Infection in Renal Transplant Recipients

Late-Onset HSV-2 Encephalitis in a Kidney Transplant Recipient: A Rare Case Report

Infections are an important cause of morbidity and mortality in renal transplant recipients. Among the viral pathogens encountered in this population, herpes simplex virus (HSV), a member of the Alphaherpesvirinae subfamily, has an important place. HSV type 2 infections in this immunosuppressed population are primarily due to viral reactivation. While HSV-2 frequently presents as genital herpes or remains asymptomatic, in rare cases, it can lead to severe neurological manifestations, such as encephalitis, particularly in the early post-transplant period with a reported mortality rate of up to 40%. We present the case of a 49-year-old male who, three years after kidney transplantation, developed acute neurological symptoms, including aphasia and disorientation. Polymerase chain reaction (PCR) analysis of cerebrospinal fluid (CSF) identified HSV-2 as the causative pathogen, enabling a swift and accurate diagnosis. The patient was promptly treated with intravenous acyclovir, adjusted for renal function, resulting in complete neurological recovery and subsequent negative follow-up CSF PCR results. This case emphasizes the vital role of PCR diagnostics as the gold standard for confirming viral encephalitis, particularly in immunosuppressed patients, where atypical presentations can complicate diagnosis. It also highlights the importance of considering HSV-2 encephalitis in the differential diagnosis even beyond the immediate post-transplant period. Early recognition and management, facilitated by the multidisciplinary approach, are critical for improving outcomes in this vulnerable patient population.

Exploring Condition-Specific Variability in the Ureteral Stent Microbiome

(1) Background: Indwelling ureteral stents are commonly used urological devices to maintain ureteral patency, yet they have been associated with complications such as infections. Some studies have shown that bacteria adhere to and create an antimicrobial-resistant biofilm on stents. One factor that may impact biofilm formation is the original condition informing stent placement, such as kidney stones and renal allografts. Both kidney stones and renal allografts are independently associated with infection, yet the differential stent microbiomes of these populations remain poorly characterized. Our objective was to characterize these microbiomes in order to inform urological health practice and help prevent ureteral stent-associated infections. (2) Methods: Stents were collected from kidney stone and renal transplant recipients undergoing routine cystoscopic stent removal. Microbial DNA was extracted from stents and analyzed using 16S Next Generation Sequencing. Descriptive statistics, alpha diversity, and beta diversity methods were used for statistical analysis. (3) Results: The microbiome of ureteral stents in kidney stone and transplant patients is composed of unique species, each with different biofilm-forming abilities. (4) Conclusions: Our findings demonstrate that the microbiome of stents differs based on preceding condition. It is important to conduct future studies that explore this microbiome further to understand what type of stent-associated infection someone may develop based on their initial condition.

Calcineurin-NFAT signaling controls neutrophils' ability of chemoattraction upon fungal infection

Calcineurin-nuclear factor of activated T cells (CN-NFAT) inhibitors are widely clinically used drugs for immunosuppression, but besides their required T cell response inhibition, they also undesirably affect innate immune cells. Disruption of innate immune cell function can explain the observed susceptibility of CN-NFAT inhibitor-treated patients to opportunistic fungal infections. Neutrophils play an essential role in innate immunity as a defense against pathogens; however, the effect of CN-NFAT inhibitors on neutrophil function was poorly described. Thus, we tested the response of human neutrophils to opportunistic fungal pathogens, namely Candida albicans and Aspergillus fumigatus, in the presence of CN-NFAT inhibitors. Here, we report that the NFAT pathway members were expressed in neutrophils and mediated part of the neutrophil response to pathogens. Upon pathogen exposure, neutrophils underwent profound transcriptomic changes with subsequent production of effector molecules. Importantly, genes and proteins involved in the regulation of the immune response and chemotaxis, including the chemokines CCL2, CCL3, and CCL4 were significantly upregulated. The presence of CN-NFAT inhibitors attenuated the expression of these chemokines and impaired the ability of neutrophils to chemoattract other immune cells. Our results amend knowledge about the impact of CN-NFAT inhibition in human neutrophils.

Targeting the epidermal growth factor receptor (EGFR/ErbB) for the potential treatment of renal pathologies

Epidermal growth factor receptor (EGFR), which is referred to as ErbB1/HER1, is the prototype of the EGFR family of receptor tyrosine kinases which also comprises ErbB2 (Neu, HER2), ErbB3 (HER3), and ErbB4 (HER4). EGFR, along with other ErbBs, is expressed in the kidney tubules and is physiologically involved in nephrogenesis and tissue repair, mainly following acute kidney injury. However, its sustained activation is linked to several kidney pathologies, including diabetic nephropathy, hypertensive nephropathy, glomerulonephritis, chronic kidney disease, and renal fibrosis. This review aims to provide a summary of the recent findings regarding the consequences of EGFR activation in several key renal pathologies. We also discuss the potential interplay between EGFR and the reno-protective angiotensin-(1-7) (Ang-(1-7), a heptapeptide member of the renin-angiotensin-aldosterone system that counter-regulates the actions of angiotensin II. Ang-(1-7)-mediated inhibition of EGFR transactivation might represent a potential mechanism of action for its renoprotection. Our review suggests that there is a significant body of evidence supporting the potential inhibition of EGFR/ErbB, and/or administration of Ang-(1-7), as potential novel therapeutic strategies in the treatment of renal pathologies. Thus, EGFR inhibitors such as Gefitinib and Erlinotib that have an acceptable safety profile and have been clinically used in cancer chemotherapy since their FDA approval in the early 2000s, might be considered for repurposing in the treatment of renal pathologies.

Brain abscess following kidney transplantation: A single centre observational study from North India

Background

Amongst the infections in kidney transplant recipients, brain abscess represents an uncommon life-threatening complication. Mortality continues to be high despite improvements in diagnostics and therapeutics.

Method

We conducted an observational study, describing the incidence, presentation, implicating pathogen, management and outcome of brain abscess following kidney transplantation at our centre.

Result

Amongst the 1492 patients who underwent kidney transplantation at our centre between June 1991 and January 2023 (cumulative follow-up: 4936 patient-years), five females and four males, developed brain abscesses. The incidence proportion (risk) is 0.6% with an incidence rate of 6.03 cases per 1000 patient years. The median duration from transplant to development of brain abscess was 5 weeks (range: 4 weeks to 9 years). The commonest presentation was a headache. A definitive microbiological diagnosis was established in eight out of nine patients. The commonest implicated organism was a dematiaceous fungus, Cladophialophora bantiana (3 patients, 33.3%). Despite the reduction in immunosuppression, surgical evacuation and optimal medical therapy, five (55.55%) patients succumbed to their illness.

Conclusions

Brain abscesses following kidney transplantation is an uncommon, life-threatening condition. It usually occurs in the early post-transplant period and the presentation is often subtle. Unlike immunocompetent individuals, a fungus is the most common causative organism in those with solid organ transplants. The management includes a reduction in immunosuppression, early antimicrobial therapy, and surgical decompression.

The Association of Organ Preservation Fluid Pathogens with Early Infection-Related Events after Kidney Transplantation

(1) Background: The need to elucidate the microbial patterns in preservation fluid and explore their relationship with early infection-related events post kidney transplant and investigate antimicrobial resistance and the effects of preemptive antibiotic therapy. (2) Methods: This retrospective study analyzed the clinical data of 514 kidney transplant donors and 808 recipients from April 2015 to October 2020. Clinical data of donor and recipient characteristics, preservation fluid microbes, early infections (≤30 days), probable donor-derived infections (P-DDIs), antimicrobial resistance and preemptive antibiotic therapy was collected. (3) Results: The incidence of bloodstream (10.3% versus 5.2%, p = 0.006) and graft-site infections (9.7% versus 4.6%, p = 0.004) was significantly higher in recipients with culture-positive preservation fluid. In addition, recipients with ESKAPE pathogens or Candida species had a notably higher rate of bloodstream infections (14.1% versus 6.9%, p = 0.033) and graft-site infections (16.7% versus 3.5%, p < 0.01) than those with other positive pathogens. Preemptive antibiotic therapy decreased the bloodstream infection rate (11.8% versus 35.7%, p = 0.047) when preservation fluid was positive for ESKAPE pathogens. (4) Conclusions: Culture-positive preservation fluid has potential implications for kidney transplant recipients. ESKAPE pathogens or Candida species in preservation fluid as well as their antimicrobial resistance properties and non-preemptive antibiotic therapy could pose a risk of early infection-related events.

The Changing Landscape of Pneumocystis Jiroveci Infection in Kidney Transplant Recipients: Single-Center Experience of Late-Onset Pneumocystis Pneumonia

BACKGROUND

Pneumocystis jiroveci pneumonia (PCP) is a life-threatening pulmonary infection after kidney transplantation (KTx). Its onset in the current era of modern immunosuppression and of routine use of universal PCP prophylaxis seems to differ from its onset in previous decades in terms of late onset with subtle clinical presentation, indicating a need for increased vigilance.

METHODS

We retrospectively studied all KTx recipients from our center who underwent bronchoscopy and bronchoalveolar lavage (BAL) between 2009 and 2018. Of these, all cases with confirmed PCP any time after the first post-KTx year were included in the analysis.

RESULTS

Among 60 patients with KTx who had undergone bronchoscopy and BAL, 12 cases with late-onset PCP were identified. PCP appeared late at a median of 10.8 (interquartile range, 2.4-15.8) years after transplantation. Patients' mean age was 59 years, and all were receiving stable low-dose immunosuppression. Most of the patients (67%) had received PCP prophylaxis after KTx. Five out of 12 patients (42%) had concomitant cytomegalovirus (CMV) reactivation at the time of PCP. In almost all cases, clinical presentation was mild. Treatment consisted of trimethoprim-sulfamethoxazole (TMP-SMX) and intravenous corticosteroid administration, and concomitant immunosuppression was temporarily reduced or withdrawn. Outcome was generally good. None of the patients developed respiratory insufficiency or required mechanical ventilation. One patient died as a result of sepsis, and 3 more with preexisting advanced chronic kidney disease subsequently lost their grafts.

CONCLUSION

Renal transplant recipients are at risk of late-onset PCP, even at a steady state of low-dose maintenance immunosuppression. Because of its subtle clinical presentation, high suspicion of the disease is warranted. Its early recognition and proper management are essential for a successful outcome.

Use of HCV-infected organs in solid organ transplantation: An ethical challenge but plausible option

Due to the unfortunate epidemic of opioid overdose deaths among people who inject drugs (PWID) in North America, there has been an increase in the availability of hepatitis C (HCV)-positive organs for transplantation and consequently the potential to decrease waiting times for solid organ transplantation if an HCV-uninfected recipient is willing to accept an HCV-positive donor. The confidence in this potential new strategy comes as a result of the advent of safe and highly effective pan-genotypic direct-acting antivirals (DAAs). This promising strategy has been the most widely studied in kidney transplantation. Liver transplantation has positive results preliminarily, but has even less available data because viable HCV-infected donor livers are typically transplanted into HCV-infected individuals. Further, while HCV-infected heart and lung transplantation, which face additional post-transplant issues, have shown encouraging results, these studies are small scale and are limited by short-term follow-up. Thus, it would be premature to implement this strategy as standard of care without large scale clinical and real-world trials and longer-term follow-up studies. Further, the ethics of this practice need to be considered. While some transplant professionals argue that more harm will be done by not utilizing HCV-infected organs, others contend that cautiously conducted multi-centre studies involving extensive post-transplant follow-up are paramount prior to endorsing widespread implementation of this strategy. The ethical permissibility of this practice hinges on whether access to DAA therapy can be secured in advance, and prospective recipients understand and accept all the risks associated with acquiring HCV.