An Iris Tumor Secondary to Talaromyces Marneffei Infection in a Patient with AIDS and Syphilis

THE CLINICAL VALUE OF β-D-GLUCAN TESTING AND NEXT-GENERATION METAGENOMIC SEQUENCING FOR THE DIAGNOSIS OF FUNGAL ENDOPHTHALMITIS

PURPOSE

To explore the clinical value of β-D-glucan (BDG) testing and metagenomic next-generation sequencing (mNGS) for detecting the pathogens of fungal endophthalmitis (FE).

METHODS

This study included 32 cases (32 eyes) with FE and 20 cases (20 eyes) with intraocular inflammation caused by other etiologies. All patients underwent extraction of aqueous humor or vitreous fluid samples for BDG testing and mNGS. The diagnostic performance and total clinical concordance rate of BDG testing and mNGS for FE were evaluated and calculated based on the results of the clinical diagnosis.

RESULTS

Among the clinically diagnosed FE, the positivity rates of BDG testing and mNGS (90.63%) were both significantly higher ( P < 0.001) than that of microbial cultures (53.13%). There was 100% consistency in pathogen identification using mNGS and culture identification for culture-positive cases. The area under the curve was 0.927 for BDG testing and 0.853 for mNGS. When the two tests were combined, sensitivity (93.75%), specificity (100.00%), and total clinical concordance rate (96.15%) were all improved, compared with the single tests.

CONCLUSION

The positive rates of BDG test and mNGS were markedly higher than those of cultures in FE identification. The combination of these two tests showed improved performance when compared with individual tests.

Molecular Diagnosis of Endemic Mycoses

Diagnosis of endemic mycoses is still challenging. The moderated availability of reliable diagnostic methods, the lack of clinical suspicion out of endemic areas and the limitations of conventional techniques result in a late diagnosis that, in turn, delays the implementation of the correct antifungal therapy. In recent years, molecular methods have emerged as promising tools for the rapid diagnosis of endemic mycoses. However, the absence of a consensus among laboratories and the reduced availability of commercial tests compromises the diagnostic effectiveness of these methods. In this review, we summarize the advantages and limitations of molecular methods for the diagnosis of endemic mycoses.

Recalcitrant infectious uveoscleritis: A case report of a coinfection by Epstein-Barr virus and Talaromyces marneffei

Introduction and importance

In an immunocompromised patient, there has never been a report of Epstein-Barr virus (EBV) and Talaromyces marneffei co-infection. Treatment with intravenous ganciclovir for EBV-associated uveitis has only been explored in a few cases.

Case presentation

A 47-year-old HIV-positive female presented with scleral nodule and vascularized iris tumor in the left eye. After the ancillary laboratory workup, EBV was detected by polymerase chain reaction on aqueous humor and scleral tissue analysis. The lesion subsided completely with systemic and local ganciclovir therapy. Subsequently, recurrent scleral nodule with iris plaque developed and was pathologically diagnosed as Talaromyces marneffei. The employed treatment, including intravenous amphotericin B and intracameral amphotericin B injection, was successful in attaining a significant regression of the lesion.

Clinical discussion

Although EBV treatment is debatable, our combination of systemic and local ganciclovir therapy demonstrated regression of EBV-caused scleral nodule and iris plaque. The organism's identification was complicated by Talaromyces marneffei, but it was easily treated.

Conclusions

In HIV-infected patients, EBV-associated sclerouveitis can be successfully treated with systemic and local ganciclovir therapy, and there is a possibility of coinfection with Talaromyces marneffei.

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EBV can co-exist with Talaromyces marneffei causing severe sclerouveitis.

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EBV-associated sclerouveitis can be successfully treated with ganciclovir therapy.

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Sclerouveitis in an immunocompromised patient can be disastrous due to its progressive course and visual deterioration.

METAGENOMIC NEXT-GENERATION SEQUENCING DETECTS PATHOGENS IN ENDOPHTHALMITIS PATIENTS

PURPOSE

To investigate the utility of metagenomic next-generation sequencing (mNGS) in identifying the pathogens in endophthalmitis.

METHODS

In this prospective study, 36 cases of endophthalmitis were recruited. All patients received surgical treatment and intraocular drug lavage. The samples of vitreous or aqueous humor were extracted for mNGS and microbiological culture. The diagnostic performance of pathogens was compared between mNGS and culture.

RESULTS

The positive rates of mNGS and culture were 88.89% (32/36) and 27.78% (10/36), respectively. There was a statistically significant difference between mNGS and culture (Chi-square = 27.657; P < 0.01). Staphylococcus epidermidis, Streptococcus pneumoniae, and Klebsiella pneumoniae were the most pathogenic bacteria in traumatic, postoperative, and endogenous endophthalmitis, respectively. The concordance of pathogen identified by mNGS and culture was 70% for culture-positive cases. Antibiotic resistance genes were identified in 9 cases. There was a marginal correlation between the final visual acuity and the microbial sequence read (Spearman correlation coefficient = 0.498; P = 0.05).

CONCLUSION

Metagenomic next-generation sequencing has a higher positive rate of identifying pathogens in endophthalmitis than in culture. It can also provide information on antibiotic resistance and visual prognosis. However, caution must be taken when interpreting the results of mNGS because they may not be concordant with culture.

Rapid Genomic Diagnosis of Fungal Infections in the Age of Next-Generation Sequencing

Next-generation sequencing (NGS) technologies have recently developed beyond the research realm and started to mature into clinical applications. Here, we review the current use of NGS for laboratory diagnosis of fungal infections. Since the first reported case in 2014, >300 cases of fungal infections diagnosed by NGS were described. Pneumocystis jirovecii is the predominant fungus reported, constituting ~25% of the fungi detected. In ~12.5% of the cases, more than one fungus was detected by NGS. For P. jirovecii infections diagnosed by NGS, all 91 patients suffered from pneumonia and only 1 was HIV-positive. This is very different from the general epidemiology of P. jirovecii infections, of which HIV infection is the most important risk factor. The epidemiology of Talaromyces marneffei infection diagnosed by NGS is also different from its general epidemiology, in that only 3/11 patients were HIV-positive. The major advantage of using NGS for laboratory diagnosis is that it can pick up all pathogens, particularly when initial microbiological investigations are unfruitful. When the cost of NGS is further reduced, expertise more widely available and other obstacles overcome, NGS would be a useful tool for laboratory diagnosis of fungal infections, particularly for difficult-to-grow fungi and cases with low fungal loads.