Journal de mycologie medicale最新文献

Objectives

Candida albicans generally remains the principal pathogenic yeast responsible for vulvovaginal candidiasis (VVC), although with variable prevalence. In this study, we evaluated the evolution of the prevalence of the non-Candida albicans Candida (NCAC) species and investigated the genotypic diversity and the population genetic structure of the circulating C. albicans strains associated with VVC in the vicinity of Franceville (Gabon).

Methods

A total of 110 independent isolates were identified using both MALDI-TOF MS and conventional techniques. The population genetic structure of the C. albicans strains was determined by multiple locus variable-number tandem repeat analysis using 4 microsatellite markers.

Results

The mean and median age of the patients was 31 years. Seven patients had a mixed infection. C. albicans accounted for 62 % (n=68) of the total isolates. NCAC were dominated by C. glabrata, followed by P. kudriavzevii, C. parapsilosis, C. tropicalis, M. guilliermondii, and C. nivariensis. The cluster analysis revealed a high diversity, with a total of 50 different genotypes. The most represented genotype was shared by only four strains, while the vast majority (39 strains) had a unique MLVA pattern. Geographic clusters were not detected.

Conclusion

The study provides information on species distribution and possible changing epidemiology while reporting for the first time C. nivariensis in VVC in Africa. This study is also the first to investigate the genotypic diversity of the circulating C. albicans strains associated with VVC in Central Africa. Such analyses would help understand the molecular epidemiology of C. albicans.

Introduction

Infection complications in lung cancer (LC), one of the most common cancers in the world, are still among the most important causes of death. Of them, P. jirovecii, which is as an opportunistic infection, causes a life-threatening type of pneumonia in cancer patients. This preliminary study aimed to determine the incidence and clinical status of P. jirovecii by PCR in lung cancer patients compared to the conventional method.

Material and methods

Sixty-nine lung cancer patients and fSorty healthy individuals were included in the study. After sociodemographical and clinical features were recorded, sputum samples were collected from attenders. Firstly, microscopic examination was made with Gomori's methenamine silver stain and then PCR was performed.

Results

P. jirovecii was detected in three of 69 lung cancer patients by PCR (4.3%), but not by microscopy. However, healthy individuals were negative for P. jirovecii by both methods. Based on clinical and radiological findings, P. jirovecii was evaluated as probable infection in one patient and colonization in the other two patients. Although PCR is more sensitive than conventional staining methods, it cannot distinguish probable and proven infections from pulmonary colonization.

Discussion

It is important to evaluate the decision of infection together with laboratory, clinical and radiological findings. Moreover, PCR may enable to know the colonization and to take precautions such as prophylaxis, due to the risk of colonization turning into an infection in immunocompromised patient groups. Further studies involving larger populations and evaluating the colonization-infection relationship in patients with solid tumors are needed.

Medicopsis romeroi is a rare, dematiaceous fungus that is difficult to identify using conventional fungal tests. Although uncommon, immunocompromised patients are particularly susceptible to this opportunistic fungus. Here, we report the case of a renal transplant recipient who presented with painful disseminated subcutaneous and soft tissue lesions. Sequencing of the Internal transcribed spacer (ITS) region of the ribosomal DNA identified the fungus as Medicopsis romeroi. Additionally, tissue samples from a non-healing wound on the left forearm grew Rhizopus spp. on Sabouraud dextrose agar, indicating a Mucormycosis superinfection. The patient's condition improved with surgical intervention and antifungal therapy with Posaconazole and Terbinafine. This case demonstrates the need for a high index of suspicion in order to facilitate early diagnosis and treatment and thus reduce the risk of dissemination.

We present a rare case of recalcitrant fungal keratitis caused by Coniochaeta mutabilis, successfully managed with a course of oral, topical, intrastromal, and intracameral antifungals. A 57-year-old male on their fourth week of treatment for presumed left herpes simplex keratitis presented to clinic with severe left-sided foreign body sensation after gardening in his yard. On examination, a white corneal plaque was observed at 8 o'clock, shown to be a dense collection of fungal hyphae on confocal microscopy. Corneal cultures revealed yeast-like cells, initially identified as Kabatiella zeae by matching 100% identity with K. zeae strains CBS 767.71 and CBS 265.32 in BLASTn search using the internal transcribed spacer (ITS) sequence. Treated for over four months with topical amphotericin B and oral voriconazole without improvement, recourse to intrastromal and intracameral amphotericin B injections, coupled with the application of cyanoacrylate glue to the lesion and a bandage contact lens, led to eventual resolution. The patient subsequently underwent cataract surgery, achieving a BCVA of 20/20 in the eye. Surprisingly, upon further sequence analyses of combined ITS and large subunit ribosomal ribonucleic acid (LSU) and investigation of the K. zeae German strain CBS 767.71, the organism was revealed to be Coniochaeta mutabilis (formerly Lecythospora mutabilis). This means that the correct name for CBS 767.71 and CBS 265.32 is C. mutabilis and should be corrected in the GenBank record to avoid misleading identification in the future. This case also underscores the urgent unmet need for improved molecular diagnostic modalities in the care of corneal infections

Objective

Central nervous system cryptococcosis (CNSc) is an AIDS defining opportunistic infection. This retrospective study aimed to analyze the changing epidemiology of CNSc cases from the period of pre- to post-emergence of HIV epidemic in south India.

Methods

Confirmed cases of CNSc from 1978 to 2015 were analyzed for demographic and clinical details with special reference to the cases diagnosed in south India during the period 1952–1977. Geographical distribution, affected age groups, clinical aspects, and comorbidities in relation to immune status were analysed

Results

The highest number of CNSc cases (n = 125) were recorded in 2006, with 89.6% HIV positivity. The highest HIV-positivity (93.6%) was documented in the years 2002 and 2009. CNSc cases have majorly changed after the introduction and spread of HIV in terms of predisposing factors, comorbidities, severity, affected age groups and treatment. Notably, an overall rise was observed in non-HIV associated CNSc cases from 1997 (8.1%) to 2015 (16.9%).

Conclusion

The peak of CNSc had already reached in south India during 2005–2006. However, the number of new infections has slowly decreased in last ten years. Progressive awareness and, early diagnosis of HIV and cryptococcosis, adequate availability of HAART and potential antifungal therapy has played crucial roles in changing epidemiology of the CNSc and its associated mortality.

Cryptococcus gattii (C. gattii) has been considered a leading cause of meningitis in immunocompetent hosts in tropical and subtropical regions. Visual loss is common but hearing impairment is relatively infrequent in C. gattii meningitis. Notably, there have been limited studies on the etiology, and especially therapy of auditory and ocular complications associated with C. gattii meningitis. Here we report a case of reversible deafness and blindness treated with a ventriculoperitoneal shunt (VPS) surgery in C. gattii meningitis. This case indicated that elevated intracranial pressure (ICP) may play a role in the concurrent hearing and vision impairments associated with C. gattii meningitis and the early VPS surgery after the initiation of the antifungal therapy may effectively improve both hearing and vision in this condition.

Cryptococcal meningitis (CM) is a serious disease with high morbidity and mortality. Although the patients who received corticosteroids were at high risk of having CM, corticosteroids also have been used as an adjunct to antifungal drugs for treating people with CM in some situations (such as immune reconstitution inflammatory syndrome, cerebral cyptococcoma, et al.). Here, we summarize the current knowledge on the application of the corticosteroids in CM, aiming to help clinicians to reasonably use corticosteroids in patients with CM.

Background

Infections caused by azole-resistant Aspergillus are a rising public health threat with high mortality rates, high treatment costs and limited available antifungals, indicating an urgent need for new antifungals or strategies. Our aim was to investigate antifungal and antibiofilm activities of auranofin, an FDA-approved anti-antirheumatic drug.

Methods

Fungal susceptibility testing for auranofin was carried out by the broth-based microdilution methods. Cell viability treated by auranofin was tested by resazurin dye testing. The synergistic effect of auranofin and antifungal drugs was evaluated using checkboard assay. The inhibitory of biofilms were measured by crystal violet staining. Gene expression level analysis and enzyme activity was investigated with qRT-PCR analysis and DTNB assay. The key amino acid residues in the binding of auranofin with A. fumigatus thioredoxin reductase (AfTrxR) were indicated by structural analyses, site-directed mutagenesis, and microscale thermophoresis (MST) assays.

Results

Auranofin has fungicidal activity and in vitro antifungal spectrum including Aspergillus flavus, Aspergillus fumigatus, Aspergillus terreus, Aspergillus niger, even itraconazole (ITC)-resistant A. fumigatus. Additionally, it has antibiofilm activities against ITC-resistant A. fumigatus by reducing the expression level of SomA and MedA. Moreover, we discovered a synergistic effect of auranofin and ITC or amphotericin B against ITC-resistant A. fumigatus. Auranofin downregulated the gene transcription of AfTrxR, and strongly inhibited the enzyme activity of AfTrxR through interacting with residues C145 and C148.

Conclusions

Auranofin has fungicidal and antibiofilm activities in Aspergillus spp. and is also a potentiator of ITC or amphotericin B in vitro.

Purpose

Invasive cerebral aspergillosis (ICA) is a rare but fatal infection affecting neutropenic immunocompromised patients. Recently cases have been reported in non-neutropenic settings also. We hereby present a series of ICA cases in non-neutropenic patients diagnosed at our tertiary care centre in Western India between March to October 2021.

Methods

All patients with clinico-radiological suspicion of CNS infections were analysed. Data regarding Clinico-radiological features, diagnosis, treatment and outcome were collected. After ruling out bacterial, viral and mycobacterial causes, appropriate samples were sent for KOH (potassium hydroxide) wet mount, fungal culture, histopathology and serum/CSF galactomannan.

Results

A total of four patients were diagnosed with ICA with a mean age of 43.5 years. Three patients had significant comorbidities; Diabetes mellitus, chronic liver disease and COVID-19 pneumonia treated with dexamethasone, respectively. One patient had no known predisposing factor. Radiologically, one patient presented with a frontal brain abscess and two patients had multiple subcortical hyperintensities. Three patients were diagnosed based on CSF galactomannan (Platelia™ Aspergillus antigen, Bio-Rad, France) with OD >1 and one patient had high serum galactomannan (OD >2). CSF culture grew Aspergillus species in two patients. All patients were treated with Voriconazole. One patient recovered, and the remaining three succumbed due to delayed presentation and extensive cerebral involvement.

Conclusion

Even in non-neutropenic patients, a high index of suspicion is warranted for cerebral aspergillosis. CSF galactomannan can be considered a reliable marker for diagnosing ICA in non-neutropenic settings. Early diagnosis allows timely antifungal therapy, which could be a key to improving the outcomes.

Infections by Trichosporon spp. are increasing worldwide and its treatment remains a challenge. Colonization of medical devices has been considered as a predisposing factor for trichosporonosis, which is related to fungal biofilm production. Thus, this study aimed to evaluate the ability of six hospital T. asahii isolates to form biofilm on abiotic surface, as well as to investigate the impact of three classic antifungals on both planktonic and biofilm forms. The fungal identification was based on macro and micromorphological characteristics, biochemical tests and confirmation by mass spectrometry assisted by the flight time desorption/ionization matrix (MALDI-TOF MS). Antifungal susceptibility assay of planktonic cells showed inhibitory and fungicidal concentrations ranging from 2.5 to 10 µg/mL for voriconazole, 2 to 8 µg/mL for fluconazole, and 1 to 4 µg/mL for amphotericin B. All T. asahii strains were able to form biofilms on the polystyrene microplates surface within 24 h, showing a simple architecture when compared with Candida spp. biofilm. On the other hand, the same antifungals did not show action in neither the inhibition of biofilm formation nor on the formed biofilm. Concluding, the present study reinforced the relevance of the MALDI-TOF MS methodology for a safe identification of T. asahii. Classic antifungals were active on the planktonic form, but not on the biofilms. All isolates formed biofilms on the polystyrene microplates and showed a simple architecture.