Chlorhexidine for the Treatment of Fusarium Keratitis: A Case Series and Mini Review.

Fungal keratitis is difficult to treat, especially Fusarium keratitis. In vitro studies show that chlorhexidine could be an interesting option as monotherapy. We describe a case series of four patients (four eyes) with Fusarium keratitis at Radboud University Medical Center (Nijmegen, the Netherlands). The patients were treated with chlorhexidine 0.02% eye drops. The in vitro activity of eight antifungals and chlorhexidine was determined according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. We also reviewed the literature on the use of chlorhexidine in the treatment of fungal keratitis. Topical chlorhexidine was well tolerated, and all patients showed complete resolution of the keratitis upon treatment with chlorhexidine. A PubMed search of the available literature was conducted (last search 8 March 2020) and yielded two randomized clinical trials (natamycin versus chlorhexidine) and one case report addressing the treatment of fungal keratitis with chlorhexidine. Chlorhexidine was found to be safe with regard to toxicity and to be superior to natamycin in the clinical trials. Chlorhexidine showed in vitro fungicidal activity against Fusarium and clinical effectiveness in our cases, supporting further clinical evaluation. Advantages of chlorhexidine are its topical application, its general availability, its low costs, its broad-spectrum activity, and its fungicidal mechanism of action at low concentrations.

Update on Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Identification of Filamentous Fungi.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based species identification has found its place in many clinical routine diagnostic laboratories over the past years, allowing significantly reduced turnaround times and high-precision results. With regard to MALDI-TOF MS for filamentous fungi, here, we discuss different approaches for sample processing and growth conditions before analysis. In particular, we review the performances of different commercially available databases as well as the potential of complementary (self-constructed) in-house databases.

External Quality Assessment Evaluating the Ability of Dutch Clinical Microbiological Laboratories to Identify Candida auris.

BACKGROUND: Candida auris is a yeast that is causing nosocomial outbreaks in healthcare facilities around the world. There is a risk of the misidentification of C. auris with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-when libraries are used that lack C. auris spectra, or when conventional biochemical methods are used. METHODS: We conducted an external quality assessment to evaluate the ability of Dutch clinical microbiological laboratories to identify C. auris, and to raise awareness about the risk of misidentification. RESULTS: 35/47 participating laboratories were able to identify C. auris correctly. Only 2/14 labs that potentially misidentified C. auris with their primary identification methods specified that they would perform additional tests to exclude C. auris when appropriate. 45/47 labs used MALDI-TOF MS systems to identify Candida species. CONCLUSIONS: There was a lack of awareness about the potential misidentification of C. auris in many labs that used MALDI-TOF MS with libraries that lacked C. auris spectra, and labs that used Vitek 2. However, as the currently available MALDI-TOF MS libraries in The Netherlands contain several C. auris spectra, we expect that currently almost all participating laboratories are able to identify C. auris correctly, as 45/47 participating laboratories use MALDI-TOF MS as their primary yeast identification method.

High-Level Pan-Azole-Resistant Aspergillosis.

High-level pan-azole-resistant Aspergillus fumigatus was recovered from four patients with chronic lung disease. In one patient, the development of progressive resistance followed long-term azole therapy and switching between antifungal azoles. The high-level pan-azole-resistant phenotypes were not associated with a specific cyp51A gene mutation. New strategies that avoid the development of progressive azole resistance are needed.

Performance of the new Platelia Candida Plus assays for the diagnosis of invasive Candida infection in patients undergoing myeloablative therapy.

The performance of the new Platelia Candida Antigen Plus (Ag Plus) and Antibody Plus (Ab Plus) assays (Biorad Laboratories, France) was evaluated using a collection of serum samples obtained from 21 patients with microbiologically proven invasive candidiasis and 30 control patients who were being treated with myeloablative chemotherapy, and the data compared with that obtained with the earlier version of the Platelia Candida assays (Ag and Ab), and 1,3-ß-D-glucan (BG) detection systems. The sensitivity of the Ag Plus and Ab Plus assays in the per patient analysis ranged from 55-70% and from 30-64% for patients with less than 15 days of neutropenia and more than 15 days of neutropenia, respectively. Sensitivity and time to detection of these new assays was not significantly better than of the conventional Platelia Candida tests. However, the specificity of the Ag-Plus assay was reduced by approximately 50% as compared to the Ag assay. Logistic regression analysis showed that this was probably due to the fact that circulating mannan was also being detected by the Ag Plus assay in patients with superficial candidiasis. Further studies are needed to confirm our results and to determine the place of the Platelia Ag Plus and Ab Plus assays in the management of haematology patients at risk for Candida infections.

Value of Candida serum markers in patients with invasive candidiasis after myeloablative chemotherapy.

Invasive Candida infections are associated with a significant morbidity and mortality. Detection of circulating biomarkers has been shown to precede conventional diagnostic methods, which is important in improving outcome. We investigated the performance of multiple biomarkers using Candida antigen and anti-Candida antibody detection systems of Platelia and Serion and beta-d-glucan detection in serial serum samples from patients, treated for leukemia, with invasive candidiasis. The performance of single assays and combined detection appeared different for patients with 1 or more episodes of neutropenia and is therefore related to the phase of therapy for the underlying leukemia of the patient. These new insights may help to optimize the diagnostic strategies for the diagnosis of invasive candidiasis.

Emergence of azole resistance in Aspergillus fumigatus and spread of a single resistance mechanism.

BACKGROUND: Resistance to triazoles was recently reported in Aspergillus fumigatus isolates cultured from patients with invasive aspergillosis. The prevalence of azole resistance in A. fumigatus is unknown. We investigated the prevalence and spread of azole resistance using our culture collection that contained A. fumigatus isolates collected between 1994 and 2007. METHODS AND FINDINGS: We investigated the prevalence of itraconazole (ITZ) resistance in 1,912 clinical A. fumigatus isolates collected from 1,219 patients in our University Medical Centre over a 14-y period. The spread of resistance was investigated by analyzing 147 A. fumigatus isolates from 101 patients, from 28 other medical centres in The Netherlands and 317 isolates from six other countries. The isolates were characterized using phenotypic and molecular methods. The electronic patient files were used to determine the underlying conditions of the patients and the presence of invasive aspergillosis. ITZ-resistant isolates were found in 32 of 1,219 patients. All cases were observed after 1999 with an annual prevalence of 1.7% to 6%. The ITZ-resistant isolates also showed elevated minimum inhibitory concentrations of voriconazole, ravuconazole, and posaconazole. A substitution of leucine 98 for histidine in the cyp51A gene, together with two copies of a 34-bp sequence in tandem in the gene promoter (TR/L98H), was found to be the dominant resistance mechanism. Microsatellite analysis indicated that the ITZ-resistant isolates were genetically distinct but clustered. The ITZ-sensitive isolates were not more likely to be responsible for invasive aspergillosis than the ITZ-resistant isolates. ITZ resistance was found in isolates from 13 patients (12.8%) from nine other medical centres in The Netherlands, of which 69% harboured the TR/L98H substitution, and in six isolates originating from four other countries. CONCLUSIONS: Azole resistance has emerged in A. fumigatus and might be more prevalent than currently acknowledged. The presence of a dominant resistance mechanism in clinical isolates suggests that isolates with this mechanism are spreading in our environment.

Single-dose fluconazole versus standard 2-week therapy for oropharyngeal candidiasis in HIV-infected patients: a randomized, double-blind, double-dummy trial.

BACKGROUND: Oropharyngeal candidiasis is the most common opportunistic infection affecting patients with human immunodeficiency virus (HIV) infection. Because of convenience, cost, and reluctance to complicate antiretroviral treatment regimens, single-dose fluconazole may be a favorable regimen for treatment of moderate to severe oropharyngeal candidiasis. We conducted a prospective, randomized, double-blind, placebo-controlled trial to compare the clinical and mycological responses, relapse rates, and safety of a single 750-mg dose and a 14-day course of treatment with fluconazole. METHODS: A total of 220 HIV-infected patients with clinical and mycological evidence of oropharyngeal candidiasis were randomly assigned in a 1:1 ratio to receive either a 750-mg single dose of orally administered fluconazole (110 patients) or 150 mg of orally administered fluconazole once per day for 2 weeks (110 patients). The primary efficacy analysis was based on clinical and mycological responses at the end of treatment. Secondary parameters were safety and relapse rate. RESULTS: Single-dose fluconazole was equivalent to a 14-day course of fluconazole in achieving clinical and mycological cure, with clinical cure rates of 94.5% and 95.5%, respectively (odds ratio, 0.825; 95% confidence interval, 0.244-2.789; P= .99), and mycological cure rates of 84.5% and 75.5%, respectively (odds ratio, 1.780; 95% confidence interval, 0.906-3.496; P= .129). Drug-related adverse events were uncommon and were not different between the treatment groups. CONCLUSION: A single dose of 750 mg of fluconazole was safe, well tolerated, and as effective as the standard 14-day fluconazole therapy in patients with HIV infection and acquired immunodeficiency syndrome who had oropharyngeal candidiasis coinfection.

Aspergillus calidoustus sp. nov., causative agent of human infections previously assigned to Aspergillus ustus.

Aspergillus ustus is a relatively rare human pathogen causing invasive infections in immunocompromised hosts. In this study isolates originating from clinical and other sources have been examined using molecular, morphological, and physiological approaches to clarify their species assignment. Phylogenetic analysis of partial beta-tubulin, calmodulin, actin, and intergenic transcribed spacer sequences indicated that none of the clinical isolates recognized previously as A. ustus belongs to this species. All but two of these isolates formed a well-defined clade related to A. pseudodeflectus based on sequence analysis of protein-coding regions. Morphological and physiological examination of these isolates indicated that they are able to grow above 37 degrees C, in contrast with A. ustus isolates, and give a positive Ehrlich reaction, in contrast with related species including A. granulosus, A. ustus, and A. pseudodeflectus. These isolates are proposed as a new species, A. calidoustus. Antifungal susceptibility testing showed that this species has decreased susceptibilities to several antifungal drugs. The triazoles are inactive in vitro, including the new azole posaconazole.