Mycobacterium tuberculosis infection in solid-organ transplant recipients: impact and implications for management

Risk of tuberculosis after lung transplantation: the value of pretransplant chest computed tomography and the impact of mTOR inhibitors and azathioprine use

BACKGROUND

It is necessary to determine the incidence and risk factors for tuberculosis (TB), as well as strategies to assess and treat latent tuberculosis infection (LTBI) in lung transplant recipients.

METHODS

A retrospective cohort study of 398 lung transplant recipients was performed. Episodes of TB were studied and the incidence rate was calculated. Logistic regression analysis was used to analyze specific variables as potential risk factors for TB.

RESULTS

Median follow-up was 558 days (range 1-6636). Six cases (1.5%) of TB were documented in 398 transplant patients. The incidence density of TB was 406.3 cases/10(5) patient-years (95% confidence interval [CI] 164.7-845), which is higher than in the general population (13.10 cases/10(5) person-years). All cases occurred in the period 1993-2006, when the tuberculin skin test (TST) and treatment of LTBI in positive TST patients were not part of the protocol. Pretransplant computed tomography (CT) showed residual lesions in 50% of patients who developed TB, although the TST was negative and the chest radiograph was inconclusive. Multivariate analysis identified the presence of residual lesions in the pretransplant chest CT (odds ratio [OR] 11.5, 95% CI 1.9-69.1, P = 0.008), use of azathioprine (OR 10.6, 95% CI 1.1-99.1, P = 0.038), and use of everolimus (OR 6.7, 95% CI 1.1-39.8, P = 0.036) as independent risk factors for TB.

CONCLUSIONS

Residual lesions in the pretransplant chest CTs and the use of azathioprine and mTOR inhibitors are associated with the risk of TB.

Tuberculosis and chronic kidney disease: an emerging global syndemic

The link between chronic kidney disease (CKD) and tuberculosis (TB) has been known for more than 40 years, but the interaction between these 2 diseases is still poorly understood. Dialysis and renal transplant patients appear to be at a higher risk of TB, in part related to immunosuppression along with socioeconomic, demographic, and comorbid factors. Meanwhile, TB screening and diagnostic test performance is suboptimal in the CKD population, and there is limited evidence to guide protocols. Given the increasing prevalence of CKD in TB endemic areas, a merging of CKD and TB epidemics could have significant public health implications, especially in low- to middle-income countries such as India and China, that are experiencing rapid increases in CKD prevalence and account for more than one-third of global TB prevalence. To begin addressing TB-CKD, a clear understanding of the relationship between these 2 conditions needs to be established, and consistent, evidence-based screening and treatment guidelines need to be developed.

Donor-derived tuberculosis in an anesthetist after short-term exposure : An old demon transplanted from the past to the present

We report a case of a 27-year-old anesthetist who acquired tuberculosis (TB) while performing general anesthesia in a renal transplant (RTX) patient who had donor-derived contagious TB. The anesthetist developed pleural TB 6 months after exposure. Contact investigations (CIs) did not include health care workers (HCWs) of the Department of Anesthesiology, thereby missing the opportunity for the early diagnosis and treatment of TB. Genomic fingerprinting revealed identical Mycobacterium tuberculosis (MT) isolates in the anesthetist and in the RTX patient. The recipient had acquired disseminated TB from the harvested renal graft. The donor (liver and kidneys), a 67-year-old immigrant, had died from brain death by cerebral herniation after a stroke. She had been treated for tuberculosis with a pneumectomy 40 years ago. Since that time, she had been suffering from latent tuberculous infection (TBI), but had been considered to have been cured.

Rifabutin: where do we stand in 2016?

Rifabutin is a spiro-piperidyl-rifamycin structurally closely related to rifampicin that shares many of its properties. We attempted to address the reasons why this drug, which was recently recognized as a WHO Essential Medicine, still had a far narrower range of indications than rifampicin, 24 years after its launch. In this comprehensive review of the classic and more recent rifabutin experimental and clinical studies, the current state of knowledge about rifabutin is depicted, relying on specific pharmacokinetics, pharmacodynamics, antimicrobial properties, resistance data and side effects compared with rifampicin. There are consistent in vitro data and clinical studies showing that rifabutin has at least equivalent activity/efficacy and acceptable tolerance compared with rifampicin in TB and non-tuberculous mycobacterial diseases. Clinical studies have emphasized the clinical benefits of low rifabutin liver induction in patients with AIDS under PIs, in solid organ transplant patients under immunosuppressive drugs or in patients presenting intolerable side effects related to rifampicin. The contribution of rifabutin for rifampicin-resistant, but rifabutin-susceptible, Mycobacterium tuberculosis isolates according to the present breakpoints has been challenged and is now controversial. Compared with rifampicin, rifabutin's lower AUC is balanced by higher intracellular penetration and lower MIC for most pathogens. Clinical studies are lacking in non-mycobacterial infections.

CKD and Infectious Diseases in Asia Pacific: Challenges and Opportunities

The exact number of patients with chronic kidney disease (CKD) in Asia Pacific is uncertain. In numeric terms, the region is home to the largest population of patients with untreated chronic kidney failure. The climatic, geographic, social, cultural, economic, and environmental diversity within this region is higher than in any other part of the world. Large parts of the region face a climate-related burden of infectious diseases. Infections contribute to the development and progression of CKD and complicate the course of patients with pre-existing CKD (especially those on dialysis therapy or who are immunosuppressed), increase the cost of CKD care, and contribute to mortality and morbidity. Kidney involvement is a feature of several infectious diseases prevalent in Asia Pacific. Examples include malaria, leptospirosis, scrub typhus, tuberculosis, hepatitis B and C virus, dengue hemorrhagic fever, and Hantaan virus infections. The contribution of infection-associated acute kidney injury to the overall burden of CKD has not been evaluated systematically. Research is needed to quantify the impact of infections on kidney health by undertaking prospective studies. Nephrologists need to work with infectious disease research groups and government infection surveillance and control programs.

Profile of infections in renal transplant recipients from India

Background:

Infectious disorders are a major cause of concern in renal transplant recipients (RTRs) leading to considerable morbidity and mortality. We studied the profile and outcomes of infectious disorders in a cohort of RTR.

Materials and Methods:

In this prospective, observational study, we evaluated all RTR who presented with the features of infection. We also included asymptomatic patients with microbiological evidence of infection. We excluded patients with acute rejection, drug toxicity, and malignancy. Descriptive statistics were used to analyze the results.

Results:

The study population (n = 45, 35 male and 10 female) had a mean age of 35.5 ± 10.4 years and follow-up after transplant was 2.1 ± 1.7 years. Urinary tract infection (UTI, n = 15) is the most common infection followed by tuberculosis (TB, n = 8), cytomegalovirus (n = 6), candidiasis (n = 7), and hepatitis (n = 11). Miscellaneous infections such as cryptosporidiosis and pneumocystis were seen in 10 patients. Simultaneous infections with two organisms were seen in 7 patients. Four patients succumbed to multiorgan dysfunction following sepsis, another 4 patients developed chronic graft dysfunction, while the remaining 35 RTR had a good graft function.

Conclusion:

Infectious complications are very common in the posttransplant period including UTI and TB. Further large scale studies are required to identify the potential risk factors leading to infections in RTR.

Donor-Derived Infections: Incidence, Prevention, and Management

Organ donors reflect the diverse US population, and there are an increasing number of donors born in, who have resided in, or who have traveled to underdeveloped areas of the world or areas with geographically restricted infections. As such, these donors are exposed to pathogens that can potentially be transmitted to recipients of the donor’s organs. Additionally, there are newer techniques to identify many pathogens that may be transmitted from the donor to the transplant recipients. Finally, high-profile reports of several donor-derived infections have heightened awareness of donor-derived infections and have likely contributed to increased recognition. In this chapter, the incidence, methods of identification and prevention, and management of unexpected donor-derived infections will be reviewed.

Infection Prevention and Control Issues After Solid Organ Transplantation

Infections are an important cause of morbidity and mortality in solid organ transplant recipients. Consequently, infection prevention is an essential component of any organ transplant program. Given their frequent and often prolonged contact with the healthcare system, solid organ transplant recipients are at high risk for healthcare-associated infections, including those caused by antibiotic-resistant organisms. In this chapter we review several different healthcare-associated infections of importance to transplant recipients, including those caused by bacterial, viral, and fungal organisms. We also describe infection prevention and control strategies applicable to this patient population. These practices focus on clinical interventions and environmental controls designed to prevent the spread of potentially pathogenic organisms in the healthcare setting. We also describe post-exposure interventions applicable to solid organ transplant recipients exposed to potential pathogens in order to reduce their risk of subsequent infection.

High-resolution CT findings of pulmonary Mycobacterium tuberculosis infection in renal transplant recipients

OBJECTIVE

Renal transplantation recipients are at increased risk of Mycobacterium tuberculosis infection because of immunosuppression. The aim of this study was to assess high-resolution CT (HRCT) findings in renal transplantation recipients diagnosed with pulmonary tuberculosis (TB).

METHODS

We reviewed HRCT findings from patients diagnosed with pulmonary TB, established by M. tuberculosis detection in bronchoalveolar lavage, sputum or biopsy sample. Two observers independently reviewed HRCT images and reached consensus decisions on the presence and distribution of: (i) miliary nodules, (ii) cavitation and centrilobular tree-in-bud nodules, (iii) ground-glass attenuation and consolidation, (iv) mediastinal lymph node enlargement and (v) pleural effusion.

RESULTS

The sample comprised 40 patients [26 males, 14 females; median age, 45 years (range, 12-69 years)]. The main HRCT pattern was miliary nodules (40%), followed by cavitation and centrilobular tree-in-bud nodules (22.5%), ground-glass attenuation and consolidation (15%), mediastinal lymph node enlargement (12.5%) and pleural effusion (10%). The distribution of findings in patients with miliary nodules was random. In patients with cavitation and centrilobular tree-in-bud nodules, 66.6% of abnormalities were found in the upper lobes. Pleural effusion was unilateral in 75% of cases. The overall mortality rate was 27.5%. This rate was 50% in patients with miliary nodules, and 72.6% of all deaths occurred in this group. Thus, mortality was increased significantly in patients with miliary nodules (p < 0.05).

CONCLUSION

The main HRCT finding in renal transplantation recipients with pulmonary TB was miliary nodules, followed by cavitation and centrilobular tree-in-bud nodules. Miliary nodules were associated with a worse prognosis in these patients.

ADVANCES IN KNOWLEDGE

We report the first series on HRCT findings of microbiologically confirmed pulmonary TB exclusively in renal transplantation recipients. The main HRCT finding was miliary nodules, and mortality was increased significantly in these patients.

Hemodialysis in Asia

BACKGROUND

Asia is the largest, most populous and most heterogeneous continent in the world. The number of patients with end-stage renal disease is growing rapidly in Asia.

SUMMARY

A fully informed report on the status of dialysis therapies including hemodialysis (HD) is limited by the lack of systematic registries. Available data suggest remarkable heterogeneities, with some countries like Taiwan, Japan and Korea exhibiting well-established HD systems, high prevalence and universal access to all patients, while low- and low-middle income countries are unable to provide HD to eligible patients because of high cost and poor healthcare systems. Many Asian countries have unregulated dialysis units, with poor standards of delivery, quality control and outcome reporting. This leads to high mortality due to preventable complications like infections. Modeling data suggest that at least 2.9 million people need dialysis in Asia, which represents a gap in availability of dialysis to the tune of -66%. The population is projected to grow rapidly in the coming years. Several countries are expanding access to HD. Innovative modifications in dialysis practice are being made to optimize outcomes. It is important to develop robust systems of documentation and outcome reporting to evaluate the effects of such changes. HD needs to develop in conjunction with effective preventive programs and improvement of health systems.

KEY MESSAGES

The practice of HD in Asia is growing and evolving. Rapid expansion will improve the currently dismal access to care for large sections of the population. Quality issues need to be addressed if the full benefit of this therapy is to reach the population. Developed countries of Asia can provide substantial messages to developing economies. HD programs must develop in conjunction with prevention efforts.

FACTS FROM EAST AND WEST

(1) While developed Western and Asian countries provide end-stage renal disease patients full access to HD, healthcare systems from South and South-East Asia can offer access to HD only to a limited fraction of the patients in need. Even though the annual costs of HD are much lower in less developed countries (for instance 30 times lower in India compared to the US), patients often cannot afford costs not covered by health insurance. (2) The recommended dialysis pattern in the West is at least three sessions weekly with high-flux dialyzers. Studies from Shanghai and Taiwan might however indicate a benefit of twice versus thrice weekly sessions. In less developed Asian countries, a twice weekly pattern is common, sometimes with dialyzer reuse and inadequate water treatment. A majority of patients decrease session frequency or discontinue the program due to financial constraint. (3) As convective therapies are gaining popularity in Europe, penetration in Asia is low and limited by costs. (4) In Asian countries, in particular in the South and South-East, hepatitis and tuberculosis infections in HD patients are higher than in the West and substantially increase mortality. (5) Progress has recently been made in countries like Thailand and Brunei to provide universal HD access to all patients in need. Nevertheless, well-trained personnel, reliable registries and better patient follow-up would improve outcomes in low-income Asian countries.

Mycobacterial infections in solid organ transplant recipients

Mycobacterial infections represent a growing challenge for solid organ transplant recipients (SOT). The adverse effects of tuberculosis (TB) therapy present a major difficulty, due to the interactions with immunosuppressive drugs and direct drug toxicity. While TB may be donor-transmitted or community-acquired, it usually develops at a latent infection site in the recipient. Pre-transplant prevention efforts will improve transplant outcomes and avoid the complications associated with post-transplant diagnosis and treatment. The present review and consensus manuscript is based on the updated published information and expert recommendations. The current data about epidemiology, diagnosis, new regimens for the treatment of latent TB infection (LTBI), the experience with rifamycins for the treatment of active TB in the post-transplant period and the experience with isoniazid for LTBI in the liver transplant population, are also reviewed. We attempt to provide useful recommendations for each transplant period and problem concerning mycobacterial infections in SOT recipients.

Latent tuberculosis in kidney and liver transplant patients: a review of treatment practices and outcomes

BACKGROUND

The standard treatment of latent tuberculosis infection (LTBI) is associated with toxicities and data are limited on tolerability among patients with advanced organ disease listed for transplant. Alternate options are available, but they have yet to be studied in this population.

METHODS

A retrospective review of the treatment of LTBI among kidney and/or liver transplant candidates was conducted to assess factors impacting therapy initiation, tolerability, and completion of therapy.

RESULTS

Of 174 eligible patients, treatment of LTBI was initiated in 129, of which 91 were listed for kidney transplant and 38 were listed for liver or liver/kidney transplant. Infectious Diseases consultation was independently associated with treatment initiation when controlling for waitlisted organ and receipt of hemodialysis (odds ratio [OR] 81.14, 95% confidence interval [CI] 23.94-274.94, P < 0.001). Documented completion of first-line therapy was 47% overall, and 49% and 39%, respectively, among kidney and liver/kidney candidates (P = not significant). On multivariable analysis, controlling for baseline aspartate aminotransferase and waitlisted organ, first-line receipt of rifampin was associated with lower rates of treatment completion (OR 0.19, 95% CI 0.05-0.77, P = 0.02).

CONCLUSION

Based on medical record documentation, completion of first-line therapy was <50% in this cohort, although this is likely an underestimate, as 34% of patients had no chart documentation that therapy was completed. Approximately 20% of patients did not complete first-line therapy because of adverse effects.

Risk factors for hepatotoxicity in solid organ transplants recipients being treated for tuberculosis

BACKGROUND

Tuberculosis (TB) is associated with high morbidity and mortality in solid organ transplant (SOT) recipients. Also, SOT patients have a 20- to 74-fold increase in the chance of developing TB compared to the general population. Here we evaluated the incidence of hepatotoxicity in SOT recipients on treatment for TB and determined risk factors for liver toxicity in these patients.

PATIENTS AND METHODS

Retrospective cohort conducted in a reference hospital for SOT in Southern Brazil. All SOT recipients who underwent TB treatment during the years 2000-2012 were considered for the study.

RESULTS

A total of 69 patients were included in the study and 23 had liver toxicity (incidence 33.3%). Independent risk factors for hepatotoxicity were rifampin use at doses of ≥600 mg daily (P = .016; OR 2.47; 95% CI, 1.18-5.15) and lung transplantation (P = .017; OR 2.05; 95% CI, 1.14-3.70). Kidney transplantation appeared as a protective factor (P = .036; OR 0.50; 95% CI, 0.26-0.96). Mortality was higher in the patients who had hepatotoxicity (43.5%), compared with those who did not (19.6%).

CONCLUSION

In this study, the use of rifampin at doses of 600 mg daily or higher was found to be an independent risk factor for liver toxicity in SOT recipients. The importance of additional risk factors for hepatotoxicity, such as lung transplantation as well as the protective role of kidney transplantation, should be better investigated in SOT recipients being treated for TB.

An Approach to a Pulmonary Infiltrate in Solid Organ Transplant Recipients

The onset of a pulmonary infiltrate in a solid organ transplant (SOT) recipient is both a challenging diagnostic and therapeutic challenge. We outline the potential aetiologies of a pulmonary infiltrate in a SOT recipient, with particular attention paid to fungal pathogens. A diagnostic and empirical therapy approach to a pulmonary infiltrate, especially invasive fungal disease (IFD) in SOT recipients, is provided.

Clinical features and outcomes of tuberculosis in transplant recipients as compared with the general population: a retrospective matched cohort study

There are no previous studies comparing tuberculosis in transplant recipients (TRs) with other hosts. We compared the characteristics and outcomes of tuberculosis in TRs and patients from the general population. Twenty-two TRs who developed tuberculosis from 1996 through 2010 at a tertiary hospital were included. Each TR was matched by age, gender and year of diagnosis with four controls selected from among non-TR non-human immunodeficiency virus patients with tuberculosis. TRs (21 patients, 96%) had more factors predisposing to tuberculosis than non-TRs (33, 38%) (p <0.001). Pulmonary tuberculosis was more common in non-TRs (77 (88%) vs. 12 TRs (55%); p 0.001); disseminated tuberculosis was more frequent in TRs (five (23%) vs. four non-TRs (5%); p 0.005). Time from clinical suspicion of tuberculosis to definitive diagnosis was longer in TRs (median of 14 days) than in non-TRs (median of 0 days) (p <0.001), and invasive procedures were more often required (12 (55%) TRs and 15 (17%) non-TRs, respectively; p 0.001). Tuberculosis was diagnosed post-mortem in three TRs (14%) and in no non-TRs (p <0.001). Rates of toxicity associated with antituberculous therapy were 38% in TRs (six patients) and 10% (seven patients) in non-TRs (p 0.014). Tuberculosis-related mortality rates in TRs and non-TRs were 18% and 6%, respectively (p 0.057). The adjusted Cox regression analysis showed that the only predictor of tuberculosis-related mortality was a higher number of organs with tuberculosis involvement (adjusted hazard ratio 8.6; 95% CI 1.2-63). In conclusion, manifestations of tuberculosis in TRs differ from those in normal hosts. Post-transplant tuberculosis resists timely diagnosis, and is associated with a higher risk of death before a diagnosis can be made.

Coexistence of Spinal Intramedullary Tuberculoma and Multiple Intracranial Tuberculomas

Spinal intramedullary tuberculoma remains a very rare entity of central nervous system tuberculosis. This is the same with the coexistence of spinal intramedullary and intracranial tuberculomas that remains extremely rare with less than 20 cases reported at present. Authors describe this uncommon case by analyzing a 65-year-old female patient who had past history of kidney transplantation due to stage 5 chronic kidney disease and pulmonary tuberculosis on medication. The patient experiences progressive paraplegia and numbness on both lower extremities. Magnetic resonance imaging demonstrated an intramedullary mass at T9-10 level and multiple intracranial enhancing nodules. Microsurgical resection of spinal intramedullary mass was performed and the lesion was histopathologically confirmed as Mycobacterium tuberculosis. Efficient diagnosis and management of this rare disease are reviewed along with previously reported cases.

Diagnosis and Management of Latent Tuberculosis Infection

The post-2015 World Health Organization global tuberculosis strategy recognizes that elimination requires a focus on reducing the pool of latently infected individuals, an estimated 30% of the global population, from which future tuberculosis cases would be generated. Tackling latent tuberculosis infection requires the identification and treatment of asymptomatic individuals to reduce the risk of progression to active disease. Diagnosis of latent tuberculosis infection is based on the detection of an immune response to Mycobacterium tuberculosis antigens using either the tuberculin skin test or interferon-γ release assays. Current treatment requires the use of antibiotics for at least 3 months. In this article, we review the current knowledge of the natural history, immunology, and pathogenesis of latent tuberculosis, describe key population groups for screening and risk assessment, discuss clinical management in terms of diagnosis and preventative treatment, and identify areas for future research.

Transplantation in the tropics: lessons on prevention and management of tropical infectious diseases

Tropical infectious diseases (IDs) remain a rare complication in transplant recipients even in tropical settings, but this topic has become increasingly important during the last decade due to multiple factors. Interestingly, non-tropical countries report most of the experiences with tropical diseases. The reported experience from non-endemic regions, however, does not always reflect the experience of endemic areas. Most of the guidelines and recommendations in the literature may not be applicable in tropical settings due to logistical difficulties, cost, and lack of proven benefit. In addition, certain post-transplant prevention measures, as prophylaxis and reducing exposure risk, are not feasible. Nonetheless, risk assessment and post-transplant management of tropical IDs in tropical areas should not be neglected, and clinicians need to have a higher clinical awareness for tropical ID occurring in this population. Herein, we review the more significant tropical ID in transplant patients, focusing on relevant experience reported by tropical settings.

Immunodiagnostic Tests' Predictive Values for Progression to Tuberculosis in Transplant Recipients: A Prospective Cohort Study

BACKGROUND

Little is known about the predictive value for progression to tuberculosis (TB) of interferon-γ release assays and how they compare with the tuberculin skin test (TST) in assessing the risk of TB infection in transplant recipients.

METHODS

We screened 50 liver transplant (LT) and 26 hematopoietic stem cell transplant (HSCT) recipients with both QuantiFERON-TB Gold In-tube (QFT-GT) and TST and prospectively followed them for a median of 47 months without preventive chemoprophylaxis.

RESULTS

In the LT cohort, 1 in 22 (4.5%) QFT-GT-positive patients developed posttransplant TB, compared with none of the QFT-GT-negative patients. In the HSCT cohort, none of the 7 QFT-GT-positive patients developed TB, whereas 1 case (5.3%) progressed to active TB among the 19 QFT-GT-negative patients. Comparable results were obtained with the TST: in the LT group, 1 of 23 TST-positive and none of the 27 TST-negative patients developed TB; and in the HSCT group, none of the 8 TST-positive and one of the 18 TST-negative patients progressed to active TB.

CONCLUSIONS

In this cohort of transplant recipients, the positive predictive value of QFT-GT for progression to active TB was low and comparable to that of TST. Although the risk of developing TB in patients with negative results at baseline is very low, some cases may still occur.

Lung transplantation for cystic fibrosis: results, indications, complications, and controversies

Survival in patients with cystic fibrosis (CF) has improved dramatically over the past 30 to 40 years, with mean survival now approximately 40 years. Nonetheless, progressive respiratory insufficiency remains the major cause of mortality in CF patients, and lung transplantation (LT) is eventually required. Timing of listing for LT is critical, because up to 25 to 41% of CF patients have died while awaiting LT. Globally, approximately 16.4% of lung transplants are performed in adults with CF. Survival rates for LT recipients with CF are superior to other indications, yet LT is associated with substantial morbidity and mortality (∼50% at 5-year survival rates). Myriad complications of LT include allograft failure (acute or chronic), opportunistic infections, and complications of chronic immunosuppressive medications (including malignancy). Determining which patients are candidates for LT is difficult, and survival benefit remains uncertain. In this review, we discuss when LT should be considered, criteria for identifying candidates, contraindications to LT, results post-LT, and specific complications that may be associated with LT. Infectious complications that may complicate CF (particularly Burkholderia cepacia spp., opportunistic fungi, and nontuberculous mycobacteria) are discussed.

Invasive Pulmonary Aspergillosis-mimicking Tuberculosis

BACKGROUND

Pulmonary tuberculosis is occasionally confused with invasive pulmonary aspergillosis (IPA) in transplant recipients, since clinical suspicion and early diagnosis of pulmonary tuberculosis and IPA rely heavily on imaging modes such as computed tomography (CT). We therefore investigated IPA-mimicking tuberculosis in transplant recipients.

METHODS

All adult transplant recipients who developed tuberculosis or IPA at a tertiary hospital in an intermediate tuberculosis-burden country during a 6-year period were enrolled. First, we tested whether experienced radiologists could differentiate pulmonary tuberculosis from IPA. Second, we determined which radiologic findings could help us differentiate them.

RESULTS

During the study period, 28 transplant recipients developed pulmonary tuberculosis after transplantation, and 80 patients developed IPA after transplantation. Two experienced radiologists scored blindly 28 tuberculosis and 50 randomly selected IPA cases. The sensitivities of radiologists A and B for IPA were 78% and 68%, respectively (poor agreement, kappa value = 0.25). The sensitivities of radiologists A and B for tuberculosis were 64% and 61%, respectively (excellent agreement, kappa value = 0.77). We then compared the CT findings of the 28 patients with tuberculosis and 80 patients with IPA. Infarct-shaped consolidations and smooth bronchial wall thickening were more frequent in IPA, and mass-shaped consolidations and centrilobular nodules (<10 mm, clustered) were more frequent in tuberculosis.

CONCLUSIONS

Certain CT findings appear to be helpful in differentiating between IPA and tuberculosis. Nevertheless, the CT findings of about one-third of pulmonary tuberculosis cases in transplant recipients are very close to those of IPA.

Outcome of latent tuberculosis infection in solid organ transplant recipients over a 10-year period

BACKGROUND

Screening and therapy of latent tuberculosis infection (LTBI) is recommended in solid organ transplant (SOT). However, there are limited data on the tolerability of LTBI therapy pretransplant and posttransplant. We studied the tolerability of LTBI therapy and effectiveness of a centralized LTBI treatment program in a low-risk population.

METHODS

Provincial TB and transplant databases were retrospectively reviewed for LTBI therapy referrals in SOT candidates and recipients over a 10-year period. Using univariate logistic regression, we examined factors associated with failure to complete therapy and followed patients for active TB.

RESULTS

From 2001 to 2010, 200/461 SOT candidates referred to the TB program (43.4%) were eligible for therapy for LTBI. Eleven patients refused therapy. The remaining patients (n=189) were initially prescribed isoniazid (73%), rifampin (12.7%), or another regimen (14.3%). Adequate LTBI therapy occurred in 122 (64.5%). Patients who were liver transplant candidates or recipients were less likely to complete therapy than nonliver transplant patients (OR, 0.20; P<0.001) as were patients treated in the posttransplant phase (OR, 0.47; P=0.034). Liver enzyme elevation led to discontinuation of therapy more often in liver transplant candidates and recipients (OR, 10.48; P<0.001) and posttransplant treatment (OR, 3.50; P=0.019). In 599.4 patient-years of follow-up posttransplant (mean, 4.9 year/patient), there were no cases of active TB.

CONCLUSION

A centralized referral program for LTBI therapy in transplant candidates is effective to prevent TB reactivation posttransplant. A significant proportion of liver transplant candidates and recipients do not tolerate standard LTBI therapy. Alternative therapies for these patients should be evaluated.

Isoniazid treatment to prevent TB in kidney and pancreas transplant recipients based on an interferon-γ-releasing assay: an exploratory randomized controlled trial

BACKGROUND

We performed a randomized trial of isoniazid treatment based on interferon-γ-releasing assay (IGRA) in kidney transplant (KT) recipients in an intermediate-TB-burden country.

METHODS

All adult patients admitted to a KT institute between June 2010 and May 2013 were enrolled. The IGRA (T-SPOT.TB assay) was performed on all patients, and isoniazid treatment was given to those with clinical risk factors for latent TB infection (LTBI). Patients with positive IGRA who had no clinical risk factors for LTBI were randomly assigned to isoniazid treatment or a control group. The development of TB after KT was monitored between June 2010 and November 2013. The primary endpoint was the development of TB.

RESULTS

Of the 784 patients who had no clinical risk factors for LTBI, 445 (57%) gave negative results in the IGRA, 76 (10%) indeterminate results and 263 (33%) positive results. Of the latter, 131 were allocated to isoniazid treatment and 132 to the control group. Three (2%) of the control group developed TB, whereas none of the isoniazid treatment group developed TB (rate difference 1.22 per 100 person-years, P = 0.09). Of the 521 patients with negative or indeterminate IGRA results, 4 [0.8%, 0.43 per 100 person-years (95% CI 0.12-1.09)] developed TB after KT.

CONCLUSIONS

IGRA-based isoniazid treatment has a trend towards reducing TB development in KT recipients without clinical risk factors, but careful monitoring of TB development is needed in negative-IGRA KT recipients.

Isoniazid-induced acute liver failure during preventive therapy for latent tuberculosis infection

Treating latent tuberculosis infection is a strategy for eliminating tuberculosis, and isoniazid is recommended as preventive therapy. However, concerns have been raised regarding the application of isoniazid due to its toxicity, particularly hepatotoxicity; however, biochemical monitoring is not routinely performed during treatment. We herein present a case of fatal isoniazid-induced acute liver failure. The patient's liver function was not periodically examined and isoniazid therapy was continued for 10 days despite the onset of symptoms associated with hepatitis. The patient died four months after hospitalization. It is essential to consider the potential toxicities of isoniazid and establish strategies to prevent acute liver failure.

Infections after orthotopic liver transplantation

Opportunistic infections are a leading cause of morbidity and mortality after orthotopic liver transplantation. Systemic immunosuppression renders the liver recipient susceptible to de novo infection with bacteria, viruses and fungi post-transplantation as well to reactivation of pre-existing, latent disease. Pathogens are also transmissible via the donor organ. The time from transplantation and degree of immunosuppression may guide the differential diagnosis of potential infectious agents. However, typical systemic signs and symptoms of infection are often absent or blunted after transplant and a high index of suspicion is needed. Invasive procedures are often required to procure tissue for culture and guide antimicrobial therapy. Antimicrobial prophylaxis reduces the incidence of opportunistic infections and is routinely employed in the care of patients after liver transplant. In this review, we survey common bacterial, fungal, and viral infections after orthotopic liver transplantation and highlight recent developments in their diagnosis and management.

Bacterial brain abscess

Significant advances in the diagnosis and management of bacterial brain abscess over the past several decades have improved the expected outcome of a disease once regarded as invariably fatal. Despite this, intraparenchymal abscess continues to present a serious and potentially life-threatening condition. Brain abscess may result from traumatic brain injury, prior neurosurgical procedure, contiguous spread from a local source, or hematogenous spread of a systemic infection. In a significant proportion of cases, an etiology cannot be identified. Clinical presentation is highly variable and routine laboratory testing lacks sensitivity. As such, a high degree of clinical suspicion is necessary for prompt diagnosis and intervention. Computed tomography and magnetic resonance imaging offer a timely and sensitive method of assessing for abscess. Appearance of abscess on routine imaging lacks specificity and will not spare biopsy in cases where the clinical context does not unequivocally indicate infectious etiology. Current work with advanced imaging modalities may yield more accurate methods of differentiation of mass lesions in the brain. Management of abscess demands a multimodal approach. Surgical intervention and medical therapy are necessary in most cases. Prognosis of brain abscess has improved significantly in the recent decades although close follow-up is required, given the potential for long-term sequelae and a risk of recurrence.

Diagnosis of latent tuberculosis infection with T-SPOT(®).TB in a predominantly immigrant population with rheumatologic disorders

PURPOSE

The objective of this study is to compare how likely positive tuberculin skin test (TST) and T-SPOT(®).TB (TSPOT) results predict risk factors for tuberculosis in a predominantly immigrant patient population at risk of latent TB infection (LTBI) and with rheumatologic conditions requiring immunomodulatory therapy (IMT).

METHODS

Prospective study conducted at a referral rheumatology clinic. Inclusion criteria included patients on various IMT, including immunosuppressive drugs that could predispose to TB progression. We studied risk factors associated with LTBI, test results, and tests' agreement.

RESULTS

We studied 101 patients. Eighty (79.2 %) were from countries where TB is prevalent and Bacille Calmette-Guérin vaccination is placed routinely. Seventy-four (73.3 %) had rheumatoid arthritis and 92 (90.7 %) were on IMT. Among patients with both TST and TSPOT results, 25 (30.9 %) were TST(+) and 20 (24.7 %) had TSPOT(+) results. Fifteen patients (18.5 %) had TST(+)/TSPOT(+) results, and 51 (63.0 %) had TST(-)/TSPOT(-) results (agreement = 81.5 %; kappa = .54 [95 % CI, .34-.74; P < .001]). Each TSPOT(+) and TST(+) results were independently associated with immigrant status and prior residence in a TB prevalent country after adjustment for immunosuppressive therapy: Adjusted OR(TSPOT+)=6.6 (95 % CI, 1.2-123.3; P = .027); and adjusted OR(TST+)=11.2 (95 % CI, 2.0-209.5; P = .003). Seven out of 10 TST(+)/TSPOT(-) cases had a TST ≥15 mm induration, including three cases with history of TST conversion.

CONCLUSIONS

TST(+) and TSPOT(+) results predict risk factors associated with LTBI independent of immunosuppressive IMT. Some TST(+)/TSPOT(-) results were unlikely to be false-negatives. The combined use of TST and TSPOT appears to be a reasonable diagnostic strategy to evaluate for LTBI in this population.

The immune response and antibacterial therapy

The host's immune defence mechanisms are indispensable factors in surviving bacterial infections. However, in many circumstances, the immune system alone is inadequate. Since the 1940s, the use of antibacterial therapy has saved millions of lives, improving the span and quality of life of individuals. Unfortunately, we are now facing an era where antibacterial agents are threatened by resistance. In addition to targeting bacteria, some antibacterial agents affect various aspects of the immune response to infection. Since many antibacterial drugs are failing in efficacy due to resistance, it has been strongly suggested that any synergy between these drugs and the immune response be exploited in the treatment of bacterial infections. This review explores the influence of antibacterial therapy on the immune response and new approaches that could exploit this interaction for the treatment of bacterial infections.

Tuberculosis in liver transplant recipients: experience of a South Indian liver transplant center

Tuberculosis (TB) is a serious disease for liver transplant recipients (LTRs). Data on post-liver transplant TB from high-burden countries are scant. The aims of this study were to describe the prevalence of TB in LTRs from a high-prevalence area and to analyze the risk factors for the development of post-liver transplant TB. We performed a retrospective review of our database and a case-control study of identified cases with TB and age-matched LTRs without TB. The overall prevalence of TB in LTRs was comparable to the prevalence of TB in LTRs from low-prevalence countries (5/214 or 2.3%). A low rate of interferon-γ release assay (IGRA) testing before liver transplantation was observed (68/214 or 31%). Most patients were screened clinically and with chest radiography alone before transplantation. TB developed variably after transplantation [median = 72 days, interquartile range (IQR) = 534 days]. The presentation was mostly extrapulmonary and/or disseminated (4/5 or 80%). When cases with posttransplant TB were compared with matched healthy LTRs, the presence of unexplained granulomas in explants (2/5 or 40%, P = 0.01) was the only factor associated with the development of TB. When all explants showing granulomas were reviewed, TB (52.9%) remained the most common cause; however, in almost half (47.1%), other attributable causes were found. Patients were treated with a standard daily regimen for a median of 12 months (IQR = 7.5 months). Posttransplant TB was associated with a high mortality rate (2/5 or 40%). In conclusion, we observed a low prevalence of TB in LTRs from a high-prevalence region. The presence of granulomas suggestive of TB in liver explants warrants isoniazid prophylaxis in the absence of disease. Post-liver transplant TB is associated with a high mortality rate. The roles of routine IGRA testing and isoniazid prophylaxis in a high-prevalence setting urgently need to be studied.

The risk factors for tuberculosis in liver or kidney transplant recipients

BACKGROUND

Liver or kidney transplant recipients are at a higher risk of developing tuberculosis (TB) than general population. We aimed to clarify the incidence density of and risk factors for TB in liver or kidney transplant recipients in the present study.

METHODS

All patients with TB following liver or kidney transplantation were investigated retrospectively at the Third Xiangya Hospital, Central South University, Changsha, China. The incidence density of TB was calculated. We performed a nested case-control study (1:1) to investigate by univariate and multivariate logistic regression analysis the potential risk factors for TB.

RESULTS

From January 2000 to August 2013, 1748 kidney and 166 liver transplant recipients were performed at a university teaching hospital. Among the 1914 recipients, 45 cases (2.4%) of TB were reported. The incidence density was 506 cases per 105 patient-years in kidney or liver transplant recipients, which was 7 times higher than in the general Chinese population (around 70 cases per 105 person-years). The median time to develop TB was 20.0 months (interquartile ratio: 5.0-70.0). The receipt of a graft from a cadaveric donor (odds ratio [OR] = 3.7; 95% confidence interval [CI] = 1.4-10.0; P = 0.010) and the preoperative evidence of latent TB (OR = 6.8; 95% CI = 2.0-22.7; P = 0.002) were identified as two risk factors for developing TB in liver or kidney transplant recipients.

CONCLUSIONS

The incidence density of TB among liver or kidney transplant recipients was much higher than in the general Chinese population. Recipients receiving a graft from a cadaveric donor and the preoperative evidence of latent TB were two major risk factors for developing TB in liver or kidney transplant recipients.

Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections

Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor.

Tuberculosis in solid-organ transplant recipients: disease characteristics and outcomes in the current era

We determined the characteristics of posttransplant tuberculosis and the impact of rifampin-based antituberculosis regimens on outcomes in the current era. Patients comprised 64 transplant recipients with tuberculosis, divided into 2 consecutive cohorts: an earlier cohort (cases occurring from 2003 to 2007) and a later cohort (cases from 2008 to 2011). Patients from the later versus earlier era had tuberculosis develop later after transplant (odds ratio, 1.01; 95% CI, 1.00-1.02; P= .05), were more likely to be liver transplant recipients (odds ratio, 4.52; 95% CI, 1.32-15.53; P= .02), and were more likely to receive tacrolimus-based immunosuppression (odds ratio, 3.24; 95% CI, 1.14-9.19; P= .03). Mortality rate was 10% in the later cohort and 21% in the earlier cohort (P= .20). Rifampin-based treatment was less likely to be used in patients with prior rejection (P= .04). However, neither rejection rate (P= .71) nor mortality (P= .93) after tuberculosis differed between recipients who received rifampin and recipients who did not. Thus, notable changes have occurred in the epidemiological characteristics of tuberculosis in transplant recipients. Overall mortality rate has improved, with about 90% of the patients now surviving after tuberculosis.

Successful bilateral lung transplantation from a deceased donor with active Mycobacterium tuberculosis infection

In the present report, we describe a case wherein a Mycobacterium tuberculosis infection developed in the recipient after successful bilateral lung transplantation because of a solitary pulmonary nodule in the donor.

Short-course isoniazid plus rifapentine directly observed therapy for latent tuberculosis in solid-organ transplant candidates

BACKGROUND

Short-course directly observed isoniazid plus rifapentine (INH/RPT) combination could have potential advantages over a standard 9-month INH regimen for the treatment of latent tuberculosis infection in solid-organ transplant (SOT) candidates.

METHODS

We prospectively assessed the safety and tolerability of 12 weeks of INH/RPT given directly observed therapy in 17 consecutive SOT candidates with latent tuberculosis infection.

RESULTS

The median age was 57 years and 82% were men. Of the 17 patients, 13 (76%) successfully completed therapy and 4 (24%) eventually underwent SOT. Treatment was prematurely discontinued in four patients. One of these patients underwent a kidney transplant. The overall dose compliance was 83% (169/204 scheduled doses), and 12 (71%) of 17 patients received 100% of scheduled doses. No patient developed transaminase elevations greater than twice baseline or greater than four times the upper limit of normal or clinical hepatotoxicity. No cases of TB developed during 20.4 months after transplant among INH/RPT-treated recipients.

CONCLUSIONS

For carefully selected SOT candidates, combination INH/RPT weekly given as directly observed therapy seems to be reasonably well tolerated and is associated with a relatively high completion rate. Future larger prospective studies to confirm the safety and high completion rates reported here and to identify the most appropriate SOT candidates for this regimen are warranted.

Antibiotic prophylaxis for preventing post solid organ transplant tuberculosis

BACKGROUND

Organ transplant recipients are at increased risk of infection as a result of immunosuppression caused inadvertently by medical treatment. Tuberculosis (TB) is a challenging infection to manage among organ transplant recipients that can be transmitted from infected people or triggered from latent infection. Organ transplant recipients have been reported to be up to 300 times more likely to develop TB than the general population. Consensus about the use of antibiotic prophylaxis to prevent post solid organ transplant TB has not been achieved.

OBJECTIVES

This review assessed the benefits and harms of antibiotic prophylaxis to prevent post solid organ transplant TB.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register up to 30 April 2013 through contact with the Trials' Search Co-ordinator using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE and EMBASE and handsearching conference proceedings.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs that compared antibiotic prophylaxis with a placebo or no intervention for recipients of solid organ transplants were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for inclusion and extracted data. We derived risk ratios (RR) for dichotomous data and mean differences (MD) for continuous data with 95% confidence intervals (CI). Methodological risk of bias was assessed using the Cochrane risk of bias tool.

MAIN RESULTS

We identified three studies (10 reports) that involved 558 kidney transplant recipients which met our inclusion criteria. All studies were conducted in countries that have high prevalence of TB (India and Pakistan), and investigated isoniazid, an oral antibacterial drug. Control in all studies was no antibiotic prophylaxis. Prophylactic administration of isoniazid reduced the risk of developing TB post-transplant (3 studies, RR 0.35 95% CI 0.14 to 0.89), and there was no significant effect on all-cause mortality (2 studies, RR 1.39, 95% CI 0.70 to 2.78). There was however substantial risk of liver damage (3 studies, RR 2.74, 95% CI 1.22 to 6.17).Reporting of methodological quality parameters was incomplete in all three studies. Overall, risk of bias was assessed as suboptimal.

AUTHORS' CONCLUSIONS

Isoniazid prophylaxis for kidney transplant recipients reduced the risk of developing TB post-transplant. Kidney transplant recipients in settings that have high prevalence of TB should receive isoniazid during the first year following transplant. There is however, significant risk of liver damage, particularly among those who are hepatitis B or C positive. Further studies are needed among recipients of other solid organ transplants and in settings with low prevalence of TB to determine the benefits and harms of anti-TB prophylaxis in those populations.