Echinocandins in invasive candidiasis

Epidemiology of Candidemia in Children over 7 Years in a Medical Center in Turkey

The aims of the study were to describe Candida species in children with candidemia, to determine the changing epidemiology of candidemia over time in our tertiary care hospital, and to examine the demographic and clinical characteristics of patients with candidemia caused by parapsilosis and nonparapsilosis Candida spp. From 2012 to 2018, we identified a total of 126 cases of candidemia. The most commonly isolated Candida sp. was C. parapsilosis (n = 71, 56.3%), followed by C. albicans (n = 34, 26.9%). A total of 21 candidemia episodes (16.6%) were caused by other Candida species. Patients were divided into two groups (parapsilosis and nonparapsilosis) to identify any potential differences between the groups in terms of risk factors, mortality, and antifungal resistance. The median age of the patients, the median durations of the hospital and pediatric intensive care unit stay, receipt of immunosuppressive therapy within 2 weeks of developing candidemia, the rate of using total parenteral nutrition, need for mechanical ventilation, and receipt of carbapenems were statistically significantly higher in the parapsilosis group than in the nonparapsilosis group (P = 0.020, P = 0.001, P = 0.011, P = 0.036, P = 0.002, P = 0.038, and P = 0.004, respectively). The overall 30-day mortality rates (4.2% versus 3.6%) and resistance to fluconazole (33.8% versus 32.7%) were similar between the groups (P = 0.790 and P = 0.860, respectively). The distribution of Candida strains isolated in this study was consistent with the global trend, with C. parapsilosis being the most commonly identified species. Determining local epidemiologic data at regular intervals in candidemia cases is important in terms of determining both the changing epidemiology and empirical antifungal agents.

IMPORTANCE In our study, the changing epidemiology of Candida species in candidemia in children was evaluated. The dominance of Candida parapsilosis species in the changing epidemiology was remarkable. We found that fluconazole resistance was high in both parapsilosis and nonparapsilosis groups. Updating local epidemiologic data at certain intervals in candidemia cases is important in determining both the changing epidemiology and empirical antifungal agents.

Anticandidal Potential of Two Cyanobacteria-Synthesized Silver Nanoparticles: Effects on Growth, Cell Morphology, and Key Virulence Attributes of Candida albicans

Candida albicans is an opportunistic human fungal pathogen responsible for 90-100% of mucosal and nosocomial infections worldwide. The emergence of drug-resistant strains has resulted in adverse consequences for human health, including numerous deaths. Consequently, there is an urgent need to identify and develop new antimicrobial drugs to counter these effects. Antimicrobial nanoagents have shown potent inhibitory activity against a number of pathogens through targeting their defense systems, such as biofilm formation. Here, we investigated the anticandidal activity of silver nanoparticles biosynthesized by the cyanobacterial strains Desertifilum sp. IPPAS B-1220 and Nostoc Bahar_M (D-SNPs and N-SNPs, respectively), along with that of silver nitrate (AgNO3), and examined the mechanisms underlying their lethal effects. For this, we performed agar well diffusion and enzyme activity assays (lactate dehydrogenase, adenosine triphosphatase, glutathione peroxidase, and catalase) and undertook morphological examinations using transmission electron microscopy. The effects of the three treatments on Hwp1 and CDR1 gene expression and protein patterns were assessed using qRT-PCR and SDS-PAGE assays, respectively. All of the three treatments inhibited C. albicans growth; disrupted membrane integrity, metabolic function, and antioxidant activity; induced ultrastructural changes in the cell envelope; and disrupted cytoplasmic and nuclear contents. Of the three agents, D-SNPs showed the greatest biocidal activity against C. albicans. Additionally, the D-SNP treatment significantly reduced the gene expression of Hwp1 and CDR1, suggestive of negative effects on biofilm formation ability and resistance potential of C. albicans, and promoted protein degradation. The mechanism involved in the biocidal effects of both D-SNPs and N-SNPs against C. albicans could be attributed to their ability to interfere with fungal cell structures and/or stimulate oxidative stress, enabling them to be used as a robust antimycotic agent.

How to treat fungal infections in ICU patients

Fungal infections represent a major burden in the critical care setting with increasing morbidity and mortality. Candidiasis is the leading cause of such infections, with C. albicans being the most common causative agent, followed by Aspergillosis and Mucormycosis. The diagnosis of such infections is cumbersome requiring increased clinical vigilance and extensive laboratory testing, including radiology, cultures, biopsies and other indirect methods. However, it is not uncommon for definitive evidence to be unavailable. Risk and host factors indicating the probability of infections may greatly help in the diagnostic approach. Timely and adequate intervention is important for their successful treatment. The available therapeutic armamentarium, although not very extensive, is effective with low resistance rates for the newer antifungal agents. However, timely and prudent use is necessary to maximize favorable outcomes.

Alginate oligosaccharides inhibit fungal cell growth and potentiate the activity of antifungals against Candida and Aspergillus spp

The oligosaccharide OligoG, an alginate derived from seaweed, has been shown to have anti-bacterial and anti-biofilm properties and potentiates the activity of selected antibiotics against multi-drug resistant bacteria. The ability of OligoG to perturb fungal growth and potentiate conventional antifungal agents was evaluated using a range of pathogenic fungal strains. Candida (n = 11) and Aspergillus (n = 3) spp. were tested using germ tube assays, LIVE/DEAD staining, scanning electron microscopy (SEM), atomic force microscopy (AFM) and high-throughput minimum inhibition concentration assays (MICs). In general, the strains tested showed a significant dose-dependent reduction in cell growth at ≥6% OligoG as measured by optical density (OD600; P<0.05). OligoG (>0.5%) also showed a significant inhibitory effect on hyphal growth in germ tube assays, although strain-dependent variations in efficacy were observed (P<0.05). SEM and AFM both showed that OligoG (≥2%) markedly disrupted fungal biofilm formation, both alone, and in combination with fluconazole. Cell surface roughness was also significantly increased by the combination treatment (P<0.001). High-throughput robotic MIC screening demonstrated the potentiating effects of OligoG (2, 6, 10%) with nystatin, amphotericin B, fluconazole, miconazole, voriconazole or terbinafine with the test strains. Potentiating effects were observed for the Aspergillus strains with all six antifungal agents, with an up to 16-fold (nystatin) reduction in MIC. Similarly, all the Candida spp. showed potentiation with nystatin (up to 16-fold) and fluconazole (up to 8-fold). These findings demonstrate the antifungal properties of OligoG and suggest a potential role in the management of fungal infections and possible reduction of antifungal toxicity.

Antimicrobial susceptibility and clinical outcomes of Candida parapsilosis bloodstream infections in a tertiary teaching hospital in Northern Taiwan

BACKGROUND

Candida parapsilosis is an emerging non-albicans Candida that is associated with central line-associated infection. C. parapsilosis has higher minimal inhibitory concentration to echinocandin than Candida albicans, and the effects of echinocandin on C. parapsilosis are ambiguous. Therefore, in this study, we aimed to investigate the susceptibility and the correlation between incidence and drug consumption.

METHODS

This retrospective study was conducted in a tertiary teaching hospital in northern Taiwan between 2008 and 2012. The Candida species distribution, the correlation between the use of antifungal agents and the incidence of C. parapsilosis bloodstream infection, demographic information, clinical characteristics, mortality rate, and in vitro susceptibility of C. parapsilosis were analyzed.

RESULTS

A total of 77 episodes from 77 patients were included for analysis. The overall 90-day mortality rate was 41.6%. The incidence of C. parapsilosis bloodstream infection showed a moderate positive correlation with the increased defined daily dose of echinocandin. The risk factors associated with mortality included malignancy or a metastatic tumor. Multivariate logistical regression analysis showed that patients with malignancy had higher odds ratios in terms of mortality. The rate of C. parapsilosis resistance to fluconazole was 3%, whereas the susceptibility rate was 95.5%.

CONCLUSION

Underlying comorbidity and malignancy were factors leading to death in patients with C. parapsilosis bloodstream infection. Catheter removal did not influence the mortality rate. The survival rate of patients receiving echinocandin was lower than the group receiving fluconazole. Fluconazole remains the drug of choice to treat C. parapsilosis bloodstream infections.