Metagenomic sequencing in the management of fungal periprosthetic joint infection

The heavy burden and treatment challenges of fungal periprosthetic joint infection: a systematic review of 489 joints

BACKGROUND

Fungal periprosthetic joint infection (FPJI) is an infrequent but devastating complication that imposes a heavy burden on patients. At present, a consensus regarding the most optimal surgical option for patients with FPJI, the ideal duration of systemic antifungal treatment, and many other issues has not been reached.

METHODS

A comprehensive literature search was performed on the PubMed and Embase databases. The search criteria employed were as follows: (fungal OR candida OR mycotic) AND periprosthetic joint infection. Initially, the titles and abstracts were screened, and subsequently, studies deemed irrelevant or duplicative were eliminated. Following this, the complete texts of remaining articles were thoroughly examined. According to the inclusion and exclusion criteria, 489 joints in 24 articles were screened out. We further extracted the demographic characteristics (age, gender, body mass index, etc.), clinical presentation, fungal species, presence of bacterial coinfection, surgical methods, systemic and local antifungal therapy, and treatment outcomes. Subgroup data were analyzed according to fungal species and bacterial coinfection. Univariate logistic regression analysis was conducted to ascertain the risk factors associated with the infection recurrence.

RESULTS

A total of 506 fungi were identified within 489 joints. The most prevalent fungal species were Candida albicans (41.5%). Out of 247 joints (50.5%) presenting with concurrent fungal and bacterial infections. Among the initial surgical interventions, two-stage exchange was the most common (59.1%). The infection recurrence rates of DAIR, resection arthroplasty, two-stage, one-stage, and three-stage exchange were 81.4%, 53.1%, 47.7%, 35.0%, and 30%, respectively. The mean duration of systemic antifungal therapy was 12.8 weeks. The most common drugs used both in intravenous (55.9%) and oral therapy (84.0%) were fluconazole. The proportion of patients who used antifungal drugs after replantation (two-stage and three-stage) was 87.6%. 33.2% of cement spacer or fixed cement contained antifungal drugs, of which amphotericin B was the main choice (82.7%). FPJI caused by candida albicans (OR = 1.717, p = 0.041) and DAIR (OR = 8.433, p = 0.003) were risk factors for infection recurrence.

CONCLUSIONS

Two-stage exchange remains the most commonly used surgical approach. The reliability of one- and three-exchange needs further evaluation due to the small sample size. Antifungal-loaded cement spacers, and direct intra-articular injections of antimycotics after reimplatation should be strongly considered. Medication is not standardized but rather individualized according to microbiology and the status of patients.

Optimization and standardization of mNGS-based procedures for the diagnosis of Mycoplasma periprosthetic joint infection: A novel diagnostic strategy for rare bacterial periprosthetic joint infection

Introduction

The diagnosis of Mycoplasma periprosthetic joint infection (PJI) is rather difficult due to its rarity and difficult in isolation, there are not standardized diagnostic procedure for Mycoplasma PJI presently. This study aimed to reported a metagenomic next-generation sequencing (mNGS)-based diagnostic strategy for Mycoplasma PJI.

Methods

In the present study, we have reported the largest number of Mycoplasma PJI that were precisely diagnosed by mNGS and verified by optimized microbial culture methods and (or) 16S PCR polymerase chain reaction (PCR).

Results

The positive rate of optimized microbial culture methods and 16S PCR in the detection of Mycoplasma PJI was 57.14% and 71.43%, respectively. The infections were well controlled by targeted treatment in all cases.

Conclusion

The standardized and optimized procedure based on mNGS presented in this study is useful for the diagnosis of Mycoplasma PJI, which might also be provided as a novel diagnostic strategy for rare bacterial PJI.

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.