic stabilizing agent poly(sodium 4-styrenesulfonate) and showed a plasmon band fully overlapping the MB absorption band. MB and AgNPrs were conjugated through electrostatic association and three different MB concentrations were tested in the nanosystems. Inactivation using red LED light (660 nm) showed a dose dependency in respect to the MB concentration in the conjugates. Using the highest MB concentration (100 µmol⋅L-1) with AgNPr, it was possible to completely inactivate the microorganisms upon a 2 min irradiation exposure. Analyzing optical changes in the conjugates we suggest that these results indicate that AgNPrs are enhancers of MB photodynamic action probably by a combined mechanism of plasmonic effect and reduction of MB dimerization. Therefore, MBAgNPrs can be considered a suitable choice to be applied in PDI of resistant microorganisms.

Photoinactivation of Yeast and Biofilm Communities of Candida albicans Mediated by ZnTnHex-2-PyP4+ Porphyrin.

Candida albicans is the main cause of superficial candidiasis. While the antifungals available are defied by biofilm formation and resistance emergence, antimicrobial photodynamic inactivation (aPDI) arises as an alternative antifungal therapy. The tetracationic metalloporphyrin Zn(II) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (ZnTnHex-2-PyP4+) has high photoefficiency and improved cellular interactions. We investigated the ZnTnHex-2-PyP4+ as a photosensitizer (PS) to photoinactivate yeasts and biofilms of C. albicans strains (ATCC 10231 and ATCC 90028) using a blue light-emitting diode. The photoinactivation of yeasts was evaluated by quantifying the colony forming units. The aPDI of ATCC 90028 biofilms was assessed by the MTT assay, propidium iodide (PI) labeling, and scanning electron microscopy. Mammalian cytotoxicity was investigated in Vero cells using MTT assay. The aPDI (4.3 J/cm2) promoted eradication of yeasts at 0.8 and 1.5 µM of PS for ATCC 10231 and ATCC 90028, respectively. At 0.8 µM and same light dose, aPDI-treated biofilms showed intense PI labeling, about 89% decrease in the cell viability, and structural alterations with reduced hyphae. No considerable toxicity was observed in mammalian cells. Our results introduce the ZnTnHex-2-PyP4+ as a promising PS to photoinactivate both yeasts and biofilms of C. albicans, stimulating studies with other Candida species and resistant isolates.

Neonatal Candidemia Caused by Candida haemulonii: Case Report and Review of Literature.

Candidemia is a frequent condition in Neonatal Intensive Care Units (NICU) and usually complicates the newborns clinical course. Several factors are responsible for candidiasis, such as prematurity and use of broad-spectrum antibiotics, and in these cases, there are the involvement of various Candida species, as C. albicans, and C. parapsilosis. However, other species as C. haemulonii has been rarely described in candidemia cases, being considered an emergent pathogen. Thus, we report a case of neonatal candidemia by C. haemulonii and a review of literature of fungemia by this yeast. The patient was a neonate with gestational age of 26 weeks and birth weight of 660 g hospitalized in a NICU from a Brazilian hospital. The identification of the etiological agent was performed by phenotypic methods, scanning electron microscopy, sequencing of the ITS region of rDNA, and mass spectrometry. Antifungal susceptibility testing was carried out according to the Clinical Laboratories and Standards Institute guidelines. The newborn was diagnosed with candidemia by C. haemulonii resistant to amphotericin B with minimal inhibitory concentration (MIC) of 8 µg/mL, sensitive to fluconazole (MIC: 8 µg/mL) and voriconazole (MIC: 0.12 µg/mL). The treatment with fluconazole (12 mg/kg/day) was established with good outcome. Candidemia by C. haemulonii is still being limited to a few sporadic cases in adults with endemic and restricted occurrences in neonates. Usually, the therapy with amphotericin B is ineffective against this species. Our results showed the importance of the mycological diagnosis associated to antifungigrama for the successful clinical management followed by important epidemiological data.

Esophagitis caused by Candida guilliermondii in diabetes mellitus: first reported case.

Diabetic patients are at risk of acquiring esophageal infections such as those caused by members of the genus Candida. Here we describe a case in which Candida guilliermondii was isolated from the esophageal mucosa of a patient with uncontrolled diabetes mellitus. Due to inappropriate and inaccurate identification, the emergence of non-C. albicans Candida species as potential pathogens has been underestimated. This should be a cause of concern since C. guilliermondii is a normal component of human microbiota. The identity of the isolate in our case was confirmed by its characteristic morphophysiological features and amplification of rDNA using species-specific primers. Fluconazole therapy produced no improvement of the esophageal symptoms, and resistance of the etiologic agent was confirmed through in vitro susceptibility tests. This is thought to be the first documented case of C. guilliermondii esophagitis in a patient with diabetes mellitus.

A case of invasive rhinosinusitis by Fusarium verticillioides (Saccardo) Nirenberg in an apparently immunocompetent patient.

A case of chronic invasive rhinosinusitis in an apparently healthy man, caused by Fusarium verticillioides, is described. The identity of the isolate as F. verticillioides was established by demonstrating characteristic morphological features and by amplification of rDNA using species-specific primers. Surgical debridement of the infected nasal tissue and therapy with amphotericin B resulted in a favorable outcome. To the best of our knowledge, F. verticillioides has not been described previously to cause this condition.