Successful treatment of Cryptococcus laurentii peritonitis in a patient on peritoneal dialysis

Peritoneal Dialysis Guidelines 2019 Part 1 (Position paper of the Japanese Society for Dialysis Therapy)

Approximately 10 years have passed since the Peritoneal Dialysis Guidelines were formulated in 2009. Much evidence has been reported during the succeeding years, which were not taken into consideration in the previous guidelines, e.g., the next peritoneal dialysis PD trial of encapsulating peritoneal sclerosis (EPS) in Japan, the significance of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), the effects of icodextrin solution, new developments in peritoneal pathology, and a new international recommendation on a proposal for exit-site management. It is essential to incorporate these new developments into the new clinical practice guidelines. Meanwhile, the process of creating such guidelines has changed dramatically worldwide and differs from the process of creating what were “clinical practice guides.” For this revision, we not only conducted systematic reviews using global standard methods but also decided to adopt a two-part structure to create a reference tool, which could be used widely by the society’s members attending a variety of patients. Through a working group consensus, it was decided that Part 1 would present conventional descriptions and Part 2 would pose clinical questions (CQs) in a systematic review format. Thus, Part 1 vastly covers PD that would satisfy the requirements of the members of the Japanese Society for Dialysis Therapy (JSDT). This article is the duplicated publication from the Japanese version of the guidelines and has been reproduced with permission from the JSDT.

Papiliotrema laurentii fungemia in a premature, very low-birth-weight neonate in Kuwait successfully treated with liposomal amphotericin B

Papiliotrema laurentii (formerly Cryptococcus laurentii) and Papiliotrema albidus (formerly Cryptococcus albidus) are yeast-like environmental fungi which are largely considered as non-pathogenic to humans. However, invasive infections caused by P. laurentii have recently been reported in some patients with an impaired immune system. Here, we describe the first case of P. laurentii fungemia in a premature, very low-birth-weight neonate in Kuwait and the Middle East. Repeated bloodstream isolates were obtained and were tentatively identified as P. laurentii by Vitek 2 yeast identification system. The identification of the yeast isolates as P. laurentii was confirmed by PCR-sequencing of ribosomal DNA (rDNA). Antifungal susceptibility testing data showed that the isolates were susceptible to amphotericin B, fluconazole and voriconazole but appeared resistant to caspofungin. The baby was successfully treated with liposomal amphotericin B.

Molecular identification, genotypic heterogeneity and comparative pathogenicity of environmental isolates of Papiliotrema laurentii

Introduction. Papiliotrema laurentii, formerly Cryptococcus laurentii, is typically isolated from environmental sources, but also occasionally from clinical specimens. Other close relatives may be misidentified as P. laurentii by phenotypic methods. P. laurentii usually lacks melanin; however, melanin-forming strains have also been isolated.

Hypothesis/Gap Statement. Although melanin production by encapsulated budding yeasts is considered a major virulence factor, the comparative pathogenicity of melanin-forming and non-melanized environmental strains of P. laurentii has rarely been studied.

Aim. We performed phenotypic and molecular identification and determined the genotypic heterogeneity among P. laurentii isolates. We also studied the pathogenicity of melanin-forming and non-melanized strains in normal and immunosuppressed mice.

Methodology. Eleven environmental isolates were tested for their identity by Vitek2 and/or ID32C systems, and by PCR-sequencing of the internal transcribed spacer (ITS) region and D1/D2 domains of ribosomal DNA (rDNA). Genotypic heterogeneity was studied by sequence comparisons. The pathogenicity of melanized and non-melanized P. laurentii strains was studied in intravenously infected normal and immunosuppressed BALB/c mice.

Results. Phenotypic methods identified seven of the environmental isolates, while PCR-sequencing of the ITS region and D1/D2 domains of rDNA detected two and five isolates, respectively, as P. laurentii. Sequence comparisons demonstrated genotypic heterogeneity among P. laurentii. The remaining four environmental isolates yielded expected results. None of the normal mice infected with 105 cells of melanized/non-melanized P. laurentii strains died. Infection of immunosuppressed mice with 107 cells caused higher mortality with non-melanized P. laurentii, while viable counts in brain/lung tissue were higher in mice infected with a melanized strain and were detectable for up to 14 days.

Conclusion. Phenotypic methods lacked specificity, but PCR-sequencing of D1/D2 domains correctly identified P. laurentii and sequence comparisons demonstrated the genotypic heterogeneity of the isolates. Both melanized and non-melanized strains at a higher dose caused mortality in immunosuppressed mice and persisted in brain/lung tissue up to 14 days post-infection.

Cryptococcus Species Other Than Cryptococcus neoformans and Cryptococcus gattii: Are They Clinically Significant?

Background

Cryptococcus spp is a major cause of opportunistic infections in immunocompromised patients, primarily due to Cryptococcus neoformans and Cryptococcus gattii. There are occasional reports of other Cryptococcus species causing invasive human disease. However, their epidemiology and clinical significance are not fully defined. We sought to describe cases with cultures positive for Cryptococcus species other than C neoformans and C gattii.

Methods

A retrospective descriptive analysis of clinical and laboratory data of patients with cultures growing Cryptococcus species other than C neoformans and C gattii from November 2011 to February 2019 was performed. Three Mayo Clinic sites in Arizona, Florida, and Minnesota were included.

Results

From 176 cases with a culture growing Cryptococcus spp, 54 patients (30%) had a culture for Cryptococcus other than C neoformans and C gattii in the study time frame. The most common species were Cryptococcus magnus, Cryptococcus laurentii, and Cryptococcus ater. The organisms were isolated and identified in culture of bronchoalveolar lavage (11), skin (11), urine (7), oral (4), sinus (3), intraoperative soft tissue (3), sputum (2), synovial fluid (2), cerebrospinal fluid (2), and intravenous catheter (2), among others (7).

Only 8 (15%) cases were considered to be potentially pathogenic, with 1 case of invasive disease. Antifungal treatment was fluconazole, itraconazole, and griseofulvin, for a mean systemic antifungal duration of 42 days.

Conclusions

This large series of patients with Cryptococcus spp other than C neoformans and C gattii suggests that these species rarely cause clinically significant infection in humans. Only 1 case of invasive disease was found.

Catheter-related infection due to Papiliotrema laurentii in an oncologic patient: Case report and systematic review

Background

Papiliotrema laurentii is one of several non-neoformans cryptococci that have rarely been associated with human infection, since it was previously considered saprophyte and thought to be non-pathogenic to humans. Nevertheless, increasing number of reports of human infection have emerged in recent years, mostly in oncologic patients.

Aim

To report a case of a female patient with pyloric obstructive cancer with a catheter-related Papiliotrema laurentii blood stream infection and systematically review the available evidence on P. laurentii infection in humans.

Methods

Retrieval of studies was based on Medical Subject Headings and Health Sciences Descriptors, which were combined using Boolean operators. Searches were run on the electronic databases Scopus, Web of Science, MEDLINE (PubMed), BIREME (Biblioteca Regional de Medicina), LILACS (Latin American and Caribbean Health Sciences Literature), Cochrane Library for Systematic Reviews and Opengray.eu. There was no language or date of publication restrictions. The reference lists of the studies retrieved were searched manually.

Results

The search strategy retrieved 1703 references. In the final analysis, 31 references were included, with the description of 35 cases. Every patient but one had a previous co-morbidity - 48.4 % of patients had a neoplasm. Amphotericin B was the most used treatment and only a single case of resistance to it was reported. Most patients were cured of the infection.

Conclusion

P. laurentii infection in humans is usually associated to neoplasia and multiple co-morbidities, and amphotericin B seems to be a reliable agent for treatment.

Future Research Priorities in Fungal Resistance

Improved understanding of basic mycological, pharmacological, and immunological processes has led to important advances in the diagnosis and treatment of invasive fungal infections. However, the rise of fungi that are resistant to existing antifungal agents poses a substantial threat to human health. Addressing this expanding problem is an urgent priority for the international research community. In this article, we highlight important diagnostic and therapeutic advances that address the rise of resistant fungi as well as new public health initiatives that warrant further investigation to help curb the spread of these potentially lethal organisms.

Cryptococcosis in HIV-negative Patients with Renal Dialysis: A Retrospective Analysis of Pooled Cases

Cryptococcosis is a lethal fungal infection mainly caused by Cryptococcus neoformans/C. gattii species. Currently, our understanding of cryptococcosis episodes in HIV-negative patients during renal dialysis remains scarce and fragmented. Here, we performed an analysis of pooled cases to systemically summarize the epidemiology and clinical characteristics of cryptococcosis among HIV-negative patients with renal dialysis. Using pooled data from our hospital and studies identified in four medical databases, 18 cases were identified and analyzed. The median duration time of renal dialysis for peritoneal renal dialysis and hemodialysis cases was 8 months and 36 months, respectively. Several non-neoformans/gattii species were identified among the renal dialysis recipients with cryptococcosis, particularly Cryptococcus laurentii and Cryptococcus albidus, which share similar clinical manifestations as those caused by C. neoformans and C. gattii. Our analyses suggest that physicians should consider the possibility of the occurrence of cryptococcosis among renal dialysis recipients even when cryptococcal antigen test result is negative. The timely removal of the catheter is crucial for peritoneal dialysis patients with cryptococcosis. In addition, there is a need for optimized antifungal treatment strategy in renal dialysis recipients with cryptococcal infections.

Misidentification of a Rare Species, Cryptococcus laurentii, by Commonly Used Commercial Biochemical Methods and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Systems: Challenges for Clinical Mycology Laboratories

Forty-two putative Cryptococcus laurentii isolates identified by the Vitek 2 system were collected in China. The gold standard, internal transcribed spacer (ITS) sequencing, confirmed that only two isolates were genuine C. laurentii. Bruker Biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry was able to identify the C. laurentii isolates with an expanded custom database.