Diagnosis and treatment of invasive fungal infections focus on liposomal amphotericin B

Efficacy of early administration of liposomal amphotericin B in patients with septic shock: A nationwide observational study

INTRODUCTION

Liposomal amphotericin B (L-AMB), a broad spectrum anti-fungicidal drug, is often administered to treat invasive fungal infections (IFIs). However, the most suitable time to initiate treatment in septic shock patients with IFI is unknown.

METHODS

Patients with septic shock treated with L-AMB were identified from the Japanese Diagnosis Procedure Combination national database and were stratified according to L-AMB treatment initiation either at septic shock onset (early L-AMB group) or after the onset (delayed L-AMB group) to determine their survival rates following septic shock onset and the shock cessation period.

RESULTS

We identified 141 patients administered L-AMB on the day of or after septic shock onset: 60 patients received early treatment, whereas 81 patients received delayed treatment. Survival rates after septic shock onset were higher in the early L-AMB group than in the delayed L-AMB group (4 weeks: 68.4% vs 57.9%, P = 0.197; 6 weeks: 62.2% vs 44.5%, P = 0.061; 12 weeks: 43.4% vs 35.0%, P = 0.168, respectively). The septic shock cessation period was shorter in the early L-AMB group than in the delayed L-AMB group (7.0 ± 7.0 days vs 16.5 ± 15.4 days, P < 0.001), with a significant difference confirmed after adjusting for confounding factors with propensity score matching (7.1 ± 7.2 days vs 16.7 ± 14.0 days, P = 0.001).

CONCLUSION

Early L-AMB administration at septic shock onset may be associated with early shock cessation.

Candida albicans Antifungal Resistance and Tolerance in Bloodstream Infections: The Triad Yeast-Host-Antifungal

Candida albicans represents the most frequent isolated yeast from bloodstream infections. Despite the remarkable progress in diagnostic and therapeutic approaches, these infections continue to be a critical challenge in intensive care units worldwide. The economic cost of bloodstream fungal infections and its associated mortality, especially in debilitated patients, remains unacceptably high. Candida albicans is a highly adaptable microorganism, being able to develop resistance following prolonged exposure to antifungals. Formation of biofilms, which diminish the accessibility of the antifungal, selection of spontaneous mutations that increase expression or decreased susceptibility of the target, altered chromosome abnormalities, overexpression of multidrug efflux pumps and the ability to escape host immune defenses are some of the factors that can contribute to antifungal tolerance and resistance. The knowledge of the antifungal resistance mechanisms can allow the design of alternative therapeutically options in order to modulate or revert the resistance. We have focused this review on the main factors that are involved in antifungal resistance and tolerance in patients with C. albicans bloodstream infections.

Invasive fungal laryngopharyngitis resulting in laryngeal destruction with complete laryngotracheal separation: Report of a case

As the treatment of hematopoietic cancers evolves, otolaryngologists will see a higher incidence of opportunistic infections. We discuss a case of invasive fungal disease that invaded the larynx, pharynx, trachea, and pulmonary parenchyma after chemotherapy. The patient, a 46-year-old woman, presented 1 week after undergoing induction chemotherapy. Her initial symptoms were odynophagia and dysphagia. Despite encouraging findings on physical examination, her health rapidly declined and she required an urgent tracheotomy and multiple operations to address spreading necrosis. Because of her inability to heal, she was not a candidate for laryngectomy, so she was treated with conservative management. The patient was then lost to follow-up, but she returned 5 months later with laryngeal destruction and a complete laryngotracheal separation. While noninvasive fungal laryngitis is routinely encountered, its invasive counterpart is rare. The literature demonstrates that some cases completely resolve with medical therapy alone but that surgery is necessary in others. We recommend surgical debridement of all necrotic tissue.

Invitro antifungal susceptibilities of Candida species to liposomal amphotericin B, determined using CLSI broth microdilution, and amphotericin B deoxycholate, measured using the Etest

The antifungal susceptibilities of 598 isolates of Candida spp. (bloodstream and other sterile sites) to liposomal amphotericin B (L-AmB) versus amphotericin B (AmB) were determined. MICs were calculated using the Clinical and Laboratory Standards Institute broth microdilution (M27-A3) method for L-AmB and the Etest method for AmB. The MIC₅₀/MIC₉₀ (µg ml⁻¹) values for L-AmB broth microdilution and AmB Etest were 0.25/1 and 0.19/0.5, respectively. The overall essential agreement (±2 dilutions) was 91.5 %, ranging from 37.5 % (Candida lusitaniae) to 100 % (Candida glabrata and Candida krusei). Categorical agreement between the two methods was categorized based on a previously published breakpoint (susceptible/resistant MIC cut-off of 1 µg ml⁻¹). The overall categorical agreement at the 48 h reading was 97.3 %, ranging from 72.7 % (C. krusei) to 100 % (Candida albicans). Major and very major discrepancies occurred in 2.3 and 0.3 %, respectively. Spearman’s ρ was 0.48 (P<0.0001). These results demonstrate the utility of the AmB Etest as a surrogate marker to predict the sensibility and resistance of Candida spp. to L-AmB and thus to support its use in antifungal treatment.

Comparison between liposomal formulations of amphotericin B

Given the clinical success of commercial amphotericin B lipid products, investigators have begun making generic formulations of liposomal amphotericin B. Generic medicines are an attractive approach to help decrease the cost and accessibility to healthcare, provided that appropriate studies are performed to ensure bioequivalence with the parent product. This is of particular concern for liposomal drugs such as amphotericin B where liposomes are used as a carrier system to reduce the toxicity of the active agent. A favorable therapeutic profile for this form of the drug has to include the proper chemical composition along with strictly controlled manufacturing processes. Studies have shown that a comparison of liposomal amphotericin B products with different or the same chemical compositions, using different methods of production, will vary in size, and have significantly dissimilar in vitro and in vivo toxicities along with reduced efficacy. These results underscore the importance of establishing appropriate bioequivalence testing for liposome products to ensure uniformity of their therapeutic index.

In vitro activities of amphotericin B deoxycholate and liposomal amphotericin B against 604 clinical yeast isolates

We determined the in vitro antifungal activity of liposomal amphotericin B (L-AmB) against 604 clinical yeast isolates. Amphotericin B deoxycholate (D-AmB) was tested in parallel against all the isolates. Susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) M27-A3 method. Overall, L-AmB was highly active against the isolates (mean MIC, 0.42 µg ml(-1); MIC90, 1 µg ml(-1); 97.2 % of MICs were ≤1 µg ml(-1)) and comparable to D-AmB (mean MIC, 0.48 µg ml(-1); MIC90, 1 µg ml(-1); 97.3 % of MICs were ≤1 µg ml(-1)). The in vitro activity of D-AmB and L-AmB was correlated (R(2) = 0.61; exp(b), 2.3; 95 % CI, 2.19-2.44, P<0.001). Candida albicans (mean MICs of D-AmB and L-AmB, 0.39 µg ml(-1) and 0.31 µg ml(-1), respectively) and Candida parapsilosis (mean MICs of D-AmB and L-AmB, 0.38 µg ml(-1) and 0.35 µg ml(-1), respectively) were the species most susceptible to the agents tested, while Candida krusei (currently named Issatchenkia orientalis) (mean MICs of D-AmB and L-AmB, 1.27 µg ml(-1) and 1.13 µg ml(-1), respectively) was the least susceptible. The excellent in vitro activity of L-AmB may have important implications for empirical treatment approaches and support its role in treatment of a wide range of invasive infections due to yeasts.

Half-life extension technologies for haemostatic agents

The use of plasma-derived and recombinant coagulation factors for the treatment of haemophilia A and B is well established and permits patients to live a relatively normal life. In order to improve treatment options, several products are in development, which have a prolonged duration of action, thus enabling less frequent prophylactic dosing and aiming to reduce the burden of treatment. Several innovative approaches are being pursued to extend the half-life of factor VIIa, factor VIII and factor IX, utilising technologies such as Fc fusion, recombinant albumin fusion and addition of polyethyleneglycol (PEG) (PEGylation). These methods prolong the time in the circulation by reducing degradation and elimination. This review summarises the technologies and products in development and their stages of development, and also discusses their pros and cons.

Neutropenia and invasive fungal infection in patients with hematological malignancies treated with chemotherapy: a multicenter, prospective, non-interventional study in China

In this study, we explored the relationship between neutropenia (absolute neutrophil count (ANC) <1,500/mm(3)) and invasive fungal infection (IFI) in Chinese patients who had hematological malignancies treated with chemotherapy. We conducted a multicenter, prospective, non-interventional study of consecutive patients with hematological malignancies undergoing chemotherapy in China and determined clinical characteristics of patients who developed neutropenia and IFI. The results indicated that for the 2,177 neutropenic patients, 88 (4.0 %) were diagnosed with IFI. We found that a high risk of IFI (P<0.05) is associated with male gender, non-remission of the primary disease, use of two or more broad-spectrum antibiotics, treatment with parenteral nutrition, presence of cardiovascular disease, history of IFI, and neutropenia. When the ANC was less than 1,000, 1,000∼500, 500∼100, and <100/mm(3), the incidence of IFI was 0.5, 5.2, 3.9, and 4.7 %, respectively (ANC>1,000/mm(3) versus other groups, P<0.001). When the ANC was less than 1,000, 500, or 100/mm(3) for 10 days or more, the incidence of IFI was 3.2 versus 6.1 % (P=0.0052), 3.5 versus 7.1 % (P=0.0021), and 3.1 versus 10.0 % (P<0.001). When the ANC was less than 100/mm(3), taking antifungal prophylaxis reduced the incidence of IFI (P<0.05). The IFI-attributable mortality rate was 11.7 %. In conclusion, Chinese patients with IFI, severe and prolonged neutropenia increases the incidence of IFI. The incidence of IFI associated with neutropenia was reduced when antifungal prophylaxis was given. IFI was associated with a significantly increased high mortality rate in hematological malignancy patients with neutropenia.