Successful treatment of C. auris shunt infection with intraventricular caspofungin

Challenges in management of Candida auris meningitis secondary to infected ventriculoperitoneal shunt - A case report

Meningitis in patients with ventriculo-peritoneal shunt (VP shunt) caused by various species of Candida have been widely described in literature. However, reports describing Candida auris as a cause of meningitis is limited. In this case report we describe a case of multidrug resistant Candida auris meningitis secondary to VP shunt infection successfully treated with intrathecal amphotericin B deoxycholate and intravenous liposomal amphotericin B. This is the second case report of successful treatment of Candida auris meningitis from India. More literature regarding the use of intrathecal/intraventricular echinocandins including optimal dosing and duration of therapy is needed.

Candida auris in skilled nursing facilities

Candida auris is a fungal organism resistant to several classes of antifungals. Since its identification in 2009, it has gained worldwide attention in healthcare for its virulence and resistance to commonly used antifungal therapeutics. Although its origin and mechanisms of transmission are not fully elucidated, it is widely recognized as a high priority healthcare-associated pathogen. Infection control efforts in skilled nursing facilities have been very challenging due to the tendency of C. auris to persist in the environment and colonize residents. In this narrative review, we discuss the epidemiology and infection prevention of C. auris in skilled nursing facilities. We also identify challenges in the diagnosis and management of both symptomatic infections and asymptomatic colonization.

Flucytosine and its clinical usage

Flucytosine is an antifungal agent first licensed in the 1970's. However, its clinical value has long been overlooked and its availability across the globe is limited. This review highlights the important clinical and pharmacological aspects of flucytosine. This a narrative review of the clinical and in vitro susceptibility literature, with a focus on clinical uses for flucytosine. Detailed literature review including early literature related to primary and acquired resistance to flucytosine. Flucytosine has good antifungal activity against Cryptococcus species, Candida species, and dematiaceous fungi. Its water solubility enables good penetration into the eye, urinary tract, central nervous system (CNS), cardiac vegetations and fungal biofilms. In combination with amphotericin B, it shows early fungicidal activity against Cryptococcus species, and this translates to ~20% improved survival in cryptococcal meningitis. Combination therapy also reduces the mortality of Candida meningitis, and should be used in neonatal candidiasis because of the high frequency of CNS infection. Monotherapy for urinary candidiasis is under-studied, but is usually effective. It is probably valuable in the treatment of Candida endocarditis and endophthalmitis: there are few data. It is not effective for aspergillosis or mucormycosis. Flucytosine monotherapy of urinary candidiasis resulted in 22% developing resistance on therapy and failing therapy, and in 29% of 21 patients with cryptococcosis. Certain regions of the world still do not have access to flucytosine compromising the management of certain severe fungal infections. Flucytosine has an important role in combination therapy for yeast and dematiaceous infections and probably as monotherapy for urinary candidiasis, with a modest risk of resistance emergence. Facilitating access to flucytosine in those regions (especially low-income countries) might alleviate the mortality of invasive fungal diseases.

Genome-wide scan for potential CD4+ T-cell vaccine candidates in Candida auris by exploiting reverse vaccinology and evolutionary information

Candida auris is a globally emerging fungal pathogen responsible for causing nosocomial outbreaks in healthcare associated settings. It is known to cause infection in all age groups and exhibits multi-drug resistance with high potential for horizontal transmission. Because of this reason combined with limited therapeutic choices available, C. auris infection has been acknowledged as a potential risk for causing a future pandemic, and thus seeking a promising strategy for its treatment is imperative. Here, we combined evolutionary information with reverse vaccinology approach to identify novel epitopes for vaccine design that could elicit CD4+ T-cell responses against C. auris. To this end, we extensively scanned the family of proteins encoded by C. auris genome. In addition, a pathogen may acquire substitutions in epitopes over a period of time which could cause its escape from the immune response thus rendering the vaccine ineffective. To lower this possibility in our design, we eliminated all rapidly evolving genes of C. auris with positive selection. We further employed highly conserved regions of multiple C. auris strains and identified two immunogenic and antigenic T-cell epitopes that could generate the most effective immune response against C. auris. The antigenicity scores of our predicted vaccine candidates were calculated as 0.85 and 1.88 where 0.5 is the threshold for prediction of fungal antigenic sequences. Based on our results, we conclude that our vaccine candidates have the potential to be successfully employed for the treatment of C. auris infection. However, in vivo experiments are imperative to further demonstrate the efficacy of our design.

In Vivo Efficacy of Amphotericin B against Four Candida auris Clades

Candida auris is a multidrug-resistant fungus against which in some clinical situations amphotericin B (AMB) remains the alternative or first line drug. We compared daily 1 mg/kg of AMB efficacy in a neutropenic murine bloodstream infection model against 10 isolates representing four C. auris clades (South Asian n = 2; East Asian n = 2; South African n = 2; South American n = 4; two of which were of environmental origin). Five days of AMB treatment significantly increased the survival rates in mice infected with isolates of the East Asian clade, and 1 isolate each from the South African and South American clades (originated from bloodstream), but not in mice infected with the South Asian and 2 environmental isolates from the South American clades. AMB treatment decreased the fungal burden in mice infected with the 2 isolates each from East Asian and South African, and 1 out of 2 bloodstream isolates from South American clades in the hearts (p < 0.01), kidneys (p < 0.01) and brain (p < 0.05). AMB treatment, regardless of clades, significantly decreased colony forming units in the urine at day 3. However, histopathological examination in AMB-treated mice revealed large aggregates of yeast cells in the kidneys and hearts, and focal lesions in the cerebra and cerebelli, regardless of precise C. auris clade. Our clade-specific data confirm that the efficacy of AMB against C. auris is weak, explaining the therapeutic failures in clinical situations. Our results draw attention to the necessity to maximize the killing at the start of treatment to avoid later complications in the heart and central nervous system.

Conventional Antifungals for Invasive Infections Delivered by Unconventional Methods; Aerosols, Irrigants, Directed Injections and Impregnated Cement

The administration of approved antifungals via unapproved formulations or administration routes (such as aerosol, direct injection, irrigation, topical formulation and antifungal-impregnated orthopedic beads or cement) may be resorted to in an attempt to optimize drug exposure while minimizing toxicities and/or drug interactions associated with conventional (systemic) administrations. Existing data regarding such administrations are mostly restricted to uncontrolled case reports of patients with diseases refractory to conventional therapies. Attribution of efficacy and tolerability is most often problematic. This review updates prior published summaries, reflecting the most recent data and its application by available prevention and treatment guidelines for invasive fungal infections. Of the various dosage forms and antifungals, perhaps none is more widely reported than the application of amphotericin B-containing aerosols for the prevention of invasive mold infections (notably Aspergillus spp.).

South Asian (Clade I) Candida auris meningitis in a paediatric patient in Iran with a review of the literature

Candida meningitis is a rare life-threatening yeast infection mostly involving immunocompromised or paediatric patients undergoing neurosurgical procedures or shunt placement. Due to difficulties in diagnosis because of diverse clinical manifestations, the number of patients affected is most likely underestimated. Therefore, the correct diagnosis may be delayed for months, and accurate species identification is highly recommended for administering appropriate antifungal therapy. We report the first case of fluconazole-resistant Candida auris meningitis in a paediatric patient in Iran. This strain was probably imported, as it genotypically belonged to Clade I from South Asia. Furthermore, we include a literature review of C auris meningitis cases, as the number of cases with C auris meningitis has increased with reports from the United Kingdom, India and Iran. This problem might increase further in the era of COVID-19 due to attrition of experienced healthcare personnel and a high workload of hospital healthcare workers. To understand the precise prevalence of this emerging multidrug resistance pathogen, epidemiological surveillance studies are urgently warranted.

In vitro and in vivo interaction of caspofungin with isavuconazole against Candida auris planktonic cells and biofilms

The in vitro and in vivo efficacy of caspofungin was determined in combination with isavuconazole against Candida auris. Drug-drug interactions were assessed utilising the fractional inhibitory concentration indices (FICIs), the Bliss independence model and an immunocompromised mouse model. Median planktonic minimum inhibitory concentrations (pMICs) of 23 C. auris isolates were between 0.5 and 2 mg/L and between 0.015 and 4 mg/L for caspofungin and isavuconazole, respectively. Median pMICs for caspofungin and isavuconazole in combination showed 2-128-fold and 2-256-fold decreases, respectively. Caspofungin and isavuconazole showed synergism in 14 out of 23 planktonic isolates (FICI range 0.03-0.5; Bliss cumulative synergy volume range 0-4.83). Median sessile MICs (sMIC) of 14 biofilm-forming isolates were between 32 and > 32 mg/L and between 0.5 and > 2 mg/L for caspofungin and isavuconazole, respectively. Median sMICs for caspofungin and isavuconazole in combination showed 0-128-fold and 0-512-fold decreases, respectively. Caspofungin and isavuconazole showed synergistic interaction in 12 out of 14 sessile isolates (FICI range 0.023-0.5; Bliss cumulative synergy volume range 0.13-234.32). In line with the in vitro findings, synergistic interactions were confirmed by in vivo experiments. The fungal kidney burden decreases were more than 3 log volumes in mice treated with combination of 1 mg/kg caspofungin and 20 mg/kg isavuconazole daily; this difference was statistically significant compared with control mice (p < 0.001). Despite the favourable effect of isavuconazole in combination with caspofungin, further studies are needed to confirm the therapeutic advantage of this combination when treating an infection caused by C. auris.

New weapons to fight a new enemy: A systematic review of drug combinations against the drug-resistant fungus Candida auris

Candida auris is an emerging and drug-resistant pathogen. Drug combination is a promising approach against such pathogens. This study was conducted to provide an overview of all the studied drug combinations against C. auris. Relevant articles reporting results of any drug/non-drug combinations against C. auris were found by a systematic search in PubMed, Scopus and Web of Science (ISI), and in Google Scholar up to 1 October 2020. From 187 articles retrieved in the primary search, 23 met the inclusion criteria. In total, 124 different combinations including antifungal with antifungal (45), antifungal with other antimicrobials (11), antifungal with non-antimicrobials (32), antifungal with natural compounds (25) and between natural compounds (11) have been reported. Complete or partial synergistic effects have been reported for 3 out of 45 (6.67%) combinations of two antifungal agents, 8 out of 11 (72.73%) combinations involving antifungal agents and antimicrobials, 15 out of 32 (46.88%) of combinations between antifungal agents with non-antimicrobials, 16 out of 25 (64%) of combinations involving antifungal agents and natural compounds, and 3 out of 11 (22.27%) of combinations involving multiple natural compounds. Antagonistic interactions have been reported for 1 out of 32 (3.13%) and 8 out of 25 (32%) of combinations between antifungal drugs with non-antimicrobials and with natural compounds, respectively. Different drugs/compounds could potentiate the activity of antifungal drugs using this approach. However, despite the availability of this promising initial data, many more studies will be required to elucidate whether favourable interactions observed in vitro might translate into tangible clinical benefits.

Update on fungal infections of the central nervous system: emerging pathogens and emerging diagnostics

PURPOSE OF REVIEW

Fungal infections of the central nervous system (CNS) are relatively uncommon but associated with significant morbidity and mortality. We reviewed recent literature highlighting new approaches to management of these complex patients.

RECENT FINDINGS

Fungal infections are increasingly recognized as important causes of CNS disease in both immunocompromised and immunocompetent hosts. Globally, cryptococcal meningitis remains a leading cause of death in HIV-infected persons in resource-limited settings. Emerging fungal pathogens with increased virulence and resistance to numerous classes of antifungal agents have been identified and represent a management challenge. Newer diagnostic techniques focused on antigen detection or molecular amplification of fungal pathogens offer promise in the expediated diagnosis and treatment of CNS fungal infections.

SUMMARY

Meningitis and brain abscess because of invasive fungal pathogens are frequently fatal infections. Newer laboratory tests allowing antigen detection or molecular amplification from cerebrospinal fluid are more sensitive than culture and allow earlier initiation of effective therapy.

Candida auris: From Multidrug Resistance to Pan-Resistant Strains

Candida auris is an emerging multidrug-resistant fungus that is rapidly spreading worldwide. Currently, C. auris cases have been reported globally from >30 countries. Most reported infections involve critically ill patients in hospitals, mainly in intensive care unit settings. Infection with C. auris is associated with high mortality rates, and it is often resistant to multiple classes of antifungal drugs. Despite the rapid global spread, it is difficult to predict the actual burden of the infection as the standard laboratory methods fail to correctly identify the fungi. Longer stays in healthcare facilities, use of tracheostomies and percutaneous endoscopic gastrostomy tubes, ventilators in clinical care units and mobile equipment in healthcare settings are shown as major risk factors of C. auris infection. Due to its propensity to cause outbreaks and its antifungal resistance, C. auris poses a risk for patients in healthcare facilities. The emergence of pan-resistant C. auris strains in some areas is an alarming signal for the disease with limited treatment options, high mortality rates, and the ability of the pathogen to spread easily in healthcare settings. In this regard, susceptibility testing on clinical isolates, mainly for patients treated with echinocandins, is needed. Increasing awareness about C. auris infection and advancing the diagnostic methods are also essential for early detection and control of the deadly fungal infection.

Diagnosis, management and prevention of Candida auris in hospitals: position statement of the Australasian Society for Infectious Diseases

Candida auris is an emerging drug-resistant yeast responsible for hospital outbreaks. This statement reviews the evidence regarding diagnosis, treatment and prevention of this organism and provides consensus recommendations for clinicians and microbiologists in Australia and New Zealand. C. auris has been isolated in over 30 countries (including Australia). Bloodstream infections are the most frequently reported infections. Infections have crude mortality of 30-60%. Acquisition is generally healthcare-associated and risks include underlying chronic disease, immunocompromise and presence of indwelling medical devices. C. auris may be misidentified by conventional phenotypic methods. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry or sequencing of the internal transcribed spacer regions and/or the D1/D2 regions of the 28S ribosomal DNA are therefore required for definitive laboratory identification. Antifungal drug resistance, particularly to fluconazole, is common, with variable resistance to amphotericin B and echinocandins. Echinocandins are currently recommended as first-line therapy for infection in adults and children ≥2 months of age. For neonates and infants <2 months of age, amphotericin B deoxycholate is recommended. Healthcare facilities with C. auris should implement a multimodal control response. Colonised or infected patients should be isolated in single rooms with Standard and Contact Precautions. Close contacts, patients transferred from facilities with endemic C. auris or admitted following stay in overseas healthcare institutions should be pre-emptively isolated and screened for colonisation. Composite swabs of the axilla and groin should be collected. Routine screening of healthcare workers and the environment is not recommended. Detergents and sporicidal disinfectants should be used for environmental decontamination.

Intrathecal Antibacterial and Antifungal Therapies

Intrathecal administration of anti-infectives is indicated in central nervous system infections by multiresistant pathogens when drugs that can reach adequate cerebrospinal fluid (CSF) concentrations by systemic therapy are not available. Antibiotics that readily pass the blood-brain and blood-CSF barriers and/or that have low toxicity allowing an increase in the daily dosage should not be used for intrathecal therapy. Intrathecal therapy is accompanied by systemic treatment. Antibacterials indispensable for intrathecal therapy include aminoglycosides, colistin, daptomycin, tigecycline, and vancomycin. Limited experience suggests the utility of the antifungals amphotericin B and caspofungin. Intraventricular administration ensures distribution throughout the CSF compartment, whereas intralumbar dosing often fails to attain adequate antibiotic concentrations in the ventricles. The individual dose is determined by the estimated size of the CSF space and by the estimated clearance from CSF. For moderately lipophilic anti-infectives with a molecular weight above approximately 1,000 g/mol, as well as for hydrophilic drugs with a molecular weight above approximately 400 g/mol, one daily dose is normally adequate. The ventricular drain should be clamped for 15 to 120 min to facilitate the distribution of the anti-infective in the CSF space. Therapeutic drug monitoring of the trough levels is necessary only in cases of therapeutic failure.

Candida auris-the growing menace to global health

A paradigm shift of candidiasis from Candida albicans to non-albicans Candida species has fundamentally increased with the advent of C. auris. C. auris, despite being a newly emerged multidrug-resistant fungal pathogen, is associated with severe invasive infections and outbreaks with high mortality rates. Initially reported from Japan in 2009, C. auris have now been found in different countries on all the continents except Antarctica. Due to its capability of nosocomial transmission and forming adherent biofilms on clinically important substrates, a high number of related hospital outbreaks have been reported worldwide. As C. auris is a multidrug-resistant pathogen and is prone to misidentification by available conventional methods, it becomes difficult to detect and manage C. auris infection and also limits the therapeutic options against this deadly pathogen. The emergence of multidrug-resistant C. auris advocates and amplifies the vigilance of early diagnosis and appropriate treatment of fungal infections. In this review, we discussed the nine-year-old history of C. auris-its trends in global emergence, epidemiological relatedness, isolation, mortality, associated risk factors, virulence factors, drug resistance and susceptibility testing, diagnostic challenges, microbiological characteristics, therapeutic options and infection prevention and control associated with this pathogen.