Toxoplasmosis in heart transplant recipients

Pre-Transplant Seroprevalence, Associated Factors, and Post-Transplant Incidence of Toxoplasma gondii Infection Among Heart Transplant Recipients in Japan

BACKGROUND

Among solid organ transplant (SOT) recipients, heart transplant (HT) recipients are at a higher risk of Toxoplasma gondii infection. As Toxoplasma seroprevalence varies by geographic location, updated local epidemiology is essential to guide preventive and therapeutic strategies. However, the Toxoplasma seroprevalence and incidence of post-transplant toxoplasmosis among SOT recipients in Japan are unknown.

METHODS

We performed a single-center retrospective observational study at an HT center in Tokyo, Japan. All HT recipients aged ≥18 years between 2006 and April 2019 were included. We reviewed patient charts and conducted a questionnaire survey to investigate the risk factors for infection.

RESULTS

Among 105 recipients included in the study, 11 (10.5%) were seropositive before transplant. Ninety-five recipients (90.5%), including all pre-transplant seropositive recipients, answered the questionnaire. The recipients who had lived in Okinawa (odds ratio [OR] 7.5 [95% CI 1.42-39.61]; P = .032) and who reported raw-meat eating habits (OR 4.64 [95% CI 1.04-23.3]; P = .021) were more likely to be seropositive. None of the patients developed symptoms of toxoplasmosis. The post-transplant incidence of other major adverse outcomes was not significantly different according to the pre-transplant serostatus.

CONCLUSIONS

About 10% of HT recipients at an HT center in Tokyo were seropositive for Toxoplasma pre-transplant, and none developed symptomatic toxoplasmosis post-transplant on trimethoprim-sulfamethoxazole. The history of raw meat consumption was associated with seropositivity; therefore, avoiding it might be recommended for HT recipient candidates.

Seroepidemiology and Associated Risk Factors of Toxoplasma gondii in Hemodialysis Patients

PURPOSE

Immunocompromised patients may be at risk for reactivation of the toxoplasmosis infection, because of defection in cell-mediated immunity. Therefore, early diagnosis would be highly desirable in these individuals. This case-control study was designed to increase information about toxoplasmosis in hemodialysis (HD) patients in Guilan province, Iran.

METHODS

The study was performed among 150 patients and 150 controls referred to hospitals of Guilan University of Medical Sciences during 2018-2019. Questionnaire forms, including demographic and epidemiological information, were completed. Peripheral blood samples were taken for serum separation and were collected into tubes and then kept at - 20 °C until use. IgG and IgM antibodies to Toxoplasma gondii were detected by a commercial ELISA kit. Accordingly, IgG absorbance levels < 9 were considered negative, 9-11 was considered borderline, and > 11 was positive; IgM absorbance levels < 0.9 were considered negative, 0.9-1.1 was assumed to be borderline, and > 1.1 was positive.

RESULTS

Throughout the study, 72.0% of HD patients and 64.7% of the control group were positive for anti-Toxoplasma IgG antibody subsequently. 2% of HD patients and 0.7% of the control group were positive for anti-Toxoplasma IgM antibody and these difference weren't significant between control and ones with HD (P > 0.05). There was no significant difference between dialysis duration factor and the seropositivity rate. Seroprevalence of T. gondii infection did not vary significantly with age, educational level, residence and presence of a cat at home. On the contrary, seroprevalence varied significantly with gender and consumption of raw vegetables.

CONCLUSION

Because of the high percentage of positivity for Toxoplasma IgG antibodies in hemodialysis patients, we suggest a periodically screening program to carry out for monitoring and evaluating the possible dissemination of toxoplasmosis during hemodialysis.

Evaluating the Antiparasitic Activity of Novel BPZ Derivatives Against Toxoplasma gondii

Prevalence studies revealed that one-third of the human population is chronically infected with Toxoplasma gondii. Presently, such infections are without medical treatment that effectively eradicates the parasite once it is in its latent form. Moreover, the therapeutics used to treat acute infections are poorly tolerated by patients and also cause the parasite to convert into long-lasting tissue cysts. Hence, there is a dire need for compounds with antiparasitic activity against all forms of T. gondii. This study examines the antiparasitic capacity of nine novel bisphenol Z (BPZ) derivatives to determine whether they possessed any activity that prevented T. gondii replication. To begin assessing the efficacy of the novel derivatives, parasites were treated with increasing concentrations of the compounds, then doubling assays and MitoTracker staining were performed. Three of the nine compounds demonstrated strong inhibitory activity, i.e., parasite replication significantly decreased with higher concentrations. Additionally, many of the treated parasites exhibited decreases in fluorescent signaling and disruption of mitochondrial morphology. These findings suggest that bisphenol Z compounds disrupt mitochondrial function to inhibit parasite replication and may provide a foundation for the development of new and effective treatment modalities against T. gondii.

Toxoplasma gondii Monitoring in Liver Transplantation Patients: A Single Center Cross-Sectional Study in an Italian Hospital

Toxoplasma gondii (TG) is one of the most widespread intracellular parasites in the world, despite the slight declining trend in industrialized countries. Whilst the infection is often asymptomatic in immunocompetent hosts, in immunocompromised patients such as organ transplant recipients it can have important clinical sequels with even fatal consequences. We retrospectively reviewed 568 primary liver transplants (LT) from deceased donors from 2012 to 2017. Data were analyzed adjusting for year, gender, and age. The study objective was to assess the incidence of post-transplant TG infection and adherence to international guidelines for primary chemoprophylaxis. Prior to transplantation, 42.4% of recipients tested seronegative and 56.5% seropositive, while 36.6% of donors were seropositive and 40.4% showed undetermined serology. Anti-TG antibody titer was higher in patients born abroad (71.4%) versus Italy (54.8%). Among recipients at high risk of post-transplant TG infection, 82.7% of them received chemoprophylaxis, while in 17.3% of cases no prophylaxis was administered. At a mean (SD) follow-up of 21.2 (12.4) months no case of TG infection has been observed. Despite the low rate of adherence to recommendations, prophylaxis of high-risk LT recipients provides control of post-transplant TG infection risk. Review of current guidelines is warranted for low-risk populations.

Treatment of toxoplasmosis: Current options and future perspectives

Toxoplasmosis is a worldwide parasitic disease infecting about one third of humans, with possible severe outcomes in neonates and immunocompromised patients. Despite continuous and successful efforts to improve diagnosis, therapeutic schemes have barely evolved since many years. This article aims at reviewing the main clinical trials and current treatment practices, and at addressing future perspectives in the light of ongoing researches.

Infections in Heart, Lung, and Heart-Lung Transplantation

Half a century has passed since the first orthotopic heart transplant took place. Surgical innovations allowed for heart, lung, and heart-lung transplantation to save lives of patients with incurable chronic cardiopulmonary conditions. The complexity of the surgical interventions, chronic host health conditions, and antirejection immunosuppressive medications makes infectious complications common. Infections have remained one of the main barriers for successful transplantation and a source of significant morbidity and mortality. Recognition of infections and its management in this setting require outstanding clinical skills since transplant recipients may not exhibit classic signs or symptoms of disease, and laboratory work has some pitfalls. The prevention, identification, and management of infectious diseases complications in this population are a priority to undertake to improve the medical outcomes of transplantation. Herein, we reviewed the historical aspects, epidemiology, and prophylaxis of infections in heart, lung, and heart-lung transplantation. We also discuss the most prevalent organisms affecting the host and the organ systems involved.

Solid Organ Transplant and Parasitic Diseases: A Review of the Clinical Cases in the Last Two Decades

The aim of this study was to evaluate the occurrence of parasitic infections in solid organ transplant (SOT) recipients. We conducted a systematic review of literature records on post-transplant parasitic infections, published from 1996 to 2016 and available on PubMed database, focusing only on parasitic infections acquired after SOT. The methods and findings of the present review have been presented based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist. From data published in the literature, the real burden of parasitic infections among SOT recipients cannot really be estimated. Nevertheless, publications on the matter are on the increase, probably due to more than one reason: (i) the increasing number of patients transplanted and then treated with immunosuppressive agents; (ii) the “population shift” resulting from immigration and travels to endemic areas, and (iii) the increased attention directed to diagnosis/notification/publication of cases. Considering parasitic infections as emerging and potentially serious in their evolution, additional strategies for the prevention, careful screening and follow-up, with a high level of awareness, identification, and pre-emptive therapy are needed in transplant recipients.

Oxidative stress generated during monensin treatment contributes to altered Toxoplasma gondii mitochondrial function

The ionophore monensin displays potent activities against several coccidian parasites of veterinary and medical importance including the opportunistic pathogen of humans, Toxoplasma gondii. While monensin is used widely in animals, toxicity impedes its use in humans. Nonetheless, given its potency, understanding its mode of action would reveal vulnerable aspects of the parasite that can be exploited for drug development. We previously established that monensin induces Toxoplasma to undergo cell cycle arrest and an autophagy-like cell death. Interestingly, these effects are dependent on the mitochondrion-localized TgMSH-1 protein, suggesting that monensin disrupts mitochondrial function. We demonstrate that monensin treatment results in decreased mitochondrial membrane potential and altered morphology. These effects are mitigated by the antioxidant compound N-acetyl-cysteine suggesting that monensin causes an oxidative stress, which was indeed the case based on direct detection of reactive oxygen species. Moreover, over-expression of the antioxidant proteins glutaredoxin and peroxiredoxin 2 protect Toxoplasma from the deleterious effects of monensin. Thus, our studies show that the effects of monensin on Toxoplasma are due to a disruption of mitochondrial function caused by the induction of an oxidative stress and implicate parasite redox biology as a viable target for the development of drugs against Toxoplasma and related pathogenic parasites.

Pulmonary toxoplasmosis in immunocompromised patients with interstitial pneumonia: a single-centre prospective study assessing PCR-based diagnosis

AIMS

Pulmonary toxoplasmosis has become a very rare parasitic infection since the advent of highly active antiretroviral therapies. It is generally diagnosed by the direct microscopic observation of Toxoplasma gondii tachyzoites in bronchoalveolar lavage fluid (BALF). The aim of this study was to assess possible improvements in diagnostic performance associated with the use of real-time PCR.

METHODS

This prospective study was carried out on BALFs obtained from immunocompromised patients over a 2-year period. We systematically compared the results of conventional staining with those of molecular detection.

RESULTS

Two cases of pulmonary toxoplasmosis were diagnosed for a total of 336 samples. PCR did not detect any additional cases and was more time-consuming than conventional staining.

CONCLUSIONS

Conventional staining is a reliable technique and is probably the most appropriate method for experienced microbiology laboratories, whereas T. gondii-specific PCR may be useful for laboratories with less experience in parasitology.

TRIAL REGISTRATION NUMBER

2015_030, May 27th 2015.

Toxoplasmosis in organ transplant recipients: Evaluation, implication, and prevention

Toxoplasmosis in organ transplant patients can be a result of donor-transmitted infection, or reactivation of latent infection, or de novo infection. Solid organ transplants including heart, liver, kidney, pancreas and small bowel, and hematogenous stem cell transplants have been implicated in the risk of acquiring infection. In contrast to a benign course in immunocompetent individuals, the spectrum of illness is severe in transplant recipients. Clinical manifestations usually occur within the first 3 months of transplant and may present as encephalitis, pneumonitis, chorioretinitis, meningitis, and disseminated toxoplasmosis with multi-organ involvement. The diagnosis of toxoplasmosis in organ transplant patients is often difficult and is an integration of clinical, radiological, and microbiological workup. Preventive measures include pretransplant evaluation and chemoprophylaxis in view of rapidly progressing and fatal outcome of toxoplasmosis in immunocompromised individuals.

Serological diagnosis of Toxoplasma gondii infection: Recommendations from the French National Reference Center for Toxoplasmosis

Toxoplasmosis manifests no clinical signs in 80% of cases in immunocompetent patient, causing immunization characterized by the persistence of cysts, particularly in brain, muscles, and retina. Assessing the serological status, based on testing for serum toxoplasma IgG and IgM antibodies, is essential in cases that are increasingly at risk for the more severe disease forms, such as congenital or ocular toxoplasmosis. This disease also exposes immunosuppressed patients to reactivation, which can lead to more widespread forms and increased mortality. By interpreting the serological results, we can estimate the risk of contamination or reactivation and define appropriate prophylactic and preventive measures, such as hygienic and dietetic, therapeutic, biological, and clinical follow-up, according to the clinical context. We hereby propose practical approaches based on serological data, resulting from a consensus of a group of experts from the French National Reference Center Network for Toxoplasmosis, according to both routine and specific clinical situations.

A rare ocular complication after a heart transplant: toxoplasma retinitis

Ocular infections after a heart transplant are rare; but when present, they generally appear during the first year after surgery. Ocular infections may cause significant loss of vision and morbidity if not diagnosed early. For that reason, heart transplant patients should undergo a routine visual examination during follow-up. We report our experience regarding the followup and treatment of a case of toxoplasma retinitis diagnosed in one of our heart transplant recipients.

Toxoplasmic encephalitis during mycophenolate mofetil immunotherapy of neuromuscular disease

Objective:

To show that immunotherapy with medications such mycophenolate mofetil (MMF) can cause serious complications in patients with neuromuscular disorders.

Methods:

Two patients with neuromuscular disorders on immunotherapy with long-term MMF who developed toxoplasmic encephalitis (TE) were included in this case series.

Results:

One patient with myasthenia gravis and one patient with inflammatory myopathy on immunotherapy with long-term MMF developed severe TE. Diagnosis was based on clinical presentation, MRI brain imaging characteristics, and CSF PCR positivity for Toxoplasma gondii. Both patients were treated with pyrimethamine, sulfadiazine, and leucovorin for 2 months without clinical improvement, and both died.

Conclusions:

Immunotherapy with medications such as MMF can cause devastating TE in non-HIV patients with neuromuscular disorders. Early consideration and recognition of this complication is important to possibly prevent unfavorable outcomes. The utility of screening and prophylaxis against toxoplasmosis in individuals with neuroimmunologic disorders and other autoimmune disorders who receive immunosuppressive therapy requires future study.

Prevalence of different forms of infarct-atypical late gadolinium enhancement in patients early and late after heart transplantation

BACKGROUND

Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) enables high-resolution myocardial tissue characterization, showing the results of different injuries, especially in the early period after heart transplantation (HTX).

OBJECTIVES

We sought to apply LGE-CMR to investigate the prevalence and patterns of infarct-atypical myocardial involvement and associated mechanisms in patients early and late after HTX.

METHODS

LGE-CMR was performed on a 1.5-T MRI scanner (Philips, Best, the Netherlands) in 89 patients: group 1 (48 patients) less than 2.5 years after operation (1.2 ± 0.5 years) and group 2 (41 patients) later this period (8.2 ± 4.2 years). Following LGE-CMR, the presence, distribution, patterns of infarct-atypical LGE and possible associated mechanisms were assessed.

RESULTS

71 % of group 1 patients (34/48) showed infarctatypical LGE whereas 57 % of group 2 patients (22/41) were affected (p = 0.25). Fewer segments/patients were involved later after HTX (1.6 ± 2.0 vs. 2.9 ± 3.1 segments/ patient; p = 0.03), but only diffuse LGE-CMR pattern decreased significantly (11.5 % of affected segments in group 1 vs. 6.5 % in group 2; p\0.001). Group 2 had lower ischemic time (181 ± 53 vs. 208 ± 61 min; p = 0.03), the donors were younger (33 ± 13 vs. 41 ± 13 years; p = 0.01) and fewer donors were Toxoplasma gondii seropositive (4 vs. 22pts; p\0.001).

CONCLUSION

Infarct-atypical LGE was found in a significant number of patients early post-HTX, however, fewer patients and myocardial segments per patient were affected later after HTX. Many potential factors seem to be involved, but the exact mechanisms are still unclear. Future studies are necessary to test prognostic implications associated with LGE-CMR patterns.

Detection of Toxoplasma gondii by PCR and mouse bioassay in rodents of Ahvaz district, southwestern Iran

Toxoplasma gondii is obligate coccidian zoonotic parasite. Felidae family is definitive and wide ranges of warm-blooded vertebrates are intermediate hosts for the parasite. Rodents are measured as an important source of T. gondii infection for the definitive host. Thus, this study aimed to investigate Toxoplasm infection in rodents of Ahvaz district, southwest of Iran. A total of 100 rodents (73 Rattus norvegicus, 21 Rattus rattus, and 6 Mus musculus) were collected and studied by GRA6PCR and mouse bioassay. The finding indicated that 6 out of 100 (6%) and 2 out of 100 (2%) samples were positive by PCR and mouse bioassay, respectively. The results show notable chronic infection in the rodent and potential transmission of the infection among animal and men in the region. Accordingly, this study recommended investigating of the T. gondii infection in definitive and other intermediate hosts in other points of Khuzestan province, Southwest, Iran.

Evaluation of the Effects of Sulfamethoxazole onToxoplasma gondiiLoads and Stage Conversion in IFN-γ Knockout Mice Using QC-PCR

Toxoplasma gondii abundance with or without sulfamethoxazole treatment was evaluated by quantitative competitive polymerase chain reaction (QC-PCR) assay in various organs of IFN-gamma knockout BALB/c (B/c) mice after peroral infection with the cyst-forming Fukaya strain. T. gondii infection was observed in the brain, skin, tongue, heart, and skeletal muscle of the mice treated with sulfamethoxazole, although the parasite was not observed during the treatment in the mesenteric lymph node, spleen, small intestine or kidney. After discontinuing the therapy, T. gondii reappeared within five days in all organs. Reverse transcriptase (RT)-PCR showed that sulfamethoxazole treatment accelerated the stage conversion of T. gondii from tachyzoites into bradyzoites in the brain, lung, and heart. In contrast, after discontinuing sulfamethoxazole treatment, T. gondii underwent stage conversion from bradyzoites into tachyzoites in these organs. These results indicate that we successfully established an animal model for evaluating chemotherapy regimens in immunocompromised hosts infected with T. gondii.

Pulmonary resection for bronchial polyp after lung transplant in a cystic fibrosis patient

Many clinical conditions should be considered in the differential diagnosis of life-threatening events in cystic fibrosis patients after a lung graft transplant. We report on a 17-year-old boy who underwent a lobectomy owing to an inflammatory endobronchial polyp complicated by massive airways bleeding 12 months after having had a bilateral sequential lung graft for cystic fibrosis. This unusual complication underscores the requirement for flexible bronchoscopy in patients with recurrent infection at any stage after transplant. Early diagnosis may prevent life-threatening complications.

Parasitic infections in solid organ transplant recipients

Parasitic diseases are rare infections after a solid organ transplant (SOT). Toxoplasmosis, Trypanosoma cruzi, and visceral leishmanias are the 3 main opportunistic protozoal infections that have the potential to be lethal if not diagnosed early and treated appropriately after SOT. Strongyloides stercoralis is the one helminthic disease that is life-threatening after transplant. This review addresses modes of transmission, methods of diagnosis, and treatment of the most serious parasitic infections in SOT. The role of targeted pretransplant screening of the donor and recipient for parasitic diseases is also discussed.

Disseminated toxoplasmosis presenting as septic shock five weeks after renal transplantation

We discuss a case of acute disseminated toxoplasmosis in a renal transplant recipient presenting with septic shock. Our literature review of disseminated toxoplasmosis presenting as septic shock reveals a disease process that is rapid and almost uniformly fatal. This unusual presentation warrants a high index of suspicion in transplant recipients with immediate administration of appropriate empiric antimicrobials.

Evaluating the risk of transmission of infection from donor to recipient of a solid organ transplantation

In the context of solid organ transplantation, screening of potential organ donors is crucial, and should be performed with great rigor to minimize the risk of transmission of certain infectious processes. This review aims to update understanding of the possible pathologies involved, as well as of emerging infections that, as a result of globalization, are gaining increasing prominence on a daily basis.

Detection of toxoplasmosis in patients with end-stage renal disease by enzyme-linked immunosorbent assay and polymerase chain reaction methods

Toxoplasmosis caused by Toxoplasma gondii is an opportunistic infection. In healthy individuals, the infection is largely asymptomatic, but in immunocompromised people the parasite can become widely disseminated, causing severe toxoplasmosis. In patients undergoing haemodialysis, the phagocytic process shows a highly significant impairment. Therefore, this study aimed to investigate toxoplasmosis in patients with end-stage renal disease (ESRD) undergoing haemodialysis in Ahvaz hospitals, southwest of Iran. A total of 280 patients and 100 healthy subjects participated in this study. The presence of serum IgM and IgG antibodies against T. gondii was detected by ELISA and the presence of Toxoplasma parasites in whole blood was evaluated by GRA6 PCR. Anti-T. gondii IgG antibodies were detected in 82 (29.3 %) haemodialysis patients and 26 (26 %) controls. In addition, anti-T. gondii IgM antibodies were detected in 7.9 % of patients and in 4 % of controls. For both the antibodies, the differences were statistically significant (P < 0.05). PCR was performed with DNA extracted from blood samples of all patients and controls. PCR gave positive results with four of the 280 blood samples from patients but none for the control blood samples. The results revealed a high percentage of positivity for Toxoplasma antibodies in patients with ESRD undergoing haemodialysis and also confirmed the parasite in whole blood, indicating disseminated infection in these patients. Patients undergoing dialysis have a higher rate of active infection with Toxoplasma likely due to reactivation of a chronic infection. Thus, parasitological examinations of ESRD patients should be periodically carried out for monitoring and evaluating the possible dissemination of toxoplasmosis during haemodialysis.

Epidemiology of and diagnostic strategies for toxoplasmosis

The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient's background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.

Parasitic infections in solid-organ transplant recipients

PURPOSE OF REVIEW

To provide an updated perspective of the most common parasitic infections occurring in solid-organ transplant (SOT) recipients.

RECENT FINDINGS

Parasitic infections are an emerging problem in SOT programs and represent a diagnostic and therapeutic challenge. Transplantation in endemic areas - including medical tourism, international travel and migration - justify the necessity of considering parasitic infections in the differential diagnosis of posttransplant complications. Molecular techniques, such as PCR, may improve the diagnostic accuracy and help during the follow-up.

SUMMARY

Parasitic infections are an uncommon but potentially severe complication in SOT recipients. An increase of donors emigrated from tropical areas and more posttransplant patients traveling to endemic areas have led to a rise in parasitic infections reported among SOT recipients. Transplant physicians should get familiar with parasitic infections and promote adherence to preventive measures in SOT recipients.

Risk factors, clinical features, and outcomes of toxoplasmosis in solid-organ transplant recipients: a matched case-control study

BACKGROUND

Solid-organ transplant (SOT) recipients are considered to be at increased risk for toxoplasmosis. However, risk factors for this infection have not been assessed. The aim of this study was to determine the risk factors, clinical features, and outcomes of toxoplasmosis in SOT recipients.

METHODS

A multicenter, matched case-control study (1:2 ratio) was conducted between 2000 and 2009. Control subjects were matched for center, transplant type, and timing. Cases were identified from the hospitals' microbiology and transplantation program databases. Logistic regression was performed to identify independent risk factors.

RESULTS

Twenty-two cases (0.14%) of toxoplasmosis were identified among 15 800 SOTs performed in 11 Spanish hospitals, including 12 heart, 6 kidney, and 4 liver recipients. Diagnosis was made by seroconversion (n = 17), histopathologic examination (n = 5), polymerase chain reaction (n = 2), and autopsy (n = 2). In a comparison of case patients with 44 matched control subjects, a negative serostatus prior to transplantation was the only independent risk factor for toxoplasmosis (odds ratio, 15.12 [95% confidence interval, 2.37-96.31]; P = .004). The median time to diagnosis following transplantation was 92 days. Primary infection occurred in 18 (81.8%) cases. Manifestations included pneumonitis (n = 7), myocarditis (n = 5), brain abscesses (n = 5), chorioretinitis (n = 3), lymph node enlargement (n = 2), hepatosplenomegaly (n = 2), and meningitis (n =1). Five patients (22.7%) had disseminated disease. Crude mortality rate was 13.6% (3 of 22 patients).

CONCLUSIONS

Although uncommon, toxoplasmosis in SOT patients causes substantial morbidity and mortality. Seronegative recipients are at high risk for developing toxoplasmosis and should be given prophylaxis and receive careful follow-up.

Parasitic infections in solid organ transplant recipients

Parasitic infections are an uncommon but potentially severe complication in solid organ transplant (SOT) recipients. An increase in donors who have emigrated from tropical areas and more transplant recipients traveling to endemic areas have led to a rise in parasitic infections reported among SOT recipients. Clinicians should include these infections in their differential diagnosis and promote adherence to preventive measures in SOT recipients.

Cardiac involvement with parasitic infections

Parasitic infections previously seen only in developing tropical settings can be currently diagnosed worldwide due to travel and population migration. Some parasites may directly or indirectly affect various anatomical structures of the heart, with infections manifested as myocarditis, pericarditis, pancarditis, or pulmonary hypertension. Thus, it has become quite relevant for clinicians in developed settings to consider parasitic infections in the differential diagnosis of myocardial and pericardial disease anywhere around the globe. Chagas' disease is by far the most important parasitic infection of the heart and one that it is currently considered a global parasitic infection due to the growing migration of populations from areas where these infections are highly endemic to settings where they are not endemic. Current advances in the treatment of African trypanosomiasis offer hope to prevent not only the neurological complications but also the frequently identified cardiac manifestations of this life-threatening parasitic infection. The lack of effective vaccines, optimal chemoprophylaxis, or evidence-based pharmacological therapies to control many of the parasitic diseases of the heart, in particular Chagas' disease, makes this disease one of the most important public health challenges of our time.

Correlation of parasite load determined by quantitative PCR to clinical outcome in a heart transplant patient with disseminated toxoplasmosis

Disseminated toxoplasmosis is a life-threatening infection in transplant recipients, which results either from reactivation of latent infection or from organ-transmitted primary infection. Preventive measures and diagnostic screening methods differ between countries and are related to the seroprevalence of Toxoplasma spp. in the general population. Here we report a case of disseminated toxoplasmosis in a heart transplant recipient with previous immunity that occurred after cotrimoxazole prophylaxis for the prevention of Pneumocystis jirovecii pneumonia was stopped. Quantitative PCR proved useful for the diagnosis and monitoring of Toxoplasma infection. Decreasing parasitic burdens in sequential samples of cerebrospinal fluid, blood, and bronchoalveolar lavage fluid correlated with a favorable outcome and allowed modulation of the immunosuppressive drug regimen. The duration of anti-Toxoplasma treatment and the need for maintenance prophylaxis are discussed, as well as prophylaxis for solid-organ transplant recipients. Although a rare event in heart transplant recipients, Toxoplasma reactivation must be investigated promptly, since early treatment improves the prognosis.

False serologic evidence for acute primary toxoplasmosis during liver transplantation for fulminant hepatitis B: a case report

Acute primary Toxoplasma gondii infection is usually considered to be a contraindication for solid organ transplantation. Recent reports of acute T. gondii infection have highlighted the need to include T. gondii serology in the pretransplant screening of solid-organ transplant recipients. However such serology might be misleading. We describe the case of a 25-year-old woman who received a liver transplantation for life-threatening liver failure due to hepatitis B virus infection. The presence of high IgM titers against T. gondii, as detected by membrane immunoassay, immunofluorescence, and mu-capture ELISA tests, together with the absence of IgG antibodies in the immediate pretransplant serology screening suggested acute primary T. gondii infection at the time of transplantation. We initiated a preemptive therapy with intravenous clindamycin and cotrimoxazole. However, negative PCR and IgA capture assays, together with the absence of a sustained IgG response finally excluded the initial diagnosis of primary toxoplasmosis, leading to discontinuation of antitoxoplasmosis therapy. This case illustrates the problem that, in the context of fulminant hepatitis B, serologic markers for acute primary toxoplasmosis can be falsely positive. Confirmation by PCR and IgA antibody determinations is required to confirm this diagnosis.

Prevention of toxoplasmosis in transplant patients

Toxoplasmosis is a life-threatening opportunistic infection that affects haematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients. Its incidence in these patients is closely related to the prevalence of toxoplasmosis in the general population, which is high in Europe. In SOT recipients, toxoplasmosis results mainly from transmission of the parasite with the transplanted organ from a Toxoplasma-seropositive donor to a Toxoplasma-seronegative recipient. This risk is high in cases of transplantation of organs that are recognized sites of encystation of the parasite, e.g. the heart, and is markedly lower in other SOT recipients. Clinical symptoms usually occur within the first 3 months after transplantation, sometimes as early as 2 weeks post transplant, and involve febrile myocarditis, encephalitis or pneumonitis. In HSCT recipients, the major risk of toxoplasmosis results from the reactivation of a pre-transplant latent infection in seropositive recipients. The median point of disease onset is estimated at 2 months post transplant, with <10% of cases occurring before 30 days and 15-20% later than day 100. Toxoplasmosis usually manifests as encephalitis or pneumonitis, and frequently disseminates with multiple organ involvement. Diagnosis of toxoplasmosis is based on the demonstration of parasites or parasitic DNA in blood, bone marrow, cerebrospinal fluid, bronchoalveolar lavage fluid or biopsy specimens, and serological tests do not often contribute to the diagnosis. For prevention of toxoplasmosis, serological screening of donors and recipients before transplantation allows the identification of patients at higher risk of toxoplasmosis, i.e. seropositive HSCT recipients and mismatched (seropositive donor/seronegative recipients) SOT recipients. Preventing toxoplasmosis disease in those patients presently relies on prophylaxis via prescription of co-trimoxazole.

Cardiac manifestations of parasitic infections part 1: overview and immunopathogenesis

Parasitic infections produce a wide spectrum of cardiac manifestations. They may involve various anatomic structures of the heart and are manifested clinically as myocarditis, cardiomyopathies, pericarditis, or pulmonary hypertension in many resource-constrained settings. However, many parasitic infections involving the heart may also be currently diagnosed in developed countries due to growing worldwide travel, blood transfusions, and increasing numbers of immunosuppression states such as organ transplantation, use of immunosuppressive agents, or HIV/AIDS. Clinicians anywhere in the globe need to be aware of the potential cardiac manifestations of parasitic diseases. This is part one of a three-part series discussing parasites of the heart. In this section, we provide a general overview and immunopathogenesis of parasitic infections of the heart.

Acute infection of Toxoplasma gondii and cytomegalovirus reactivation in a pediatric patient receiving liver transplant

A 7-year-old Mexican boy with end-stage cirrhosis underwent liver transplantation and was maintained with cyclosporine and prednisolone. No specific data about Toxoplasma gondii or cytomegalovirus (CMV) infections in the cadaver donor were available. The recipient was seronegative for Toxoplasma, but CMV-IgG positive before transplantation. Ganciclovir was administered for prophylaxis during 3 months, but 5 months later he presented with icterus and increased transaminases. Acute transplant rejection was ruled out by biopsy. A seroconversion for T. gondii IgM and IgG and a small increase in CMV-IgM antibodies were observed, although the CMV-polymerase chain reaction (PCR) was negative. Ganciclovir was re-started, and the patient improved, but 6 months later he relapsed, and chorioretinitis lesions compatible both with T. gondii and CMV infections appeared. Pyrimethamine, sulfadiazine, folinic acid, and ganciclovir were administered. The boy showed favorable clinical improvement and remained stable for 12 months. Then, new retinal CMV lesions appeared in both eyes and the PCR for CMV became positive; therefore, the patient received a new regimen of ganciclovir, and clinically improved. From these data we concluded that the child presented a reactivation of CMV and a primary infection with T. gondii after transplantation.

First case of toxoplasmosis following small bowel transplantation and systematic review of tissue-invasive toxoplasmosis following noncardiac solid organ transplantation

BACKGROUND

Toxoplasmosis prophylaxis is standard following heart and heart lung transplantation, when an increased risk of allograft transmitted Toxoplasma is well-recognized. In contrast, prophylaxis and routine serologic evaluation of donors and recipients for Toxoplasma in noncardiac solid organ transplantation (SOT) is not recommended. We report the first case of disseminated toxoplasmosis following small bowel transplantation, presumably transmitted via the transplanted intestine and systematically review reported cases of toxoplasmosis in noncardiac SOT recipients to determine if current guidelines should be reconsidered.

METHODS

Systematic MEDLINE review was performed for tissue invasive toxoplasmosis in noncardiac SOT recipients and analysis of clinical features, serologic status, and treatment regimens with respect to mortality.

RESULTS

Fifty-two cases of toxoplasmosis in noncardiac SOT recipients were identified. Eighty-six percent developed disease within 90 days of transplantation. Presentation was nonspecific and consisted of fever (77%), respiratory distress (29%), neurologic manifestations (29%), and bone marrow suppression (26%). Multivariate analyses demonstrated that localized disease (odds ratio [OR]=37.36, 95% CI 1.85-754.85), treatment received (OR=1.814, 95% CI 1.193-3.480) and donor and recipient serostatus (OR=1.39, 95% CI 1.068-1.815) were predictors of survival. High-risk recipients (donor seropositive/recipient seronegative) developed disease earlier (16 days vs. 31 days P=0.002) and were less likely to survive (OR=0.14, 95% CI 0.03-0.69) than standard-risk recipients.

CONCLUSIONS

Toxoplasmosis is recognized following noncardiac SOT. Reduction of morbidity and mortality necessitates knowledge of donor and recipient Toxoplasma serostatus, prophylaxis, early diagnosis, and treatment. The findings support a reconsideration of pretransplantation evaluation and prophylaxis strategies in SOT recipients.

Suspected toxoplasma-associated myocarditis in a cat

Clinical toxoplasmosis is commonly reported in the cat, with the most consistent findings being ocular, pulmonic, hepatic, neurological, gastrointestinal and muscular abnormalities. Myocarditis, whilst frequently identified at post-mortem examination, has not been identified ante-mortem. In immunocompromised humans, myocarditis associated with toxoplasmosis is not an uncommon complication. In such cases, lymphocytic myocardial infiltration can lead to depressed myocardial function, which can be associated with congestive heart failure, rhythm disturbances and pericardial effusions. In addition, myocardial failure has been reported in immunocompetent humans associated with active toxoplasmosis [Chandenier J, Jarry G, Nassif D, Douadi Y, Paris L, Thulliez P, Bourges-Petit E, Raccurt C (2000) Congestive heart failure and myocarditis after seroconversion for toxoplasmosis in two immunocompetent patients. European Journal of Clinical Microbiological Infectious Disease 19, 375-379]. Here we describe a cat with echocardiographic changes consistent with infiltrative or inflammatory disease, and elevated IgG and IgM titres to Toxoplasma gondii. There was resolution of these myocardial changes once the toxoplasmosis was treated.

Disseminated toxoplasmosis with pulmonary involvement after heart transplantation

We report a case of pulmonary toxoplasmosis after heart transplant despite the prophylactic anti-toxoplasmic treatment that was given but was not sufficient to prevent toxoplasmosis. However, the patient survived thanks to early diagnosis confirmed by polymerase chain reaction on blood and by serological techniques, and early treatment.