First Report of Ventriculoperitoneal Shunt Infection due to Cyberlindnera fabianii

A case of prosthetic joint infection due to the rare opportunist yeast, Cyberlindnera fabianii

Background and Purpose

Invasive fungal infections caused by Cyberlindnera fabianii (Cy. fabianii) have recently increased despite the low virulence potential of this yeast. However, limited information about the widely-used commercial biochemical identification systems has led to an underestimation of Cy. fabianii infections in clinical settings.

Case report

This study reports a case of prosthetic joint infection in a patient who had a previous history of total knee replacement surgery. Cy. fabianii was recovered from intraoperative culture specimens identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and confirmed using molecular assays. It was, however, initially misidentified as Candida utilis by phenotypic identification.

Conclusion

Due to the emergence of uncommon yeast species, it is important to accurately identify and perform antifungal susceptibility testing on uncommon yeast isolates for appropriate management.

Four uncommon clinical fungi, Lodderomyces elongisporus, Kodamaea ohmeri, Cyberlindnera fabianii and Wickerhamomyces anomalus, isolated in superficial samples from Côte d'Ivoire

AIMS

The rare yeast species Lodderomyces elongisporus, Kodamaea ohmeri, Cyberlindnera fabianii, and Wickerhamomyces anomalus are increasingly implicated in severe mycoses in immunocompromised patients. This study aimed to assess the prevalence of uncommon yeast species in Côte d'Ivoire.

METHODS

The yeast isolates from superficial samples, mainly vaginal swabs, were collected at the Pasteur Institute of Abidjan in a study on the molecular epidemiology of clinical yeast species. Identification relied on MALDI-TOF MS and ITS sequence analysis. Antifungal susceptibility testing was performed using the CLSI method.

RESULTS

Of the 315 strains analysed from 227 outpatients, 14 belonged to 4 uncommon species: Lodderomyces elongisporus, Kodamaea ohmeri, Cyberlindnera fabianii, and Wickerhamomyces anomalus. None exhibited elevated fluconazole, amphotericin B, caspofungin, ketoconazole, or flucytosin MIC.

CONCLUSIONS

The presence of these rare yeasts represents a risk in immunocompromised people. Their adequate and timely identification is a priority. Overall, enhancing the mycoses diagnostic capacities in Côte d'Ivoire, and more generally in African clinical laboratories with limited resources is a critical aim.

The Flo Adhesin Family

The first step in the infection of fungal pathogens in humans is the adhesion of the pathogen to host tissue cells or abiotic surfaces such as catheters and implants. One of the main players involved in this are the expressed cell wall adhesins. Here, we review the Flo adhesin family and their involvement in the adhesion of these yeasts during human infections. Firstly, we redefined the Flo adhesin family based on the domain architectures that are present in the Flo adhesins and their functions, and set up a new classification of Flo adhesins. Next, the structure, function, and adhesion mechanisms of the Flo adhesins whose structure has been solved are discussed in detail. Finally, we identified from Pfam database datamining yeasts that could express Flo adhesins and are encountered in human infections and their adhesin architectures. These yeasts are discussed in relation to their adhesion characteristics and involvement in infections.

Rates of cerebrospinal fluid infection and the causative organisms following shunt procedures in Saudi Arabia. A retrospective study based on radiological findings

Objectives:

To assess the incidence of infection following various cerebrospinal fluid (CSF) shunt procedures among patients with hydrocephalus and related conditions, based on the age of the patient, and to determine the types of pathogens responsible for shunt infections.

Methods:

This retrospective single center study reviewed the records of patients with culture-confirmed CSF shunt infection diagnosed between January 2012 and December 2017. Cases without central nervous system imaging investigations were excluded.

Results:

The incidence rate of shunt-related infections was 32.2%. Among the 189 patients whose records were included, Staphylococcus epidermidis (47.5%) and Acinetobacter baumannii (18%) were the most common causative organisms. The incidence of postoperative infection was higher among those who underwent external ventricular drain procedures (65%) than among those who underwent ventriculoperitoneal shunt procedures (24%). There were no intraoperative deaths. However, the postoperative death rate was 12.2% during hospital stay (mean duration = 9 days); 2% of these deaths occurred after shunt removal.

Conclusion:

The incidence of infections after CSF shunt procedures was high in our tertiary academic hospital during the study period, compared to those reported in similar clinical settings and before developing a detailed standardized protocol for infection control. Although gram-negative organisms were the most prevalent cause of CSF infections, S. epidermidis (a gram-positive organism) was the most commonly encountered causative agent. Shunt protocols should be implemented to address perioperative shortcomings and to reduce overall mortality and morbidity.

Unequivocal identification of an underestimated opportunistic yeast species, Cyberlindnera fabianii, and its close relatives using a dual-function PCR and literature review of published cases

Although Cyberlindnera fabinaii is a rare opportunist yeast species, its ability to cause septicemia, produce biofilm, and rapid acquisition of resistance to fluconazole and voriconazole, reinforced the urge for its identification from its closely related species. Widely used biochemical assays mainly identify Cyberlindnera fabinaii as Cyberlindnera jadinii and Wickerhamomyces anomalus, resulting in underestimation of this yeast in clinical settings. Moreover, the urge for a reliable molecular means of identification remains unsolved for 28 years. In order to unequivocally differentiate Cy. fabianii, Cy. mississipiensis, Cy. jadinii, and W. anomalus, we designed a dual-function multiplex polymerase chain reaction (PCR) assay. Challenging our dual-function multiplex PCR assay with 30 most clinically important yeast species, proved its specificity. Although conventional PCR could differentiate four target species, the real-time PCR counterpart due to Tm overlap misidentified Cy. mississipiensis as Cy. jadinii. Alongside of presenting a comprehensive literature review of published cases of Cy. fabianii from 1990 to 2018, we collected various clinical isolates from Tehran, Shiraz, and Fasa (July 1, 2017, to December 31, 2017) to find a passive relative distribution of these closely-related species in Iran. Subjecting our Iranian collection of yeast isolates to matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS and LSU and ITS rDNA sequencing revealed six isolates of Cy. fabianii (central venous catheter n = 2 and vaginal swabs n = 4) and one isolate of Cy. jadinii (vaginal swabs). Due to the use of biochemical assays in global ARTEMIS study, we encourage reidentification of clinical isolates of Cy. jadinii and Cy. jadinii using MALDI-TOF or Sanger sequencing that might lead to correcting the distribution of this fungus.

Identification and Antifungal Susceptibility Profiles of Cyberlindnera fabianii in Korea

Invasive fungal infections caused by Cyberlindnera fabianii have recently increased. However, biochemical kits such as API 20 C AUX and Vitek-2C have misidentified this species as other Candida spp. such as C. pelliculosa or C. utilis due to no information of Cy. fabianii in yeast database. During our 2016-2017 surveys, eleven isolates of Cy. fabianii were obtained in International St. Mary's Hospital in Korea. Here, we describe its morphological and molecular characteristics and tested its antifungal susceptibility against nine antifungal agents. The sequences of the ITS region and the D1/D2 region of LSU revealed 100% identity with the sequences of Cy. fabianii. In comparison with the results from MALDI-TOF mass spectrometry, we found that Cy. fabianii can be distinguished from other species. In antifungal susceptibility test, voriconazole and echinocandins exhibited good antifungal activities against the majority of Cy. fabianii isolates despite the absence of standard criteria.

Multiple organ dysfunction syndrome and death secondary to Cyberlindnera fabianii

Cyberlindnera fabianii is a yeast present in soil rarely associated with invasive infection. Due to advanced diagnostic and therapeutic techniques, pathogenicity is increasingly recognized.

A 37-year-old male with B cell lymphoma on rituximab developed multiple organ dysfunction syndrome secondary to C. fabianii bacteremia. Specialized species identification techniques were required after failure of standard methods. Despite extracroporeal membrane oxygenation (ECMO) the patient died on day 26 after admission.

First fungemia case due to environmental yeast Wickerhamomyces myanmarensis: detection by multiplex qPCR and antifungal susceptibility

AIM

Presenting the first clinical case of Wickerhamomyces myanmarensis.

PATIENTS & METHODS

Yeast cells were isolated from blood and central venous catheter of a 5.5-year-old male subject. API 20C AUX, MALDI-TOF MS, ITS and LSU rDNA sequencing, and our qPCR assay were used for identification and the MIC values were determined by CLSI M27-A3.

RESULTS

ITS and LSU rDNA sequencing identified both isolates as W. myanmarensis, while API 20C AUX and MALDI-TOF MS did not identify them correctly. Our qPCR specifically distinguished W. myanmarensis from W. anomalus. Isolate obtained from blood showed a higher MIC value for fluconazole, voriconazole and posaconazole.

CONCLUSION

Utilization of reliable identification tools might reveal the genuine spectrum of opportunistic yeast species.

Peritonitis in a neonate due to Cyberlindnera fabianii, an ascomycetic yeast

The ascomycetous yeast Cyberlindera fabianii is not only present in the environment, but is also occasionally pathogenic. Especially, neonates seem to be prone to infection. Here, we describe a case of peritoneal infection of a neonate after congenital heart surgery. The correct identification of this peculiar species is made by MALDI-TOF and especially by molecular biology methods, whereas the standard biochemical identification methods fail.The neonate with a hypoplastic left heart syndrome had a Norwood palliation followed by transient ECMO therapy for 3 days. The patient developed a renal insufficiency, so that peritoneal dialysis was initiated. After a few days, a peritoneal infection due to C. fabianii emerged. The proper source of this rare and particular yeast remains obscure. In spite of a reasonable antimycotic therapy, the patient developed a capillary leak syndrome and died finally in septic shock with multiorgan failure. One reason is probably that the yeast population, which was highly susceptible to all common antimycotic drugs at the beginning of therapy with fluconazole (and for a short period with caspofungin and liposomal amphotericin B), became rapidly resistant.