Pichia anomala Fungal Keratitis

Fungemia With Wickerhamomyces anomalus: A Case Report and Literature Review

We report the case of an 84-year-old man with a history of IgG4-related sclerosing cholangitis who was diagnosed with advanced esophageal cancer and underwent radiation and chemotherapy. An implantable central venous access port was placed for chemotherapy and total parenteral nutrition. The patient presented with a fever and received antimicrobial therapy for acute cholangitis but remained febrile, and subsequently, yeast was detected in the aerobic bottle of blood culture obtained from the central venous line. The yeast was identified as Wickerhamomyces anomalus. Liposomal amphotericin B was administered, and the central line access port was removed. After confirmation of negative blood cultures and 14 days post treatment, he underwent reinsertion of the central line access port. Due to persistent pain at the insertion site, fluconazole was added for an additional 14 days, and the patient was discharged and transferred to another hospital. Wickerhamomyces anomalus is a rare fungal infection with other synonyms including Pichia anomala, Hansenula anomala, and Candida pelliculosa. A literature review of 53 case reports of Wickerhamomyces anomalus, Pichia anomala, Hansenula anomala, and Candida pelliculosa was conducted, with a total of 211 cases reviewed. Fungemia was reported in 94% of cases, with central venous catheterization, parental feeding, low birth weight, and immunocompromised status identified as major risk factors. The majority of cases were pediatric, particularly neonatal, and there were reports of nosocomial infections causing outbreaks, with some cases involving the eye such as endophthalmitis or keratitis.

A Repertoire of the Less Common Clinical Yeasts

Invasive fungal diseases are a public health problem. They affect a constantly increasing number of at-risk patients, and their incidence has risen in recent years. These opportunistic infections are mainly due to Candida sp. but less common or rare yeast infections should not be underestimated. These so-called "less common" yeasts include Ascomycota of the genera Candida (excluding the five major Candida species), Magnusiomyces/Saprochaete, Malassezia, and Saccharomyces, and Basidiomycota of the genera Cryptococcus (excluding the Cryptococcus neoformans/gattii complex members), Rhodotorula, and Trichosporon. The aim of this review is to (i) inventory the less common yeasts isolated in humans, (ii) provide details regarding the specific anatomical locations where they have been detected and the clinical characteristics of the resulting infections, and (iii) provide an update on yeast taxonomy. Of the total of 239,890 fungal taxa and their associated synonyms sourced from the MycoBank and NCBI Taxonomy databases, we successfully identified 192 yeasts, including 127 Ascomycota and 65 Basidiomycota. This repertoire allows us to highlight rare yeasts and their tropism for certain anatomical sites and will provide an additional tool for diagnostic management.

Wickerhamomyces Anomalus Postoperative Endophthalmitis

INTRODUCTION

We describe the case of a postoperative fungal endophthalmitis caused by Wickerhamomyces anomalus, an opportunistic yeast common in nature but rare as a causative agent in ocular infections. This would be the second reported case of W. anomalus endophthalmitis.

CASE REPORT

A patient came to our hospital with a dense hemovitreous caused by an inadvertent ocular perforation and retinal detachment during a cataract surgery. In the days following the first vitreoretinal surgery a chronic postoperative endophthalmitis was evidenced. Only after several surgeries as well as intravitreal antibiotics and sample takings, Wickerhamomyces was detected. The treatment with oral voriconazole and an intraocular lens extraction controlled the infection.

DISCUSSION

Wickerhamomyces anomalus, despite not being particularly aggressive in our case, was resistant to various consequent vitreoretinal surgeries. The unresponsiveness to treatment led us to contemplate the fungal etiology, and fortunately the cultures were positive for this yeast. In conjunction to antifungal therapy, it is possible that the IOL explantation played an important role in the treatment.

CONCLUSION

A high index of suspicion must be held in cases of fungal endophthalmitis. Both IOL explantation and oral antifungal therapy are useful treatment options in cases of W. anomalus endophthalmitis.

Investigation of the Emerging Nosocomial Wickerhamomyces anomalus Infections at a Chinese Tertiary Teaching Hospital and a Systemic Review: Clinical Manifestations, Risk Factors, Treatment, Outcomes, and Anti-fungal Susceptibility

Wickerhamomyces anomalus is an emerging pathogen, which has been associated with clonal outbreaks and poor clinical outcomes. Despite being an important emerging yeasts species, our understanding concerning the microbiological and clinical characteristics of infections due to this species is limited. Herein, we are reporting a retrospective analysis of fungemia patients with W. anomalus from a 2,100-bed hospital in Shanghai during 2014–2016. Moreover, we conducted an extensive literature review to gain a deeper clinical and microbiological insights. Detailed clinical data were recorded. Antifungal susceptibility testing (AFST) followed CLSI M27-A3, and isolates were identified using MALDI-TOF MS. In total, 13 patients were identified with a mortality rate of 38.5% (5/13). Central venous catheter (CVC), broad-spectrum antibiotic therapy, total parenteral nutrition (TPN), surgery, and mechanical ventilation were the most frequently observed risk factors. Eight patients (61.5%) experienced mixed bacterial/Candida bloodstream infections, and four patients developed mixed candidemia (MC). W. anomalus isolates showed high minimum inhibitory concentrations (MICs) against all azoles tested and flucytosine, while AMB showed the highest in vitro activity. Azoles were used for 84.6% (11/13) of the cases, while 36.4% (4/11) of them died. When combining with the AFST data and the literature review, our study highlights the poor efficacy of azoles and optimal efficacy of AMB and LAMB against infections caused by W. anomalus. In conclusion, our study highlights the emerging threat of W. anomalus affecting both neonates and adults. Furthermore, our results advocate the use of AMB formulations rather than azoles among patients infected with W. anomalus. Future studies are warranted to reach a definitive consensus regarding the utility of echinocandins among such patients.

Infectious Keratitis Caused by Rare and Emerging Micro-Organisms

PURPOSE

To provide a comprehensive review of rare and emerging micro-organisms causing infectious keratitis.

MATERIAL AND METHODS

A literature search was performed using PubMed Medline, Cochrane Library Database, EMBASE and Scopus (1960 onwards), using the terms: keratitis caused by rare pathogens; mycotic keratitis; fungal keratitis; bacterial keratitis; infectious keratitis; infective keratitis; atypical fungal keratitis; fungal keratitis caused by rare organisms; fungal keratitis caused by rare ocular pathogen; atypical bacterial keratitis; bacterial keratitis caused by rare organisms; bacterial keratitis caused by rare ocular pathogen. All relevant articles were included in this review.

RESULTS

A total of 1232 articles matched our search strategy of which 124 articles were included in this mini-review. The rare and emerging bacteria causing keratitis include atypical mycobacteria, Nocardia spp., Chrysebacterium spp., Delftia acidovorans, Kocuria spp., Enterococcus spp., Bartonella henslae, Achromobacter spp. and others. The rare and emerging fungi causing keratitis include Pythium spp., Alternaria spp., Acremonium spp., Cladosporium spp., Curvularia spp., Bipolaris spp., Microsporidia spp., Pseudallescheria spp., Colletotrichum spp., and others. The clinical presentation of these cases is variable. While a few organisms produce characteristic clinical features, rest present similar to bacterial or fungal keratitis with variable response to routine treatment. A strong degree of suspicion is therefore essential for its diagnosis. Special investigations like polymerase chain reaction, gene sequencing, mass spectroscopy and enzyme-linked immunosorbent assay are required for accurate identification of these organisms. Culture-sensitivity is extremely useful as drug resistance to routinely used anti-microbial drugs is common. Prognosis is usually poor for keratitis with Pythium spp., Pseudallescheria spp., Arthrographis spp., Purpureocillium spp., Kociria spp. and Achromobacter spp.

CONCLUSION

Keratitis caused by rare and emerging micro-organisms must be suspected in cases where the infection runs an unusual course or shows a poor response to standard anti-microbial drugs. Early diagnosis and timely treatment hold the key for a good outcome.

Uptake of clinical yeast isolates by human epithelial cell line

OBJECTIVE

The occurrence of yeast infections in humans has increased, with the species belonging to genus Candida still being the most common cause of infection. Nevertheless, infections caused by less common yeasts have been widely reported in recent years. The main objective of this study was to assess the potential of these less common saprophytic yeasts to invade the host cell, which is essential for causing systemic infections.

MATERIAL AND METHODS

Various yeast isolates were identified by DNA sequence information of PCR amplified ITS region. The purported saprophytic yeasts were characterized for internalization by mammalian cells in vitro, by staining the F-actin.

CONCLUSION

The identification of different yeast isolates from various patients revealed that 70% of the isolates belonged to the genus Candida, while remaining 30% of the isolates were yeasts not belonging to genus Candida. These non-Candida clinical isolates, either in yeast or hyphal forms, were efficiently internalized by human epithelial cells. The internalization was marked by a process of actin polymerization surrounding the invading yeast. Such uptake by epithelial cells signifies traversal of cell barrier by yeast cells during infection in vivo.

Wickerhamomyces anomalus fungal keratitis responds to topical treatment with antifungal micafungin

We describe a 91-year-old woman who suffered from fungal keratitis after corneal transplantation. The causative organism was identified as Wickerhamomyces anomalus (formerly Pichia anomala or Hansenula anomala) on the basis of morphological characteristics and the sequence of the internal transcribed spacer region of the ribosomal RNA gene. The patient was successfully treated with topical micafungin (MCFG) only. We present the first report of a case of W. anomalus fungal keratitis that responded to topical treatment with the antifungal MCFG.

Pichia anomala (Candida pelliculosa) fungemia in a patient with sickle cell disease

This case report discusses a patient with sickle cell disease who presented with fungemia from Pichia anomala (teleomorph: Candida pelliculosa). The organism was identified as P. anomala by MALDI-TOF VITEK mass spectrometry and VITEK 2 yeast identification card. Pichia anomala should be considered in sickle cell patients with recurrent fungemia.