Infections in recipients of kidney transplants

Simultaneous detection of opportunistic viral infections among renal transplant patients from Sina Hospital, Tehran

Aim: A proportion of renal transplant (RT) recipients are at high risk for acquisition of opportunistic infections. Methods: A total of 101 plasma and urine specimens were collected from RT patients with raised plasma creatinine. These were tested for three common viral pathogens under suspicion of post-transplant nephropathy. Results: A total of 19 (18.8%), 15 (14.8%) and 10 (9.9%) tested positive for BK virus, cytomegalovirus and Epstein–Barr virus in their plasma and/or urine, respectively. Out of the 19 BK virus positive patients, 12 (63%) were in the tested plasma samples and 17 (89%) were in the urine samples. Four asymptomatic patients had high levels of Epstein–Barr virus shedding in their urine. No co-infected patients showed nephropathy. Conclusion: Relying on plasma creatinine rising levels alone may be an unreliable indicator for evaluating opportunistic viral infections in post-transplant RT subjects.

An Unusual Case of Pulmonary Mucormycosis

Invasive fungal infections in solid organ transplant recipients are associated with significant morbidity and mortality. Of these fungal infections, mucormycosis presents as an aggressive, frequently fatal angioinvasive infection. Immunocompromised hosts and diabetes are important risk factors. These infections are frequently difficult to diagnose. A high index of suspicion in the appropriate setting and early, aggressive treatment with the newer antifungal agents have altered the previously grave prognosis. We present the first reported case of cavitating pulmonary mucormycosis in a renal transplant recipient caused by an unusual species of Mucorales. The patient was treated with a combination of lobectomy and antifungal treatment comprising of amphotericin B and posaconazole. He remains free of disease recurrence on monotherapy with posaconazole.

Management of Opportunistic Infections in Solid-Organ Transplantation

Solid-organ transplantation is often the last alternative in many patients with end-stage organ disease. Although advances in immunosuppressive regimens, surgical techniques, organ preservation, and overall management of transplant recipients have improved graft and patient survival, infectious complications remain problematic. Bacterial, fungal, viral, and parasitic infections are implicated after transplantation depending on numerous factors, such as degree of immunosuppression, type of organ transplant, host factors, and period after transplantation. Proper prophylactic and treatment strategies are imperative in the face of chronic immunosuppression, nosocomial and community pathogens, emerging drug resistance, drug-drug interactions, and medication toxicities. This review summarizes the pathophysiology, incidence, prevention, and treatment strategies of common post-transplant infections.

The epidemiology of fungemia in an infectious diseases hospital in Mexico city: A 10-year retrospective review

The epidemiology of invasive fungal infections has recently changed in immunosuppressed populations as a result of HIV infection, organ transplant, chemotherapy and in elderly patients. The diagnosis of invasive fungal infections by culture is prolonged since fungi grow slowly in vitro. we wanted to estimate the frequency of fungemia diagnoses established through the Clinical Mycology Laboratory over the past 10 years; through a retrospective study; data was obtained from the laboratory patient registry in the Infectious Disease Hospital's laboratory registry of patients with a systemic fungal isolate between 2005 and 2014. One hundred and thirty two (132) systemic fungal infections were identified. They were more prevalent in males, in the age group between 20 and 59 years and in patients with a diagnosis of AIDS. The most frequently isolated agents belonged to the genus Candida and others such as Histoplasma sp., Cryptococcus sp., Aspergillus sp., and Coccidioides sp. Of all blood and bone marrow cultures received 17.9% had fungal development; of these, in 70% of cases it was through blood cultures. In general, fungal agents were not diagnostically suspected. We identified that Sixty percent (60%) of fungemias developed in AIDS patients, followed by patients with sepsis. The most common agents belonged to the genus Candida, predominantly the albicans species. They were more frequently identified by blood culture than by bone marrow culture. Invasive fungal infections have not followed a usual clinical pattern and are not easily recognizable.

Fungal infections in renal transplant patients

Organ transplantation has always been considered to be the standard therapeutic interventions in patients with end-stage organ failure. In 2008, more than 29,000 organ transplants were performed in US. Survival rates among transplant recipients have greatly improved due to better understanding of transplant biology and more effective immunosuppressive agents. After transplant, the extent of the immune response is influenced by the amount of interleukin 2 (IL-2) being produced by the T-helper cells. Transplant immunosuppressive therapy primarily targets T cell-mediated graft rejection. Calcineurin inhibitor, which includes cyclosporine, pimecrolimus and tacrolimus, impairs calcineurin-induced up-regulation of IL-2 expression, resulting in increased susceptibility to invasive fungal diseases. This immunosuppressive state allows infectious complication, leading to a high mortality rate. Currently, overall mortality due to invasive fungal infections (IFIs) in solid organ transplant recipients ranges between 25% and 80%. The risk of IFI following renal transplant is associated with the dosage of immunosuppressive agents given, environmental factors and post-transplant duration. Most fungal infections occur in the first 6 months after transplant because of the use of numerous immunosuppressors. Candida spp. and Cryptococcus spp. are the yeasts most frequently isolated, while most frequent filamentous fungi (molds) isolated are Aspergillus spp. The symptoms of systemic fungal infections are non-specific and early detection of fungal infections and proper therapy are important in improving survival and reducing mortality. This article will provide an insight on the risk factors and clinical presentation, compare variation in treatment of IFIs in renal transplant patients, and evaluate the role of prophylactic therapy in this group of patients. We also report the course and management of two renal transplant recipients admitted to Staten Island University Hospital, both of whom developed pulmonary complications secondary to Aspergillus infection.

Emerging trends in infections among renal transplant recipients

Outcomes following renal and simultaneous kidney-pancreas transplants have improved significantly due to better surgical techniques and improved modalities of antirejection therapy. However, infection remains a significant cause of morbidity and mortality. The use of new modalities of immunosuppression and routine use of antimicrobial prophylaxis has changed the pattern of infections post-transplantation. Cytomegalovirus remains a significant problem and BK virus has emerged as an important pathogen. New antimicrobial agents are now available to treat infection, however, antimicrobial resistance remains a concern.

Gene therapy with adenovirus-delivered indoleamine 2,3-dioxygenase improves renal function and morphology following allogeneic kidney transplantation in rat

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme in the tryptophan catabolism, has recently emerged as an important immunosuppressive enzyme involved in the regulation of both physiologic (maternal tolerance), as well as pathologic (neoplasia, autoimmune diseases, asthma) processes. Accumulating evidence points to a role for IDO in suppressing T-cell responses, thereby promoting tolerance. In the present study, we investigate the effects of adenovirus-mediated gene therapy with IDO on the acute rejection of the transplanted kidneys.

METHODS

The experiments were performed in a rat Fisher to Lewis acute renal rejection model. RGD modified adenovirus carrying IDO gene (RGD-AdTIDO, n = 9) or RGD modified adenovirus carrying green fluorescent protein gene (RGD-AdTL, n = 8) were injected into the renal artery of the donor kidney before transplantation. A group receiving saline (n = 8) served as control. Rats were sacrificed after 7 days.

RESULTS

Successful gene delivery was confirmed with real-time polymerase chain reaction and immunohistochemistry. RGD-AdTIDO significantly decreased elevated plasma creatinine (93.7 ± 18.9 µmol/l) compared to the RGD-AdTL (248.2 ± 43.6 µmol/l) and saline (228.3 ± 46.4 µmol/l) treated rats. Moreover, RGD-AdTIDO therapy diminished the infiltration of CD8+ T cells and macrophages into the graft and reduced renal interstitial pre-fibrosis. Also, it limited the up-regulation of kidney injury molecule-1, interleukin (IL)-2, IL-17 and transforming growth factor-β mRNA expression, and increased foxp3 mRNA expression compared to controls.

CONCLUSIONS

RGD-AdTIDO therapy improves renal function and morphology in a clinically relevant model of acute rejection.

Fungal infections in transplant and oncology patients

Recent shifts in the epidemiology of invasive fungal infections (IFIs) among transplant and oncology populations have led to new recommendations on treatment; however, they have also brought new controversies. New pharmacologic therapies are being studied and guidelines for management of several IFIs have been changed accordingly. More information is being discovered about unique genetic factors that put some transplant recipients at greater risk than others for fungal infection. The role of immunomodulation continues to be investigated, and the delicate balance of maintaining some immune integrity while assuring protection of the graft remains critical. For transplant and oncology patients, the diagnosis and management of IFIs remain challenging, and improving outcomes depends on continued progress in all of these arenas. This article highlights recent advances and important factors to consider when treating transplant and oncology patients with IFIs.

Urinary tract infections in renal transplant recipients

Urinary tract infection (UTI) is the most common infectious complication after renal transplantation. Although Escherichia coli remains the most common cause of UTI, Enterococcus spp and drug-resistant Enterobacteriaceae have emerged as important uropathogens in these patients. As a result, symptomatic UTIs warrant pathogen-specific antibiotic therapy guided by culture and susceptibility data. In the early transplant period, prophylaxis of UTI with trimethoprim-sulfamethoxazole is generally effective. Until the natural history and optimal management of asymptomatic bacteruria are better defined, therapy of asymptomatic bacteruria is generally unnecessary.

Drug interactions in transplant patients: what everyone should know

PURPOSE OF REVIEW

Adverse events due to drug-drug interactions remain a challenge in the postsurgical care of transplant recipients. A combination of potent and selective immunosuppressive drugs, which have a narrow therapeutic index, with medications for the treatment of comorbidities such as dyslipidemia, infection, psychiatric conditions, and hypertension, can lead to life-threatening drug-drug interactions.

RECENT FINDINGS

There are a number of important drug-drug interactions which are important for physicians to consider. It is critical to understand the pharmacodynamics and pharmacokinetics of drug-drug interactions, their potential impact on patient care, and the management strategies.

SUMMARY

Close therapeutic drug monitoring and evaluation of drug-specific side effects continue to be an important key to minimize adverse events due to drug-drug interactions.

Postoperative infectious complications of abdominal solid organ transplantation

There is a rapidly growing population of immunocompromised organ transplant recipients. These patients are at risk of a large variety of infections that have significant consequences on mortality, graft dysfunction, and graft loss. The diagnosis and treatment of these infections are facilitated by an understanding of the preoperative, perioperative, and postoperative risk factors; the typical pathogens; and their characteristic time of presentation. On the basis of these factors, we put forth an algorithm for diagnosing and treating suspected infections in solid organ transplant recipients.

Adenovirus-mediated interleukin-13 gene therapy attenuates acute kidney allograft injury

BACKGROUND

Kidney transplantation is possible by virtue of systemic immunosuppression, which is in turn accompanied by serious side effects. The search for novel therapeutic agents and strategies is ongoing. Here we investigate the effects of adenovirus-mediated gene therapy with interleukin (IL)-13, which is a cytokine with strong immunomodulatory properties, on acute renal allograft injury. In addition, we compare the effects of local (intrarenal) and systemic (intramuscular) IL-13 gene therapy in kidney transplantation.

METHODS

The experiments were performed in a rat Fisher to Lewis acute rejection model of kidney transplantation. An adenovirus-IL-13 or adenovirus-luciferase was injected either into the donor kidney before transplantation (local treatment) or into the hind leg muscle of recipient rats (systemic treatment). A group with no treatment served as control. No additional immunosuppressive therapy was applied. The rats were sacrificed after 8 days and inflammatory markers and renal pre-fibrosis were assessed.

RESULTS

Efficient gene transfer was confirmed by ELISA, immunohistochemistry and real-time PCR. IL-13 gene therapy diminished graft infiltration with macrophages and cytotoxic T cells and limited up-regulation of mRNA levels of the adhesion molecule E-selectin and pro-inflammatory cytokines TNF-alpha and IFN-gamma. Moreover, reduced renal interstitial pre-fibrosis was found in the rats receiving IL-13 gene therapy. The effects of local and systemic therapy were similar.

CONCLUSIONS

This study demonstrates that IL-13 gene therapy in the graft significantly attenuates acute renal allograft damage, suggesting local therapy with IL-13 as a strategy to reduce the need for systemic immunosuppressive medication and thereby its side effects.

Disseminated histoplasmosis presenting as thrombotic microangiopathy

BACKGROUND

Thrombotic microangiopathies (TMA) are systemic vasoocclusive disorders associated with significant morbidity and mortality. Rapid and reliable diagnosis of TMA is critical. The diagnosis is complicated by a lack of objective and sensitive laboratory testing as well as multiple concurrent diseases, including infectious processes.

CASE STUDY

We report two cases of disseminated histoplasmosis associated with TMA manifestations in renal transplant recipients, including one patient with histologically documented renal microthrombi; both patients were referred for plasma exchange. After the diagnosis of histoplasmosis, the treatment plan was changed to antifungal medications, reduced immuno-suppression, and supportive care, with progressive resolution of TMA manifestations.

CONCLUSION

TMA occurs in transplant populations in association with infections, medications, and other factors. Appropriate management includes recognition and treatment of possible etiological factors. Disseminated histoplasmosis should be considered in transplant patients presenting with TMA.

Biological cost of fluoroquinolone resistance in Escherichia coli implicated in polyclonal infection

Polyclonal Escherichia coli strains were isolated in a transplanted patient who experienced successive septic shocks. Fluoroquinolone susceptible and resistant strains were corresponding to different PFGE fragment profiles. The gyrA S83L mutation was associated with a reduction in biological fitness. Resistant strain was selected by a long-term single use of ofloxacin.

Infectious complications in renal transplant recipients

Post-kidney transplant infection is the most common life-threatening complication of long-term immunosuppressive therapy. Optimal immunosuppression, in which a balance is maintained between prevention of rejection and avoidance of infection, is the most challenging aspect of posttransplantation care. The study of infectious complications in immunologically compromised recipients is changing rapidly, particularly in the fields of prophylactic and preemptive strategies, molecular diagnostic methods, and antimicrobial agents. In addition, emerging pathogens such as BK polyomavirus and West Nile flavivirus infections and the introduction of newer immunosuppressive agents that constantly change the risk profiles for opportunistic infections has added layers of complexity to this burgeoning field. Although remarkable progress has been made in these disciplines, comprehensive understanding of the clinical manifestations of infections remains limited, and the standardization of prophylaxis, diagnosis, and treatment of most infections is yet inadequately defined. The long-term goal for optimal care of transplant recipients, with respect to infection, is the prevention and/or early recognition and treatment of infections while avoiding drug-related toxicities.

Screening for Tuberculosis in the Study of the Living Renal Donor in a Developing Country

Given the high prevalence of tuberculosis (Tb) in the Mexican population, a strict program to detect Tb in the potential donor is required. Chest x-ray, excretory urogram, urinalysis with microscopic exam of the sediment, urine cultures for M. tuberculosis, and tuberculin skin test (TST) with PPD-RT23 performed for evaluation of 222 living donors were reviewed. Isoniazid prophylaxis before kidney donation was gathered. Donors and recipients were followed up for a minimum of 2 years. According to the TST result, 36.8% of the donors had latent tuberculosis; however, all other studies were normal or negative in all of them. Use of isoniazid prophylaxis in TST-positive donors made no difference in risk of transmission of tuberculosis to the recipient or development of tuberculosis among the donors. Normal chest x-ray and excretory urogram, along with a negative microscopic examination of the urine, safely exclude tuberculosis transmission to recipients.

Predictors and Outcomes of Candiduria in Renal Transplant Recipients

BACKGROUND

The epidemiology of candiduria in renal transplantation is unknown.

METHODS

We performed a nested case-control study to evaluate the epidemiology of candiduria in renal transplant recipients at the University of Wisconsin (Madison) over an 8-year period.

RESULTS

Renal transplantations were performed on 1738 patients during this period, 192 of whom had 276 episodes of candiduria. Candida glabrata, which was recovered from 98 (51%) of 192 case patients, was the most common pathogen identified. Most case patients were asymptomatic. Independent predictors of candiduria were female sex (odds ratio [OR], 12.5; 95% confidence interval [CI], 6.7-23.0), intensive care unit admission (OR, 8.8; 95% CI, 2.3-35.0), antibiotic use during the month before candiduria (OR, 3.8; 95% CI, 1.7-8.3), presence of an indwelling bladder catheter (OR, 4.4; 95% CI, 2.1-9.4), diabetes (OR, 2.2; 95% CI, 1.3-3.9), neurogenic bladder (OR, 7.6; 95% CI, 2.1-27), and malnutrition (OR, 2.4; 95% CI, 1.3-4.4). Log-rank testing of Kaplan-Meier curves revealed that 60-day, 90-day, and cumulative survival rates were significantly different between case and control patients; there was no difference in the survival rate during the first 30 days after transplantation. A variety of regimens were used for treatment; 119 case patients (62%) underwent removal of the indwelling bladder catheter within 1 week after diagnosis of candiduria. Candiduria cleared in 148 case patients (77%). Treatment of candiduria was not associated with an improved survival rate.

CONCLUSIONS

Candiduria occurs commonly in renal transplant recipients. Risk factors for candiduria in such persons are similar to those in hospitalized patients who have not received a transplant. Candiduria is associated with reduced survival rates among persons who have undergone renal transplantation; this is likely a marker for severity of illness. Treatment of asymptomatic candiduria in renal transplant recipients does not appear to result in improved outcome.

Tuberculous infection in southern Chinese renal transplant recipients

A retrospective study of the prevalence and pattern of tuberculosis among renal transplant patients in a single centre in southern China was performed. Twenty-three cases of tuberculosis were diagnosed among 440 patients between January 1991 and December 2002. There were 18 men and five women. The mean age of the patients was 39.3 +/- 13.4 yr. There were 13 living-related and 10 cadaveric renal transplants. The interval between renal transplantation and the development of tuberculosis ranged from 3 to 127 months with a median of 46 months. There were 18 cases of pulmonary tuberculosis, two cases of pulmonary plus laryngeal tuberculosis, two cases of disseminated tuberculosis, and one case of tuberculosis involving the urinary tract. Diagnosis was established by positive culture for Mycobacterium tuberculosis in 21 patients and response to empirical anti-tuberculosis treatment in two patients. The duration of symptoms before the diagnosis of tuberculosis was 27 +/- 12 d. The patients were treated with standard anti-tuberculosis drugs for 11 +/- 3 months. The anti-tuberculosis treatment was in general well-tolerated. Five patients developed transient hepatitis, three patients developed thrombocytopenia and five patients developed gouty arthritis. One patient died 2 months after initiation of anti-tuberculosis therapy. All other patients completed anti-tuberculosis treatment. No recurrence of tuberculosis was observed after a median follow-up of 90 months. We concluded that (i) tuberculosis is prevalent among southern Chinese renal transplant recipients; (ii) high index of suspicion for tuberculosis among renal transplant recipients is warranted to ensure early diagnosis and prompt initiation of treatment; and (iii) treatment with standard anti-tuberculosis drugs for an extended period of time is well-tolerated and is associated with favourable outcome.

Management of opportunistic infections in solid-organ transplantation

Solid-organ transplantation is often the last alternative in many patients with end-stage organ disease. Although advances in immunosuppressive regimens, surgical techniques, organ preservation, and overall management of transplant recipients have improved graft and patient survival, infectious complications remain problematic. Bacterial, fungal, viral, and parasitic infections are implicated after transplantation depending on numerous factors, such as degree of immunosuppression, type of organ transplant, host factors, and period after transplantation. Proper prophylactic and treatment strategies are imperative in the face of chronic immunosuppression, nosocomial and community pathogens, emerging drug resistance, drug-drug interactions, and medication toxicities. This review summarizes the pathophysiology, incidence, prevention, and treatment strategies of common posttransplant infections.

Immune suppression and considerations for dental care

Immunocompromised individuals present a challenge to oral health care providers. As the spectrum of patients with dysfunctional immune responses continues to broaden, practitioners should be able to identify these patients, understand the potential for complications, and manage their dental care safely and effectively. This article reviews various immune deficiencies, addresses complications that may result from an individual's immune status, and discusses dental considerations for these patients.

Results of combined and sequential liver-kidney transplantation

Experience with combined liver-kidney transplantation (L-KTx) has increased, but controversy regarding this procedure continues because the indications are not clearly defined yet. Between 1984 and 2000, 38 patients underwent simultaneous L-KTx and 9 patients underwent sequential transplantation, receiving either a liver before a kidney or a kidney before a liver. Main indications for a simultaneous procedure were polycystic liver-kidney disease with cirrhosis and coincidental renal failure. The main indications for sequential procedure were cirrhosis caused by viral infection for the liver and glomerulonephritis for the kidneys. Outcomes in these patients were evaluated retrospectively. Regarding simultaneous transplantation, 28 (73.7%) long-term survivors were followed up for 0.7 to 12.5 years. Currently, 24 (63.2%) patients are alive with good liver function. Fourteen patients died; 10 patients died in the early postoperative phase because of septic complications, and most of them were cirrhotic with a poor preoperative clinical status. Currently, 2 of the surviving patients (8%) have returned to dialysis, 4 (17%) have reduced renal function, and 18 (75%) have good renal function. Five liver and 2 kidney retransplantations were performed during the follow-up. In cases of sequential grafting, patients undergoing kidney transplantation in the presence of a previously transplanted stable liver did better than those who underwent liver transplantation after kidney transplantation. When liver transplantation was performed early and electively before substantial worsening, combined L-KTx is a safe procedure offering excellent long-term palliation.

Fungal Infections in Solid Organ Transplant Patients

BACKGROUND

Solid organ transplantation is becoming increasingly more common in the treatment of end-stage organ failure. Opportunistic fungal infections are a frequent life-threatening complication of transplantation.

MATERIALS AND METHODS

In this article, a review of the infections in the different organ transplant recipients is presented.

RESULTS

The incidence of fungal infections in organ transplant patients ranges from 2% to 50% depending on the type of organ transplanted, kidney recipients being the least frequent and liver recipients having the highest rate of infection. New antifungal medications and immunosuppressants have changed the spectrum of fungal treatment and prevention.

CONCLUSION

Prompt recognition and treatment of infection is imperative for successful therapy. Further advancements in early detection and the development of less toxic medications will lead to refinements in the treatment of fungal infections.

Molecular diagnosis of viral infections in renal transplant recipients

PURPOSE OF REVIEW

To discuss biological and methodological aspects of virus infection monitoring in the renal transplant setting.

RECENT FINDINGS

New insights on the molecular pathogenesis of acute and persistent virus infections and rapid developments in real-time monitoring techniques are changing the current diagnostic routine. Accurate risk-assessment prior to transplantation and quantitative monitoring of parameters that reflect virus activity in the post-transplant period, including genome load fluctuations and aberrant viral mRNA or protein expression, provide early signs of undesired viral behaviour and allow pre-emptive therapeutic intervention. As opposed to prophylactic administration of antiviral drugs, a pre-emptive approach is more selective and will allow for antiviral immune responses to build, which may have a long-term beneficial effect. In addition, these virus-monitoring techniques allow for on-line assessment of therapeutic efficacy and rapid identification of emerging resistant strains. The combination of virus-monitoring techniques with rapid assessment of host immune responses using FACS and ELISPOT techniques, will improve overall patient management and long-term survival.

SUMMARY

Viral infections continue to be a significant complication in the transplant setting. Diagnostic monitoring allows timely and accurate therapeutic intervention. Knowledge of pathogenic mechanisms leading to disease is important for clinical decision making as well as for the selection of appropriate molecular parameters discriminating normal and disease-related activity of human pathogenic viruses. The increasing availability of effective antiviral drugs permits pre-emptive intervention that strongly depends on accurate viral monitoring procedures.