Cutaneous ulcerations caused by Paecilomyces variotii in a renal transplant recipient

Species Identification and In Vitro Antifungal Susceptibility of Paecilomyces/Purpureocillium Species Isolated from Clinical Respiratory Samples: A Multicenter Study

Paecilomyces spp. are emerging fungal pathogens, where Paecilomyces lilacinus and Paecilomyces variotii are the most reported species. Taxonomic and phylogenetic revisions in this genus have shown that P. variotii represents a species complex, whereas P. lilacinus is related to another genus called Purpureocillium. The aims of this study were to identify clinical isolates of Paecilomyces spp. at the species level, and to determine their antifungal susceptibility profiles. 70 clinical Paecilomyces spp. isolates were identified by MALDI-TOF Mass Spectrometry (MS) and by multilocus rDNA genes sequencing including ITS and the D1/D2 genes. Among the 70 Paecilomyces spp. isolates, 28 were identified as P. lilacinum, 26 as P. variotii stricto sensu, and 16 as P. maximus. For antifungal susceptibility testing, Minimal Inhibitory Concentrations (MICs) or Minimal Effective Concentrations (MECs) were determined for 8 antifungals. All P. lilacinum isolates had high MICs and MECs of amphotericin B and echinocandins, respectively, unlike P. variotii and P. maximus. For azole drugs, MICs were molecule- and species- dependent. The differences in in vitro susceptibility to antifungals underline the importance of accurate species identification. The MALDI–TOF MS can be a good alternative in routine laboratory to ensure fast identification of Paecilomyces spp. and P. lilacinum.

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.

Characterization and outcome of invasive infections due to Paecilomyces variotii: analysis of patients from the FungiScope® registry and literature reports

Objectives

To provide a basis for clinical management decisions in Paecilomyces variotii infection.

Methods

Unpublished cases of invasive P. variotii infection from the FungiScope^® registry and all cases reported in the literature were analysed.

Results

We identified 59 cases with P. variotii infection. Main baseline factors were presence of indwelling devices in 29 cases (49.2%), particularly peritoneal catheters (33.9%) and prosthetic heart valves (10.2%), haematological or oncological diseases in 19 (32.2%), major surgery in 11 (18.6%), and diabetes mellitus in 10 cases (16.9%). The most prevalent infection sites were peritoneum (n = 20, 33.3%) and lungs (n = 16, 27.1%). Pain and fever were frequent (n = 35, 59.3% and n = 33, 55.9%, respectively). Diagnosis was established by culture in 58 cases (98.3%). P. variotii caused breakthrough infection in 8 patients. Systemic antifungals were given in 52 patients (88.1%). Amphotericin B was administered in 39, itraconazole in 15, and posaconazole in 8 patients. Clinical isolates were frequently resistant to voriconazole, whereas the above-mentioned antifungals showed good in vitro activity. Infections of the blood and CNS caused high mortality. Overall mortality was 28.8% and death was attributed to P. variotii in 10 cases.

Conclusions

P. variotii causes life-threatening infections, especially in immunocompromised and critically ill patients with indwelling devices. Patients undergoing peritoneal dialysis are at particular risk. Multidisciplinary management is paramount, including molecular techniques for diagnosis and treatment with efficacious systemic antifungals. Amphotericin B, itraconazole and posaconazole are regarded as treatments of choice. Combination with flucytosine may be considered. Surgical debridement and removal of indwelling devices facilitate favourable outcome.

Disseminated Intravascular Infection Caused by Paecilomyces variotii: Case Report and Review of the Literature

Paecilomyces variotii is a ubiquitous environmental saprophyte with worldwide distribution. Commonly found in soil and decomposing organic material [1, 2], P. variotii can also be isolated from drinking water [3] and indoor and outdoor air [4-6]. In immunocompetent hosts, P. variotii has been reported as a cause of locally invasive disease including prosthetic valve endocarditis [7, 8], endophthalmitis [9, 10], rhinosinusitis [11, 12], and dialysis-associated peritonitis [13, 14]. In contrast, disseminated infections are more commonly reported in immunocompromised patients, including those with chronic granulomatous disease [15], solid malignancy [16], acute leukemia [17], lymphoma [18], multiple myeloma [19], and after stem cell transplant for myelodysplasia [20]. In 1 case series examining invasive infections by non-Aspergillus molds, P. variotii was the most common cause after Fusarium spp. [21]. Here, we present the case of an immunocompetent patient with extensive intravascular infection involving prosthetic material. We describe successful induction therapy with combination antifungals and extended suppression with posaconazole with clinical quiescence and eventual normalization of serum fungal biomarkers.