Pharmacokinetics and pharmacodynamics of anidulafungin for experimental Candida endophthalmitis: insights into the utility of echinocandins for treatment of a potentially sight-threatening infection

Vitrectomy using 0.025% povidone-iodine irrigation for treating post-traumatic endophthalmitis due to intraocular foreign bodies: Two case reports

Traumatic eye injury-related endophthalmitis is a serious traumatic complication that threatens the vision of many patients worldwide. Herein, we present two cases of traumatic endophthalmitis that underwent 0.025% povidone-iodine treatment and hoped to introduce the bactericidal effect of 0.025% povidone-iodine in balanced salt solution PLUS (0.025% PI-BSS PLUS) and its use in vitrectomy for traumatic endophthalmitis. The 0.025% PI-BSS PLUS solution is bactericidal and nontoxic when used as an irrigation solution in pars plana vitrectomy. The two cases of traumatic endophthalmitis were resolved by pars plana vitrectomy using 0.025% PI-BSS PLUS.

Anidulafungin versus fluconazole in the treatment of Candida albicans chorioretinitis

BACKGROUND

Candida albicans chorioretinitis is the most common cause of endogenous fungal endophthalmitis. Echinocandins are recommended as first-line therapy in the treatment of invasive candidiasis (IC), but in clinically stable patients with IC and endophthalmitis caused by Candida species susceptible to azole compounds these are the first-line treatment due to their better intraocular penetration.

CASE REPORT

A 42-year-old woman admitted to hospital for duodenal perforation after gastrointestinal surgery and treated with broad-spectrum antibiotics developed C. albicans candidemia. According to protocol, an antifungal treatment with anidulafungin was given. The patient presented no visual symptoms but on routinary ophthalmoscopic examination multiple bilateral chorioretinal lesions were observed. Systemic therapy was changed to fluconazole, with good systemic and ocular results.

CONCLUSIONS

Azole compounds are the first-line therapy for endophthalmitis associated with candidemia. However, clinical guidelines often propose echinocandins as the first option for IC. In some cases, C. albicans chorioretinitis will require a change in the systemic treatment to assure better intraocular penetration. According to the current evidence and our own experience, routine funduscopy is not necessary in all IC patients. However, we do recommend fundus examination in patients with visual symptoms or those unable to report them (paediatric patients and patients with an altered level of consciousness), and in those who are being treated with echinocandins in monotherapy.

Antimicrobial guide to posterior segment infections

PURPOSE

This review article is meant to serve as a reference guide and to assist the treating physician in making an appropriate selection and duration of an antimicrobial agent.

METHODS

Literature review.

RESULTS

Infections of the posterior segment require prompt medical or surgical therapy to reduce the risk of permanent vision loss. While numerous options exist to treat these infections, doses and alternative therapies, especially with contraindications for first-line therapy, are often elusive. Antimicrobial agents to treat posterior segment infections can be administered via various routes, including topical, intravitreal, intravenous, and oral.

CONCLUSIONS

Although there are many excellent review articles on the management of endophthalmitis, we take the opportunity in this review to comprehensively summarize the appropriate antimicrobial regimen of both common and rare infectious etiologies of the posterior segment, using evidence from clinical trials and large case series.

Evaluation of Susceptibility and Innate Immune Response in C57BL/6 and BALB/c Mice During Candida albicans Endophthalmitis

Purpose

Candida remains the leading cause of fungal endophthalmitis. However, the pathobiology and innate immune responses in this disease are not well characterized. Here, we developed two murine models of candida endophthalmitis and evaluated their disease susceptibility and differential immune response.

Methods

Endophthalmitis was induced in C57BL/6 (B6) and BALB/c mice by intravitreal injection of Candida albicans (CA). Disease progression was monitored by slit-lamp examination and clinical scoring, followed by retinal function assessment using electroretinography (ERG). Enucleated eyes were used to estimate fungal burden and retinal tissue damage by hematoxylin and eosin and TUNEL staining. The level of inflammatory mediators were determined by quantitative Polymerase Chain Reaction (qPCR) and enzyme-linked immunosorbent assay, whereas neutrophil infiltration was assessed by flow cytometry and immunostaining.

Results

Intravitreal injection of CA at 6500 colony-forming units resulted in sustained (non-resolving) ocular inflammation in both B6 and BALB/c mice as evidenced by increased levels of inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, and interleukin-6) and chemokine (CXCL2/MIP-2). In both mouse strains, fungal burden peaked at 24 to 48 hours post-infection (hpi) and decreased by 72 to 96 hpi. CA-infected eyes exhibited increased polymorphonuclear neutrophils (PMN) infiltration and retinal tissue damage. Overall retinal function declined rapidly, with a significant reduction in ERG response at 12 hpi and near-total loss by 24 hpi. Differential analyses revealed increased pathology in BALB/c versus B6 mice.

Conclusions

C. albicans was able to cause endophthalmitis in mice. Although BALB/c mice were found to be more susceptible to CA endophthalmitis, both BALB/c and B6 models could be used to study fungal endophthalmitis and test therapeutic modalities.

Chromatographic methods for echinocandin antifungal drugs determination in bioanalysis

The increase of fungal resistance to drugs, such as azole family, gave rise to the development of new antifungals. In this context, echinocandins emerged as a promising alternative for antifungal therapies. Following the commercialization of caspofungin in 2001, echinocandins became the first-line therapy for invasive candidiasis in different patient populations. The quantification of these drugs has gained importance since pharmacokinetic/pharmacodynamic and resistance studies are a paramount concern. This fact has led us to exhaustively examine the methodologies used for the analysis of echinocandins in biological fluids, which are mainly based on LC coupled to different detection techniques. In this review, we summarize the analytical methods for the quantification of echinocandins focusing on sample treatment, chromatographic separation and detection methods.

Intravitreal Injection of 1.25% Povidone Iodine Followed by Vitrectomy Using 0.025% Povidone Iodine Irrigation for Treating Endophthalmitis

Purpose

To investigate the safety and effectiveness of intravitreal injection (IVI) of 1.25% povidone iodine (PI) followed by vitrectomy using 0.025% PI irrigation for treating endophthalmitis.

Methods

Prospective case series study. Nine eyes of 8 patients with postoperative or endogenous endophthalmitis treated at the Nihon University Hospital between April 2015 and October 2017 were studied. First, IVI of 0.1 mL/1.25%PI was conducted, followed by anterior chamber irrigation and vitrectomy using 0.025%PI irrigation solution. Corneal epithelial damage, anterior chamber inflammation, and vitreous inflammation were assessed and fundus examinations were performed, using a slit-lamp microscope and indirect ophthalmoscopy. A specular microscope, Goldmann perimetry, and electroretinography (ERG) were also used.

Results

In all but case 7, endophthalmitis resolved rapidly and good visual acuity was maintained. No adverse events were noted. Furthermore, the perioperative ERG showed improvements in the oscillatory potentials amplitudes on ERG and flicker ERG, as well as in the implicit time of the a-wave, suggesting functional recovery in the retinal outer and inner layers after therapy.

Conclusions

IVI of PI followed by vitrectomy was thought to be a safe and effective treatment for endophthalmitis.

Translational Relevance

We succeeded in proving the clinical safety of IVI of PI followed by vitrectomy with PI irrigation as well as previous experimental reports. PI is available in world widely, therefore this method will be optimal treatment for endophthalmitis.

Intermittent Dosing of Micafungin Is Effective for Treatment of Experimental Disseminated Candidiasis in Persistently Neutropenic Rabbits

BACKGROUND

The current standard of treatment of invasive candidiasis with echinocandins requires once-daily therapy. To improve quality of life, reduce costs, and improve outcome, we studied the pharmacokinetics (PK), efficacy, and safety of alternate dosing regimens of micafungin (MFG) for the treatment of experimental subacute disseminated candidiasis.

METHODS

MFG was administered for 12 days starting 24 hours after intravenous inoculation of 1 × 10(3) Candida albicans blastoconidia. Study groups consisted of MFG at 1 mg/kg every 24 hours (MFG1), 2 mg/kg every 48 hours (MFG2), and 3 mg/kg every 72 hours (MFG3), and untreated controls. PK of MFG were determined on day 7 by high-performance liquid chromatography and modeled using nonparametric adaptive grid program. A 2-compartment PK model with volume of the central compartment (Vc), clearance (SCL), and the intercompartmental rate constants Kcp and Kpc was used. The fungal burden in 7 tissues was determined 312 hours after the initiation of therapy.

RESULTS

PK of MFG were linear and the parameter means ± SD were Vc = 0.41 ± 0.18 L, Kcp = 2.80 ± 1.55/hour, Kpc = 1.71 ± 0.93/hour, and SCL = 0.16 ± 0.003 L/hour (r(2) = 0.99). The area under the plasma drug concentration - time curve for MFG1, MFG2, and MFG3 was 198.7 ± 19.8, 166.3 ± 36.7, and 192.8 ± 46.2 mg × hour/L, respectively (P = .24). All treatment groups showed significant and comparable resolution of (1→3)-β-D-glucan levels and clearance of C. albicans from liver, spleen, kidney, brain, lung, vitreous humor, and vena cava in comparison to untreated controls (P ≤ .05). There were no differences in hepatic or renal function among study groups.

CONCLUSIONS

Less fractionated MFG regimens of every 48 and 72 hours are safe and as effective in experimental disseminated candidiasis as once-daily therapy in neutropenic hosts.

Pharmacodynamics for antifungal drug development: an approach for acceleration, risk minimization and demonstration of causality

The treatment of invasive fungal diseases constitutes a significant unmet medical need. There are relatively few antifungal agents in clinical development and a paucity of novel targets. Morbidity and mortality remain high and clinical outcomes are compromised by submaximal efficacy, emergence of drug resistance and drug-related toxicity. Thus, new antifungal agents are urgently required. A deep understanding of exposure-response relationships underpins the development of safe and effective clinical regimens of any therapeutic agent. Pharmacokinetics (PK) and pharmacodynamics (PD) is increasingly recognized as a vital tool in the development of new antimicrobial agents and maximizes the probability that the right dose will be studied the first time. There is currently no information or agreement as to what constitutes an adequate PK/PD package for the development of a new antifungal agent. This review provides a summary of the achievements of antifungal PK/PD for the treatment of invasive candidiasis, invasive aspergillosis and cryptococcal meningoencephalitis, and outlines the necessary components of a PK/PD package for a new antifungal agent. Such information is critical for the accelerated and efficient development of new agents and enables improved clinical outcomes to be secured.

A Comparative Study of the Effects of Intravitreal Anidulafungin, Voriconazole, and Amphotericin B in an Experimental Candida Endophthalmitis Model

PURPOSE

To compare the safety and efficacy of intravitreal anidulafungin injection with voriconazole and amphotericin B (Amp B) in an experimental Candida endophthalmitis (CE) model.

METHODS

Intravitreal 1 × 10⁵ CFU/0.1 ml Candida albicans was injected into the right eyes of 24 New Zealand rabbits, which were divided into 4 groups. Voriconazole 50 μg/0.1 ml, Amp B 10 μg/0.1 ml, and Anidulafungin 50 μg/0.1 ml were injected by intravitreal injection 72 h after inoculation. The control group was injected with 0.1 ml 0.9% NaCl. Clinical scoring was performed by assessing the cornea, conjunctiva, iris, and vitreous on days 3 and 7 of therapy. At the end of the study, the right eyes of all rabbits were enucleated and histopathological evaluation was performed. Therapy groups were compared according to the clinical, histopathological, and microbiological analysis scores.

RESULTS

Total clinical scores were significantly different between treatment groups and the control group (p < 0.05). On day 7 of the therapy, clinical scores of the anidulafungin group were found to be significantly lower when compared with the other therapy groups, while a significant improvement was observed in the eyes of rabbits in the anidulafungin group (p < 0.05). Also, microbiological scores of the anidulafungin group were lower than those of the control group (p < 0.05). Histopathological scores of the anidulafungin treatment group were significantly better than the voriconazole and control groups. Inflammation was evidently suppressed and marked retinal toxicity was not observed with anidulafungin.

CONCLUSIONS

This is the first study comparing the efficacy of anidulafungin with other antifungal agents. In this CE model, an intravitreal single dose of anidulafungin was shown to be noninferior to voriconazole and Amp B. As an alternative to Amp B or voriconazole, intravitreal anidulafungin is suggested as an effective antifungal agent for the treatment of CE.

Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Tissue penetration of antifungal agents

Understanding the tissue penetration of systemically administered antifungal agents is critical for a proper appreciation of their antifungal efficacy in animals and humans. Both the time course of an antifungal drug and its absolute concentrations within tissues may differ significantly from those observed in the bloodstream. In addition, tissue concentrations must also be interpreted within the context of the pathogenesis of the various invasive fungal infections, which differ significantly. There are major technical obstacles to the estimation of concentrations of antifungal agents in various tissue subcompartments, yet these agents, even those within the same class, may exhibit markedly different tissue distributions. This review explores these issues and provides a summary of tissue concentrations of 11 currently licensed systemic antifungal agents. It also explores the therapeutic implications of their distribution at various sites of infection.