Epidemiology of candidemia in NICE area, France: A five-year study of antifungal susceptibility and mortality

Outbreak of Candida parapsilosis fungemia in an intensive care unit during a COVID surge: an epidemic within a pandemic

We sought to investigate epidemiology, risk factors, clinical features, and outcome of the C. parapsilosis blood stream infection (BSI) outbreaks observed during the first surges of COVID-19 pandemic in our population. Retrospective, monocentric observational study in the 24 bed intensive care unit (ICU) of a tertiary care medical center in northern Italy, from 2019 to 2021 first 5 months. 2030 patients were enrolled, of whom 239 were COVID-19 positive. The total incidence of Candida-BSI was 41.9 per 1000 admissions, with two outbreaks during 2020 spring and winter's COVID surges. The total numbers of C. parapsilosis BSI cases are 94, of which 21 during the first outbreak and 20 during the second. In our population, COVID-19 was strongly associated with C. parapsilosis BSI (OR 4.71, p < 0.001), as well as continuous renal replacement therapy (CRRT) (OR 3.44, p = 0.001), prolonged antibiotic therapy (OR 3.19, p = 0.004), and delayed infusion sets replacements (OR 2.76, p = 0.015). No statistically significant association was found between Candida-BSI episodes and mortality, when adjusted for other known outcome risk factors. COVID surges undermined the infectious control measures in our ICU, leading to two outbreak of C. parapsilosis BSI. A stricter, thorough management of intravascular devices and infusion set is crucial in prevention of catheter related BSI, and awareness must be kept high, especially in emergencies circumstances, such as the ongoing COVID-19 pandemic.

Characterization and susceptibility of non-albicans Candida isolated from various clinical specimens in Lebanese hospitals

Background

Invasive fungal infections have presented a challenge in treatment. In the past, it was known that the frontrunner in such infections is Candida albicans with little emphasis placed on non-albicans Candida species (NAC). Studies worldwide have shown a rise in fungal infections attributed to non-albicans Candida species. The aim of this study is to describe the epidemiology of NAC infections along with an overview of resistance in Lebanese hospitals.

Methods

This is a two-year observational multi-central descriptive study. Between September 2016 and May of 2018, a total of 1000 isolates were collected from 10 different hospitals distributed all over the country. For the culture, Sabouraud Dextrose Agar was used. Antifungal Susceptibility was evaluated by determining the Minimum Inhibitory Concentration (MIC) in broth (microdilution) of the different antifungal treatments.

Results

Out of the 1000 collected isolates, Candida glabrata, being the most isolated species (40.8%), followed by Candida tropicalis: 231(23.1%), Candida parapsilosis: 103(10.3%), and other NAC species at lower percentage. Most of these isolates (88.67%) were susceptible to posaconazole, 98.22% were susceptible to micafungin, and 10% were susceptible to caspofungin.

Conclusion

The change of etiology of fungal infections involving a significant increase in NAC cases is alarming due to the different antifungal susceptibility patterns and the lack of local guidelines to guide the treatment. In this context, proper identification of such organisms is of utmost importance. The data presented here can help in establishing guidelines for the treatment of candida infections to decrease morbidity and mortality. Future surveillance data are needed.

Antifungal drug resistance in oral Candida isolates from HIV-infected and healthy individuals and efficacy of chitosan as an alternative antifungal agent

OBJECTIVE

This study aimed to investigate antifungal resistance in oral Candida isolates and the efficacy of chitosan, a natural polymer, against drug-resistant Candida.

DESIGN

Oral Candida isolates were collected from HIV-infected and healthy individuals in our previous study (n = 66 isolates/group). The minimum-inhibitory-concentration (MIC) of amphotericin-B and fluconazole was determined by Epsilometer test. Minimal-fungicidal-concentration (MFC) of 3 chitosan derivatives: high-molecular-weight chitosan (HMWC, 150-200 kDa), oligomer (7-9 kDa) and polymer (900-1000 kDa) chitosan, were investigated by agar dilution method. Statistical analysis was performed using Chi-square or Fisher's exact tests as appropriate.

RESULTS

Fluconazole-resistant C. albicans were significantly more prevalent in HIV-infected than in healthy individuals (P = 0.02), while amphotericin-B-resistant C. parapsilosis were more common in healthy individuals (P = 0.03). The majority of Candida isolates were killed by HMWC at ≤ 40 mg/ml, as well as by oligomer and polymer chitosan at ≤ 6 mg/ml. Remarkably, chitosan was effective against most antifungal drug-resistant isolates.

CONCLUSIONS

Antifungal drug resistance was prevalent among oral C. albicans isolates from HIV-infected individuals. Chitosan could serve as a complementary antifungal agent against drug-resistant strains.

Continuing Shifts in Epidemiology and Antifungal Susceptibility Highlight the Need for Improved Disease Management of Invasive Candidiasis

Invasive candidiasis (IC) is a systemic life-threatening infection of immunocompromised humans, but remains a relatively neglected disease among public health authorities. Ongoing assessments of disease epidemiology are needed to identify and map trends of importance that may necessitate improvements in disease management and patient care. Well-established incidence increases, largely due to expanding populations of patients with pre-disposing risk factors, has led to increased clinical use and pressures on antifungal drugs. This has been exacerbated by a lack of fast, accurate diagnostics that have led treatment guidelines to often recommend preventative strategies in the absence of proven infection, resulting in unnecessary antifungal use in many instances. The consequences of this are multifactorial, but a contribution to emerging drug resistance is of primary concern, with high levels of antifungal use heavily implicated in global shifts to more resistant Candida strains. Preserving and expanding the utility and number of antifungals should therefore be of the highest priority. This may be achievable through the development and use of biomarker tests, bringing about a new era in improved antifungal stewardship, as well as novel antifungals that offer favorable profiles by targeting Candida pathogenesis mechanisms over cell viability.

Synergistic In Vitro Interaction of Isavuconazole and Isoquercitrin against Candida glabrata

In vitro interactions of broad-spectrum azole isavuconazole with flavonoid isoquercitrin were evaluated by a broth microdilution checkerboard technique based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference methodology for antifungal susceptibility testing against 60 Candida strains belonging to the species Candida albicans (n = 10), Candida glabrata (n = 30), Candida kefyr (n = 6), Candida krusei (n = 5), Candida parapsilosis (n = 4), and Candida tropicalis (n = 5). The results were analyzed with the fractional inhibitory concentration index and by response surface analysis based on the Bliss model. Synergy was found for all C. glabrata strains, when the results were interpreted by the fractional inhibitory concentration index, and for 60% of the strains when response surface analysis was used. Interaction for all other species was indifferent for all strains tested, whatever interpretation model used. Importantly, antagonistic interaction was never observed.

In Vitro Synergy of Isavuconazole Combined With Colistin Against Common Candida Species

Interactions of isavuconazole and colistin were evaluated against 57 common Candida strains belonging to the species Candida albicans (n = 10), Candida glabrata (n = 10), Candida kefyr (n = 8), Candida krusei (n = 10), Candida parapsilosis (n = 9), and Candida tropicalis (n = 10) by a broth microdilution checkerboard technique based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference methodology for antifungal susceptibility testing. Results were analyzed with the fractional inhibitory concentration index and by the response surface analysis. Interpretation by the fractional inhibitory concentration index showed synergy for 50%, 80%, 90%, and 90% of the C. kefyr, C. krusei, C. glabrata, and C. tropicalis strains, respectively. Combination of isavuconazole with colistin against C. albicans and C. parapsilosis exhibited only indifference for 100% and 90% of the strains, respectively. The results were confirmed by response surface analysis for all species except for C. glabrata, for which an indifferent interaction was found for the majority of strains. Antagonistic interaction was never seen regardless of the interpretation model was used.

Rationalisation of Antifungal Properties of α-Helical Pore-Forming Peptide, Mastoparan B

The high mortality associated with invasive fungal infections, narrow spectrum of available antifungals, and increasing evolution of antifungal resistance necessitate the development of alternative therapies. Host defense peptides are regarded as the first line of defense against microbial invasion in both vertebrates and invertebrates. In this work, we investigated the effectiveness of four naturally occurring pore-forming antimicrobial peptides (melittin, magainin 2, cecropin A, and mastoparan B) against a panel of clinically relevant pathogens, including Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida glabrata. We present data on the antifungal activities of the four pore-forming peptides, assessed with descriptive statistics, and their cytocompatibility with cultured human cells. Among the four peptides, mastoparan B (MB) displayed potent antifungal activity, whereas cecropin A was the least potent. We show that MB susceptibility of phylogenetically distant non-candida albicans can vary and be described by different intrinsic physicochemical parameters of pore-forming α-helical peptides. These findings have potential therapeutic implications for the design and development of safe antifungal peptide-based drugs.