Salvage Treatment of Mucormycosis Post-Liver Transplant With Posaconazole During Sirolimus Maintenance Immunosuppression

Epidemiology, Clinical Manifestations, and Outcome of Mucormycosis in Solid Organ Transplant Recipients: A Systematic Review of Reported Cases

Mucormycosis is an emerging disease primarily affecting the immunocompromised host, but scarce evidence is available for solid organ transplant recipients (SOTRs). We systematically reviewed 183 cases occurring in SOTRs, exploring epidemiology, clinical characteristics, causative pathogens, therapeutic approaches, and outcomes. Kidney transplants accounted for half of the cases, followed by heart (18.6%), liver (16.9%), and lung (10.4%). Diagnosis showed a dichotomous distribution, with 63.7% of cases reported within 100 days of transplantation and 20.6% occurring at least 1 year after transplant. The 90-day and 1-year mortality rates were 36.3% and 63.4%, respectively. Disseminated disease had the highest mortality at both time points (75% and 93%). Treatment with >3 immunosuppressive drugs showed a significant impact on 90-day mortality (odds ratio [OR], 2.33; 95% CI, 1.02-5.66; P = .0493), as did a disseminated disease manifestation (OR, 8.23; 95% CI, 2.20-36.71; P = .0027) and the presence of diabetes (OR, 2.35; 95% CI, 1.01-5.65; P = .0497). Notably, prophylaxis was administered to 12 cases with amphotericin B. Further investigations are needed to validate these findings and to evaluate the potential implementation of prophylactic regimens in SOTRs at high risk.

Pharmacological management of invasive mold infections in solid organ transplant recipients

INTRODUCTION

Solid organ transplant (SOT) recipients face an increased susceptibility to invasive fungal infection (IFI) due to filamentous fungi. Post-transplant invasive aspergillosis (IA) and mucormycosis are related to exceedingly high mortality rates and graft loss risk, and its management involve a unique range of clinical challenges.

AREAS COVERED

First, the current treatment recommendations for IA and mucormycosis among SOT recipients are critically reviewed, including the supporting evidence. Next, we discussed particular concerns in this patient population, such as drug-drug interactions (DDIs) between triazoles and post-transplant immunosuppression or treatment-related toxicity. The role for immunomodulatory and host-targeted therapies is also considered, as well as the theoretical impact of the intrinsic antifungal activity of calcineurin inhibitors. Finally, a personal opinion is made on future directions in the pharmacological approach to post-transplant IFI.

EXPERT OPINION

Despite relevant advances in the treatment of mold IFIs in the SOT setting, such as the incorporation of isavuconazole (with lower incidence of DDIs and better tolerability than voriconazole), there remains a large room for improvement in areas such as the position of combination therapy or the optimal strategy for the reduction of baseline immunosuppression. Importantly, future studies should define the specific contribution of newer antifungal agents and classes.

Initial sirolimus dosage recommendations for pediatric patients with PIK3CD mutation-related immunodeficiency disease

Sirolimus is used to treat pediatric patients with PIK3CD mutation-related immunodeficiency disease. However, the initial dosages of sirolimus remain undecided. The present study aims to explore initial dosages in pediatric patients with PIK3CD mutation-related immunodeficiency disease. Pediatric patients with this disease were analyzed using the population pharmacokinetic (PPK) model and the Monte Carlo simulation. Body weight and concomitant use of posaconazole were included in the final PPK model, where, under the same weight, clearances of sirolimus were 1 : 0.238 between children without and children with posaconazole. Without posaconazole, the initial dosages of sirolimus were 0.07, 0.06, 0.05, and 0.04 mg/kg/day for body weights of 10–14, 14–25, 25–50, and 50–60 kg, respectively. With posaconazole, the initial dosages of sirolimus were 0.02 mg/kg/day for body weights of 10–60 kg. This is the first attempt to build a sirolimus PPK model for recommending initial dosages in children with PIK3CD mutation-related immunodeficiency disease, thereby providing a reference for individualized clinical drug administration.

Postliver Transplantation Rhino-Orbital Mucormycosis, an Unexpected Cause of a Downhill Course

The COVID-19 pandemic has impacted transplantation worldwide in a major way with infections and post-COVID-19 complications contributing to increased mortality and morbidity. We present a case of a 42-year-old lady who developed rhino-orbital mucormycosis in a postliver transplantation period. The initial presentation of the patient was very subtle. She never had overt COVID-19 infection before surgery and in the recovery period. Though cases of mucormycosis in the wound site have been reported, this would be one of the rare cases of rhino-orbital mucormycosis postliver transplantation. This infection leads to a rapid downhill course and the death of the patient. Atypical infections and presentations need to be monitored in postliver transplantation patients who are getting operated on during this pandemic, and a high level of clinical suspicion is required to pick up these cases at an early stage.

Antifungal Drugs TDM: Trends and Update

PURPOSE

The increasing burden of invasive fungal infections results in growing challenges to antifungal (AF) therapeutic drug monitoring (TDM). This review aims to provide an overview of recent advances in AF TDM.

METHODS

We conducted a PubMed search for articles during 2016-2020 using "TDM" or "pharmacokinetics" or "drug-drug-interaction" with "antifungal," consolidated for each AF. Selection was limited to English language articles with human data on drug exposure.

RESULTS

More than 1000 articles matched the search terms. We selected 566 publications. The latest findings tend to confirm previous observations in real-life clinical settings. The pharmacokinetic variability related to special populations is not specific but must be considered. AF benefit-to-risk ratio, drug-drug interaction (DDI) profiles, and minimal inhibitory concentrations for pathogens must be known to manage at-risk situations and patients. Itraconazole has replaced ketoconazole in healthy volunteers DDI studies. Physiologically based pharmacokinetic modeling is widely used to assess metabolic azole DDI. AF prophylactic use was studied more for Aspergillus spp. and Mucorales in oncohematology and solid organ transplantation than for Candida (already studied). Emergence of central nervous system infection and severe infections in immunocompetent individuals both merit special attention. TDM is more challenging for azoles than amphotericin B and echinocandins. Fewer TDM requirements exist for fluconazole and isavuconazole (ISZ); however, ISZ is frequently used in clinical situations in which TDM is recommended. Voriconazole remains the most challenging of the AF, with toxicity limiting high-dose treatments. Moreover, alternative treatments (posaconazole tablets, ISZ) are now available.

CONCLUSIONS

TDM seems to be crucial for curative and/or long-term maintenance treatment in highly variable patients. TDM poses fewer cost issues than the drugs themselves or subsequent treatment issues. The integration of clinical pharmacology into multidisciplinary management is now increasingly seen as a part of patient care.

Delayed Graft Dysfunction due to Invasive Hepatic Mucormycosis After Living Donor Liver Transplantation

Mucormycosis is a rare but emerging fungal infection complicating solid organ transplantation. It is associated with a high mortality rate. We describe an unusual case of hepatic mucormycosis in a living donor liver transplant recipient presenting as delayed graft dysfunction, which was successfully treated with combination of liposomal amphotericin B and oral posaconazole therapy, without surgical resection. The patient had clinical improvement with normalization of liver function tests.

Adipose tissue-derived stem cells from affected and unaffected areas in patients with multiple symmetric lipomatosis show differential regulation of mTOR pathway genes

BACKGROUND

Multiple symmetric lipomatosis is a rare disease characterized by the excessive growth of uncapsulated masses of adipose tissue. Although the etiology has yet to be elucidated, a connection to brown adipose tissue has been proposed recently. The mTOR pathway which is found to be regulated in lipomatous tissue as well as associated with brown adipose tissue can be inhibited by a compound called rapamycin.

METHODS

We isolated adipose tissue derived stem cells from both affected and unaffected tissue and treated these cells with different concentrations of rapamycin.

RESULTS

The differences in both proliferation and differentiation between adipose tissue derived stem cells (ASCs) from lipomatous and normal tissue decreased after mTOR pathway inhibition. In some patients regulation of mTOR genes was opposed in the ASCs from the two different tissues.

CONCLUSIONS

Treatment with rapamycin might be a novel therapeutical approach for patients suffering from multiple symmetric lipomatosis.

Cutaneous mucormycosis postcosmetic surgery: A case report and review of the literature

BACKGROUND

Mucormycosis is a rare, aggressive, and life-threatening infection that is caused by organisms belonging to the order Mucorales. It is usually acquired through direct means and virtually always affects immunocompromised patients with the port of entry reflecting the site of infection, in this case, cutaneous. Unlike other mucormycoses, patients affected by Apophysomyces elegans (A elegans) are known to be immunocompetent. This locally aggressive disease penetrates through different tissue plains invading adjacent muscles, fascia, and even bone causing extensive morbidity and may prove fatal if treated inadequately. Cutaneous mucormycosis is associated with disruption of cutaneous barriers such as trauma. However, rarely, it may be iatrogenic. No cases have been previously reported postcosmetic surgery, especially one that is so commonly performed, lipofilling.

CASE REPORT

The patient is a, previously healthy, 41-year-old middle-eastern female who was admitted to the plastic surgery department 17 days after undergoing cosmetic surgery. She suffered from extensive tissue inflammation and necrosis in both gluteal regions. Following admission, she was initially started on empirical antimicrobial therapy which was changed to an antifungal agent, voriconazole, when preliminary microbiological results showed filamentous fungi. This was discontinued and liposomal amphotericin B was commenced when further mycological analysis identified A elegans. Furthermore, she underwent a total of 10 sessions of extensive debridement to the extent that portions of the sacrum and left femoral head became exposed. Her clinical status and wounds improved with the appropriate management and she remained an inpatient for 62 days. Subsequently, she had defects in both gluteal regions which required reconstructive surgery.

CONCLUSION

A elegans is an uncommon cause of iatrogenic cutaneous mucormycosis. A high index of clinical suspicion is required, especially in the absence of clinical improvement despite conventional methods of treatment, so that early diagnosis can be reached and the appropriate management instigated promptly in order to mitigate morbidity and mortality. Reversal of predisposing risk factors, regular extensive surgical debridement, and antifungal therapy remain the cornerstones of therapy for this life-threatening condition.